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The role of short-term dynamics in the modulation of MD-PFC activity-loop

Title
The role of short-term dynamics in the modulation of MD-PFC activity-loop
Authors
Jungmin Lee
DGIST Authors
Lee, Jungmin; Rah, Jong-Cheol; Moon, Cheil
Advisor(s)
문제일
Co-Advisor(s)
Jong-Cheol Rah
Issue Date
2019
Available Date
2020-02-28
Degree Date
2019-02
Type
Thesis
Abstract
Persistent neural activity in the prefrontal cortex has been broadly inspired as the substrate of short-term memory for perceptual decision making. Recent studies have shown that reciprocal excitation of the mediodorsal nucleus (MD) of the thalamus and frontal cortices supports the persistent activity during the short-term memory. However, little is known how the neurons in the prefrontal cortex maintain the activity. Although MD-driven disynaptic feedforward inhibition in the medial prefrontal cortex (mPFC) has been reported to determine the time window of integration of excitatory synaptic inputs, it has never been examined how feedforward inhibition is modulated during the persistent activity. We examined whether the integration time window is changed by the consecutive thalamic activity by using whole-cell patch clamp recording with optogenetic stimulation of thalamocortical axons. We observed the greater short-term synaptic depression in disynaptic inhibition compared with thalamic excitatory synapses during high-frequency (5-10 Hz) stimulation. Consequently, the strength of the feedforward inhibition becomes weaker as the stimulation continues, which, in turn, enhances the range of firing jitter in the frequency dependent way. These findings suggest that MD-mPFC pathway is dynamically regulated by the excitatory-inhibitory balance in an activity-dependent manner. During low-frequency, excessive excitation is inhibited, and firing is restricted in limited temporal range by the strong feedforward inhibition. Whereas during high-frequency, such as in case of during the short-term memory, the excitation transfer will be enabled to occur in broader temporal range by the decreased feed-forward inhibition.
Table Of Contents
Abstract 1 Table of contents 3 Abbreviation table 4 Ⅰ. INTRODUCTION 5 Ⅱ. MATERIALS AND METHODS 10 2.1 Animals 10 2.2 Viral vectors 10 2.3 Stereotaxic surgery 11 2.4 Electrophysiology 11 2.5 Drug application 13 2.6 Histology 14 2.7 Data analysis and statistics 14 Ⅲ. RESULTS 16 3.1 MD thalamus drives feedforward inhibition in the dACC L2/3 neuron 16 3.2 Fast-depressing MD-to-PFC thalamocortical synapses 19 3.3 Length of integration window increases at high frequency 22 3.4 Changes in spike output of dACC L2/3 pyramidal neurons 23 Ⅳ. DISCUSSION 25 Ⅴ. Figures 32 Ⅵ. REFERENCES 45 Ⅶ. 요약문 49
URI
http://dgist.dcollection.net/common/orgView/200000171532
http://hdl.handle.net/20.500.11750/10701
DOI
10.22677/thesis.200000171532
Degree
MASTER
Department
Brain and Cognitive Sciences
University
DGIST
Related Researcher
  • Author Moon, Cheil Laboratory of Chemical Senses
  • Research Interests Brain convergent science based on chemical senses; olfaction; 감각신경계 기반 뇌융합과학; 후각 신경계
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Collection:
Department of Brain and Cognitive SciencesThesesMaster


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