Electronic Theses and Dissertations

Identifier

2479

Date

2015

Date of Award

7-17-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Psychology

Concentration

Experimental Psychology

Abstract

The P300 is a psychophysiological response that occurs 300-500 ms after the onset of a novel stimulus. This signal has been recorded in humans using EEG methods, but the recording method for non-human mammals has been surgically intrusive. While beneficial to determining specific brain regions that elicit the P300, a survey of current research indicates that targeting specific areas for recording does not yield substantial benefits over more global measures of neurophysiological activity. As such, we tested rats in an auditory oddball task to demonstrate if a less-intrusive means of recording the P300, using subcutaneous electrodes, can be achieved in non-human mammals. We expected to find a robust P300, as the rats were tested in an active task wherein the oddball target stimulus was rare and meaningful. Futhermore, we expected that the amplitude of the P300 would be dose-dependently reduced following IP administration of ethanol (0.75 and 1.5 g/kg) versus vehicle (IP saline). When the average amplitude for the target tone was compared to the average amplitude for the standard tone (latency 300/400 ms) for all trials, a P300 to the target tone was identified that had a significantly higher average amplitude than that for the standard tone. Furthermore, while not statistically significant using parametric analyses, large effect sizes (f > .40) suggested the P300 to the target was larger in females than in males and that the amplitude of the P300 was reduced by acute ethanol administration. Analysis of the behavioral results for the oddball task indicated the rats did not demonstrate very accurate performance. When comparing hits (i.e., correct responses to the target) versus correct rejections (i.e., no response to the standard tone) a substantial number of trials had to be eliminated from the ERP analysis due to premature responding before either tone was presented. As such, the resulting waveforms contained too much noise to deduce typical auditory ERP waveforms, thus preventing direct examination of P300 amplitude for only the correct behavioral response trials. Overall, these resuts indicate that despite poor behavioral performance, the target tone elicited a P300 and was thus more salient than the standard tone.

Comments

Data is provided by the student

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses and dissertation (ETD) repository.

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