PMID-6769536[0] Operant control of precentral neurons: Control of modal interspike intervals
- Question: can monkeys control the ISI of operantly controlled neurons?
- Answer: Seems they cannot. Operant and overt movement cells have about the same ISI, and this cannot be changed by conditioning.
- Task requires a change from tonic to phasic firing, hence they call it "Differential reinforcement of Tonic Patterns".
- That is, the monkey is trained to produce spikes within a certain ISI window.
- PDP8 control, applesauce feedback.
- modal ISI, in this case, means mode (vs. mean and median) of the ISI.
- Interesting: "It was not uncommon for a neuron to display bi- or trimodal ISI distributions when the monkey was engaged in a movement unrelated to a unit's firing"
- For 80% of the units, the more tightly a neuron's firing was related to a specific movement, the more gaussian its ISI became.
- As the monkey gained control over reinforced units, the ISI became more gaussian.
- Figure 2: monkey was not able to significantly change the modal ISI.
- Monkeys instead seem to succeed at the task by decreasing the dispersion of the ISI distribution and increasing the occurrence of the modal ISI.
- Monkeys mediate response through proprioceptive feedback:
- Cervical spinal cord sectioning decreases the fidelity of control.
- When contralateral C5-7 ventral roots were sectioned, PTN responsive to passive arm movements could not be statistically controlled.
- Thus, monkeys operantly control precentral neurons through peripheral movements, perhaps even small and isometric contractions.
- Excellent paper. Insightful conclusions.
____References____
[0] Wyler AR, Lange SC, Neafsey EJ, Robbins CA, Operant control of precentral neurons: control of modal interspike intervals.Brain Res 190:1, 29-38 (1980 May 19) |
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