Major cognitive and emotional faculties are dominantly lateralized in the human cerebral
cortex. The mechanism of this lateralization has remained elusive owing to the inaccessibility
of human brains to many experimental manipulations. In this study we demonstrate the
hemispheric lateralization of observational fear learning in mice. Using unilateral
inactivation as well as electrical stimulation of the anterior cingulate cortex (ACC),
we show that observational fear learning is controlled by the right but not the left
ACC. In contrast to the cortex, inactivation of either left or right thalamic nuclei,
both of which are in reciprocal connection to ACC, induced similar impairment of this
behavior. The data suggest that lateralization of negative emotions is an evolutionarily
conserved trait and mainly involves cortical operations. Lateralization of the observational
fear learning behavior in a rodentmodelwill allow detailed analysis of cortical asymmetry
in cognitive functions.
