Biomedical subjects

C H Hillman

Publications and source records attributed to C H Hillman.

4 recordsLinked to original sources

PubMed2006

Cardiorespiratory fitness and acute aerobic exercise effects on neuroelectric and behavioral measures of action monitoring.

Cardiorespiratory fitness and acute aerobic exercise effects on cognitive function were assessed for 28 higher- and lower-fit adults during a flanker task by comparing behavioral and neuroelectric indices of action monitoring. The error-related negativity, error positivity, and N2 components, as well as behavioral measures of response speed, accuracy, and post-error slowing were measured following a 30-minute acute bout of treadmill exercise or following 30-minutes of rest. A graded maximal exercise test was used to measure cardiorespiratory fitness by assessing maximal oxygen uptake. Results indicated that higher-fit adults exhibited reduced error-related negativity amplitude, increased error positivity amplitude, and increased post-error response slowing compared with lower-fit adults. However, acute exercise was not related to any of the dependent measures. These findings suggest that cardiorespiratory fitness, but not acute aerobic exercise, may be beneficial to behavioral and neuroelectric indices of action monitoring following errors of commission by increasing top-down attentional control.

Adult↗

PubMed2000

An electrocortical comparison of executed and rejected shots in skilled marksmen.

Electroencephalographic (EEG) activity during the preshot period was investigated in seven skilled marksmen. Specifically, alpha and beta spectral power were obtained for the 4-s period prior to the execution or rejection of shots. Rejected shots were defined as those that resulted in the marksman's self-initiated decision to withdraw their rifle from the target rather than execute the shot. EEG activity during the preparatory period was contrasted between the executed and rejected shots to better understand the involved attentional processes associated with the preshot state. Results for rejected compared with executed shots revealed a progressive increase in alpha and beta power for rejected compared with executed shots, which increased across the preparatory period. Furthermore, increased spectral power was found in the left compared with the right hemisphere for both executed and rejected shots, and in the different regions of the scalp. Therefore, the decision to reject a shot seems to be characterized by inappropriate allocation of the neural resources associated with task execution.

Adult↗

PubMed2000

Motor and nonmotor event-related potentials during a complex processing task.

Identification of the necessary stimulus properties to elicit the stimulus preceding negativity (SPN) has been the impetus for numerous research studies. The current study was conducted to explore the possibility that the SPN is an index of cognitive resource allocation. An auditory warning stimulus (S1) indicated whether an easy or difficult discrimination would occur at S2. The SPN was collected before a nonmotor discrimination task (S2) that consisted of identifying the higher of two bars. To eliminate the influence of motor processing prior to S2, a button press on the side of the higher bar was held until perception of a response cue (S3). Additionally, P3, contingent negative variation (CNV), and behavioral measures were collected to assist in assessing the SPN. Results indicated that although the SPN exhibited increased negativity, no differences were observed based on task difficulty. However, task difficulty did affect P3 data for both the warning tone and the discrimination task, an effect not observed for the CNV. Overall, the data did not support that hypothesis that the SPN provides an index of cognitive demand.

Adolescent↗

PubMedDate not supplied

Food deprivation and emotional reactions to food cues: implications for eating disorders.

Two studies examined emotional responding to food cues. In experiment 1, normal college students were assigned to 0-, 6- or 24-h of food deprivation prior to presentations of standard emotional and food-related pictures. Food deprivation had no impact on responses elicited by standard emotional pictures. However, subjective and psychophysiological reactions to food pictures were affected significantly by deprivation. Importantly, food-deprived subjects viewing food pictures showed an enhanced startle reflex and increased heart rate. Experiment 2 replicated the food deprivation effects from experiment 1, and examined participants reporting either a habitual pattern of restrained (anorexia-like) or binge (bulimia-like) eating. Food-deprived and binge eater groups showed startle potentiation to food cues, and rated these stimuli as more pleasant, relative to restrained eaters and control subjects. The results are interpreted from the perspective that startle modulation reflects activation of defensive or appetitive motivation. Implications of the data for understanding eating disorders are considered.

Adult↗