Brain circuit for cognitive control is shared by task and language switching

Controlling multiple languages during speech production is believed to rely on functional mechanisms that are (at least partly) shared with domain-general cognitive control in early, highly proficient bilinguals. Recent neuroimaging results have indeed suggested a certain degree of neural overlap between language control and nonverbal cognitive control in bilinguals. However, this evidence is only indirect. Direct evidence for neural overlap between language control and nonverbal cognitive control can only be provided if two prerequisites are met: language control and nonverbal cognitive control should be compared within the same subjects and the task requirements of both conditions should be closely matched. To provide such direct evidence for the first time, we used fMRI to examine the overlap in brain activation between switch-specific activity in a linguistic switching task and a closely-matched non-linguistic switching task, within participants, in early, high proficient Spanish-Basque bilinguals. The current findings provide direct evidence that in these bilinguals, highly similar brain circuits are involved in language control and domain-general cognitive control.