Aspiration removal of orbitofrontal cortex disrupts cholinergic fibers of passage to anterior cingulate cortex in rhesus macaques.

The study of anthropoid nonhuman primates has provided valuable insights into frontal cortex function in humans, as these primates share similar frontal anatomical subdivisions (Murray et al. 2011). Causal manipulation studies have been instrumental in advancing our understanding of this area. One puzzling finding is that macaques with bilateral aspiration removals of orbitofrontal cortex (OFC) are impaired on tests of cognitive flexibility and emotion regulation, whereas those with bilateral excitotoxic lesions of OFC are not (Rudebeck et al. 2013). This discrepancy is attributed to the inadvertent disruption of fibers of passage by aspiration lesions but not by excitotoxic lesions. Which fibers of passage are responsible for the impairments observed? One candidate is cholinergic fibers originating in the nucleus basalis magnocellularis (NBM) and passing nearby or through OFC on their way to other frontal cortex regions (Kitt et al. 1987). To investigate this possibility, we performed unilateral aspiration lesions of OFC in three macaques, and then compared cholinergic innervation of the anterior cingulate cortex (ACC) between hemispheres. Histological assessment revealed diminished cholinergic innervation in the ACC of hemispheres with OFC lesions relative to intact hemispheres. This finding indicates that aspiration lesions of the OFC disrupt cholinergic fibers of passage, and suggests the possibility that loss of cholinergic inputs to ACC contributes to the impairments in cognitive flexibility and emotion regulation observed after aspiration but not excitotoxic lesions of OFC.

Hospice: a place for healing and dying well.

AIDS: Caregivers of people with end-stage AIDS face difficult challenges in working with the young, disabled, and dying as they try to help these individuals learn to live and die well. A hospice, a place where people come to die, is based on the philosophy that death can be experienced as a meaningful stage of life. The role of the hospice counselor is to assist dying clients in moving toward inner peace and self-possession, the ultimate goal of dying well. Counselors and caregivers of people with AIDS find their clients dealing with denial, anger, and depression. In the residential hospice setting, staff daily face the need to respond to these issues and the dynamic nature of HIV disease in a community made up of residents, families, partners, volunteers, and other staff. The goal of a hospice is to establish an environment that allows growth, communication, and achievement, despite physical and emotional decline. Hospice care enables individuals to experience the full spectrum of life with all of its emotions while facing the reality of death.^ieng