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Contribution of the Temporoammonic Pathway to Hippocampal Processing


Dvorak-Carbone, Hannah (1999) Contribution of the Temporoammonic Pathway to Hippocampal Processing. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/AYRT-5Y12.


The temporoammonic (TA) pathway is the direct, monosynaptic projection from layer III of entorhinal cortex to the distal dendritic region of area CA1 of the hippo­ campus. Although this pathway has been implicated in various functions, such as memory encoding and retrieval, spatial navigation, generation of oscillatory activity, and control of hippocampal excitability, the details of its physiology are not well understood. In this thesis, I examine the contribution of the TA pathway to hippocampal processing. I find that, as has been previously reported, the TA pathway includes both excitatory, glutamatergic components and inhibitory, GABAergic components. Several new discoveries are reported in this thesis. I show that the TA pathway is subject to forms of short-term activity-dependent regulation, including paired-pulse and frequency­ dependent plasticity, similar to other hippocampal pathways such as the Schaffer collateral (SC) input from CA3 to CA1. The TA pathway provides a strongly excitatory input to stratum radiatum giant cells of CA1. The excitatory component of the TA pathway undergoes a long-lasting decrease in synaptic strength following low-frequency stimulation in a manner partially dependent on the activation of NMDA receptors. High­ frequency activation of the TA pathway recruits a feedforward inhibition that can prevent CA1 pyramidal cells from spiking in response to SC input; this spike-blocking effect shows that the TA pathway can act to regulate information flow through the hippocampal trisynaptic pathway.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Biology, temporoammonic, pathway, hippocampal
Degree Grantor:California Institute of Technology
Major Option:Biology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Schuman, Erin Margaret
Thesis Committee:
  • Schuman, Erin Margaret (chair)
  • Konishi, Masakazu
  • Laurent, Gilles J.
  • Lester, Henry A.
  • Pine, Jerome
Defense Date:14 April 1999
Record Number:CaltechTHESIS:05202015-142019062
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8871
Deposited By: Dan Anguka
Deposited On:20 May 2015 21:58
Last Modified:01 Sep 2022 23:55

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