Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 78-82).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

α-MSH immunoreactive peptides were fractionated and characterized in rat and human brain and rat pituitary by reversed phase high pressure liquid chromatographic techniques. α-MSH and deacetylated α-MSH were two major naturally existing peptides in both brain and pituitary gland. Subsequent experiments examined the roles of these two peptides in neuronal function. The α-MSH was clearly more effective than deacetylated α-MSH in improving performance on a visual discrimination task after intraperitoneal administration and in inducing excessive grooming after intraventricular administration. The difference in behavioral potency may be explained by the fact that α-MSH was much more resistant to peptidase degradation than was deacetylated α-MSH. N-acetylation of α-MSH may be an effective regulatory process for modulating the behavioral potency of the secretory product of α-MSH-containing pituitary cells and neurons.

Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Psychology. / Microfiche copy available in Archives and Humanities. / Vita. / Bibliography: leaves 66-72. / Ph.D.

No description available.

<p> The study contains two discriminatory tasks which are attempted separately and simultaneoulsly. The subject is asked to judge the relative positions of successively presented points of light and/or to decide whether a test tone is added to continuous white noise during the interval between the two lights. It is noted that this design is similar to a retroactive interference paradigm. Analysis of the data shows that there is little interaction between decisions to each of the psychophysical tasks when they are attempted simultaneously. There also appears to be no significant change in sensitivity whether the tasks are attempted alone or together. It is suggested that-further experiments, involving different forms of visual memory, are needed.</p> / Thesis / Master of Arts (MA)

No description available.

No description available.

"Stable multi-day recordings from chronically implanted microelectrodes within the dorsolateral prefrontal cortex of two monkeys performing three Go/NoGo visual discrimination tasks (one requiring well-learned responses, two requiring learning) demonstrated that the majority of prefrontal neurons were 'functionally stable'. Action potentials of 94 neurons were stable over 2-9 days; 66/94 (70%) of these cells responded each day, 22/94 (23%) never responded significantly, and 6/94 (6%) responded one day but not the next. Of 66 responsive neurons, 55 were selective for either Go or NoGo trials, individual stimuli, or eye movements." (Greenberg and Wilson, 2004) Selectivity was maintained, for 46/55 neurons across all recording days. Response strength (baseline vs. post-stimulation firing rates) and event-related response timing also displayed stability. Stability generalized across neuronal response type suggesting that functional stability is a general property. Long-term recordings from other studies supported similar conclusions suggesting that neurons throughout the brain are functionally stable. Single-day recordings from different neurons within the same cortical regions demonstrated neuronal response flexibility while monkeys learned associations among visual cues, and Go/NoGo behavioral responses. Of 116 neurons, 57 (49%) displayed significant change points in firing rates during novel learning (n=18), reversal learning (n=12), or both tasks (n=27). Six of 57(10.5%) neurons had firing rates changes prior to learning and might have been causally related to the monkeys' behavioral changes. However, only 18/152 (12%) of the total number of firing rate changes occurred prior to the monkeys' learning meaning that most appeared to be the consequences of learning rather than the causes.

The electrosensory and visual adaptations of elasmobranchs to the environment have been more studied than most other senses, however, work on these senses is mostly limited to descriptive analyses of sensitivity, morphology, and behavior. The goal of this work was to explore electrosensory and visual capabilities in a more ecological context. To gain an understanding of the content of bioelectric signals, the magnitude and frequency of these stimuli were recorded from a broad survey of elasmobranch prey items... Color vision adaptations also correlated to the photic environment of each species; cownose rays inhabit turbid, green-dominated waters and had two cone visual pigments that maximize contrast of objects against the green background... Yellow stingrays were trichromatic and likely possess the ability to discriminate colors in their clear, reef and seagrass habitats, which are spectrally rich. Both species showed evidence of ultraviolet sensitivity, which may aid in predator and conspecific detection as an enhanced communication channel. Future studies should investigate the integration of sensory input and sensory involvement in intraspecific communication to gain more insight into ecological adaptations. / by Christine N. Bedore. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.