I missed the paper survey last week, but this week we are back in full effect (albeit a day late!).
English,German and Japanese language researchers led by Cathy Price demonstrates in a fMRI study published in Friday's Science that the left caudate nucleus plays an important role in monitoring and controlling which language is used by bilinguals. German-English and Japanese-English bilinguals were tested on a semantic task, and neuronal responses within the left caudate turned out to be sensitive to changes in the language used or the meaning of the words read by the subjects. Very interesting! Incidentaly, voxel-based morphometry analysis of the affected members of the KE Family (where a point mutation on the FOXP2 gene has led to aphasia) showed abnormalities in the caudate nucleus. So, perhaps the time has come for a more concerted investigation into the role played by the caudate in language production and comprehension. [Link to paper.]
Oxford University Press is starting a new journal this summer called Social Cognitive and Affective Neuroscience. Mattew Lieberman is the editor. If you have an institutional access to OUP's journals, you can find a number of paper in press here. Ray Dolan, Hugo Critchley and their group at FIL in London report an intersting experiment targeting the neuronal mechanisms engaged in the processing of sadness. From the paper's abstract: "We investigated whether observed pupil size modulates our perception of other’s emotional expressions and examined the central mechanisms modulated by incidental perception of pupil size in emotional facial expressions. We show that diminishing pupil size enhances ratings of emotional intensity and valence for sad, but not happy, angry or neutral facial expressions. This effect was associated with modulation of neural activity within cortical and subcortical regions implicated in social cognition. In an identical context, we show that the observed pupil size was mirrored by the observers’ own pupil size. This empathetic contagion engaged the brainstem papillary control nuclei (Edinger–Westphal) in proportion to individual subject’s sensitivity to this effect. These findings provide evidence that perception–action mechanisms extend to non-volitional operations of the autonomic nervous system." [Link to paper.] Another fascinating study by Marco Iacobini's group demonstrate that repetitive TMS stimulation of the right parietal cortex induces a "virtual lesion" that disrupts the ability to discriminate between your ow face and that of others. Wow! [Link to paper.]
The hyperscanning guys from Baylor College of Medicine in Houston and CalTech have a new paper out concerning the neurobiology of social exchange (Science, May 19, 2006). From the abstract: "During a social exchange with a partner, one fundamental variable that must be computed correctly is who gets credit for a shared outcome; this assignment is crucial for deciding on an optimal level of cooperation that avoids simple exploitation. We carried out an iterated, two-person economic exchange and made simultaneous hemodynamic measurements from each player’s brain. These joint measurements revealed agent-specific responses in the social domain (‘‘me’’ and ‘‘not me’’) arranged in a systematic spatial pattern along the cingulate cortex. This systematic response pattern did not depend on metrical aspects of the exchange, and it disappeared completely in the absence of a responding partner." [Link to paper.] Now, just what is the cingulum doing!