No description available.

The aim of these experiments was to investigate learning and memory extensively in two nonverbal domains (olfactory and visual), and to determine similarities and differences in the function of the neural substrates that subserve these modalities. Two complementary methodological approaches were taken: (1) examination of learning and retention in patients with resection from left (LR) or right (RR) temporal lobe, and (2) study of brain function via Positron Emission Tomography (PET) of healthy subjects during memory processing. / Two parallel recognition tests were developed (one olfactory, one visual) that examined memory at three stages: following a single exposure to test stimuli, after four exposures, and following a 24hr delay interval. In the olfactory patient study, LR and RR groups performed significantly worse than the healthy control subjects, with no difference between the patient groups; thus suggesting a lack of hemispheric superiority for this task. The PET study of healthy individuals supported the bilateral participation of piriform cortex during olfactory recognition. The results from these two studies, along with findings from animal work, suggest that the piriform cortices may play a role in odor memory processing, not simply in perception. / On the face memory task, LR and RR patients showed different results. Only RR patients were impaired, while LR patients did not perform differently from controls. This unique face learning paradigm was sensitive to right temporal lobe damage, and correctly classified patients by side of resection with a sensitivity rate of 82% and specificity rate of 79%, suggesting its possible utility as a clinical tool. PET face memory findings indicated greater participation of fusiform regions during long-term recognition, and greater right prefrontal activity during short-term recognition, when these conditions are directly compared to each other. / Finally, PET was used to study the same healthy subjects performing parallel odor and face working-memory tasks, focusing on regions previously shown to be important for working memory. Results revealed similar regions of activation in dorsolateral prefrontal cortex in the two modalities. This indicates an overlap in the brain regions that process olfactory and visual information when the same cognitive manipulations are being carried out online.

No description available.

The brain areas required for latent learning in the rat are not currently understood. Previous tasks used to assess latent learning, defined as the acquisition of neutral information that does not immediately influence behavior, have shared characteristics that prevented their use to determine the neurobiology of latent learning. This thesis describes a new task called the Latent Cue Preference (LCP) task, derived from the Conditioned Cue Preference (CCP) task that has been successfully used to determine the brain areas required for conditioning in the rat and other animals. In the LCP task, water deprived rats alternately drink a salt solution in one distinctive compartment of a CCP box apparatus and water in the other compartment over 8 days (training trials). They are then given a choice between the two compartments with no solutions present (preference test). The results of the behavioral experiments showed that this training results in two parallel forms of learning: (1) latent learning of an association between salt and salt-paired compartment cues, and (2) conditioning to water-paired compartment cues. Latent learning itself involved two components: (1) the latent association between salt and salt-paired cues, and (2) motivational information about salt deprivation used to retrieve the latent association, and used to compete with the conditioning to water-paired cues. In addition, the findings showed that latent learning and conditioning involve different neural circuits. Latent learning required an intact cortical-to-hippocampus circuit via the entorhinal cortex, while conditioning required an intact subcortical-to-hippocampus circuit via the fimbria-fornix. The acquisition and storage of the latent association depended on an intact entorhinal cortex/dorsal hippocampus circuit, while the use of motivational information to retrieve the association recruited the ventral hippocampus. Conditioning, on the other hand, required an intact fimbria-fornix, lateral amygdala, and hippocampus. These findings provide new knowledge to the field of learning and memory research, and allowed an update of the current Multiple Memory Systems model.

Objectives. The purpose of this study was too determine whether there were significant kinematic differences between recreational and elite hockey players and between contra-lateral lower limbs during forward hockey skating. / Methods. While skating on a hockey treadmill subjects were filmed with four synchronized digital video cameras while wearing reflective marker triads on the thighs, shanks and skates. Subjects skated within a calibrated volume at a self selected speed that they could maintain comfortably for one minute. Each subject completed three trials separated by 5 minutes of rest. Data was reduced and analyzed using programs written in MATLAB. Two-way ANOVA and Tukey Post Hoc tests were used to determine statistic significance. / Results. Elite and recreational subjects were significantly different (p≤0.05) during knee abduction and knee rotation at push off, as well as during knee abduction and knee flexion at blade contact. Contra lateral lower limbs were significantly different (p≤0.05) during ankle abduction and hip rotation at blade contact as well as during knee abduction at push off. / Conclusion. Some aspects of the skating stride are similar in elite and recreational hockey skaters but there were several kinematic differences between skill levels and contra-lateral legs. The skating kinematics of elite hockey players may serve as a model for young hockey players and recreational hockey players, helping them develop a more efficient and effective stride.

The purpose of this study was to determine the effects of an upper respiratory illness (URI) on running mechanics during a maximal VO2 exercise treadmill test. The specific measurements assessed were stride length (SL), stride frequency (SF), range of motion (ROM) of the hip, knee, and ankle, and the displacement of the center of mass (COM) during the stride cycle. Fifty-three subjects (female=25, male=28) between 18 and 30 years of age completed the study. The participants in the study were characteristically non-smokers, drank fewer than five alcoholic drinks per week, had no orthopedic problems, were not pregnant, did not suffer from hay fever or chronic colds, and were not allergic to penicillin. Rhinovirus Type 16 was used in the inoculation of the individuals. The subjects performed two maximal V02 treadmill test. The first test was before the inoculations and the second test was during the height of the illness. Stride length and SF data were derived from accelerometer data. Statistical analysis using ANOVA revealed no significant changes in SL or SF between pre- and post-inoculation treadmill tests. Based on the results of this study it was concluded that Rhinovirus Type 16 does not effect running mechanics during a maximal V02 treadmill test. / School of Physical Education

Plasma choline levels have been reported to be significantly reduced in athletes at the endof prolonged, exhaustive exercise (marathon running), and this may affect the release of acetylcholine at the neuromuscular junction (16). The purpose of the present investigation was to examine the influence of two levels of choline (from soy lecithin) ingestion on plasma choline levels and exercise performance. Ten endurance-trained male cyclists exercised on an electrically resisted ergometer for 105 minutes at a load equal to 70% V02 max, followed by an all-out, self-paced 15 minute performance ride on an isokinetic cycle. Three randomly ordered trials were performed four hours after the feedings of (A) 0.0 g, (B) 1.1 g, or (C) 1.8 g choline. Dietary intake of choline was controlled. Before and after the trials, blood samples were drawn and analyzed for serum choline (umol/liter) using an HPLC method. Feedings of 1.1 g and 1.8 g of choline significantly (p < 0.05) elevated serum choline values compared to control (A = 34.16 [± 0.63], B 38.17 [+ 0.96], and C = 42.32 [+ 0.59]).Post-exercise serum choline values, however, were not significantly different (p > 0.05) from pre-exercise levels. In addition, there were no significant differences (p > 0.05) in performance between placebo, 1.1 g, and 1.8 choline trials (2.11 x 105, 2.07 x 105, 2.07 x 105 Newton-meters, respectively). This study indicates a dose response to choline ingestion, with no effect on performance. / School of Physical Education

Viral illnesses are the most common agents affecting humans. Due to their widespread affects, viruses may have a particular influence on exercise functional capacity. Therefore, the purpose of this study was to determine the impact of an Upper Respiratory Infection (URI) on exercise functional capacity, as measured by VO2max. In addition, submaximal exercise responses, changes in resting pulmonary function, the impact of select symptoms, and level of initial fitness on performance during an URI were also determined. Forty-five subjects (females=21, male=24) between 18 and 29 years of age participated in this study and were assigned to a mild or severe illness group based on symptom severity. There was also a control group of 10 subjects (female=5, male=5). An initial serological screening was performed on all experimental subjects to assess for the RV16 antibody.Subjects testing negative for the antibody performed a baseline graded exercise test to volitional fatigue, as well as pulmonary function tests. Each subject was inoculated two consecutive days with the RV16 virus within ten days of the baseline exercise test. The day following the second inoculation (peak illness) the subjects performed post-pulmonary function and exercise tests. The control subjects performed two resting pulmonary function and exercise tests separated by one week. Significance was set at p<0.05. Repeated measures ANOVA revealed a significant interaction in V02 at submaximal and maximal levels between trials for all groups (p<0.045). A significant interaction for VE for all levels and all groups was found (p<0.002). No impairment in resting pulmonary function was observed. Analyses of symptoms, and initial V02 in regard to performance, also revealed no significant differences. Therefore, the results seem to indicate that an URI does not limit one's ability to perform at submaximal or maximal levels of exercise, however, some relationship seems to exist. Further research is needed to clarify the effects of an URI on physical performance. / School of Physical Education

The purpose of this research was to examine the effects of a premovement silent period (PSP), and an involuntary small amplitude countermovement (CM) on the maximal height of the squat jump (SJ). Fifteen elite male volleyball players (20.6 ± 1.6 yrs) and thirteen untrained males (20.2 ± 1.7 yrs) performed ten maximal effort SJs from identical starting positions. The electromyographic activity of the vastus lateralis and biceps femoris was measured in conjunction with the vertical ground reaction force, and the vertical displacement measured by a cable-extension transducer. The presence of a PSP or small amplitude CM did not increase maximal SJ height significantly (p > 0.05). These findings indicate that in the SJ, facilitation effects of the PSP and small amplitude CM are minimal. This is important to past and future studies utilizing the SJ, as it is often difficult for individuals to perform SJs with no detectable CM. / School of Physical Education

Despite similar rates of energy expenditure during training, competitive swimmers have been shown to store significantly greater amounts of body fat than competitive runners. In an attempt to explain these discrepancies, male collegiate swimmers (n=8) and runners (n=8) were monitored during 45 min of swimming and running, respectively (75% V02 max), and during two hours of recovery. In addition, a group of male competitive triathletes (n=6) were similarly monitored during and after both swimming and running exercise.Blood samples were obtained after 15 min rest prior to exercise and at 0, 15, 30, 60 and 120 min of recovery and were analyzed for glucose, lactate, glycerol, free fatty acids, insulin, glucagons, norepinephrine (NE) and epinephrine (E). Respiratory gases were collected at 15 min intervals during exercise and at 15, 30, 45, 60, 90 and 120 min of recovery. Heart rate and mean body temperature were recorded at 10 min intervals throughout recovery. There were no differences in post-exercise oxygen consumption or heart rate while the RER suggested increased fat oxidation after exercise for the swimmers and the swimming triathletes. The mean body temperature and mean skin temperatures were significantly lower throughout 120 min of recovery for the swimmers compared to the runners. The triathletes demonstrated a similar tendency but these differences were not significant. The serum glucose levels were significantly greater (P<0.05) immediately post-exercise for the runners compared to the swimmers (6.71 +0.29 and 4.97 +0.19 mmol•1-1, respectively). Blood glucose values were also significantly greater immediately post-run for the triathletes (6.40 +0.26 and 4.87 ±0.18 mmol-l-1 for running and swimming, respectively). Blood glucose values remained elevated for runners and the running triathletes up to 30 min of recovery. Free fatty acids were similar after the run and the swim, but glycerols were increased immediately after running in the runners (P<0.05) and the triathletes (P<0.05). Differences in blood glucose levels or fat release were not explained by differences in NE, E or cortisol. The glucagon-to-insulin (G:I) ratio was significantly increased after exercise in the swimmers and the swimming triathletes. This, combined with a reduced RER after the swimming trials, suggests that the reduced glucose levels were due to reduced hepatic glycogen stores. The results of this study suggest that there were differences in substrate utilization during running and swimming exercise of the same intensity. These differences were not explained by NE, E or cortisol; however, the increased G:T ratio suggests increased carbohydrate use during exercise in the swimmers. Finally, body fat differences between runners and swimmers were not explained by differences in post-exercise energy expenditure or fat oxidation.