International conference: NeuroPsychoLinguistic Perspectives on Aphasia

Call for papers (CALL_EN) : International conference NPL-Aphasia
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NeuroPsychoLinguistic Perspectives on Aphasia
International conference
21-22-23 June 2012, Toulouse, France
Languages of the conference: English and French

Website: http://npl-aphasia-2012.com/
E-Mail: npl.aphasia.2012@gmail.com
Abstract submission:
http://www.easychair.org/conferences/?conf=nplaphasia2012

Guest speakers:

Marie-Pierre De Partz, Université Catholique de Louvain
Marina Laganaro, University of Geneva
Jean-Luc Nespoulous, University of Toulouse 2-Le Mirail
Michel Paradis, McGill University & UQÀM

Call for abstracts:

The study of acquired language disorders, and specifically the study of aphasia in adult patients, brings together various research perspectives around language and cognitive sciences, such as:
. Linguistics (involving different representational levels and their
interfaces: phonetics, phonology, prosody, morphology, semantics,
lexicon, syntax, discourse, pragmatics, …);
. Psycholinguistics (regarding the different levels of decoding and
encoding processes) ;
. Neurolinguistics (investigating the neurobiological grounding of
language and cognition).

The meeting is dedicated to illustrate different approaches to aphasia research, including qualitative and quantitative studies of language disorders in patients with left hemisphere and / or right hemisphere lesions (stroke, traumatic injury, dementia) — both case and group studies — relating to one or a combination of several of the research areas mentioned above.

The conference particularly invites papers investigating theoretical aspects of language disorders (underlying impairments, functional reorganisation, development of compensation strategies, etc.) or
exploring practical aspects (treatment outcomes, novel proposals for therapy, etc.), based on one or several of the following perspectives (but not restricted to them):
. Modelisation of language and cognitive structures and functions;
. Remediation programs for therapy (development of treatment and
assessment methods based on clinical research) ;
. Across-thematic perspectives:
- Disorders and normality;
- Bilingualism and crosslinguistic approaches;
- Empirical and experimental research methodologies;
- Variability and stability of performance;
- Aphasia therapy and recovery, language assessment, treatment programs,
- Spontaneous and elicited strategies and their clinical implications.

We encourage papers exploring dissociations, that are relevant or not, and papers with consideration to language structure, processing and use in pathological contexts and in “normality” with original empirical and experimental methods (computational, formal, corpus analysis, eye-tracking, study of intra- and inter-task, -individual, -language variability, dissociations between modalities : production -
comprehension / speech - writing - non verbal, fMRI, PET, awake surgery, …).

The contributions will be presented and discussed during oral (20 minutes + questions) and poster sessions. Additionally, workshops intended to stimulate discussions will be organised, with special focus on:
1- Crosslinguistic and typological approaches;
2- Empirical and experimental methods;
3- Clinical applications: elaboration of treatment programs;
4- Social readaptation of aphasic persons: improving communication to
live better.

Abstracts (maximum of 600 words including references, see the submission guidelines: http://www.npl-aphasia-2012.com/submission/) should indicate which type of presentation (talk, poster or talk/poster for a workshop) is preferred.


Important dates:

Sept. 2011> Call for abstracts
31 Dec. 2011> Deadline for abstract submission
Feb. - March 2012 > Notification of acceptance and confirmation for
attendance
March - June 2012 > Registration (early bird: before 15/04, late: after
15/04)
May 2012 > Program
21-22-23 June 2012 > Conference

POST-DOC POSITION – MEG/EEG – National Institutes of Health, NIDCD

POSTDOCTORAL POSITION – MEG/EEG – National Institutes of Health, NIDCD Division of Intramural Research

Applications are invited for a postdoctoral position in the Language Section, NIDCD, National Institutes of Health, to work on language, social communication, and relevant neurological disorders using MEG/EEG. The research will focus on discourse level language comprehension, production, and all aspects of natural ecologically valid language use.   Investigations will be carried out in normal adults and clinical populations including stroke, traumatic brain injury and stuttering. Major experimental methods include MEG source analysis, time-frequency analysis and simultaneous EEG-fMRI.

Applicants should have a doctoral-level degree in neuroscience, psychology, medicine or a related area. Prior experience in MEG/EEG experimental design, data acquisition and analysis is necessary. Advanced skills for time series analysis and MATLAB programming are highly desirable. Experience with fMRI is preferred but not required. Salary will be commensurate with the salary scale of the National Institute of Health, NIDCD Division of Intramural Research. The position is funded for two to five years. Applications will be considered until the position is filled.

For further information or to submit an application (including a brief CV and two references) please contact Allen Braun, M.D.  email: brauna@nidcd.nih.gov.

fMRI, TMS, and Coldplay

I never thought I'd see these three nouns woven into a blog entry but Brad Buchsbaum makes it work on his FlowBrain Blog. It's actually a really nice discussion of how useful TMS really is in terms of addressing the "epiphenomenon issue" with fMRI data. Check it out: http://flowbrain.blogspot.com/2011/07/exposing-epipenomenon-with-tms.html

Mirror Neuron Forum - Role of mirror neurons in speech and language processing - Part II

Marco Iacoboni's response to my argument that the motor system is not necessary for speech perception was short and sweet, so let's break it down line by line.

In a ‘‘virtual lesion’’ repetitive TMS (rTMS) study on speech perception, the TMS effects over premotor cortex were, if anything, a little stronger than the TMS effects over the auditory cortex (Meister et al., 2007). However, the effects were not reliably different, suggesting that both structures participated in the functional process, in contrast to GH’s suggestion that motor processes play a small, modulatory role in speech perception.

Meister et al. found that TMS to premotor cortex resulted in a modest decline in performance in identifying synthesized CV syllables presented in noise in the context of a three-alternative forced choice paradigm. There has been no study that I'm aware of to show that such an effect is found when natural stimuli are used. The stimuli have to be degraded, i.e., partially ambiguous. Can we conclude that premotor cortex is playing an "essential role in speech perception" as the title suggests? No, we can only conclude that it is playing a modest role in the performance of an artificial task under degraded listing conditions. And we can't even tell what aspect of the task is being disrupted. It is possible that TMS is not interfering with the perception at all but rather interfering with the sensory-motor memory of which response button corresponds to which syllable. This one piece of evidence is held up to counter the array of studies that I cited showing that damage to the motor speech system, developmental failure of the motor speech system, complete biological lack of the capacity for a motor speech system, does not prevent speech perception. Where does the weight of the evidence leave us? The motor system plays a modest modulatory role if that. Why didn't STG stimulation cause a greater decline in performance? There is abundant evidence that speech perception is bilaterally mediated in the STG (Hickok & Poeppel, 2000, 2004, 2007).

Again, I find it counterproductive to focus on dichotomous models (‘‘it’s auditory,’’ ‘‘no, it’s motor’’). These models, although didactically useful, tend to provide a limited understanding of the functional processes at play. Indeed, consistent with the model in GH’s Figure 2D, the most successful recent computational models of action and perception disclose the intimate relationship between motor control and perception (Friston, Daunizeau, Kilner, & Kiebel, 2010; Friston, Mattout, & Kilner, 2011).

I outlined four possible models, only two of which were dichotomous. I'm not denying that action and perception are intimately related. They are! But the functional relation is precisely the reverse to what the mirror neuron claim holds.

Eventually, we will have to get rid of these labels altogether, because they seem to get in the way of a better understanding of the phenomena under investigation.

Call it what you like, it doesn't change the fact that systems in the posterior frontal lobe aren't necessary for speech perception, whereas bilateral systems in the superior temporal lobe are. As much as some folks would like the cortex to one big happy interacting neural network with no differentiation, the fact is that damage to different parts of the system have different effects. We have to deal with these facts. Returning to the facts, here's a quote from Meister et al.

The present results demonstrate that the involvement of the premotor cortex in perception is not merely epiphenomenal and suggest that sensory regions are not sufficient alone for human perception. p. 1695

and a figure from Rogalsky et al. 2011 which shows comprehension, word discrimination, and syllable discrimination performance of two cases with lesions involving the human mirror system.

It seems pretty clear that Meister et al.'s claim is false. The recent follow up to Rogalsky et al. using a sample of 24 cases with Broca's area lesions confirms what was found in these two cases.

So, I've covered the response to my criticisms of mirror neuron theory by two of the most prominent and thoughtful defenders of the theory. Given the opportunity to present their strongest possible rebuttal to direct critiques in the Mirror Neuron Forum, both Gallese and Iacoboni failed to mount a viable defense of their model. This, of course, is my view. I'm sure they will disagree and again I invite them to post their own comments as guest entries on this blog. So far I have not heard a peep from either of them despite direct email invitations to participate.

References

Gallese, V., Gernsbacher, M., Heyes, C., Hickok, G., & Iacoboni, M. (2011). Mirror Neuron Forum Perspectives on Psychological Science, 6 (4), 369-407 DOI: 10.1177/1745691611413392

Hickok, G., & Poeppel, D. (2000). Towards a functional neuroanatomy of speech perception. Trends in Cognitive Sciences, 4, 131-138.

Hickok, G., & Poeppel, D. (2004). Dorsal and ventral streams: A framework for understanding aspects of the functional anatomy of language. Cognition, 92, 67-99.

Hickok, G., & Poeppel, D. (2007). The cortical organization of speech processing. Nature Reviews Neuroscience, 8(5), 393-402.

Meister, I. G., Wilson, S. M., Deblieck, C., Wu, A. D., & Iacoboni, M. (2007). The essential role of premotor cortex in speech perception. Curr Biol, 17(19), 1692-1696.

Rogalsky, C., Love, T., Driscoll, D., Anderson, S. W., & Hickok, G. (2011). Are mirror neurons the basis of speech perception? Evidence from five cases with damage to the purported human mirror system. Neurocase, 17(2), 178-187

Mirror Neuron Forum - Role of mirror neurons in speech and language processing - Part I

Now on to my favorite mirror neuron topic, Question 2 of the Mirror Neuron Forum:

Do Mirror Mechanisms Causally Contribute to Speech Perception and Language Comprehension?

There are two questions here, each logically independent of the other, but findings from one domain may provides hints regarding the other. The first is whether mirror neurons are the basis of speech sound recognition. This was the first language-related ability that mirror neuron function was generalized to in humans. The second question is whether the motor system -- often defined as the somatotopically organized fields such as M1, which is generally consider NOT to be part of the mirror system, but no one seems to worry about that for some reason -- is involved in the representation of action-related concepts. One question is a perceptual issue, the other is a semantic/conceptual issue.

I focused on the first question for two reasons. One is its primacy in the history of the development of theories of mirror neuron function in humans. The second is that there is a TON of data on the topic, allowing us to draw firm conclusions. I consider this a test case for the MN theory and suggested that if the theory fails here, we need to seriously question its role in other domains. I then presented a list of the evidence proving (I almost never use this word, but I think it is justified here) that the motor speech system is NOT necessary for speech recognition.

Gallese did not dispute this claim. Instead he questioned whether findings from the speech perception literature should lead us to question findings in other domains.

VG: According to GH, the roles of MNs in speech perception and language understanding are to be considered tightly related: If a relationship between MNs and speech perception cannot be established, so the argument goes, it would follow that the connection between MNs and language understanding would be falsified. I disagree with this logic.

Note that I didn't actually say that findings from speech perception would falsify claims regarding language semantics. I said, "If the action understanding interpretation fails for speech perception, it raises serious questions about the theory generally." Why do I say this? Because this is the domain in which we have the most evidence. It is a test case. If the theory holds up for speech perception, then it passed a rigorous test and we might be more lenient in accepting weaker data in other domains. If it fails the rigorous test, this leads us to question the weaker data. Could data from other studies lead to the firm conclusion that motor systems play a role in action knowledge representation (or empathy or whatever)? Yes. But we are not there yet. Speech perception is the ONLY domain where the results are conclusive and the theory failed. This was my point.

Now, in another recently published paper, I reviewed the evidence claimed to support the theory that the motor system is critically involved in action semantics and found the evidence weak at best (Hickok, 2010). So let's look at what Gallese takes to be some of the strongest claims.

VG: In humans, the cortical motor system is activated during the observation of a variety of motor behaviors

Activation does not imply causation.

VG: right handers preferentially activate the left premotor cortex during lexical decisions on manual-action verbs (compared with nonmanual-action verbs), whereas left handers preferentially activate right premotor areas (Willems, Hagoort,&Casasanto, 2010). Thus, right and left handers, who performactions differently, use correspondingly different areas of the brain for representing action verb meanings

That's nice but unsurprising and easily explainable without assuming that the meaning of the verbs is coded in the motor system. If I say a word like throw this will activate in your brain a network of systems and representations that have previously been associated with that word. Chances are, you have previously linked that word with the very action itself: "Throw me the ball!" upon which you generate the movement. So even if the movement itself is not part of the meaning of the word, motor programs for generating the movement just might activate when you hear the word. So given that lefties and righties throw with different hands, you would expect to see the observed difference. Depending on your recent life experiences, upon hearing throw you might also activate the word up and the memory of a wild party, but that doesn't mean that up and WILD PARTY are part of the meaning of to throw, it just means they are associated at some level.

How can we test this idea more directly? One prediction is that damage to the motor system should cause deficits in understanding actions. Some studies have been published which are suggestive in this direction, e.g., in Parkinson's patients, but these cases are far from complication free as I noted in my 2010 review. Unfortunately, there is not a lot of (convincing) experimental evidence available. However, I will again point out that we can readily understand actions that we cannot perform such as the coiling of a snake or the flying of a bird. Further, from an evolutionary standpoint, these are actions that are critical to understand because survival can depend on it. This indicates that action understanding, at a fundamental level, cannot be dependent on motor representations. So to sum up: the MN theory of action understanding has failed its only rigorous test. The evidence supporting the role of MNs in action semantics is debatable. There is evidence that the motor system is not critical for understanding actions generally. Together, this leads me to "seriously question" the claim that actions semantics depends on the motor system.
References

Gallese, V., Gernsbacher, M., Heyes, C., Hickok, G., & Iacoboni, M. (2011). Mirror Neuron Forum Perspectives on Psychological Science, 6 (4), 369-407 DOI: 10.1177/1745691611413392

Hickok, G. (2010). The role of mirror neurons in speech perception and action word semantics. Language and Cognitive Processes, 25, 749 - 776.

Job posting: Assistant or Associate Professor of Communication Sciences and Disorders (CSD) - Penn State Univ.

Assistant or Associate Professor of Communication Sciences and Disorders (CSD)

Work Unit: College Of Health & Human Development
Department: Communication Sciences and Disorders
Job Number: 34660
Affirmative Action Search Number: 023-105

The Department of Communication Sciences and Disorders (CSD) ( http://csd.hhdev.psu.edu/), College of Health and Human Development at The Pennsylvania State University seeks candidates for a full-time continuing (36-week) tenured or tenure-track position of Assistant or Associate Professor to begin Fall 2012.

The responsibilities of this position will be to establish or continue a line of research in a specialty area(s) related to language, speech or voice science, autism, and/or fluency. Specialty interests in neuroscience, neurogenics, neuromotor disorders and/or aging considered a plus. In addition, will teach undergraduate and graduate courses in area of specialty; supervise undergraduate and graduate (M.S./Ph.D.) research; be actively involved in enhancing and building the Ph.D. program; provide service to the Department, College, and University; and contribute to the clinical aspects of the program. Opportunities exist for interdisciplinary collaborations across the University Park and Hershey Medical Center campuses. These collaborations include the Penn State Social Science Research Institute, the Center for Healthy Aging, the Social, Life, and Engineering Sciences Imaging Center (which houses a human electrophysiology facility and a 3 Tesla fMR unit), the Penn State Center for Language Science, the Huck Institutes of the Life Sciences, and numerous departments including Biobehavioral Health, Psychology, Kinesiology, Bioengineering, Human Development and Family Studies and departments in the College of Medicine such as Neurology.

Candidates must have an earned Ph.D., with an active research and scholarship program. Previous teaching experience and/or post-doctoral experience desired. CCC-SLP is desirable. Review of credentials will begin immediately and continue to be accepted until the position is filled. Interested candidates should submit a letter of application, current curriculum vitae, copies of relevant research articles or presentations, along with the names, addresses, email and telephone numbers of three professional references, to:

Krista Wilkinson, Ph.D., Chair of the Search Committee
Professor,Communication Sciences and Disorders
c/o Sharon Nyman, Adminstrative Assistant
Department of Communication Sciences and Disorders
The Pennsylvania State University
308 Ford Building
University Park, PA 16802

Or, send via email to: SAN5@psu.edu

Penn State is committed to affirmative action, equal opportunity and the diversity of its workforce.

Neurobiology of Language Conference (NLC 2011) -- Scientific Program

The scientific program for the 2011 NLC meeting in Annapolis, Maryland has just been posted online. It looks like a fantastic slate of keynotes, debates, and platform sessions. As an SNL board member, I was involved in selecting the keynote and debate speakers, but the platform session speakers are chosen based on a blind ranking of abstracts done by an army of volunteer reviewers. The result is a very nice mix of topics and speakers. I just had my first look at the program and I don't think there is a single session that I can bug out on! This may be the very first meeting of any conference where I attend all the sessions...

Check out the program here: http://www.neurolang.org/Scientific_Program.php

Don't forget to register and see you in Annapolis!

The planum temporale is not a functionally homogeneous region

I'm not sure that anyone really believes that the planum temporale (PT) is a functional monolith but you wouldn't know it from the literature. People talk about THE planum temporale -- e.g., Griffiths and Warren's The Planum Temporale as a Computational Hub -- as if it were one functional thing. Cytoarchitectonic data tells us that this is highly unlikely. There are multiple fields in the PT and the posterior half is not even considered part of auditory cortex, based on its laminar organization. Now we have fMRI evidence clearly showing at least two functional subdivisions in the PT.

Two functions that have repeatedly been linked to the PT are spatial hearing and auditory-motor integration. Some authors have linked these two abilities computationally into a single mechanism:

This expanded scheme ... proposes a common computational structure for space processing and speech control in the postero-dorsal auditory stream. -Rauschecker & Scott, 2009, p. 722.

This raises the question, are the same regions in the PT involved in processing spatial and auditory-motor information? A new study addresses this question directly.

In an fMRI study subjects participated in four auditory conditions: listening to stationary noise, listening to moving noise, listening to pseudowords, and shadowing pseudowords (covert repetition). As with previous studies, contrasting the shadow and listen conditions should activate regions specific to auditory-motor processes, while contrasting the stationary and moving noise conditions should activate regions involved in spatial hearing. Subjects (N = 16) showed greater activation for shadowing in left posterior PT (yellow), area Spt, when the shadow and listen conditions were contrasted. The motion vs. stationary noise contrast revealed greater activation in a more medial and anterior portion of left PT (red).

Seeds from these two contrasts were then used to guide the DTI analysis in an examination of connectivity via streamline tractography, which revealed different patterns of connectivity.

It's not straightforward to infer computational function from mapping data, but given that completely different areas are involved and given that the connectivity patterns appear to be different, perhaps the computational mechanisms for spatial hearing and auditory-motor integration are not shared after all.

In any case, it is now very clear that, as with Broca's area, the PT is not functionally homogeneous.

References

Isenberg, A., Vaden, K., Saberi, K., Muftuler, L., & Hickok, G. (2011). Functionally distinct regions for spatial processing and sensory motor integration in the planum temporale Human Brain Mapping DOI: 10.1002/hbm.21373

Griffiths, T. D., & Warren, J. D. (2002). The planum temporale as a computational hub. Trends in Neuroscience, 25(7), 348-353.

Rauschecker, J. P., & Scott, S. K. (2009). Maps and streams in the auditory cortex: nonhuman primates illuminate human speech processing. Nature Neuroscience, 12(6), 718-724

V.S. Ramachandran on critiques of mirror neuron theory

While I'm on the topic of mirror neurons...

A Talking Brains reader recently pointed me towards a published cover story and interview with V.S. Ramachandran in the magazine Khabar that included some discussion of mirror neurons. Rama, of course, is famous for many things including his bold prediction that mirror neurons will do for psychology what DNA did for biology and he has written extensively on the topic. It was pointed out in the interview that there are critics who question the significance of mirror neurons in action understanding. Here is the question and his response:

Some critics like Gregory Hickok of UC Irvine have argued that there is little evidence to support the mirror neuron theory of action understanding. How do you respond to that?

There are two issues. In my book, I do address various criticisms—I’m not familiar with that particular one. It seems plausible there is no direct evidence, but we often go by circumstantial evidence. I’d argue with him that there is no definitive proof of action understanding, but given their properties it seems reasonable to argue that it exists. I mean, you can always say about any neuron system that it’s just a correlation, that it’s not really doing the job. I’ll give you an analogy. They found cone cells in the eye which are responsible for seeing color. Now you can say it’s just a correlation, that they are sitting there and not doing anything. I know it’s an extreme example, but it’s the same logic. (quoted from: http://www.khabar.com/magazine/cover-story/Brain_Man)

So Rama admits that the theory is based on circumstantial, rather than more direct evidence. I will agree with him that we often do develop hypotheses based on circumstantial evidence, or even intuition. And there's nothing wrong with that. I've pointed out previously that the initial proposal regarding the function of mirror neurons was reasonable and interesting. However, as more and more data poured in over the next two decades, many empirical problems with the theory have been revealed. To use Rama's example, the fact that cones fire to specific wavelengths of light is highly suggestive of a role in color vision but this is still just a correlation. In the case of cones though, much other research has confirmed the hypothesis more directly such as cases where cones are dysfunctional and color vision is disrupted. The mirror system has been put to a similar test, but unlike the cone theory of color vision, the mirror neuron theory of action understanding has failed miserably: disruption of the mirror system does not cause substantial deficits in action understanding (see this post, for example). So the mirror neuron theory is based on circumstantial evidence and there is direct evidence to the contrary. Open and shut case in any court of law.

Why isn't the cased dismissed in academic circles? The mirror neuron theory of action understanding is so simple and powerful and the correlations between neuronal activity and behavior so compelling at first glance that it apparently blinds many researchers from seeing the broader array of facts. In one comment in the Mirror Neuron Forum I compared the situation to the powerful intuitive pull of the notion that the sun revolves around the Earth. It is a compelling observation that led to a very reasonable geocentric theory. However, upon further observation the theory failed to account for other, less intuitively compelling but equally valid observations such as apparent retrograde motion of planets. While a geocentric model can explain observations about the apparent motion of the sun, only the heliocentric model explains all the facts. It's an extreme example, but the logic is the same. It is time that we all look a bit more closely at ALL the facts when thinking about the function of mirror neurons and the mirror system.

Mirror Neuron Forum - Some additional discussion - Part IV

Here is some commentary on Iacoboni’s response to my answers to question 1.

Iacoboni writes,

“The ventral/dorsal dichotomous interpretational framework (as invoked in GH’s answer to Question 1) is too simplistic to account for extant data on the MN system (and probably other systems too). We now know that MNs exist in areas well outside the classical dorsal stream (Mukamel et al., 2010).”

In Mukamel et al. it was reported that cells in the human medial temporal lobe respond both during action execution and action observation. We could argue about whether or not these are “real” mirror neurons in sense of functioning to support action understanding given that they are outside of the motor system and as such not likely to be involved in motor simulation. But that is beside the point. The question is whether the existence of mirror neurons in the human hippocampus calls into question my claim that the dorsal stream mirror system supports sensory motor integration while the ventral stream supports action understanding. As a single data point, the existence of hippocampal mirror neurons is irrelevant to my claim. We can see this clearly if we consider the same argument in a different context: suppose I claimed that neurons with an ON-center Off-surround receptive field were critically involved in pitch perception in auditory cortex and someone countered that ‘it is more complicated than that because ON-center Off-surround cells have been found well outside the auditory system including the retina’. The argument misses the point completely.

Iacoboni continues,

“Furthermore, it is unclear why hypotheses about the functions of MNs must be mutually exclusive …. It is likely … that association learning plays some role in shaping the responses of MNs. However, there is no reason to assume, as GH does, that because association learning plays a role in shaping MN responses that MNs cannot implement any form of action understanding.”

I agree completely. MNs could in principle be involved in multiple processes. But again, it’s an empirical question. My point is simply that the empirical record as a whole does not support the action understanding interpretation.

Mirror Neuron Forum - Some additional discussion - Part III

This is a continuation of my commentary on the recently published Mirror Neuron Forum. The start of this thread can be found here.

I have suggested that the ventral stream supports action understanding. Here is Gallese’s response to that idea:

“GH’s statement that action understanding is a function ofthe ventral semantic or “what” stream can also be questioned. Where is the“what” of action in the ventral stream? Perhaps, GH would argue, it can be found in the STS. However, no evidence supports this argument…”

Sticking to the monkey data, let me quote from Rizzolatti and Craighero (2004):

“Neurons responding to the observation of actions done by others are present not only in area F5. A region in which neurons with these properties have been described is the cortex of the superior temporal sulcus (STS; Figure 1) (Perrett et al. 1989, 1990; Jellema et al. 2000; see Jellema etal. 2002). Movements effective in eliciting neuron responses in this region are walking, turning the head, bending the torso, and moving the arms. A small set of STS neurons discharge also during the observation of goal-directed hand movements (Perrett et al. 1990). If one compares the functional properties ofSTS and F5 neurons, … [the] STS appears to code a much larger number of movements than F5…” (p. 171).

This evidence is no less correlative than the evidence from F5 but it is evidence nonetheless, in contrast to VG’s statement, and no less valid than the correlative evidence from F5. Further, given that STS units appear to code a wider range of movements and do it with more specificity than mirror neurons, it is clear that the circumstantial evidence for STS being the seat of action understanding is stronger than that for the mirror system.

Gallese continues…

“and in contrast current evidence demonstrates quite the opposite. As recently shown by Cattaneo et al. (2010), only the motor system—and not the STS—can generalize a given motor goal independently from the effector accomplishing it.”

Now Gallese slips out of the monkey literature and into the human literature where according to VG we have no reason to assume that a “neural mechanism found in different species must necessarily preserve identical characteristics”. In any case, let’s consider this study, which involved stimulating the hand area of motor cortex and measuring TMS induced motor evoked potential (MEPs) in a hand muscle while subjects watched videos of actions. The main finding was that the goal of the action, rather than the particular movements themselves, modulated MEPs during observation. Does this mean that the motor system is “generalizing the goal”? No. Nor does this experiment even address that question. Notice that TMS was not applied to the mirror system (Broca’s area or PPC) or to the STS (the systems in question). It was applied to the output portion of the cortical machinery, M1. We can infer that something modulated M1, but we can’t tell what the source of that modulation is; it could be any network upstream to M1. So it could be that the abstract goal was coded in STS and this ultimately modulated M1. It could also be that Broca’s area coded the abstract goal. We simply can’t tell. Certainly we cannot conclude from this study that, “only the motor system—and not the STS—can generalize a given motor goal…”

So that’s the end of Gallese’s response to my answer toquestion #1. I see nothing in his rebuttal that carries even a hint of theoretical or empirical weight.

References

Cattaneo, L., Caruana, F., Jezzini, A., & Rizzolatti,G. (2009). Representation of goal and movements without overt motor behavior inthe human motor cortex: a transcranial magnetic stimulation study. Journal ofNeuroscience, 29(36), 11134-11138.

Rizzolatti, G., &Craighero, L. (2004). The mirror-neuron system. Annual Review of Neuroscience,27, 169-192.

Does damage to Broca's area cause speech perception deficits?

The field seems to be a bit divided on this question as the following quotes indicate.

"...many patients with Broca’s aphasia actually do show severe phonemic perception deficits..."  (Wilson & Iacoboni 2006)

"Broca’s aphasia is associated with speech perception deficits..." -Iacoboni, in Gallese et al. 2011

"The findings reviewed in the present paper indicate that areas in the frontal lobe involved in speech production are specifically contributing to speech perception, and that activity in the motor system can alter speech discrimination, directly indicating that sensory-motor processes interact during speech comprehension. The experimental evidence of a causal relationship between activity in motor areas and speech perception ([D'Ausilio et al., 2009] and [Meister et al., 2007] ) provide evidence that activation of motor areas during listening to speech is NOT the consequence of a corollary cortico-cortical connection ... but reflects the sensory-motor nature of perceptual representations."  (D'Ausilio, et al. 2010)

“…lesion studies show that aphasics with damage to frontal motor-related structures largely retain the ability to perceive speech sounds.”  (Hickok 2010)

A critical piece of evidence in this debate is the speech perception ability of individuals with damage to Broca’s area and/or Broca’s aphasia.  Proponents of the view that damage to frontal, motor-related regions are critically involved in speech perception often refer to the literature of the 1970s and 1980s which reported various degrees of impairment on some speech perception tasks.  But this older literature did not typically utilize neuroradiological data to confirm the location of the lesions, nor did these studies use signal detection methods. 

I recently had the opportunity to team up with one of the major players in that earlier literature, Gabriele Miceli and his group, to re-examine this issue in a new sample of aphasics.  From Miceli’s database of patients, we identified all of the cases that had substantial damage to Broca’s area, confirmed radiologically; the lesions typically involved surrounding regions as well.  Twenty-four cases were identified.  Nineteen were classified as Broca’s aphasics, 5 were on the border between Broca's and conduction aphasia, and 1 was classified as a conduction aphasic. 

We assessed the ability of these patients to perceive speech sounds using a variety of tasks including same-different syllable discrimination and auditory word-to-picture matching with phonological and semantic distracter pictures.  Of course, if Broca’s area and surrounding motor regions are critical for speech sound perception, we would expect to find substantial deficits on our tasks. 

In fact, performance was remarkably good.  On the syllable discrimination task the group averaged 94% correct with a d’ = 4.18, i.e., 4 standard deviations above chance performance.   On the auditory comprehension task, performance was even better at 97% correct.  Task still matters!

Speech output fluency varied across the sample.  There was one fluent aphasic in the sample (the one not classified as a Broca’s aphasic).  The rest were all non-fluent to various degrees, consistent with the diagnosis of Broca’s aphasia.  We removed the fluent patient then grouped the rest in terms of their severity of non-fluency -- mild, moderate, severe -- and examined receptive speech abilities as a function of output fluency.  If there is a relation between motor speech ability and speech perception, more severely non-fluent patients should perform more poorly on receptive speech tasks. There was no difference between groups (p-value = 0.39). 

Thus, the stroke/aphasia literature is consistent with evidence from Wada studies, developmental anarthria studies, normal development studies, and animal studies of speech perception: the motor system is not necessary for speech perception. 

References

D'Ausilio, A., Craighero, L., & Fadiga, L. (in press). The contribution of the frontal lobe to the perception of speech. Journal of Neurolinguistics. doi: 10.1016/j.jneuroling.2010.02.003

Hickok, G. (2010). The role of mirror neurons in speech perception and action word semantics. Language and Cognitive Processes, 25, 749 - 776.

Hickok, G., Costanzo, M., Capasso, R., & Miceli, G. (2011). The role of Broca’s area in speech perception: Evidence from aphasia revisited Brain and Language DOI: 10.1016/j.bandl.2011.08.001

Wilson, S. M., & Iacoboni, M. (2006). Neural responses to non-native phonemes varying in producibility: evidence for the sensorimotor nature of speech perception. Neuroimage, 33(1), 316-325.

Tenure-track position -- University of Illinois at Urbana-Champaign

The Department of Linguistics at the University of Illinois at Urbana-Champaign invites applications for a full-time, tenure-track position in Second Language Acquisition with specialization in psycholinguistics, neurolinguistics, or cognitive neuroscience of language, at the rank of Assistant Professor. The candidate must possess demonstrated strength in theoretical and/or experimental linguistics. The candidate's record should provide clear evidence of a strong research program and an excellent research trajectory. The successful candidate should demonstrate a commitment to excellence in teaching, and will be expected to contribute to both undergraduate and graduate instruction. Research specialty in one of the languages offered by the Linguistics department or another department in the School of Literatures, Cultures and Linguistics is a plus, as is experience in second and/or foreign language teaching. The PhD should be in hand prior to the target date of appointment, August 16, 2012. Salary is commensurate with the experience and qualifications of the candidate.

To apply, create your candidate profile through https://jobs.illinois.edu <https://jobs.illinois.edu/>  and upload the following application materials through this system: letter of application, CV (including phone number and e-mail address), contact information for 3 references, up to 3 representative publications, statement of teaching and research interests, and teaching evaluations or other evidence of strength in teaching. Referees will be contacted electronically upon submission of the application. Only electronic applications submitted through https://jobs.illinois.edu <https://jobs.illinois.edu/>  will be accepted.

For further information please contact: Professor Tania Ionin, C/O Marita Romine, SLCL-HR@illinois.edu. To ensure full consideration, all required materials must be received no later than December 1, 2011. Letters of reference must be received no later than December 8, 2011. The department highly recommends that complete applications be submitted prior to Dec. 1, to ensure that referees have enough time to submit their letters of recommendation.

The University of Illinois is an Affirmative Action / Equal Opportunity Employer and welcomes individuals with diverse backgrounds, experiences, and ideas who embrace and value diversity and inclusivity (www.inclusiveillinois.illinois.edu <http://www.inclusiveillinois.illinois.edu/> ).

Mirror neuron-like simulation in the sensory system?

I've been busy lately working on a grant proposal so I have not had a chance to continue my comments on the recently published Mirror Neuron Forum.  There hasn't been any involvement in that discussion by the forum participants anyway (unfortunately) so my motivation to work on it has dropped off a bit.  I'll get back to that soon.

Right now I'm just curious if anyone has noticed that the mirror system has extended its reach into sensory systems.  A recent review by Keysers, Kaas, and Gazzola (2010), for example, discusses the role of somatosensory cortex in social perception via simulating the experience of others.  I haven't looked at this literature carefully, but on first glance it strikes me as rather odd to claim, as a novel idea inspired by mirror neurons, that sensory systems in the brain might be involved in sensing what is happening in the environment.  What will the next claim be, that the visual system is important for object identification via simulation of object features?  Radical!  I must be missing something.

Keysers C, Kaas JH, & Gazzola V (2010). Somatosensation in social perception. Nature reviews. Neuroscience, 11 (6), 417-28 PMID: 20445542

Postdoctoral Position to Study the Neurobiology of Language in Real-World Contexts

The Language, Action, and Brain Lab (http://lablab.hamilton.edu/) at Hamilton College is seeking a postdoctoral-fellow interested in understanding the organization of language and the brain from a more naturalistic social, developmental, and cognitive neuroscience perspective. We seek an individual who has recently graduated with a Ph.D. and who has experience with eye-tracking, high-density electroencephalography (EEG), and/or functional magnetic resonance imaging (fMRI) and evidence of productive research. Applicants will be working with a large number of highly intelligent and motivated undergraduate research assistants. There is opportunity to work in collaboration with the nearby Center for Language and Brain (http://www.colgate.edu/academics/centersandinstitutes/languageandbrain). Hamilton College is located at the foot of the Adirondack Mountains in beautiful New York State and is within driving distance of New York City. The position is for two years and offers a competitive salary (funded by NIH-NICHD R00 HD060307 – “Neurobiology of Speech Perception in Real-World Contexts”).

To apply, please submit a curriculum vita, cover letter, two letters of recommendation, and representative publications to Dr. Jeremy I. Skipper at jskipper@hamilton.edu before December 1st. The position will begin when filled. Hamilton College is an affirmative action, equal opportunity employer and is committed to diversity in all areas of the campus community.