Wednesday, April 27, 2011

Language switching survey from the Wicha lab

New Language survey for a chance to win a $50 prize!
Dear friends and students,

I am conducting a very short new on-line survey to investigate language switching.  I would be extremely grateful if you could participate, and forward this to your students and friends.  We are looking for Spanish/English bilingual participants.

This survey takes 5-10 minutes.

Participants will be entered in a drawing to win a $50 gift card to Amazon.com.

Here is a link to the survey:
https://www.surveymonkey.com/s/NewLanguageSurvey

Email wichalabgroup@gmail.com for questions.

Thank you for your participation!

--

Wicha Bilingualism Lab
Neurobiology Department
University of Texas at San Antonio
One UTSA Circle
San Antonio, TX 78249
210-458-7012

Tuesday, April 26, 2011

Relation between production and perception of voice onset time in aphasia

I'm constantly amazed at how much good information is available in the literature going back decades. It is unfortunate that much of this information is effectively lost to the current generation of researchers leaving us to re-invent the wheel in many cases. Even papers that we may be familiar with can contain tidbits of information that were overlooked. This is the case with a classic 1970s paper by Sheila Blumstein and colleagues -- including my former PhD advisor, Edgar Zurif, who I mention because he will enjoy the attention ;-). The paper is titled, The perception and production of Voice-Onset Time in aphasia and was published in Neuropsychology, 1977, Vol. 15, 371-383.

This is a paper that I've been citing and talking about for sometime. I was interested in it originally because it clearly showed a dissociation between the ability to comprehend speech and perform syllable discrimination, the task effect that David and I have been talking about for a decade. I recently re-read the paper because Gabriele Miceli, another major player in aphasia research in the 1970s and 1980s (and still very active!), pointed out to me that the article is also quite relevant to the issue of the relation between perception and production of speech, as the title previews.

What the authors did was measure VOT in aphasics' own speech utterances (they read a set of words aloud) and compared it their ability to discriminate syllables that differ in terms of the same VOT dimension. You can see the implication for motor theories: If a patient cannot reliable produce correct VOTs, then this should affect their ability to perceive (discriminate) VOT.

So what did they find? I'll let Blumstein et al. summarize:

It is quite clear, at least for the anterior aphasics (Broca and Mixed Anterior), that the ability to perceive the VOT continuum relates in no way to the ability to produce voiced and voiceless stops. Thus, the anterior aphasics maintain the ability to perceive this distinction, but make both phonemic as well as phonetic substitutions.


This is a cool result because is zooms in on one feature, VOT, and shows a direct non-correspondence between perception and production of this speech dimension.


Blumstein, S., Cooper, W.E., Zurif, E.B., & Carmazza, A. (1977). The perception and production of Voice-Onset Time in aphasia Neuropsychologia, 15 (3), 371-372 DOI: 10.1016/0028-3932(77)90089-6

Monday, April 11, 2011

Society for the Neurobiology of Language -- Logo design contest

As announced, the Society for the Neurobiology of Language (SNL) is launching its first Logo design competition! The objective of the competition is to provide the SNL with a contemporary, recognizable and meaningful visual identity. Creativity, originality, suitability, aesthetics, use of space and color will all be used to measure the logo's merit. Logos should include the phrase "Society for the Neurobiology of Language" somewhere in the design. Beyond that, it's all you.

The competition is open to anyone involved directly or indirectly with the SNL. The winner will receive free registration for the 2011 (USA) and 2012 (Spain) annual Neurobiology of Language meetings (NLC 2011 and NLC 2012).

For more information, visit our website or send us an email.

*** Mark you calanders : the competition opens April 15th and closes July 1st 2011! ***

May the best design win!

Thursday, April 7, 2011

The new semantic hub: the posterior middle temporal gyrus

Most of us agree that conceptual information is represented in a broadly distributed network throughout cortex, but there is disagreement about what the organizational principles of this knowledge might be (see debates between Alfonso Caramazza and Alex Martin or Friedemann Pulvermuller), as well as a debate about the system, or "hub", that binds all of this information together. Here I'm going to focus on the latter question.

One hypothesis is that the anterior temporal lobe serves as the brain's semantic hub (Patterson, et al. 2007). The evidence for this claim comes primarily from semantic dementia, a degenerative condition in which patients have debilitating semantic deficits that seems to cut across language, visual objects, and hearing; i.e., it looks like an amodal conceptual semantic deficit. The neural degeneration is particularly evident in the anterior temporal lobes (among other regions). If you were at the Neurobiology of Language Conference last year in San Diego, you heard a very lively debate over this issue by Carolyn Patterson and Alex Martin, which raised several questions for the ATL=semantic hub position.

An alternative position has been suggested previously on the basis of stroke data, namely, that the posterior middle temporal region is critical for some form of lexical semantic integration. For example, we argued that this region serves as a sound-to-meaning interface (Hickok & Poeppel, 2004) or in other terminology, as a "lexical interface" (Hickok & Poeppel, 2007). Why? Because damage to that part of the brain is associated with (primarily) semantic comprehension deficits (Dronkers, et al. 2004; Bates, et al. 2003).

A new paper by Turken and Dronkers (2011) adds important new information to this debate and goes so far as to elevate the MTG to the status of a "semantic hub". They used publicly available DTI and resting state fMRI datasets to map the fiber tracts and functional connectivity of several ROIs define on the basis of Dronkers et al. (2004) lesion study. The basic result was that the MTG ROI was found to be wired up, tract wise, to a broad network including STS/AG, STG, and frontal area BA 47 (the functional connectivity map shows similar areas, see below, bottom portion). This same set of regions have been independently identified by Jeff Binder's group as being involved in semantic processes on the basis of a recent meta-analysis of functional imaging studies (see below, top portion) (Binder et al. 2009).



What's interesting to me about these images is that the "semantic" areas seem to form a ring around the lower-level auditory-motor areas (STG <-> PT <-> pIFG), suggesting a hierarchical organization associated with phonological (lower-level) and semantic processes (higher level). It is worth mentioning as well that the connectivity pattern of the MTG was bilateral, both in the fiber tracing and functional connectivity analyses.

The ATL ROI was more sparsely connected both in terms of fiber tracts and functional connectivity.

An analysis of the connectivity of the STS region showed that it was largely connected to "dorsal stream" structures, but also, importantly, connected with the MTG.

In general, this strikes me as a fairly nice confirmation of the broad organization laid out in the dual stream model (HP, 2004, 2007), but I might be biased. I'm interested in your thoughts!

References

Bates, E., Wilson, S. M., Saygin, A. P., Dick, F., Sereno, M. I., Knight, R. T., et al. (2003). Voxel-based lesion-symptom mapping. Nat Neurosci, 6(5), 448-450.

Binder, J. R., Desai, R. H., Graves, W. W., & Conant, L. L. (2009). Where is the semantic system? A critical review and meta-analysis of 120 functional neuroimaging studies. Cereb Cortex, 19(12), 2767-2796.

Dronkers, N. F., Wilkins, D. P., Van Valin, R. D., Jr., Redfern, B. B., & Jaeger, J. J. (2004). Lesion analysis of the brain areas involved in language comprehension. Cognition, 92(1-2), 145-177.

Hickok, G., & Poeppel, D. (2004). Dorsal and ventral streams: a framework for understanding aspects of the functional anatomy of language Cognition, 92 (1-2), 67-99 DOI: 10.1016/j.cognition.2003.10.011

Hickok, G., & Poeppel, D. (2007). The cortical organization of speech processing Nature Reviews Neuroscience, 8 (5), 393-402 DOI: 10.1038/nrn2113

Patterson, K., Nestor, P., & Rogers, T. (2007). Where do you know what you know? The representation of semantic knowledge in the human brain Nature Reviews Neuroscience, 8 (12), 976-987 DOI: 10.1038/nrn2277

Turken AU, & Dronkers NF (2011). The neural architecture of the language comprehension network: converging evidence from lesion and connectivity analyses. Frontiers in systems neuroscience, 5 PMID: 21347218

Wednesday, April 6, 2011

Neurobiology of Language Conference - Take 3!

Planning for the next NLC is moving forward at a rapid pace. We have already confirmed our debaters (you won't want to miss them - anyone care to wager on who they might be?), and we are close to nailing down our venue. It should be another exciting meeting. I hope you all plan to attend. Here is the official preliminary announcement:

The newly established Society for the Neurobiology of Language is excited to announce the third annual Neurobiology of Language Conference (NLC 2011).

This year’s NLC will be held on November 10th and 11th in the Washington DC Area.
As in 2009 and 2010, the conference will boast the trademark debate sessions in which two leading experts discuss controversial topics in the field, keynote lectures, slide sessions highlighting the very best research and of course plenty of possibilities for interaction.

Abstract submission for NLC 2011 opens May 1st and will be closing on June 1st 2011 so start preparing your exciting findings!

To ensure NLC maintains its high scientific standard, we need your help. Please volunteer as a reviewer by signing up on our website. Should you have any questions, send an email to laura.menenti@glasgow.ac.uk .

Early registration opens July 1st and closes September 1st. Be sure to take advantage of our early registration fees!


We look forward to your participation in NLC 2011.



The programme committee for NLC 2011,

Guinevere Eden, Ph.D, Georgetown University, Washington, DC, USA
Gregory Hickok, Ph.D., University of California, Irvine, USA
Marta Kutas, Ph.D., The University of California, San Diego, USA
Laura Menenti, Ph.D., University of Glasgow, Glasgow, UK
Colin Phillips, Ph.D, University of Maryland, College Park, MD, USA
Steven L. Small, Ph.D, M.D., University of California, Irvine, USA
Pascale Tremblay, Ph.D., University of Trento, Trento, Italy