Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008. / Source: Dissertation Abstracts International, Volume: 69-11, Section: B, page: 7172. Adviser: David E. Irwin. Includes bibliographical references (leaves 75-80) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6759. Adviser: Jason McCarley. Includes bibliographical references (leaves 102-115) Available on microfilm from Pro Quest Information and Learning.

The literature has fairly consistently reported a difference in how well humans perceive synchrony depending on the order of auditory and visual stimuli. When the auditory stimulus occurs first and the visual stimulus follows, subjects are more sensitive and so perceive asynchrony with smaller time delay between the stimuli. On the other hand, when the auditory follows the visual stimulus, the subjects are more tolerant and perceive stimuli with larger time delays as synchronous. Thresholds of synchrony perception in these two conditions are thus asymmetrical. The present study attempts to test the Lewkowicz Model, by which the asymmetrical thresholds are explained as a result of arrival-time differences between auditory and visual stimuli to the brain, such that visual stimulus takes longer in processing to be perceived versus auditory one. Reaction-times to these stimuli were measured to determine the arrival-time difference and plotted with synchrony perception. On the basis of Lewkowicz Model we predicted that reaction-time difference between the two stimuli correlate with subjective synchrony. The results did not support the Lewkowicz Model. The expected tendency of 30--40ms of subjective synchrony was not shown. The subjects took, in average, only 7.7ms to detect asynchrony when the auditory stimulus followed the visual stimulus. That the subjects did not tolerate greater temporal gap when the auditory followed versus when it preceded the visual stimulus was a very different result from majority of previous studies. Different factors in perceiving synchrony are discussed in this paper, as well as the application of the research in telecommunications.

To examine the relation between cognitive and response processes, event-related potentials (ERPs) were recorded from 10 subjects during semantically primed lexical decisions in an Accuracy condition (response deadline 700 msec) and a Speed condition (deadline 450 msec). Targets were the prime's antonym, an unrelated word, or a nonword. The Speed condition reduced response time (RT) and accuracy, but not the latency of ERP deflections. RT varied with the amplitude of negativity 250-450 msec only for semantically primed targets. RT was dissociated from the N400 deflection elicited by unrelated and nonword targets. Individual differences in task performance and ERPs suggested that the most accurate subjects favoured early motor inhibition and data-driven processing, whereas slightly faster but significantly less accurate subjects relied on resource-driven processing. Regardless of RT condition, individual differences in processing, and positive response priming, the probability of correctly rejecting a nonword began to rise monotonically after the N400 peak and approached.90 before the peak of the late positive complex. Continuous transmission of response selection information to motor processes before stimulus evaluation processes have been completed is consistent with a parallel distribution of word recognition and response production processes.

This is a study of factors which may influence responses to leading questions within a questionnaire format. As such, this study provides insight into how and why leading questions exert social influence in the expression of attitudes. Following an extensive interdisciplinary review of the literature, the effects of questionnaire wording are initially proposed as a form of experimenter bias; it is then pointed out that the respondents' motives in participating in a study have been identified as key to understanding the experimenter bias process. From there, the motives associated informational social influence, and normative social influence, are proposed as intervening motives when subjects yield to leading questions. The personality variables of social desirability (or approval dependency) and self-monitoring were predicted to predispose individuals to yield to leading questions. This investigation was conducted within an opinion poll paradigm, whereby subjects completed an opinion poll with leading questions embedded within it; the leading questions for this study suggest their desired responses through parenthesized, numeric suggestions, or cognitive anchors. In order to test the various hypotheses, different conditions were created by varying the introductory remarks of the opinion poll. Support for the role of informational social influence in yielding to leading questions was provided by the finding that people yield more to leading questions which are apparently designed by experts (professional pollsters) than by nonexperts (highschool students). Support for the role of normative social influence was provided by the significant association between responses which subjects provide for themselves, and responses which they provide to represent those of their peers--i.e., subjects they tend to assume that their biased responses are congruent with those of their peers. The personality variables of social desirability and self-monitoring were also found to affect responses to leading questions; the relationship between these two variables appears to be interactive, and not compounded as predicted. A post-hoc study suggests that the results may be confounded by the situational demands of the questionnaire, such as a situational demand for "honesty". This study's particular form of leading questions may have also confounded the results, and more varied forms of leading questions would be worthy of future investigation.

Ten untreated patients with narcolepsy-cataplexy and ten age and sex matched normals between the ages of 20 and 71 underwent pupillometric analyses immediately prior to each of five Multiple Sleep Latency Test (MSLT) sessions. Although narcoleptics were sleepier in terms of both their Stanford Sleepiness Scale (SSS) ratings and their latencies to sleep onset, the baseline pupil diameter, pupillary light reflex and pupillary orienting response did not differentiate between groups. Narcoleptics did, however, exhibit a significantly greater frequency of spontaneous oscillations in the dark-adapted state than did controls. These findings indicate that pupillary stability may serve as a supplementary diagnostic tool for narcolepsy-cataplexy. The results are discussed with the view that psychosensory restoration of alertness, among other extraneous variables, must be controlled for when utilizing pupillometric techniques. A review of the literature indicates a variety of methodological and statistical shortcomings that must be amended. Suggestions are made for improving the reliability and validity of the pupillometric approach.

In recent years, social psychological processes, such as attitudes, and goals, have been shown to be in part automatic (Bargh, 1997). The purpose of the present thesis was to apply the concept of automaticity to intrinsic and extrinsic motivation (Deci & Ryan, 1985, 1987, 1991). The present thesis is composed of two articles. The first article comprises two studies designed to verify if intrinsic and extrinsic motivation could be in part regulated by automatic nonconscious processes. Using the Scramble Sentence procedure (Srull & Wyer, 1979), we automatically activated either an intrinsic or an extrinsic motivation in an initial task. Then, participants were asked to work on a subsequent task presented as unrelated to the initial task. Results of these two studies showed that, participants primed in the initial experiment with an intrinsic motivation were more motivated, performed better, were more interested, and perceived more choice while working on the subsequent task than participants primed with an extrinsic motivation. The findings of the first article supported the hypothesis that intrinsic and extrinsic motivation can be in part regulated by automatic processes. The second article is also composed of two studies that examined the interplay of chronically accessible and temporary primed intrinsic and extrinsic motivation. In the first study of the second article, a measure designed to assess individuals' chronically accessible academic motivational orientations was developed. In the second study, the hypothesis about the motivational resilience of intrinsic and extrinsic chronics to nonconsciously primed motivation was specifically tested. Results showed that the level of motivation, perceptions, and behavior of individuals without a chronically accessible motivational orientation were affected by a temporary primed motivation. In contrast, intrinsic and extrinsic chronics spontaneously resisted the influence of a primed competing motivation. All these effects took place without individuals' conscious guidance or awareness. The susceptibility of nonchronics to the nonconsciously primed motivation in combination with the absence of susceptibility of chronics supported the existence of a motivational resilience regulated by automatic processes. The implications of the findings of the present thesis will be discussed in relation to Self-Determination Theory and the study of motivation in general.

Following lesions that elevate frequency thresholds for medial forebrain bundle self-stimulation, thresholds often rapidly return toward pre-lesion levels. Why the stimulation's rewarding effect recovers has not been well understood. Small radiofrequency lesions were made through the stimulating electrode to explore some of the mechanisms that could underlie the functional recovery. By tracking post-lesion thresholds under different stimulation regimens, results of Experiment 1 indicated that the electrical stimulation itself did not promote the recovery. Experiment 2 studied the reaction of thresholds at bilateral stimulating electrodes following a unilateral lesion to determine whether a dopamine receptor supersensitivity or another distally-occurring compensation might underlie the recovery. Injection of apomorphine (0.5 mg/kg) after thresholds had returned to pre-lesion levels showed that dopamine receptor supersensitivity did not explain the recovery. As recovery took place at lesioned electrodes, thresholds at intact sites did not decrease, indicating that the recovery may not have been due to a post-lesion compensation occurring distal to the lesion site. In Experiment 3, regional post-lesion decreases in tissue resistance indicated that applying a lesion stimulus induced a change that altered resistance and accounted for threshold increases. Experiment 4 extended that investigation by comparing the effects of lesions on thresholds under constant-current and constant-voltage sources of stimulation. Post-lesion threshold increases seen under constant-current stimulation were not evident when voltage levels were not permitted to vary, indicating that when resistance was altered following a lesion, the effectiveness of the stimulation was reduced. Results of Experiment 5 showed that the refractoriness was not altered after a lesion. A sustained increase in local potential summation was noted, indicating that the lesions affected cells close to the tip of the electrode more than those further away in the stimulation field. The post-lesion recovery of thresholds may be due to local changes in ionic concentration or the occurrence of edema in the tissue around the electrode that temporarily reduces resistance before normalizing over time.

This dissertation deals with the chronobiology of sleep and sleepiness in narcolepsy-cataplexy. The text consists of a series of papers: three research papers, and a theoretical paper, with a technical paper appended. The first research paper presents an ambulatory EEG study in which subjects were free to go about their routine home activities, wearing the portable recorder for 24 hours. The timing and duration of sleep episodes were calculated relative to nocturnal midsleep time. Results demonstrated that the most frequent timing of naps was about 1-1.5 h in advance of that found for normal healthy subjects who show greatest sleep propensity 180 degrees out of phase with nocturnal midsleep time. The second paper is a theoretical review of circasemidean sleep-wake propensity and proposes a new modelling approach. The third and fourth papers represent companion papers from a 3-condition within-subjects experiment on the effects of scheduled naps on performance. Sleep schedules were based on habitual total sleep time amounts and experimental sleep schedules devised for each subject. A no-nap condition scheduled 100% of total sleep time at night, and nap conditions scheduled 25% of total sleep time in either a single long nap or 5 equidistantly spaced short naps. The first of these papers measures the efficacy of naps in terms of their effects on performance over the whole day and by time-of-day category divisions. Results indicated that for reaction time, performance in the single long nap condition was significantly improved over a no-nap control condition, attributable to post-nap improvements in performance. However, logical reasoning test results were actually better in the no-nap condition, but this may indicate that a longer nocturnal sleep period may be necessary for optimal performance on this task. The timing of unscheduled sleep episodes was again seen to be in advance of the most frequent nap time for normal subjects. The second of these papers examines the related sleep inertia effects. Sleep inertia was found after the short naps as measured by the descending subtraction task, is evident following all but the first and is most prolonged following the third, short nap. Sleep inertia was also found for reaction time variables following short, but was absent following the long nap. Sleep inertia effects on reaction time were significantly greater on SWS arousals. A paper on the technical details of the sleep-wake scheduling and performance testing software is appended.

Effects of the optical isomers of pentazocine and cyclazocine upon responding maintained by second-order schedules of intravenous morphine reinforcement in squirrel monkeys (Saimiri sciureus). Monkeys were trained under schedules in which either every 10th (FR 10) or 30th (FR 30) response during a fixed-interval of 50 min (FI 50 min) produced a brief presentation of an external signal (S), unaccompanied by an injection;. the first ratio-requirement completed after expiry of the FI produced the signal (S) accompanied by an i.v. infusion of morphine. Morphine pretreatment (1-5.6 mg/kg i.m.) suppressed drug-seeking behaviour in a dose-dependent manner. Naloxone pretreatment (0.1 mg/kg) when given alone exerted no effect on response-rate; when given in combination with graded doses of morphine, morphine-induced suppression of drug-seeking behaviour was antagonized. 1-Pentazocine (0.1-10 mg/kg i.m.) pretreatment suppressed responding more effectively than d-pentazocine at equivalent doses. 1-Cyclazocine (0.01-1.0 mg/kg i.m.) suppressed responding whereas d-cyclazocine at equivalent doses did not. Pentazocine isomers failed to antagonize the effects of morphine pretreatment. 1-Cyclazocine antagonized the effects of morphine pretreatment more effectively than pentazocine but d-cyclazocine was ineffective at equivalent doses. Cyclazocine and pentazocine differ in their capacity: (i) to suppress morphine-reinforced responding, and (ii) to antagonize the effects of morphine pretreatment upon such patterns of drugseeking behaviour. The stereoisomers of these drugs were found to be less potent than naloxone in reversing morphine-induced suppression of morphine-seeking behaviour.