The executive control of action: Evidence from language switching
A key aspect of higher cognitive function is the ability to switch rapidly and efficiently between alternative modes of response where this is appropriate behaviourally. Such suppression appears to be highly dependent upon the integrity of the prefrontal cortex, yet other cortical areas are likely to be necessary in order to implement response switching. Thus, functional brain imaging studies have demonstrated parietal cortex activation during repeated language switching within a translation task. In my talk I describe some recent studies in which we have used event-related dense-sensor EEG recording techniques and transcranial magnetic stimulation to examine the time course of response switching during a visually cued language switching task in which bilingual subjects named digits in either their first or second language. Switch-related modulation of ERP components was evident over parietal and frontal cortices and in the latter case, showed an asymmetry across first and second languages. Correspondence with a frontal ERP component found when suppressing manual responding in a go/no-go reaction time task may imply that similar inhibitory mechanisms are involved in both response suppression and response switching.