Gamma Band Activity is Decreased in an Animal Model of Schizophrenia

Anh Huynh, and Dr. David Crowe, Department of Biology, Augsburg University, 2211 Riverside Avenue, Minneapolis, MN 55454

Schizophrenia (SCZ) is a serious psychotic disorder affecting about 1% of the U.S. population. The cause of SCZ is poorly understood, especially at the cellular level because of the difficulty in measuring the activity of individual neurons in humans. Therefore, we employed animal model wherein we block NMDA receptors with phencyclidine (PCP). MNDAR is a glutamate receptor throughout the brain. Hypofunction of NMDAR has been shown to be associated with SCZ-like symptoms.

In our research, monkey subjects performed a cognitive task that has previously been performed by schizophrenic patients. The same pattern of errors was observed in both species. On each trial of the task, the animals saw two stimuli (cue and probe), separated in time by a delay period. The animals moved a joystick either left or right based on the combination of stimuli presented.

We used microelectrodes to measure local field potentials within parietal and prefrontal cortices, the brain areas associated with the cognitive processes required by our task (e.g. working memory and cognitive control). We converted the field potentials into a time course of power in five frequency bands. We focus here on the gamma band because it is associated with cognitive processes such as working memory, and because its power has been observed to be decreased in patients with SCZ.

We found that PCP injection reduced the strength of gamma power but did not delay the evoked response. This reduction in power was particularly strong in the trial type on which humans and monkeys made the most errors, potentially explaining the pattern of error seen in both species. There were no major differences in gamma activity between parietal and prefrontal cortices. These results provide insights into cognitive deficits in SCZ and strengthen our confidence in using PCP in an animal model of the disease.

Additional Abstract Information

Presenter: Anh Huynh

Institution: Augsburg University

Type: Poster

Subject: Biology

Status: Approved

Time and Location

Session: Poster 3
Date/Time: Mon 4:30pm-5:30pm
Session Number: 3076