How does the brain select visual targets for eye movements? We recorded neural activity while macaques performed visual search in which they were trained to move their eyes to a target stimulus among an array of distractor stimuli for a reward. Three signals were used to measure the relationship between the decision to move the eyes to a target and neural activity: spike rates from neurons in the frontal eye field (FEF), local field potentials from FEF, and event-related potentials recorded from the skull. We found that (1) FEF neurons cooperated and competed to select visual targets, measured using correlations between spike times of simultaneously recorded neurons, (2) FEF neurons interacted more when the visual search task was easier (i.e., the target and distractors were easily discriminable), measured using a multivariate analysis and decreased firing variability before eye movements, (3) FEF neurons decreased firing variability around the time of target selection by the mean firing rate, (4) FEF neurons were distinguished both functionally and biophysically, on the basis of action potential width, (5) FEF selected search targets from distractors before the macaque homologue of a human cognitive event-related potential (the N2pc) that marks the allocation of attention, and (6) the time between visual search array presentation and the time that FEF neurons discriminated between target and distractors was later when there were more stimuli the animal needed to choose from.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-12032009-110833 |
| Date | 03 December 2009 |
| Creators | Cohen, Jeremiah Yaacov |
| Contributors | Martin Paré, René Marois, Mark T. Wallace, Jeffrey D. Schall |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-12032009-110833/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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