Pyramidal cell types drive functionally distinct cortical activity patterns during decision-making.

Understanding how cortical circuits generate complex behavior requires investigating the cell types that comprise them. Functional differences across pyramidal neuron (PyN) types have been observed within cortical areas, but it is not known whether these local differences extend throughout the cortex, nor whether additional differences emerge when larger-scale dynamics are considered. We used genetic and retrograde labeling to target pyramidal tract, intratelencephalic and corticostriatal projection neurons and measured their cortex-wide activity. Each PyN type drove unique neural dynamics, both at the local and cortex-wide scales. Cortical activity and optogenetic inactivation during an auditory decision task revealed distinct functional roles. All PyNs in parietal cortex were recruited during perception of the auditory stimulus, but, surprisingly, pyramidal tract neurons had the largest causal role. In frontal cortex, all PyNs were required for accurate choices but showed distinct choice tuning. Our results reveal that rich, cell-type-specific cortical dynamics shape perceptual decisions.

Informal Caregivers' Administration of Concentrated Liquid Morphine to Hospice Patients Receiving Home Care: Does Regimen Matter?

Background: Hospice patients receiving care at home rely on caregivers to manage liquid morphine for pain and dyspnea during the dying process. Medication is prescribed under varying regimens, yet caregivers are not required to record when morphine is used. Therefore, it is not known whether morphine use varies by regimen for hospice patients dying at home. Design and methods: A retrospective review of medication records from 227 deceased hospice patients who received routine home care in a residential setting in the U.S. Concentrated liquid morphine doses prescribed by hospice and doses administered by caregivers were calculated 7 days prior to death and on the day of death. Percent of maximum dose prescribed was determined by regimen type (scheduled, pro re nata, or combination) and by prescription flexibility (varied vs set doses/times). Results: Morphine was prescribed to 60.4% of patients a week prior to death and to 86.8% of patients on the day they died. Doses prescribed and percent morphine administered increased over the last week (P < .05), but percent of morphine administered was low 1 week prior to death (23.40%) and on the day of death (30.68%). On patients' day of death, nearly half (48.6%) of prescriptions included flexibility, and administration rates were lower (P < .01) with flexible prescriptions (21.84%) than with structured regimens (39.52%). Conclusion: Morphine was frequently prescribed in the last week of life, but administration rates by caregivers were low, especially with less structured regimens. Caregivers may need more guidance regarding morphine's use at home, especially with more flexible regimens.