Neuroscience 2003 Abstract
| Presentation Number: | 293.14 |
|---|---|
| Abstract Title: | Single neurons in anterior insular cortex of Rhesus monkey related to reward predictability during multi-trial reward schedules. |
| Authors: |
Mizuhiki, T.*1
; Richmond, B. J.2
; Shidara, M.3
1Grad. Sch. of Tsukuba Univ., Tsukuba-shi, Japan 2MD, 1-1-1 Tennoudai, 305-8575, 3USA, 1-1-1 Tennoudai, 305-8575, |
| Primary Theme and Topics |
Cognition and Behavior - Motivation and Emotion |
| Session: |
293. Motivation & Cognition Poster |
| Presentation Time: | Sunday, November 9, 2003 2:00 PM-3:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # J39 |
| Keywords: | insular cortex, rhesus monkey, single unit recording, reward schedule task |
We previously showed that single neurons in anterior insular cortex of rhesus monkey responded during multi-trial reward schedules (SFN meeting 2002). During the task, the monkey was required to complete 1, 2, 3 or 4 red-green visual discriminations to obtain a juice reward. A visual cue is also presented in each trial, with the brightness of this cue indicating how many trials remain before the rewarded trial. In cued condition, the visual cue was brightest in all rewarded trials. The cue brightness was proportional to the amount of work remaining before the rewarded trial in the other non-rewarded trials. The reward was delivered only at the end of the schedule. A new schedule was picked randomly. In shuffled condition the order of cue brightness was shuffled within each schedule, making the relation between the cue and reward probabilistic.
135/146 anterior insular neurons responded during the task in cued condition. 106 were tested in shuffled condition. Anterior insular neurons tended to respond near the end of schedules, and near the end of those trials. 75 /106 responded during the rewarded trial in cued condition, and 30/75 responses just preceded the rewarding event. 5/30 responded with graded modulation according to the schedule fraction in shuffled condition. 4/5 neurons invariably responded when the cue was brightest in shuffled condition. When the cue was not brightest, the responses were small in the first trial, and became larger as task progressed. Thus, insular neurons emphasize the ends of schedules. In addition, these results suggest that the monkey knows about the reward from the cue in cued condition, and by estimating the probability of a reward by a process akin to counting (based on past about the number of trials possible) in shuffled condition.
135/146 anterior insular neurons responded during the task in cued condition. 106 were tested in shuffled condition. Anterior insular neurons tended to respond near the end of schedules, and near the end of those trials. 75 /106 responded during the rewarded trial in cued condition, and 30/75 responses just preceded the rewarding event. 5/30 responded with graded modulation according to the schedule fraction in shuffled condition. 4/5 neurons invariably responded when the cue was brightest in shuffled condition. When the cue was not brightest, the responses were small in the first trial, and became larger as task progressed. Thus, insular neurons emphasize the ends of schedules. In addition, these results suggest that the monkey knows about the reward from the cue in cued condition, and by estimating the probability of a reward by a process akin to counting (based on past about the number of trials possible) in shuffled condition.
Supported by AIST; IRP/NIMH
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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