In light of the relationship between neurodegenerative diseases and deterioration of higher nervous activity, it is important to definitively clarify HAP1 expression in a cognitively important brain region, the retrosplenial-retrohippocampal area.
The present study first demonstrated that HAP1 is abundantly expressed in spinal neurons of the somatosensory, viscerosensory, and autonomic regions but absent in somatomotor neurons, suggesting that the spinal motoneurons are, due to lack of putative HAP1 protectivity, more vulnerable to stresses in neurodegenerative diseases than other HAP1-expressing neurons probably involved in spinal sensory and autonomic functions.