Neuroanatomical and Neurochemical Bases of Theory of Mind

This paper presents a novel neurobiological model of theory of mind (ToM) that incorporates both neuroanatomical and neurochemical levels of specificity. Within this model, cortical and subcortical regions are functionally organized into networks that subserve the ability to represent cognitive and affective mental states to both self and other. The model maintains that (1) cognitive and affective aspects of ToM are subserved by dissociable, yet interacting, prefrontal networks. The cognitive ToM network primarily engages the dorsomedial prefrontal cortex, the dorsal anterior cingulate cortex and the dorsal striatum; and the affective ToM network primarily engages the ventromedial and orbitofrontal cortices, the ventral anterior cingulate cortex, the amygdala and the ventral striatum; (2) self and other mental-state representation is processed by distinct brain regions within the mentalizing network, and that the ability to distinguish between self and other mental states is modulated by a functionally interactive dorsal and ventral attention/selection systems at the temporoparietal junction and the anterior cingulate cortex; and (3) ToM functioning is dependent on the integrity of the dopaminergic and serotonergic systems which are primarily engaged in the maintenance and application processes of represented mental states. In addition to discussing the mechanisms involved in mentalizing in terms of its component processes, we discuss the model's implications to pathologies that variably impact one's ability to represent, attribute and apply mental states.