Neural mechanisms involved in memory formation and retrieval within the rodent hippocampus : an in vivo electrophysiological study

While it is well established that the rodent hippocampus plays a crucial role in the formation and retrieval of spatial memories, the neural mechanisms underlying this process have not been completely characterized. In this thesis I have combined large-scale recordings from multiple single cells within the hippocampus of behaving rodents with pharmacological and genetic manipulations of hippocampal function in order to investigate how the cellular and network properties of the hippocampus contribute to memory storage and retrieval. In Part I of this thesis, extracellular recordings are used to monitor systematic changes in the cellular properties of hippocampal pyramidal cells in vivo. These studies demonstrate that the biophysical characteristics of CA1 pyramidal cells undergo both short term (activity-dependent) and long-term (experience-dependent) modulations during behavior. Short tem changes in the biophysical state of hippocampal pyramidal cells interact with changes in synaptic input to determine the probability with which CA1 pyramidal cells generate single spikes or bursts of action potentials and may play an important role in influencing where and when mechanisms of plasticity are engaged during behavior (Chapters: 3-4). Longer term changes include: 1) input specific reductions in amplitude attenuation - consistent with an increase in dendritic excitability (Chapter 4), 2) increases in the rate of spike repolarization (Chapter 5), 3) reductions in spike count variability within bursts (Chapter 5), and modulations in burst length both during behavior and sleep (Chapter5).

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Brain and Cognitive Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Quirk, Michael C. (Michael Clayton), 1974-

Advisor dc:contributor.advisor

• Matthew Wilson.

• Brain and Cognitive Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8353

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8353