Tuesday, November 28, 2006

Sie Ist Gefundene Steuerung Über Two Languages: Part 2

In the last post, The Neurocritic examined an fMRI experiment by Crinion et al. (2006) that utilized a semantic priming design to examine language switching in fluent bilinguals. It turned out that activity in a subcortical region in the basal ganglia, or more specifically, the head of the caudate nucleus in the left hemisphere, showed a semantic priming effect when pairs of words were in the same language, but not in different languages:

prime-target pairs ... were either semantically related (bathtub-SHOWER) or unrelated (spoon-SHOWER). We then identified language-dependent semantic responses by comparing the effect of semantic priming when prime and target were in the same language (trout-SALMON in English or forelle-LACHS in German) or different languages (e.g., trout-LACHS or forelle-SALMON).

The time between the onset of the prime word and the onset of the target word was short: 250 msec. This short interval skews semantic access to processes that are more automatic and less "controlled"or predictive (i.e., you don't have time to generate SHOWER as a semantic neighbor to bathtub in less than 250 msec). So the experiment was measuring relatively automatic semantic priming processes. We don't know what would happen if a long prime-target interval was used in order to tap controlled or attentional or predictive processes.

The graph to the left indicates that bathtub-SHOWER (S, semantically related) pairs elicit less activity than spoon-SHOWER (U, unrelated) pairs. But when the prime and target are in different languages, there is no semantic priming effect. The authors' interpretation is that "the left caudate plays a universal role in monitoring and controlling the language in use." My interpretation is that the left caudate does not show automatic semantic priming when the prime and target are in different languages. But that relatively bland line won't get you published in Science.

Since the left head of the caudate was the only region in the entire brain to show this response pattern, I decided to have more fun with BrainMap!!
...an online database of published functional neuroimaging experiments with coordinate-based (Talairach) activation locations. The goal of BrainMap is to provide a vehicle to share methods and results of brain functional imaging studies. It is a tool to rapidly retrieve and understand studies in specific research domains, such as language, memory, attention, reasoning, emotion, and perception, and to perform meta-analyses of like studies.
where one can do
coordinate-based meta-analyses according to the activation likelihood estimation (ALE) method.
So I did something along the lines of an ALE reverse inference (Aguirre, 2003; Poldrack, 2006) meta-analysis for imaging studies that observed activations in the left head of the caudate, to determine what other task conditions produced relative activations in this region. [Of course, it would be facile to expect a "one brain region, one function" mapping, but let's look at the outcome, anyway.]

To the left is the focus of activity in the left head of the caudate nucleus, as expected since the BrainMap database was queried with that specific search term.

And below is a list of the studies included in the meta-analysis, along with their varied behavioral domains: action execution, attention, working memory, explicit memory, emotion (especially happiness, but also sadness), auditory perception, somatesthetic (bodily) perception, and finally language (including orthography, phonology, semantics, syntax, and speech). With such a varied set of experimental tasks and behavioral domains associated with the left head of the caudate, it's no wonder that no clear interpretation of these findings has emerged from the ALE literature.

Year 1st Auth. Behavioral Domain
2001 Katanoda K Action.Execution
2003 Riecker A Action.Execution
1996 Fox PT Action.Execution.Speech,Cognition.Language.Speech
1994 Decety J Action.Imagination
2002 Mayberg HS Action.Rest
2000 Mayberg HS Action.Rest,Pharmacology
2000 Anderson ND Cognition.Attention
1996 Blaxton TA Cognition.Attention
1996 Blaxton TA Cognition.Attention
2003 Weiss EM Cognition.Attention
1998 Goldberg TE Cognition.Attention,Cognition.Reasoning
2003 Binder JR Cognition.Language.Orthography
1992 Sergent J Cognition.Language.Phonology
1999 Henke K Cognition.Language.Semantics
2000 Kuperberg GR Cognition.Language.Semantics,Cognition.Language.Syntax
1994 Price CJ Cognition.Language.Speech
1997 Cabeza R Cognition.Memory.Explicit
2000 Eldridge LL Cognition.Memory.Explicit
2002 Henson RNA Cognition.Memory.Explicit
2002 Henson RNA Cognition.Memory.Explicit
2005 Ongur D Cognition.Memory.Explicit
2003 Sperling RA Cognition.Memory.Explicit
2004 Cairo TA Cognition.Memory.Working
2003 Gruber O Cognition.Memory.Working
2003 Gruber O Cognition.Memory.Working
2005 Volle E Cognition.Memory.Working
1998 Goldberg TE Cognition.Reasoning,Cognition.Attention
1997 Lane RD Emotion
2000 Pietrini P Emotion
2000 Royet JP Emotion
2006 Britton JC Emotion.Happiness
2006 Britton JC Emotion.Happiness
1998 Canli T Emotion.Happiness
2000 Damasio AR Emotion.Happiness
1998 Beauregard M Emotion.Sadness
1995 George MS Emotion.Sadness
1996 George MS Emotion.Sadness
2001 Brannan SK Interoception.Air-Hunger
2002 Arnow BA Interoception.Sexuality
2000 Griffiths TD Perception.Audition
2002 Pastor MA Perception.Audition
2001 Rao SM Perception.Audition
1996 Blaxton TA Perception.Audition,Perception.Somesthesis
2000 Hui KK Perception.Somesthesis
2005 Hui KK S Perception.Somesthesis
2005 Hui KK S Perception.Somesthesis
1991 Meyer E Perception.Somesthesis
2003 Kumari V Perception.Somesthesis,Cognition.Attention
2001 Becerra LR Perception.Somesthesis.Pain
1997 Doricchi F Perception.Vision.Motion,Action.Execution
1997 Doricchi F Perception.Vision.Motion,Action.Inhibition
1996 Sweeney JA Perception.Vision.Motion,Action.Inhibition
1996 Sweeney JA Perception.Vision.Motion,Action.Inhibition
2004 Calhoun VD Perception.Vision.Shape,Pharmacology.Alcohol,Cognition.Space


References

Aguirre GK (2003). Functional Imaging in Behavioral Neurology and Cognitive Neuropsychology. In: T.E. Feinberg & M.J. Farah (Eds.), Behavioral Neurology and Cognitive Neuropsychology. New York: McGraw Hill.

Poldrack RA (2006). Can cognitive processes be inferred from neuroimaging data? Trends in Cognitive Sciences 10: 59-63.

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