Year: 2009
Type: dissertation
Abstract: Previous research from our laboratory has demonstrated that the spinal cord is\ncapable of a simple form of instrumental learning. In this instrumental learning\nparadigm, rats typically receive a complete spinal transection at the second thoracic\nvertebra, and are tested 24 hours after surgery. Subjects that receive shock to a hind leg\nquickly learn to maintain the leg in a flexed position, reducing net shock exposure\nwhenever that leg is extended (controllable shock). Subjects that receive shock that is\nindependent of leg position do not exhibit an increase in flexion duration (uncontrollable\nshock). This behavioral deficit can be induced with shock to the leg or tail and as little\nas 6 minutes of uncontrollable shock impairs learning for up to 48 hours.\nThe present thesis explores how the related α-amino-3-hydroxy-5-methyl-4-\nisoxazole propionic acid-receptor (AMPAR) ionotropic glutamate receptor affects spinal\ninstrumental learning. Experiment 1 showed that inactivation of the AMPAR by\nadministration of an antagonist blocks the acquisition of instrumental learning in a dose\ndependant fashion. Experiment 2 demonstrated that blocking the AMPAR after the\nacquisition of the instrumental response subsequently blocked the maintenance of that response. Experiment 3 revealed that antagonizing the AMPAR during uncontrollable\nshock blocked the acquisition of the learning deficit. Experiments 4-6 demonstrated that\nthe activation of the AMPAR at high levels could acutely block the acquisition spinal\ninstrumental learning. Understanding how the AMPAR influences learning in the spinal\ncord will lead us to develop therapeutic strategies for recovery of function after spinal\ncord injury.
Author: Kevin C. Hoy
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2288212882