Neuroscientist Yukiyasu Kamitani have in a small-scale study scanned a dozen students watching images by Picasso and Dalí trying to find patterns in their brain activity. Through the findings they purport that scientists will be able to read your mind when it comes to the exacts neural differences between artworks by different artistic hands. New Scientist reports.

The study was conducted at ATR Computational Neuroscience Laboratories in Kyoto, Japan where the team showed 12 students images of Picasso and Dalí while scanning their brains using functional MRI. A computer program then identified patterns in activity that were supposed to be unique for each of the two artists. But the program “merely” completed about 80% of the guessing game, a bit more than just guessing.

Crucifixion (Hypercubic Body) by Salvador Dalí

The most interesting finding was that to identify the artists, the computer program relied on activity in multiple brain regions, not just the visual ones. But, we must be very wary to make statements about how the brain process styles, since this is not just biochemically given, it is also a matter of training the brain to see and identify images off multiple sorts.

Studies conducted on chess players find that a trained eye can remember and identify a given set of chess pieces but only if it correlates with a known scenario within the game of chess. A control group then has much harder remembering any such scenario, random or not.  So memory and constructed patterns in our minds can surely play a vital role for how these relults play out. I would advise mr Kamitani to continue the interesting research but extending it to art students and artists alike.

Join me in a conversation about empathy and neurology.  The short version is that the individual experiences empathy and the light goes on! Today’s inquiry explores the philosophical significance for empathy of the research on the mirror neurons, the related shared manifold hypothesis, micro expressions and the investigations that have grown up around them. Three of the consequences will be explicitly addressed. Evidence that such a capacity as empathy exists at all will be provided, but in the ironic spirit of proofs of common sense. In turn, the inquiry into existence will lead to the rehabilitation of introspection as a method of investigation proper to empathy, albeit with certain conditions and qualifications. Finally, the scope and limits of the shared manifold hypothesis, which conceptually implements the functional and causative role of mirror neurons, will be engaged. The result will be that the shared manifold is less transparent the more that it is shared. A bigger magnet will not make a difference.  [Please see chphilsignifempathyneurology20081118 ]

What's on your mind, Big Brother? The little people want to know.

To say that 2008 and 2009 have exposed a crisis in global leadership is beyond understatement.  The lapses in judgment, both in government and in financial services, leading to this devastating economic crisis are arguably unforgivable.  Countless lives have been wrecked in a seeming single fell stroke for the sake of corporate greed, especially in the financial sector. We find ourselves repeatedly asking, “Who the heck is in charge?”  And if the global economy had any of the forward momentum that the Exxon Valdez had in 1989…We have to ask, “Have all the captains of this global ship been on a permanent infusion of vodka?”  We simply don’t deserve this kind of leadership.  We deserve far better.

From the constant erosion of, and final repeal of, central Glass–Steagall provisions to the acceptance of massive bonuses post-bailout.  The finger-prints of ruinous avarice are upon every key, every doorknob.  Everyday global citizens are left treading water without life preservers.  They weren’t the ones living lavishly on the party barge.  They were the one’s carrying the trays with martinis to the captains.  The captains got out in silk-lined life boats.

So what were the big-shots thinking?  That’s really the question.  Isn’t it?  Wouldn’t it be nice if we could have known what they were thinking before we handed them the keys to the ship?  Before we gave them license to drive our banks, our Senates, our corporations?  What might a driving test for corporate leadership look like?

Technology may one day enable us to set much higher standards for our leadership.

If 2008-2009 goes down in history as one of the greatest economic calamities of the century, there may be a watershed scientific footnote attached to 2008 well.  2008 may well go down as the year of the advent of mind-reading. A flurry of functional MRI research over the past few years culminated in researchers in Kyoto, Japan reading the visual cortices of subjects.  Computers at ATR Computational Neuroscience Laboratories successfully recreated rough duplicates of black and white letters that subjects saw with their eyes.  A spate of speculation and ethical debate soon followed.

I was less inspired by the visual aspect (dreams and such) than by the potential to read thought patterns in other parts of the mind. I suspect, for example, that an fMRI of Bernard Madoff’s frontal lobe would betray a sub-zero glacial landscape devoid of emotional activity (except possibly the pleasure of wealth mingled with a dash of uncontrollable rage at any personal loss).  The technology is unquestionably evolving to assess patterns like empathy.

2008 may well go down as the year of the advent of mind-reading.

One day soon we’ll be able to flash up a few photographs of physical or financial ruin and find out whether or not a subject gives a flying flip for anyone but themselves.  Want to know whether your potential new CEO cares about shareholders?  Customers?  Employees?  Slap ‘em in an fMRI and see whether their neurons go neon when others are in need or exclusively when they see their own personal pay-day at the end of the yellow brick road.

I think it should ultimately become a kind of driving test for large corporations (or governments).  The results should be made public, too.  It would be kind of like a drug test on steroids, particularly well suited to corporate governance.  Say you’ve got a big manufacturer swaggering into your sleepy little rural hamlet promising 3,000 new jobs in exchange for juicy tax breaks.  Demand that their 5 top executives take a spin in the fMRI and find out how loyal they’ll be in the next major recession.  If they don’t cut the mustard say, “Thanks, but we’re saving this dance for another.”

Think of it as spinning Orwell’s 1984 up on it’s head.  The internet is already rapidly democratizing information and injecting transparency in a way that will enable us to demand far more of leadership in the decades ahead. I call it “inverse accountability.” We’re just now learning to blog the good guys into leadership and the bad guys into oblivion.  In the future, maybe we’ll be able to peer inside Big Brother’s head and see how well his/her noodle functions before we hire or elect him.

Here’s to 4891,
SevenCell

-SevenCell
http://sevencell.wordpress.com

Following up on that story yesterday of a man who had been trapped in his body, conscious but unable to respond for twenty-three years, there’s now some apparently well-founded skepticism about the report. I first saw this at Pharyngula, where he makes the point that “facilitated communication” looks an awful lot like somebody using an unconscious person’s finger to type. James Randi has a related post. The latter half of the MetaFilter thread is likewise awash in skepticism, including of the fMRI technique used to determine his brain activity, which had previously been used to establish that a (dead) fish was able to respond to the emotional state of human beings.

Hard to know what to think about this; it’s horrible just about any way you look at it.

After reading the story in the Wall Street Journal about “Why wine ratings are badly flawed?” it got me thinking. Not about wine ratings because that part of the article I agree with, wine ratings are subjective, and can generally be inconsistent across various types of “raters”. I’ve always thought it weird that one wine in Spectator can get a “90” and then in Enthusiast receive a “78” or vice versa.

“There is a rich history of scientific research questioning whether wine experts can really make the fine taste distinctions they claim. For example, a 1996 study in the Journal of Experimental Psychology showed that even flavor-trained professionals cannot reliably identify more than three or four components in a mixture, although wine critics regularly report tasting six or more.”

The above comment is the one that got me thinking and one that I disagree with. Personally I know that I can taste more than 3 distinct flavors in any wine. Also, my years working in Sensory Research did many studies with trained panelists in which they identified more than three components in a mixture. I tried to find the study with no avail and was kind of disturbed that the author of the article in the WSJ didn’t put in any reference to the exact article. So, I couldn’t look at that particular study and examine exactly how that experiment was conducted.

In searching for some rebuttal papers I came across a cool article that I remember reading years back in the Journal “NeuroImage”. Using Functional Magnetic Resonance Imaging (fMRI) this study showed that trained wine tasters, in this case 7 sommeliers, showed higher brain function when it came to tasting wine versus untrained wine consumers.

“A larger and well-defined cerebral network elicited by wine tasting was identified in sommeliers compared to naïve subjects that included the left insula and adjoining caudal orbitofrontal cortex, the left putamen, the right inferior frontal gyrus (opercular portion), and the inferior portion of the middle frontal gyrus in the dorsolateral prefrontal cortex (DLPFC) bilaterally.”

“…A final intriguing finding was the consistent activation in sommeliers of the inferior DLPFC. In this region the BOLD signal time-course peaked initially during the taste period and then well after the cue to swallow had been given, suggesting higher cognitive processing modulated by expertise.”

So basically the paper is saying that people trained in wine tasting have a additional cognitive processing that is linking both taste, olfactory and somatosensory sensations together to evaluate the wine. Pretty cool! With all this extra brain functioning going on, I don’t know how someone who is a trained taster could not detect more than three flavors in a wine or a mixture.

If anybody knows the exact journal number that was referenced in this WSJ article let me know, I would love to look at it.

Cheers!

References:

MLODINOW, LEONARD. “A Hint of Hype, A Taste of Illusion.” Wall Street Journal 14 Nov 2009,

Castriota-Scanderbeg, Alessandro, Gisela Hagberg, Antonio Cerasa, and Giorgia Committeri. “The appreciation of wine by sommeliers: a functional magnetic resonance study of sensory integration.” NeuroImage. 25.2 (2005): 570-578.

Attingendo ancora al materiale che ho raccolto al meeting di neuroscienze di Chicago, riporto alcune delle risorse che possono venire utili per gli studi di Risonanza Magnetica Funzionale (fMRI).

• Princeton Multi-Voxel Pattern Analysis Toolbox: una serie di script in MatLab per facilitare l’esplorazione di tecniche d’analisi di pattern multi-voxel. Un articolo sulla metodica può essere trovato qui [Norman et al. 2006 TICS].
• SUIT: un template del cervelletto e del tronco encefalico per SPM. Qui una pubblicazione di Diedrichsen [Neuroimage 2006] relativa a questo template.
• A probabilistic MR atlas of the human cerebellum [Diedrichsen et al. 2009, Neuroimage]: qui l’articolo.
• fMRIrobot.org: un sito dedicato ad apparecchiature robotizzate compatibili con la risonanza, dedicate per lo più allo studio del controllo e dell’apprendimento motorio.

By Darren Schreiber

We’ve got lots of new work showing showing the role of the default mode network, specifically in social cognition (1, 3, 4, 8, 10).  While this was a speculation when I was writing about it five years ago, it seems to be quite cemented now.  We’ve also got a set of articles discussing reward processing (2, 6, 7).  I thought the overview piece on the Allen Brain Atlas was interesting (11).  Currently, the mouse brain is the most complete, but Wired Magazine had a fascinating piece about the work that is currently proceeding on doing the same thing for the human brain.

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1) Functional connectivity and alterations in baseline brain state in humans.
2) The impact of social comparison on the neural substrates of reward processing: an event-related potential study.
3) Neural correlates of social cognition in naturalistic settings: a model-free analysis approach.
4) Understanding others’ actions and goals by mirror and mentalizing systems: a meta-analysis
5) Double dissociation between action-driven and perception-driven conflict resolution invoking anterior versus posterior brain systems.
6) The influence of context valence in the neural coding of monetary outcomes.
7) Different representations of relative and absolute subjective value in the human brain
Neural Systems of Social Comparison and the “Above-Average” Effect
9) Experimental evolution of bet hedging
10) What does the retrosplenial cortex do?
11) The Allen Brain Atlas: 5 years and beyond
12) The functional anatomy of the frontal lobes

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1) Martuzzi et al. Functional connectivity and alterations in baseline brain state in humans. Neuroimage (2010) vol. 49 (1) pp. 823-34

This work examines the influence of changes in baseline activity on the intrinsic functional connectivity fMRI (fc-fMRI) in humans. Baseline brain activity was altered by inducing anesthesia (sevoflurane end-tidal concentration 1%) in human volunteers and fc-fMRI maps between the pre-anesthetized and anesthetized conditions were compared across different brain networks. We particularly focused on low-level sensory areas (primary somatosensory, visual, and auditory cortices), the thalamus, and pain (insula), memory (hippocampus) circuits, and the default mode network (DMN), the latter three to examine higher-order brain regions. The results indicate that, while fc-fMRI patterns did not significantly differ (p<0.005; 20-voxel cluster threshold) in sensory cortex and in the DMN between the pre- and anesthetized conditions, fc-fMRI in high-order cognitive regions (i.e. memory and pain circuits) was significantly altered by anesthesia. These findings provide further evidence that fc-fMRI reflects intrinsic brain properties, while also demonstrating that 0.5 MAC sevoflurane anesthesia preferentially modulates higher-order connections.

2) Qiu et al. The impact of social comparison on the neural substrates of reward processing: an event-related potential study. Neuroimage (2010) vol. 49 (1) pp. 956-62

Event-related potentials (ERPs) were recorded to explore the electrophysiological correlates of reward processing in the social comparison context when subjects performed a simple number estimation task that entailed monetary rewards for correct answers. Three social comparison stimulus categories (three relative reward levels/self reward related to the other subject’s) were mainly prepared: Self:Other=1:2 (Disadvantageous inequity condition); Self:Other=1:1 (Equity condition); and Self:Other=2:1 (Advantageous inequity condition). Results showed that: both Disadvantageous and Advantageous inequity elicited a more negative ERP deflection (N350-550) than did Equity between 350 and 550 ms, and the generators of N350-550 were localized near the parahippocampal gyrus and the medial frontal/anterior cingulate cortex, which might be related to monitor and control reward prediction error during reward processing. Then, Disadvantageous and Advantageous inequity both elicited a more late negative complex (LNC1 and LNC2) than did Equity between 550 and 750 ms. The generators of LNC1 and LNC2 were both localized near the caudate nucleus, which might be related to reward processing under social comparison.

3) Wolf et al. Neural correlates of social cognition in naturalistic settings: a model-free analysis approach. Neuroimage (2010) vol. 49 (1) pp. 894-904

Neuroimaging studies have consistently identified a network of brain regions subserving inferences of other humans’ mental states. This network consists of the superior temporal sulcus, temporoparietal junction, medial prefrontal cortex, temporal poles, and precuneus. Little is known, however, about the neural substrate underlying Theory of Mind processes in close to real-life conditions. To investigate those processes in more naturalistic settings, we used an fMRI adaptation of the video-based Movie for the Assessment of Social Cognition (MASC; Dziobek et al., 2006), which considers separate analysis of implicit mental state reasoning during rapidly changing perceptual cues as demanded in naturalistic settings and explicit mental state reasoning. We analyzed fMRI data by means of both a standard general linear model (GLM) approach and a tensor probabilistic independent component analysis (T-PICA), which is a novel model-free approach that allows decomposition of activation into independent spatio-temporally coherent functional networks. The model-based GLM approach revealed the typical explicit mental state reasoning network. Complementary to the GLM approach, the model-free T-PICA approach showed that those regions are also recruited during implicit mental state reasoning and that they are represented in three independent, functionally connected networks. The first component, mediating face processing and recognition, comprises the occipito-parietotemporal cortices, while the second component, involved in language comprehension, comprises the temporal lobes, lateral prefrontal cortex, and precuneus. The dorsomedial prefrontal cortex and the precuneus comprise the third component, which is likely responsible for self-referential mental activity. These results show that the mental state reasoning network can be decomposed into circumscribed functional networks mediating differential aspects of Theory of Mind.

4) Van Overwalle and Baetens. Understanding others’ actions and goals by mirror and mentalizing systems: a meta-analysis. Neuroimage (2009) vol. 48 (3) pp. 564-84

This meta-analysis explores the role of the mirror and mentalizing systems in the understanding of other people’s action goals. Based on over 200 fMRI studies, this analysis demonstrates that the mirror system – consisting of the anterior intraparietal sulcus and the premotor cortex – is engaged when one perceives articulated motions of body parts irrespective of their sensory (visual or auditory) or verbal format as well as when the perceiver executes them. This confirms the matching role of the mirror system in understanding biological action. Observation of whole-body motions and gaze engage the posterior superior temporal sulcus and most likely reflects an orientation response in line with the action or attention of the observed actor. In contrast, the mentalizing system – consisting of the temporo-parietal junction, the medial prefrontal cortex and the precuneus – is activated when behavior that enables inferences to be made about goals, beliefs or moral issues is presented in abstract terms (e.g., verbal stories or geometric shapes) and there is no perceivable biological motion of body parts. A striking overlap of brain activity at the temporo-parietal junction between social inferences and other, non-social observations (e.g., Posner’s cuing task) suggests that this area computes the orientation or direction of the behavior in order to predict its likely end-state (or goal). No conclusions are drawn about the specific functionality of the precuneus and the medial prefrontal cortex. Because the mirror and mentalizing systems are rarely concurrently active, it appears that neither system subserves the other. Rather, they are complementary. There seems, however, to be a transition from the mirror to the mentalizing system even when body-part motions are observed by perceivers who are consciously deliberating about the goals of others and their behavioral executions, such as when perceived body motions are contextually inconsistent, implausible or pretended.

5) Schulte et al. Double dissociation between action-driven and perception-driven conflict resolution invoking anterior versus posterior brain systems. Neuroimage (2009) vol. 48 (2) pp. 381-90

The ability to select and integrate relevant information in the presence of competing irrelevant information can be enhanced by advance information to direct attention and guide response selection. Attentional preparation can reduce perceptual and response conflict, yet little is known about the neural source of conflict resolution, whether it is resolved by modulating neural responses for perceptual selection to emphasize task-relevant information or for action selection to inhibit pre-potent responses to interfering information. We manipulated perceptual information that either matched or did not match the relevant color feature of an upcoming Stroop stimulus and recorded hemodynamic brain responses to these events. Longer reaction times to incongruent than congruent color-word Stroop stimuli indicated conflict; however, conflict was even greater when a color cue correctly predicted the Stroop target’s color (match) than when it did not (nonmatch). A predominantly anterior network was activated for Stroop-match and a predominantly posterior network was activated for Stroop-nonmatch. Thus, when a stimulus feature did not match the expected feature, a perceptually-driven posterior attention system was engaged, whereas when interfering, automatically-processed semantic information required inhibition of pre-potent responses, an action-driven anterior control system was engaged. These findings show a double dissociation of anterior and posterior cortical systems engaging in different types of control for perceptually-driven and action-driven conflict resolution.

6) Hardin et al. The influence of context valence in the neural coding of monetary outcomes. Neuroimage (2009) vol. 48 (1) pp. 249-57

The emotional significance of objects and events depends on the context in which they occur. Using functional magnetic resonance imaging, we examined the modulation of neural responses to monetary outcomes while subjects performed a decision-making task in a positive and a negative economic context. Neural responses indicated a relative regional specialization in the neural coding of outcome valence and followed three distinct patterns. The nucleus accumbens (NAc) and orbital frontal cortex (OFC) appeared to code the most extreme outcome in each context, with a potentiated response for favorable outcomes by a positive context. The amygdala and insula appeared to also code highly salient outcomes, but showed a potentiated response to unfavorable outcomes occurring in a negative context. The medial prefrontal cortex (medPFC), on the other hand, only coded favorable responses occurring in a positive context. Moreover, the medPFC showed large inter-individual variability when responding to outcomes in a negative context, suggesting that its role in a negative context may depend on a number of individual factors. The results of this work provide evidence of complex valence-based regional dissociations that are influenced by contextual factors.

7) Grabenhorst and Rolls. Different representations of relative and absolute subjective value in the human brain. Neuroimage (2009) vol. 48 (1) pp. 258-68

Relative reward value is important for the choice between a set of available rewards, and absolute reward value for stable and consistent economic choice. It is unclear whether in the human brain subjective absolute value representations can be dissociated from relative reward value representations. Using fMRI, we investigated how the subjective pleasantness of an odor is influenced by whether the odor is presented in the context of a relatively more pleasant or less pleasant odor. We delivered two of a set of four odors separated by a delay of 6 s, with the instruction to rate the pleasantness of the second odor, and searched for brain regions where the activations were correlated with the absolute pleasantness rating of the second odor, and for brain regions where the activations were correlated with the difference in pleasantness of the second from the first odor, that is, with relative pleasantness. Activations in the anterolateral orbitofrontal cortex tracked the relative subjective pleasantness, whereas activations in the anterior insula tracked the relative subjective unpleasantness. In contrast, in the medial and midorbitofrontal cortex activations tracked the absolute pleasantness of the stimuli. Thus, both relative and absolute subjective value signals which provide important inputs to decision-making processes about which stimulus to choose are separately and simultaneously represented in the human brain.

Beer and Hughes. Neural Systems of Social Comparison and the “Above-Average” Effect. Neuroimage (2009) pp.

Extant neural models of self-evaluation are dominated by associations with medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC) function and have mostly been developed from studies differentiating self-evaluation from evaluation of other people. Although self-evaluation is robustly characterized by systematic biases, current neural models of self-evaluation cannot speak to their neurobiology because of a lack of research. The few extant studies have made claims about associations between bias and ventral anterior cingulate cortex (vACC) function but have confounded bias with the valence of experimental stimuli. In Study 1, fMRI was used to examine the neurobiology of the “above average” effect, a robust self-evaluation bias. The majority of people judge their personality to be more desirable (i.e. more positive and less negative traits) than their peers’ personalities. MPFC and PCC were significantly more activated by a condition that reduced susceptibility to “above average” judgments. However, MPFC and PFCC activity were not modulated by individual differences in “above average” judgments. VACC activity distinguished positive from negative valence but did not predict individual differences in “above average” judgments. Instead, the extent to which participants viewed themselves as “above average” was negatively correlated with orbitofrontal cortex (OFC) and, to a lesser extent, dorsal anterior cingulate cortex (dACC) activation. A complementary study found that mental load increases “above average” judgments (Study 2). These findings are the first to directly examine the neural systems involved in social judgment bias and have implications for the association between frontal lobe dysfunction and poor insight.

9) Beaumont et al. Experimental evolution of bet hedging. Nature (2009) vol. 462 (7269) pp. 90-3

Bet hedging-stochastic switching between phenotypic states-is a canonical example of an evolutionary adaptation that facilitates persistence in the face of fluctuating environmental conditions. Although bet hedging is found in organisms ranging from bacteria to humans, direct evidence for an adaptive origin of this behaviour is lacking. Here we report the de novo evolution of bet hedging in experimental bacterial populations. Bacteria were subjected to an environment that continually favoured new phenotypic states. Initially, our regime drove the successive evolution of novel phenotypes by mutation and selection; however, in two (of 12) replicates this trend was broken by the evolution of bet-hedging genotypes that persisted because of rapid stochastic phenotype switching. Genome re-sequencing of one of these switching types revealed nine mutations that distinguished it from the ancestor. The final mutation was both necessary and sufficient for rapid phenotype switching; nonetheless, the evolution of bet hedging was contingent upon earlier mutations that altered the relative fitness effect of the final mutation. These findings capture the adaptive evolution of bet hedging in the simplest of organisms, and suggest that risk-spreading strategies may have been among the earliest evolutionary solutions to life in fluctuating environments.

10) Vann et al. What does the retrosplenial cortex do?. Nat Rev Neurosci (2009) vol. 10 (11) pp. 792-802

The past decade has seen a transformation in research on the retrosplenial cortex (RSC). This cortical area has emerged as a key member of a core network of brain regions that underpins a range of cognitive functions, including episodic memory, navigation, imagination and planning for the future. It is now also evident that the RSC is consistently compromised in the most common neurological disorders that impair memory. Here we review advances on multiple fronts, most notably in neuroanatomy, animal studies and neuroimaging, that have highlighted the importance of the RSC for cognition, and consider why specifying its precise functions remains problematic.

11) Jones et al. The Allen Brain Atlas: 5 years and beyond. Nat Rev Neurosci (2009) vol. 10 (11) pp. 821-8

The Allen Brain Atlas, a Web-based, genome-wide atlas of gene expression in the adult mouse brain, was an experiment on a massive scale. The development of the atlas faced a combination of great technical challenges and a non-traditional open research model, and it encountered many hurdles on the path to completion and community adoption. Having overcome these challenges, it is now a fundamental tool for neuroscientists worldwide and has set the stage for the creation of other similar open resources. Nevertheless, there are many untapped opportunities for exploration.

12) Nachev et al. The functional anatomy of the frontal lobes. Nat Rev Neurosci (2009) vol. 10 (11) pp. 829

In their illuminating recent article (Is the rostro-caudal axis of the frontal lobe hier- archical? Nature Rev. Neurosci. 10, 659–669 (2009))1, Badre and D’Esposito generalize to the frontal lobes as a whole a point we recently made about the medial frontal cor- tex2: that the functional architecture suggests a continuous rostro-caudal gradient reflect- ing the conditional complexity of the associ- ated behaviour. Reviewing a broad swathe of behavioural and neurophysiological studies, they argue — convincingly, in our view — that a wealth of data now supports this new conceptual framework for frontal lobe func- tion. However, there are some important consequences of such a perspective that might not be apparent at first glance and that merit some further consideration.

Semantic memory refers to knowledge about people, objects, actions, relations, self, and culture acquired through experience. The neural systems that store and retrieve this information have been studied for many years, but a consensus regarding their identity has not been reached. Using strict inclusion criteria, we analyzed 120 functional neuroimaging studies focusing on semantic processing. Reliable areas of activation in these studies were identified using the activation likelihood estimate (ALE) technique. These activations formed a distinct, left-lateralized network comprised of 7 regions: posterior inferior parietal lobe, middle temporal gyrus, fusiform and parahippocampal gyri, dorsomedial prefrontal cortex, inferior frontal gyrus, ventromedial prefrontal cortex, and posterior cingulate gyrus. Secondary analyses showed specific subregions of this network associated with knowledge of actions, manipulable artifacts, abstract concepts, and concrete concepts. The cortical regions involved in semantic processing can be grouped into 3 broad categories: posterior multimodal and heteromodal association cortex, heteromodal prefrontal cortex, and medial limbic regions. The expansion of these regions in the human relative to the nonhuman primate brain may explain uniquely human capacities to use language productively, plan, solve problems, and create cultural and technological artifacts, all of which depend on the fluid and efficient retrieval and manipulation of semantic knowledge.

from Cerebral Cortex

In an fMRI experiment, we tested experienced singers with singing tasks to investigate neural correlates of voluntary and involuntary vocal pitch regulation. We shifted the pitch of auditory feedback (±25 or 200 cents), and singers either: 1) ignored the shift and maintained their vocal pitch or 2) changed their vocal pitch to compensate for the shift. In our previous study, singers successfully ignored and compensated for 200-cent shifts; in the present experiment, we hypothesized that singers would be less able to ignore 25-cent shifts, due to a prepotent, corrective pitch-shift response. We expected that voluntary vocal regulation during compensate tasks would recruit the anterior portion of the rostral cingulate zone (RCZa) and posterior superior temporal sulcus (pSTS), as our earlier study reported; however, we predicted that a different network may be engaged during involuntary responses to 25-cent shifts. Singers were less able to ignore 25-cent shifts than 200-cent shifts, suggesting that pitch-shift responses to small shifts are under less voluntary control than responses to larger shifts. While we did not find neural activity specifically associated with involuntary pitch-shift responses, compensate tasks recruited a functionally connected network consisting of RCZa, pSTS, and anterior insula. Analyses of stimulus-modulated functional connectivity suggest that pSTS and intraparietal sulcus may monitor auditory feedback to extract pitch-shift direction in 200-cent tasks, but not in 25-cent tasks, which suggests that larger vocal corrections are under cortical control. During the compensate tasks, the pSTS may interact with the RCZa and anterior insula before voluntary vocal pitch correction occurs.

from Neuropsychologia

Fancy images, impressive results, but can we really trust the reports of the majority of the neuroimaging studies out there? Here’s a couple of papers discussing the limitations of fMRI that you can read, if you’re interested in learning more about this method:

1. a great review by Nikos K. Logothetis published in Nature a year ago. Here’s the abstract:

Here I give an overview of the current state of fMRI, and draw on neuroimaging and physiological data to present the current understanding of the haemodynamic signals and the constraints they impose on neuroimaging data interpretation. Functional magnetic resonance imaging (fMRI) is currently the mainstay of neuroimaging in cognitive neuroscience.
Advances in scanner technology, image acquisition protocols, experimental design, and analysis methods promise to push forward fMRI from mere cartography to the true study of brain organization. However, fundamental questions concerning the interpretation of fMRI data abound, as the conclusions drawn often ignore the actual limitations of the methodology.”

2. Professor D. Attwell questions the neural basis of functional brain imaging signals:

“The haemodynamic responses to neural activity that underlie the blood-oxygen-level-dependent (BOLD) signal used in functional magnetic resonance imaging (fMRI) of the brain are often assumed to be driven by energy use, particularly in presynaptic terminals or glia.However, recent work has suggested that most brain energy is used to power postsynaptic currents and action potentials rather than presynaptic or glial activity and, furthermore, that haemodynamic responses are driven by neurotransmitter-related signalling and not directly by the local energy needs of the brain. A firm understanding of the BOLD response will require investigation to be focussed on the neural signalling mechanisms controlling blood flow rather than on the locus of energy use.”

P.S: For an introduction to fMRI, visit fMRI 4 Newbies website.

Mathematician Marcus du Sautoy is becoming an increasingly regular front-man for the BBC science documentary Horizon and, to date, his contributions have always been satisfyingly informative. The recent episode The Secret You is no exception.

In his quest to discover the underlying biochemistry and physiology of consciousness, du Sautoy visits a number of laboratories around the world where self-awareness and the notion of “the inner me” are being investigated. In doing so, he frequently participates in experiments; at one point he quips “another day, another scanner”(50:49).

Marcus du Sautoy takes part in many experiments as part of his search for the basis of consciousness

There are a raft of ethical questions which arise from functional Magnetic Resonance Imaging (fMRI) and other neuroimaging methods, some of which I have written about elsewhere (see Disorders of consciousness: do state-of-the-art neuroimaging techniques shed new light on the brain-injured patient?).

For me, the most interesting ethical questions in the programme arise from the work of Professor Adrian Owen. du Sautoy and Owen discuss experiments conducted with patients in PVS, a Persistent Vegetative State (16:44 to 19:22, though the discussion makes most sense if you start at 15:30).

Prof Adrian Owen of Cambridge University has made exciting discoveries about the awareness of a patient in PVS

Previously our abililty to tell whether or not a PVS patient was genuinely conscious was constrained by the fact that they had no physical ability to demonstrate their awareness. In ground-breaking experiments, however, Owen and his colleagues have communicated with patients by asking them to imagine performing certain tasks, for example playing tennis, and using fMRI to show that the appropriate areas of their brains are activate. By developing this further, it is possible to get the patient to imagine two different activities which are clearly distinguishable from one another in terms of brain activity. These can then serve as proxy signals as “yes” and “no” answers to questions posed.

A patient could be trained to make certain areas of her brain active as a proxy answer to questions posed by researchers (e.g. by imaging she was playing tennis or walking around her house)

These experiments have revolutionised our understanding of brain-injured patients. In particular it brings into question the practice of withdrawing food and water from patients in PVS on the assumption that the are not aware.

Horizon: The Secret You (TRILT code 01210858) was first broadcast on BBC2 on 20th October 2009. It is available to watch on iPlayer until 28th November 2009 (UK only).

Understanding how language emerged in our species calls for a detailed investigation of the initial specialization of the human brain for speech processing. Our earlier research demonstrated that an adult-like left-lateralized network of perisylvian areas is already active when infants listen to sentences in their native language, but did not address the issue of the specialization of this network for speech processing. Here we used fMRI to study the organization of brain activity in two-month-old infants when listening to speech or to music. We also explored how infants react to their mother’s voice relative to an unknown voice. The results indicate that the well-known structural asymmetry already present in the infants’ posterior temporal areas has a functional counterpart: there is a left-hemisphere advantage for speech relative to music at the level of the planum temporale. The posterior temporal regions are thus differently sensitive to the auditory environment very early on, channelling speech inputs preferentially to the left side. Furthermore, when listening to the mother’s voice, activation was modulated in several areas, including areas involved in emotional processing (amygdala, orbito-frontal cortex), but also, crucially, a large extent of the left posterior temporal lobe, suggesting that the mother’s voice plays a special role in the early shaping of posterior language areas. Both results underscore the joint contributions of genetic constraints and environmental inputs in the fast emergence of an efficient cortical network for language processing in humans.

from Brain and Language

videos show what is happening inside brain on lsd …. so when are they going to use this to film what our brains are like on psycho-meds? And what impacts these meds are having on the rest of our bodies? HUH?

(image source: jmelt.deviantart.com/art/Your-Brain-on-Drugs-…_)

ON Major Depressive Disorders & Cortisol Levels

Levels of cortisol, a hormone associated with the human “fight-or-flight” response, have long been studied as possible biological markers for depression. In many adults, cortisol levels rise when the person is acutely depressed and return to normal when the depression passes. Research findings have been inconsistent regarding cortisol levels in children and adolescents, although there is some evidence that higher levels of cortisol secretion are associated with more severe depressive symptoms and with a higher likelihood of recurrence. As of 2002, however, cortisol levels are not considered to be reliable enough to be useful in diagnosing MDD.

I am currently reading J. D. Trout’s The Empathy Gap, which is (briefly) about our capacity to empathize with others who are suffering or are worse off in general, and why it is that relying on these feelings (and trusting in the charity they supposedly effect) makes for bad policy — not only are our emotions often short-lived, but we also possess an impressive (or depressing, depending on how you look at it) lineup of cognitive shortcomings that allow us to ignore or redirect our empathy, or occasionally to ignore empathy and “blame the victim.”  the best policy, he argues, would be transform the empathy we feel for our neighbors and for others around the world into concrete, consistent government programs that can create a safety net for others in order to reduce poverty and alleviate suffering around the world.  (not that the solutions are always easy to come by, but we need policies in place that will direct our better intentions into reliable, effective programs.)

anyway, Trout relies a lot on cognitive and psychological research, esp. lab experiments, much of which is very similar to what can be found in Gary Marcus’ Kluge, which I reviewed a few weeks ago (in fact, some of the same experiments in Marcus’ book illustrating some of these “kluge-y” features of our brain can be found in Trout’s).  to this can be added a new experiment discussed today over at Newsweek in which our ability (or tendency) to backtrack and adjust our thinking when we find ourselves with conflicting positions was measured using — what else? — fMRIs.

the researchers were trying to examine the brain activity engaged when participants experienced “cognitive dissonance” — the brain hurties felt when one holds two contradictory beliefs.  in short, they were looking at hypocrisy in the brain.  the experiment illustrated the activity of the dorsal anterior cingulate cortex when participants were asked to change their account of their experience in a claustrophobic fMRI for the benefit of other, more nervous participants or for a cash reward.

two things are of particular note.  first, in addition to having faulty memories and the far-from-perfect reasoning mechanisms (framing, anchoring, confirmation bias, etc.), we have a part of our brain that kicks in to help us handle the discomfort caused by the “cognitive dissonance.”  but instead of being alerted of a contradiction and being able to stick to our guns (abandoning one or other position), we re-reason and create stories that ultimately allow us to hold contradictory positions or — more illustrated in this experiment — forget our true feelings and adjust them according to what we want to believe.

second, those who adjusted their accounts for the sake of others (who were supposedly nervous) not only had more brain activity during the process, but also were more likely to report that they genuinely enjoyed the experience later (when in fact they had not, as they initially reported).  in short, in lying about (sugar-coating?) their experience to others, they fooled themselves. so our brains have the built-in capacity to alter our accounts (more powerful when for the benefit of others, I guess) and to then remove any traces of a contradiction so that we can forget how we felt (or what we thought) previously, all for the sake of avoiding the unpleasant “dissonance” caused by conflicting feelings (or thoughts).

as the author of the article writes, “The greater the cognitive dissonance a person feels, the more likely he is to change his beliefs to accord with his actions. How convenient.”

Each year when the Society for Neuroscience Meeting rolls around, all of the major journals devote extra space to neuroscience, publishing hot articles to attract the attention of the 30,000 plus attendees at the conference.  This year is no exception, and one of the most important articles came out this past week in Nature with the heady title “Intracellular dynamics of hippocampal place cells during virtual navigation“.  The paper, by Chris Harvey, Forrest Collman, Daniel Dombeck & Dave Tank is a tour de force investigation which combines new technology with insightful experimental manipulations and shows, according to an accompanying commentary by Doug Nitz, that “it is not impossible to examine brain correlates of higher cognitive processes and at the same time identify their underlying causes at the cellular level”.

The detailed results are probably too technically specific for most people in the field of neuroethics, but this study highlights some of the reasons that hard-core neuroscientists view fMRI with disdain.  Given the prominence that imaging the human brain has come to play in neuroethical discourse, I encourage readers to take a few moments to at least try to appreciate what the issues might be.

First, let’s take a look at what Dave Tank’s group at Princeton have done.  For over 35 years, neuroscientists have known that the firing rate of a subset of hippocampal pyramidal cells (the so-called place cells) change in predictable fashion as the animals navigate through a spatial environment.  In particular, the firing rate of a place cell reflects both the animal’s present spatial position and the path the animal has taken to reach that position.  Think about that for a second: the output of a single neuron reflects a highly nuanced and information rich algorithm.  But it does not stop there.  When multiple place cells are recorded at the same time, they exhibit a phenomenon called phase precession.  Nitz’ commentary sums it up nicely:

The firing order for a set of hippocampal place cells with partially overlapping place fields is found to match the animal’s physical trajectory corresponding to those fields. Phase precession stands as perhaps the most robust example of temporal coding of information in the mammalian brain.

So we have a nuanced algorithm which operates at both the single cell level, and in even more remarkable fashion, across groups of neurones in the hippocampus.  What has eluded neuroscientists until now is how the synaptic information is integrated to produce this phenomenon.  Enter Dave Tank’s group who developed a technique whereby they could carry out intracellular recordings of place cells while the animals approximated natural motion by running on a large ball whose movement was immediately translated into the visual projection on the screen by the open source video game Quake 2.  You can see a very cool demonstration in the video at the bottom of the post, but I want to return to Nitz’ effusive commentary:

The broader promise of the technique lies in learning exactly how the myriad incoming synaptic potentials to any given neuron are integrated to yield spike-firing patterns that closely track specific thoughts, perceptions or actions.

Let us now return to the issue of fMRI.  I don’t want to rehash old arguments here about the problems with spatial and temporal resolution of fMRI, as they are probably known to most readers.  What I do want to draw your attention to is the overall objective of fMRI: to be able to visualize the brain in action, and to derive from that information some insight into how the living brain does what it does.  In the mouse experiments, the key observation was that phase precession was encoded by small changes in the membrane potential of place cells, and that these changes arose secondarily to synaptic inputs. In other words, the experiments provide an initial glimpse (and I really mean glimpse – these data are fantastic but they only hint at the kinds of remarkable insights that will come in the future) at what appear to be the real workings of a complex cognitive construct – encoding not just the location of the animal in space but the trajectory by which it arrived there – and this phenomenon is manifest at the subcellular level.

I must say that I empathize with the despair that the smart and well-intentioned people who have put a great deal of honest work into developing thoughtful fMRI protocols should might feel upon reading about these new data.  For I think it is inevitable that this experimental result raises a new round of substantive questions about whether the BOLD signal can provide the type of insight that fMRI practitioners seek.  My conclusion is that, barring some major technological advance, it does not.

A key to keeping minds sharp through the later years might entail getting the elderly population online. In a study of 24 people with an average age of 66, researchers found that engaging in Internet searches, along with other online activity, was associated with increased brain function. Before and after the experiment, the subjects’ brains were scanned with fMRI, which shows blood flow and can be used to assess the activity of areas of the brain.

Half of the study group had little or no experience using the Internet, but with just two weeks practice, their brains were already showing increased activity in the frontal gyrus regions. Those areas are important in decision-making and memory. After the two-week period, the brain scans of the previously inexperienced users were similar to those of the control group, whose subjects were Internet savvy. The findings hold promise that one way to preserve brain function in elderly populations is through something as simple as casual web browsing. Pending more research, it would be a low-cost way of keeping aging minds healthy.

Read more about the study here.

Abstract
Children with congenital left hemisphere damage due to perinatal stroke are capable of acquiring relatively normal language functions despite experiencing a cortical insult that in adults often leads to devastating lifetime disabilities. Although this observed phenomenon is accepted, its neurobiological mechanisms are not well characterized. In this paper we examined the functional neuroanatomy of lexical processing in 13 children/adolescents with perinatal left hemispheric damage. In contrast to many previous perinatal infarct fMRI studies, we used an event-related design, which allowed us to isolate trial-related activity and examine correct and error trials separately. Using both group and single subject analysis techniques we attempt to address several methodological factors that may contribute to some discrepancies in the perinatal lesion literature. These methodological factors include making direct statistical comparisons, using common stereotactic space, using both single subject and group analyses, and accounting for performance differences. Our group analysis, investigating correct trial-related activity (separately from error trials), showed very few statistical differences in the non-involved right hemisphere between patients and performance matched controls. The single subject analysis revealed atypical regional activation patterns in several patients; however, the location of these regions identified in individual patients often varied across subjects. These results are consistent with the idea that alternative functional organization of trial-related activity after left hemisphere lesions is in large part unique to the individual. In addition, reported differences between results obtained with event-related designs and blocked designs may suggest diverging organizing principles for sustained and trial-related activity after early childhood brain injuries.

from Brain and Language

Children with congenital left hemisphere damage due to perinatal stroke are capable of acquiring relatively normal language functions despite experiencing a cortical insult that in adults often leads to devastating lifetime disabilities. Although this observed phenomenon is accepted, its neurobiological mechanisms are not well characterized. In this paper we examined the functional neuroanatomy of lexical processing in 13 children/adolescents with perinatal left hemispheric damage. In contrast to many previous perinatal infarct fMRI studies, we used an event-related design, which allowed us to isolate trial-related activity and examine correct and error trials separately. Using both group and single subject analysis techniques we attempt to address several methodological factors that may contribute to some discrepancies in the perinatal lesion literature. These methodological factors include making direct statistical comparisons, using common stereotactic space, using both single subject and group analyses, and accounting for performance differences. Our group analysis, investigating correct trial-related activity (separately from error trials), showed very few statistical differences in the non-involved right hemisphere between patients and performance matched controls. The single subject analysis revealed atypical regional activation patterns in several patients; however, the location of these regions identified in individual patients often varied across subjects. These results are consistent with the idea that alternative functional organization of trial-related activity after left hemisphere lesions is in large part unique to the individual. In addition, reported differences between results obtained with event-related designs and blocked designs may suggest diverging organizing principles for sustained and trial-related activity after early childhood brain injuries.

from Brain and Language

Airline travelers are quite used to metal detectors and x-ray machines by now.  And they may be getting used to what I call “the puffing thing,” but is referred to as a trace portal machine by the TSA.  (That’s the device that you walk into, and it puffs air at you, analyzes bits of debris it has dislodged, and lets you go on your merry way.)   Travelers are probably not yet used to the millimeter wave scanner, which I experienced over the weekend in DC.

For the uninitiated, the millimeter wave scanner is essentially radar for your body, and it allows the government to see through your clothes.  Supposedly, if you don’t want to let them do that, you’re supposed to be able to say, “No, I’d rather you pat me down instead, thank you,” and there’s supposed to be a sign saying so:

In my experience, though, I didn’t see that sign.  I could have been distracted, though, and I just wanted to come home.  So whatever, I went into the thing, and someone somewhere got to look at me through my clothes.  Hope they had a good time.  I did think that the machine, apart from being irritating and an invasion, had some flaws.  For one thing, at the end of the scan (which did go quickly) they asked me to put my arms out in front of me.  The problem with that, though, was that my hands would extend outside the machine.  Not sure if it matters, but it led to awkward movements.

Anyway, this post is titled “Biometrics and the TSA,” not “Adventures with MMW.”  This is because, in addition to the puffing thing (which costs about $160,000 a device, and which apparently don’t work very well) and the MMW scanner (which costs about $120,000), CNN is reporting on a brand new way of screening passengers:  The Wii Fit.

“Researchers took a Wii balance board — a device people stand on to interact with certain Nintendo Wii video games — and altered it to show how someone’s weight shifts. Studies are now under way to determine whether there is a level of fidgeting that would suggest the need for secondary screening.”

There’s a reason why polygraphs aren’t generally admissible as evidence in trial, and that is because biometric data is unreliable to interpret.  See, e.g., Frye v. United States, 293 F. 1013, 1014 (D.C. Cir. 1923) (“the systolic blood pressure deception test has not yet gained such standing and scientific recognition among physiological and psychological authorities as would justify the courts in admitting expert testimony deduced from the discovery, development, and experiments thus far made.”)  Frye isn’t the best case to cite, however, as it has been overturned, questioned, and superseded on a variety of grounds, and it is true that polygraphs and other technologies (such as the plethysmograph) are used in other aspects of prosecution (such as supervised release and the like). Nonetheless, it states pretty clearly the problem of using the body’s biometric functions to determine guilt or innocence.

All in all, biometric interpreters are dicey things to start implementing at airports, where stress levels are undeniably higher than in the controlled environment of a trained polygrapher’s office.  How accurate will the Wii’s Balance Board (or whatever extrapolation of the technology is devised) be when the subject needs to pee, is tired, is irritated at her husband for forgetting to make car rental reservations, and is angry at little Timmy for swallowing that penny he found on the floor?  It’s just one more impediment to the vast majority of us who aren’t doing anything wrong.

As an interesting aside, it does make me think of a story in Wired from March of this year, where defense attorneys wanted to introduce evidence from an MRI to establish a defendant’s innocence.  (The request was apparently withdrawn later that month.)  In short fMRI works this way:

Laboratory studies using fMRI, which measures blood-oxygen levels in the brain, have suggested that when someone lies, the brain sends more blood to the ventrolateral area of the prefrontal cortex. In a very small number of studies, researchers have identified lying in study subjects with accuracy ranging from 76 percent to over 90 percent. But some scientists and lawyers like Greely doubt that those results will prove replicable outside the lab setting, and others say it just isn’t ready yet.

(Source is the Wired article, with internal linking omitted.)

Dyslexia is primarily associated with a phonological processing deficit. However, the clinical manifestation also includes a reduced verbal working memory (WM) span. It is unclear whether this WM impairment is caused by the phonological deficit or a distinct WM deficit. The main aim of this study was to investigate neuronal activation related to phonological storage and rehearsal of serial order in WM in a sample of 13-year-old dyslexic children compared with age-matched nondyslexic children. A sequential verbal WM task with two tasks was used. In the Letter Probe task, the probe consisted of a single letter and the judgment was for the presence or absence of that letter in the prior sequence of six letters. In the Sequence Probe (SP) task, the probe consisted of all six letters and the judgment was for a match of their serial order with the temporal order in the prior sequence. Group analyses as well as single-subject analysis were performed with the statistical parametric mapping software SPM2. In the Letter Probe task, the dyslexic readers showed reduced activation in the left precentral gyrus (BA6) compared to control group. In the Sequence Probe task, the dyslexic readers showed reduced activation in the prefrontal cortex and the superior parietal cortex (BA7) compared to the control subjects. Our findings suggest that a verbal WM impairment in dyslexia involves an extended neural network including the prefrontal cortex and the superior parietal cortex. Reduced activation in the left BA6 in both the Letter Probe and Sequence Probe tasks may be caused by a deficit in phonological processing. However, reduced bilateral activation in the BA7 in the Sequence Probe task only could indicate a distinct working memory deficit in dyslexia associated with temporal order processing.

from Neuroscience Research

Human behavioral data indicate that older adults are slower to perform lexical decisions (LDs) than young adults but show similar reaction time gains when these decisions are primed semantically. The present study explored the functional neuroanatomic bases of these frequently observed behavioral findings. Young and older groups completed unprimed and primed LD tasks while functional magnetic resonance imaging (fMRI) was recorded, using a fully randomized trial design paralleling those used in behavioral research. Results from the unprimed task found that age-related slowing of LD was associated with decreased activation in perceptual extrastriate regions and increased activation in regions associated with higher level linguistic processes, including prefrontal cortex. In contrast to these age-related changes in brain activation, the older group showed a preserved pattern of fMRI decreases in inferior temporal cortex when LD was primed semantically. These findings provide evidence that older adults’ LD abilities benefit from contexts that reduce the need for frontally mediated strategic processes and capitalize on the continued sensitivity of inferior temporal cortex to automatic semantic processes in aging.

from Cerebral Cortex

Meaning retrieval of a word can proceed fast and effortlessly or can be characterized by a controlled search for candidate lexical items and a subsequent selection process. In the current study, we facilitated meaning retrieval by increasing the number of words that were related to the final target word in a triplet (e.g., lion–stripes–tiger). To induce higher search and selection demands, we presented ambiguous words as targets (i.e., homonyms like ball) in half of the trials. Hereby, the dominant (game), low-frequent (dance), or both meanings of the homonym were primed. Participants performed a relatedness judgment during functional magnetic resonance imaging. Activation in a bilateral network (angular gyrus, rostromedial prefrontal cortex) increased linearly with multiple related primes, whereas the posterior left inferior prefrontal cortex (pLIPC) showed the reverse activation pattern for unambiguous trials. When homonyms served as targets, pLIPC responded strongest when both meanings or low-frequent concepts were addressed. Additional anterior left inferior prefrontal cortex activation was observed for the latter trials only. The data support an interaction between 2 distinct cerebral networks that can be linked to automatic bottom-up support and top-down control during meaning retrieval. They further imply a functional specialization of the LIPC along an anterior–posterior dimension.

from Cerebral Cortex

Five nonfluent aphasia patients participated in a picture-naming treatment that used an intention manipulation (opening a box and pressing a button on a device in the box with the left hand) to initiate naming trials and was designed to re-lateralize word production mechanisms from the left to the right frontal lobe. To test the underlying assumption regarding re-lateralization, patients participated in fMRI of category-member generation before and after treatment. Generally, the four patients who improved during treatment showed reduced frontal activity from pre- to post-treatment fMRI with increasing concentration of activity in the right posterior frontal lobe (motor/premotor cortex, pars opercularis), demonstrating a significant shift in lateraliity toward the right lateral frontal lobe, as predicted. Three of these four patients showed no left frontal activity by completion of treatment, indicating that right posterior lateral frontal activity supported category-member generation. Patients who improved in treatment showed no difference in lateralization of lateral frontal activity from normal controls pre-treatment, but post-treatment, their lateral frontal activity during category-member generation was significantly more right lateralized than that of controls. Patterns of activity pre- and post-treatment suggested increasing efficiency of cortical processing as a result of treatment in the four patients who improved. The one patient who did not improve during treatment showed a leftward shift in lateral frontal lateralization that was significantly different from the four patients who did improve. Neither medial frontal nor posterior perisylvian re-lateralization from immediately pre- to immediately post-treatment images was a necessary condition for significant treatment gains or shift in lateral frontal lateralization. Of the three patients who improved and in whom posterior perisylvian activity could be measured at post-treatment fMRI, all maintained equal or greater amounts of left-hemisphere perisylvian activity as compared to right. This finding is consistent with reviews suggesting both hemispheres are involved in recovery of language in aphasia patients.

from the Journal of Voice