Neuroanatomy of a Potential Mouse Model of Hemispatial Neglect

Hemispatial neglect is a condition in which patients fail to recognize stimuli in the hemispace contralateral to a brain lesion, such as a stroke. Hemispatial neglect can be detected in up to 50% of patients who have suffered a middle cerebral artery stroke. In rats, lesions in associative areas including medial agranular cortex (AGm), posterior parietal cortex (PPC), and dorsocentral striatum (DCS) are known to result in hemispatial neglect. Although these brain regions have been identified as key components of a cortical‐basal ganglia‐thalamo‐cortical loop mediating directed attention in the rat, this network has not been investigated in mice. Herein, we hypothesized that mice possess a cortical‐basal ganglia‐thalamic‐cortical loop similar to that described previously in the rat. Anterograde tract tracing was performed to detail the efferent projections of the mouse AGm homologue, which allowed for the identification of a robust terminal field in the dorsocentral striatum (DCS), as seen in rats. Retrograde tract tracing was performed by making injections in the DCS in order to identify other likely cortical areas and thalamic nuclei which project to this region in the mouse. We concluded that mice possess similar interconnections between AGm and DCS, and have defined other brain regions likely to play a role in mediating directed attention in the mouse. Grant Funding Source : None