Friday, March 30, 2012

Post doc position - Cognitive Neuroscience of Language Lab, U of Maryland

Applications are solicited for a postdoctoral position in the Cognitive Neuroscience of Language lab at the University of Maryland Department of Linguistics to conduct fMRI research on written and spoken language comprehension. This postdoctoral fellow will work with Dr. Ellen Lau to implement fMRI research projects, oversee the establishment of fMRI analysis pipelines, and provide support to PhD students conducting fMRI experiments. The appointment would be for one year beginning in Fall or Winter 2012, with possibility of renewal for a second year. Applicants should have a PhD in cognitive neuroscience, psychology, linguistics, or a related field, and demonstrated experience conducting language processing research with fMRI. International applicants are welcome.  

The Department of Linguistics (http://ling.umd.edu) is part of a large and vibrant community of language scientists across the UMD campus (http://languagescience.umd.edu/). The 3T MRI scanner was installed on campus last year as the centerpiece of the new Maryland Neuroimaging Center, and the department also houses state-of-the-art facilities for conducting EEG and MEG research. 

Applicants should send a cover letter, a statement of research interests, relevant manuscripts and publications, and 3 letters of reference to Dr. Ellen Lau at ellenlau@umd.edu.

How does visual speech modulate auditory speech perception?

There are two current views.  One is that visual speech provides cues as to the motor gestures that generated the speech sounds and this motor information generates an efference copy that modulates auditory speech.  



AV speech elicits in the listener a motor plan for the production of the phoneme that the speaker might have been attempting to produce, and that feedback in the form of efference copy from the motor system ultimately influences the phonetic interpretation.  -Skipper et al. 2007
The other is that AV integration is achieved without the motor system, via cross-sensory integration in the STS (Nath & Beauchamp, 2012).

 I came across a 15-year-old study recently that make a pretty strong case against the motor-based account.  Rosenblum et al. (1997) decided to assess whether individuals who do not know how to produce speech, nonetheless show a McGurk effect.  Their study population?  5-month-old infants.  The paradigm? Habituation of looking time (present the same thing over and over and see how long it takes the kid to get bored and stop looking).  Basic result from four experiments?  Habituation to auditory syllables was modulated by visual speech information: pre lingual infants show a McGurk effect.  

AV integration seems to be primarily sensory-, not motor-driven.



Nath, A.R. and M.S. Beauchamp, A neural basis for interindividual differences in the McGurk effect, a multi sensory speech illusion. Neuroimage, 2012. 59(1): p. 781-7.

Rosenblum, L.D., M.A. Schmuckler, and J.A. Johnson, The McGurk effect in infants. Percept Psychophys, 1997. 59(3): p. 347-57.


Skipper, J.I., et al., Hearing lips and seeing voices: how cortical areas supporting speech production mediate audiovisual speech perception. Cereb Cortex, 2007. 17(10): p. 2387-99.

Tuesday, March 27, 2012

New Rule #1

Use of the following terms are now banned when used without qualification:

  • phonological processing
  • morphological processing
  • syntactic processing

Such terms need to be followed by phrases such as "___ in the context of task ..." or something similar. To use these terms alone is meaningless.  David tried to point this out back in 1996:


Poeppel, D., A critical review of PET studies of language. Brain and Language, 1996. 55: p. 317-351


(PET studies?  What's that?  Dude, you're old, ha!)  The point was that the pattern of neural activity varies depending on what task is used to measure "x processing".  This point was again underlined in each of the Hickok and Poeppel papers.  Yet, I still see people saying things like "Broca's area activity is strongly correlated with phonological processing ability".  That's kind of like the language equivalent of saying V5/MT activity is strongly correlated with visual processing.  Ok, true in some cases, but not in others and even when it is true the statement isn't very helpful in the context of understanding neural circuits for information processing.  

Sixteen years after David's 1996 paper (dude, you're old!) we know a little bit more about how language is organized in the brain.  The circuits that are involved in x processing vary depending on whether the task is production or comprehension based, whether the materials are written or spoken, whether the task requires conscious attention to x or is more automatic, and so on.  There's no excuse for using vague terminology anymore.  It's just muddling the field.


Wednesday, March 21, 2012

Post-Doctoral Fellowship in Cognitive Neuroimaging, University of Saskatchewan

 Applications are invited for a Post-Doctoral Fellow, jointly supported by Dr. Ron Borowsky’s Cognitive Neuroscience of Language lab (Dept. of Psychology, College of Arts and Science), and the Department of Medical Imaging (College of Medicine), effective July 1, 2012 or Sept 1, 2012, for one year, with the possibility of renewal for a second year pending successful review and budget. The salary is $40000-$50000 CDN, depending on expertise.  Applicants should have a PhD in the field of Cognitive Neuroscience, and demonstrated experience in advanced neuroimaging techniques including functional Magnetic Resonance Imaging (fMRI) and diffusion-tensor imaging (DTI).  The successful applicant will be supervised by Prof. Borowsky (Cognitive Neuroscience of Language lab), and will spend approximately 25%-time doing clinical fMRI, and 75%-time doing research fMRI, at Royal University Hospital along with faculty in the Department of Medical Imaging.  Some teaching to Medical Imaging staff and trainees is expected.  For every hour of clinical fMRI magnet time, an hour of research fMRI magnet time will be accrued for collaborative research with the Cognitive Neuroscience of Language lab.  The candidate should be proficient with Brain Voyager and/or related fMRI analysis software, as well as EPrime experimental programming software.  Proficiency in Diffusion Tensor Imaging is also an asset.  Applying to tri-council agencies (eg., NSERC, CIHR) for post-doctoral funding for any years after the first year is expected.
 
Applications consisting of a cover letter, statement of research background and interests, cv, copies of relevant publications, and 3 letters of reference should be sent electronically and by mail to:
Prof. Ron Borowsky (ron.borowsky@usask.ca)
Psychology Department
University of Saskatchewan
9 Campus Drive
Saskatoon, Saskatchewan
Canada S7N 5A5
Review of applications will begin April 30th, 2012 until the position is filled.
The University of Saskatchewan is located in Saskatoon, Saskatchewan, a city with a diverse and thriving economic base, a vibrant arts community and a full range of leisure opportunities.
Located in the heart of Saskatoon, the University of Saskatchewan is one of Canada’s leading research-intensive universities. It is home to the Canadian Light Source national synchrotron and the VIDO-International Vaccine Centre, and features a robust research community. Signature areas of strength include human and animal health; synchrotron sciences; engagement and scholarship with Aboriginal peoples; agriculture, food and bioproducts; energy and mineral resources; and water security.
The University offers a full range of undergraduate, graduate, and professional programs to a student population of more than 20,000. World-class research facilities, renowned faculty and award-winning students make the U of S a leader in post-secondary education.

Monday, March 19, 2012

On the relation between linguistic categories and neural systems - Guest post from Harvey Sussman

Guest post from Harvey Sussman, Department of Linguistics, UT Austin.

Don’t get me wrong, I love adjectives. They are among my favorite words, but I don’t think they should play a role in investigations in how language is represented in the human brain.  They certainly have a role to play for phonologists attempting to uncover the natural classes of segments in the world’s languages.  Linnaeus did well with his taxonomic system, so why shouldn’t phonologists have a go at it too? The real problem, in my mind, arises when linguists use featural specifications to explain how language is structured in a biological system: “the natural phonological classes must arise from and be explained by the particular way in which UG [Universal Grammar] organizes the information that determines how human language is articulated and perceived” (Kenstowicz, 1994, p. 19).  So these descriptive features (the adjectives), be they acoustic or gestural, define the natural classes of language sounds, which in turn reflect the phonetic properties of our biologically endowed, genetically specified, language faculty.  Once defined, they lead us to the phonologically active classes that, in turn, control the phonological processes underlying language (Mielke, 2008). Those are pretty amazing and magical descriptive labels.
            When fMRI studies are designed to uncover the existence of discrete representations of features in language cortex, or MEG data interpreted by turning to underspecification notions of featural representations,  we fall into the isomorphism fallacy— “to take the products of description and assign them explanatory, causal status” (Bellugi & Studdert-Kennedy, 1980, p. 92).  Real explanations must come from “principles that are independent of the domain of the observations themselves (Lindblom, 1980, p. 18).”
            The linguistically-driven search for memory structures in the human brain mapping featural-based entities could be compared to neuroethologists investigating echo location processing in the bat and claiming to find areas showing [+fast/-fast] or [+far/-far] ‘features’ in auditory areas of the bat’s brain.  Such descriptive labels do not substitute for real time explanations such as auditory neurons sensitive to the various doppler shifts in the returning second harmonic (60kHz) echo, or the time delay of the echo signal relative to the emitting pulse.  Acoustic signals shaped by the laws of physics is what the brain listens to and what underlies the perception and ultimate representations of sounds, whether they be contrastive segments of a human language, or species-specific sounds heard by bats.   Admittedly, such sounds are arranged along a continuum, and do not lend themselves to binary classifications, but the analogy should hit home.  Ultimately, the physical signals that shape the information-bearing parameters of speech segments is all we need to concern ourselves with.  Combination-sensitive auditory neurons do not care about featural labels.  Taxonomic classifications of sound systems are meant for textbooks and box and arrow functional models of language structure, not biological tissue.

References
Bellugi, U ., and Studdert-Kennedy M, . (1980) ( Eds.) . "Signed and spoken
            language: Biological constraints on linguistic form," Life Sci. Res. Rep.
            19, Report of the Dahlem Workshop, 24-28 March, Berlin; Verlag Chemie,
            Weinheim.


Kenstowicz, M. (1994).  Phonology in Generative Grammar, Oxford: Blackwell.
Lindblom, B. (1980). The goal of phonetics, its unification and application.
            Phonetica, 37, 7-26.
Mielke, J. (2008). The Emergence of Distinctive Features. Oxford: Oxford
            University Press.

Friday, March 16, 2012

Carl Wernicke reflecting on science

I came across this quote that I think reveals something about Wernicke's thoughtful and careful approach to science and in particular his penchant for questioning dogma.  It is from roughly two decades after the publication of his ground-breaking 1874 monograph on aphasia.

In the course of years I have yet much to learn, but also much I have accepted as true from others has proved inaccurate.  I believe that this double-edged discovery spares no one who holds an earnest striving, and that one need not thereby be wholly disenchanted.   
If man would not be a mere counting-machine or registrar, he remains exposed to error.  But should he, therefore, hold the counting-machine as his ideal? May that thought hold as little sway in my riper years, as it has in the past.  
-Carl Wernicke, Breslau, 1892

Monday, March 5, 2012

Dept of Psychology, University of Wisconsin - Postdoctoral position in language


Postdoctoral Position in Language.  Faculty in the Department of Psychology and the Department of Communicative Disorders at the University of Wisconsin-Madison are soliciting applications for a postdoctoral position in their NIH-funded Language Training Program: Acquisition and Adult Performance. The Program emphasizes the continuum of language acquisition to the adult state, including both language comprehension and production and both typical and atypical performance. The participating Psychology faculty are Martha Alibali, Morton Ann Gernsbacher, Maryellen MacDonald, Tim Rogers, Jenny Saffran, and Mark Seidenberg; participating faculty in Communicative Disorders are Jan Edwards and Susan Ellis Weismer. More information about language research and training faculty can be found at http://psych.wisc.edu/gradstudies/NewLanguage.html (for the six Psychology faculty) and at http://www.comdis.wisc.edu/research.htm (for Drs. Edwards and Ellis Weismer).
The successful candidate will benefit from our cohesive group of faculty whose interests span language processes from speech perception to discourse, typical and atypical performance, and from infancy through adulthood. Applicants should have developed research interests in one or more areas of language acquisition, adult comprehension, or adult production.  They should be open to expanding their understanding of the relationship between acquisition and adult performance, though there is no requirement to conduct research in multiple age groups.
The position is for one year, with renewal for a second year pending satisfactory performance. Salary and benefits are set by NIH guidelines. Provisions of the training program limit funding to US citizens and permanent residents (green card holders).  The candidate must have completed the Ph.D. before beginning the position. Ideally the position will begin in the Fall of 2012, but starting dates up to April 30, 2013 are permitted.
Applicants should send a CV, several reprints or preprints, and a statement of research interests. This statement should indicate a Language Training Program faculty member who would serve as a primary mentor, and optionally indicate additional training faculty to serve as a secondary mentor(s).The statement should also describe the candidate's goals for research and training during a postdoctoral position, including potential directions in which the candidate would like continue ongoing research and/or to expand his/her expertise into additional areas of language research, consistent with the goals of the training program. Applicants should also provide names of three recommenders and arrange for letters of recommendation to be sent separately. Applicant quality and fit with program faculty research are the primary criteria.  Application materials and inquiries about the training program should be sent to languagepostdocs@mailplus.wisc.edu.  Inquiries about faculty research can be directed to individual faculty. For fullest consideration, all materials should be received by April 30, 2012; however, we will consider applications until the position is filled. UW-Madison is an Affirmative Action/Equal Opportunity Employer. Women and members of underrepresented groups are encouraged to apply.