Thursday, September 29, 2011
NeuroPsychoLinguistic Perspectives on Aphasia
21-22-23 June 2012, Toulouse, France
Languages of the conference: English and French
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
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.
Sept. 2011> Call for abstracts
31 Dec. 2011> Deadline for abstract submission
Feb. - March 2012 > Notification of acceptance and confirmation for
March - June 2012 > Registration (early bird: before 15/04, late: after
May 2012 > Program
21-22-23 June 2012 > Conference
Tuesday, September 27, 2011
Saturday, September 24, 2011
Friday, September 23, 2011
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. 1695and 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.
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.
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
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 behaviorsActivation 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 meaningsThat'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.
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.
Thursday, September 22, 2011
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.
Wednesday, September 21, 2011
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).
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
Tuesday, September 20, 2011
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)
Monday, September 19, 2011
Here is some commentary on Iacoboni’s response to my answers to question 1.
“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.
“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.
“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…”
“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).
“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.”
"...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)
Friday, September 16, 2011
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/> ).
Thursday, September 15, 2011
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
Saturday, September 3, 2011
To apply, please submit a curriculum vita, cover letter, two letters of recommendation, and representative publications to Dr. Jeremy I. Skipper at email@example.com 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.