Neural activity in the posterior thalamus and hippocampus during time interval discrimination in rats

Organisms have developed different mechanisms to quantify time over a wide range of durations, from microseconds to daily circadian rhythms. Interval timing, which refers to timing in the range of seconds-to-minutes durations, is a prerequisite for numerous daily behaviors, including the perception and production of speech and dance, as well as estimation of the time that remains before the occurrence of an important event. Currently it is unclear what model of timing best describes temporal processing across seconds and minutes timescales in tasks with different response requirements. Two general models have been described how the passage of time is perceived. One emphasizes that the judgment of the duration of a stimulus depends on the operation of dedicated neural mechanisms specialized for representing the temporal relationships between events. Alternatively, there is no specialized brain system for representing temporal information. In order to investigate whether the distributed model of timing accounts for neural activity underlying interval timing, I examined activity of single neurons recorded from the dorsal CA1 of hippocampus and posterior thalamus in the same rats performing a temporal discrimination task. In this task, the animals were required to discriminate six randomly presented time interval durations ranging from 3018 to 4784 ms into short or long ones to obtain water reward. The probability for the animal to choose the long target increased as a function of the sample duration, and it was well accounted for by a logistic regression model. Diverse types of activity were observed in both areas of the brain, and neuronal ensembles recorded from both areas conveyed significant amounts of information about the passage of time. A larger proportion of neurons conveyed temporal information based on monotonically changing activity profiles in the posterior thalamus than hippocampus. On the other hand, hippocampus was more likely to convey temporal information based on sequential activation of multiple neurons than the posterior thalamus. These results suggest that temporal information processing might be ubiquitous across widespread areas of the brain based on diverse neural processes. These findings are also consistent with the distributed model of timing.

Author dc:creator

• 이, 지현

Contributors dc:contributor

• 김, 병곤
• 대학원 의학과
• 200624275

• hippocampus
• posterior thalamus
• interval timing
• bisection discrimination task
• distributed time model
• 해마
• 시상후부
• 인터벌타이밍
• 시간구분과제
• 시간 분산모델

Language dc:language

en

Identifier

http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000016544
000000016544

OAI identifier oai:identifier

oai:repository.ajou.ac.kr:201003/10917