Wednesday, August 31, 2011

Society for the Neurobiology of Language - Award announcement

Society for the Neurobiology of Language Merit and Travel Awards 2011 The Society for the Neurobiology of Language (SNL) announces several awards funded by the National Institute on Deafness and Communication Disorders (NIDCD) to help cover travel and registration costs for the 2011 Neurobiology of Language Conference (NLC) in Annapolis, Maryland. SNL particularly encourages and aims to foster the participation of junior scientists who are members of underrepresented groups as defined by the National Institutes of Health (http://grants.nih.gov/training/faq_diversity.htm).

 Graduate Student Abstract Merit Awards (2)

 Graduate students who submit top ranked abstracts will receive the SNL Graduate Student Abstract Merit Award to pay conference registration. All graduate students who are the first author on a submitted abstract will be automatically considered. No application is required. Two awards will be given. Post Doctoral Abstract Merit Awards (2) Post docs who submit top ranked abstracts will receive the SNL Post Doctoral Abstract Merit Award to pay conference registration. All post docs who are the first author on a submitted abstract will be automatically considered. No application is required. Two awards will be given.

 Travel Awards (12)

 Graduate and post-doctoral students who are not first authors on an abstract or who did not submit an abstract to the meeting are eligible for a travel award to attend the 3rd Annual Neurobiology of Language Conference. The awards will cover the cost of registration as well as provide $550 toward the cost of travel to the meeting. Application required. To apply, submit the following materials: your CV, a brief personal statement that outlines why you deserve the award, and whether or not you fall into one of the underrepresented groups as defined by the National Institutes of Health (http://grants.nih.gov/training/faq_diversity.htm) to: awards@neurolang.org.

 Deadline to submit an application for a Travel Award is October 1, 2011.

Thursday, August 18, 2011

Mirror Neuron Forum - some additional discussion - Part II

In my answer to Question 1 I suggested that mirror neurons can be viewed analogously to canonical neurons, that is, as a sensory-motor association system involved in action selection, not action understanding. Here is Gallese's response to this suggestion:

According to GH, both classes of neurons instantiate the action-oriented coding typical of the dorsal stream, whereas object and action semantics would be exclusively provided by the ventral stream. However, an exclu- sive action-oriented characterization of the dorsal stream falls short of explaining the functional role exerted by the ventral part of the dorsal stream (the ventro-dorsal stream) that reci- procally connects cortical areas of the inferior parietal lobe to ventral premotor areas (see Gallese, 2000, 2007a, 2007b; see also Rizzolatti & Gallese, 2006; Rizzolatti & Matelli, 2003). The meaning we attribute to objects is not exclusively the out- come of their visual description as instantiated by extra-striate visual areas within the ventral stream. That is, objects are not merely identified and recognized by virtue of their physical ‘‘appearance’’ but also in relation to the effects of the potential interaction with an agent...


Here is the problem with Gallese's counter-argument: it's not an argument at all. He states that my idea "falls short of explaining the functional role exerted by the ventral part of the dorsal stream" which I take to be spelled out in his next statement that "The meaning we attribute to objects is not exclusively the outcome of their visual description..." Gallese is describing his hypothesis, not an observation that needs explanation. Basically what Gallese is saying is that my view falls short of matching what he thinks is going on. The "argument" structure is: GH proposes Function A for the system. VG proposes Function B. Function A does not include Function B. Therefore Function A is wrong. Obviously, this is not an argument and should be disregarded.

What we need instead is to discuss how well the two hypotheses account for the available data. Is there any evidence that suggests that monkeys (remember this question is about MNs in monkeys) fail to understand objects or actions when the dorsal stream is damaged? No. All we have is evidence that cells in the dorsal stream fire both during movements directed at objects and during observation of actions or objects. Correlation does not imply causation as we all know so there is no direct evidence for Gallese's claim. Do we have direct evidence for my claim? Well, object recognition deficits can be induced by disruption of ventral visual areas (e.g., see the classic work by Ungerleider and Mishkin) and while not direct, the fact that the response properties of cells in the ventral stream have the right features for object and action recognition (specificity, invariant to size, etc.) is consistent with my proposal. In other words, there are empirical reasons why the "standard view" of dorsal and ventral stream function in the monkey visual system is what it is.

The predictable response from Gallese et al. will be that yes, the ventral stream is good at recognition but this recognition is devoid of true meaning. Again, this is a non-argument in that all it is, is a counter-hypothesis that is not supported empirically in the macaque. This is where the argument slips into human data as we'll see in Gallese's next point. (But I thought there was no reason to assume human and macaque systems would be doing the same thing Vittorio?)

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

Tuesday, August 16, 2011

Mirror Neuron Forum - Some additional discussion - Part I

Now that people have had a chance to digest the recently published "Mirror Neuron Forum" (Perspectives on Psychological Science 6(4) 369–407) I think it would be useful to revisit some of the claims and counter-claims. I will start working through some of the points in a series of posts. Of course, my focus will be on the parts of the forum that I participated in, but if you have some comments and thoughts on any part of it, feel free to email me and I'll post it as "guest post".

I would like to get the forum participants involved in this less formal discussion. I hope they will join in and of course, I will be happy to post anything from my co-forum participants.

Question 1: Do Mirror Neurons in Macaques or Humans Make an Important Contribution to Action Understanding?

I suggested in my answer to this question that if we have reason to question the role of macaque mirror neurons (MNs) in action understanding then we have reason to question the role of the mirror system in humans in action understanding and the various functions to which the system has been generalized.

Here is Gallese's response to my point:

VG. I will respond to some of the points raised by GH. First, the major premise of his initial argument is debatable. Accord- ing to GH, if one can question the relevance of MNs to action understanding in monkeys, then this would automatically jeopardize any conclusion about the role of MNs in human social cognition. Why? Do we assume that a given trait or neural mechanism found in different species must necessarily preserve identical characteristics? Evolutionary theory patently contradicts this assumption.


Gallese is right, of course. There is no reason to assume that a given system's function will be preserved evolutionarily. It is perfectly legitimate to assess the empirical merits of theories of MN function in macaque separately from the empirical merits of theories of the so-called mirror system function in humans; they may have very different functions, a point I made in my Eight Problems paper (it was problem #4). However, this is not how many people, including Gallese's group, have approached the two systems. Rather, theories of the function of the human mirror system has been built on the foundation of the MN theory of action understanding in macaques. Consider the abstract from one of Gallese's highly influential papers:

How do we understand other people's behavior? How can we assign goals, intentions, or beliefs to the inhabitants of our social world? A possible way to answer these challenging questions is to adopt an evolutionary frame of reference, both in phylogenetical and ontogenetical terms, envisaging these ‘mind-reading' capacities as rooted in antecedent, more ‘ancient' and simple mechanisms. This approach can capitalize on the results of different fields of investigation: neurophysiology can investigate the neural correlates of precursors of these mechanisms in lower species of social primates such as macaque monkeys. Developmental psychology can study how the capacity to attribute propositional attitudes to others develops.
In the present article we will propose that humans' mind-reading abilities rely on the capacity to adopt a simulation routine. This capacity might have evolved from an action execution/observation matching system whose neural correlate is represented by a class of neurons recently discovered in the macaque monkey premotor cortex: mirror neurons (MNs). Gallese and Goldman, 1998


So the logic is:
-MNs in macaques perform motor simulation/action recognition during observation
-humans posses a parallel motor simulation system (an assumption not mentioned in the abstract but one that gets its own section in the paper)
-therefore, mind-reading is evolutionarily built on this motor simulation function of MNs.

The point in my response to the MN Forum question was that if macaque MNs are not doing motor simulation/action recognition then the standard argument put forward by Gallese and others needs to be re-evaluated. Why? Because the logic of the argument in Gallese and Goldman, for example, would become this:

-MNs in macaques are NOT performing motor simulation/action understanding during observation
-humans posses a parallel system that may or may not be performing motor simulation/action understanding during observation
*therefore, mind-reading is evolutionarily built on this motor simulation function of macaque MNs -- Oops, doesn't follow! (neither did it follow logically above either, but here it is a larger stretch to even attempt the linkage).

Practical point: Gallese and others have used the claimed function of macaque mirror neurons to develop theories of the neural basis of everything from speech perception to mind-reading in humans. This is a reasonable approach. But if we learn that macaque mirror neurons are doing something else, then by the same approach -- i.e., to "adopt an evolutionary frame of reference, both in phylogenetical and ontogenetical terms" and to "capitalize on the results of different fields of investigation" -- we need to reconsidered our theories of the human mirror system.


References

Gallese, V., Gernsbacher, M.A., Heyes, C., Hickok, G., & Iacoboni, M. (2011). Mirror neuron forum. Perspectives on Psychological Science, 6, 369–407.

Gallese V, & Goldman A (1998). Mirror neurons and the simulation theory of mind-reading. Trends in cognitive sciences, 2 (12), 493-501 PMID: 21227300

Department Chair position -- University of South Carolina

Department Chair: The Dept. of Communication Sciences and Disorders in the Arnold School of Public Health, University of South Carolina, is inviting applications for the position of Department Chair at the level of associate or full professor. This is a 9-month tenure-track position with a set start date for fall 2012. Qualified applicants will have a Ph.D. in Communication Sciences/Disorders or related fields; preference will be given to applicants who hold a Certificate of Clinical Competence in speech-language pathology (CCC-SLP). Other qualifications include: (a) demonstrated excellence in the area of leadership and the ability to serve at the college, university, and national level; (b) strong track record in the areas of teaching and research; (c) demonstrated ability to work effectively with faculty, staff and students who represent a wide array of ethnic, cultural, and socioeconomic backgrounds; and (d) desire to work in a progressive research friendly environment.

The Department of Communication Sciences and Disorders offers two master’s degrees and a Ph.D. in speech-language pathology. The University of South Carolina is a Carnegie Doctoral/Research Extensive Institution with an aggressive program of expansion in the areas of language development and adult neurogenics with potential for further expansion in the applicant’s area of interest. Salary is competitive and commensurate with experience. Interested applicants should send application letter, CV, three letters of recommendation, and other supporting material to: Julius Fridriksson, Ph.D. Search Committee Chair, C/O Karen Mullis, Dept. of Communication Sciences & Disorders, University of South Carolina, Columbia, SC 29208 (jfridrik@sc.edu). Review of applications will begin November 1st, 2011 and will continue until the position is filled. The University of South Carolina is an AA/EOE. Women and minorities are encouraged to apply. Visit the department website at: www.sph.sc.edu/comd

Friday, August 12, 2011

How amodal are phonological representations?

Something has been bothering me lately with respect to phonological theory. It is assumed that phonological representations are abstract entities not tied to any sensory or motor systems. Why then are phonological representations defined in terms of motor articulatory features? Does this bother anyone?

Monday, August 1, 2011

Mirror Neuron Forum published in Perspectives in Psychological Science

If you haven't seen it already, check out the mirror neuron forum recently published online in Perspectives in Psychological Science. Organized by Art Glenberg, the forum includes answers to ALL the important questions regarding mirror neurons from a group of scientists who represent a range of perspectives on the issues. Authors include Gallese, Gernsbacher, Heyes, Hickok, and Iacoboni. The best part of the forum, though, is that each author wrote responses to the other authors' answers, providing for some interesting discussion.

The mirror neuron forum can be found here.

I'd love to hear your thoughts on the discussion.