Neuronal activity in medullary dorsal horn of awake monkeys trained in a thermal discrimination task. III. Task-related responses and their functional role.

Publisher Website
Google Scholar
Abstract
Medullary dorsal horn neurons of rhesus monkeys exhibited responses associated with the initiation of the trial and with panel release in thermal and visual tasks. These task-related responses occurred only during performance of the task and were most prominent following sensory cues that led directly to reinforcement: the onset of the temperature decrease on reinforced trials in the thermal task, and the onset of the 2nd light cue in the visual task. Task-related responses were observed in thermal nociceptive neurons and in neurons sensitive only to mechanical stimuli. Some medullary dorsal horn neurons differ along 2 response dimensions: sensory-discriminative properties in response to thermal and mechanical stimuli, and task-related responses independent of stimulus parameters. Task-related responses appear to result from the integration of sensory input and the central neural evaluation of its behavioral relevance or significance. They are evoked by environmental sensory cues that reliably predict reinforcement. Neurons with task-related responses probably activate pathways involved in sensory and motor preparation leading to successful completion of the task and reception of liquid reinforcement.