Correlation between Changes in Stress-Induced Corticosterone Secretion and GR mRNA Levels

The current study was conducted to determine the potential relationship between stress-induced corticosterone secretion and corticosteroid receptor mRNA levels after 5 days of intermittent stress. In particular, we were interested in the rate at which animals terminate a stress response, and how this termination may be altered by repeated stress. Adult male Sprague-Dawley rats were subjected to either 5 days of restraint stress or 5 days of an unpredictable stress paradigm. Restraint-stress induced corticosterone secretion was measured on Days 1 and 5 in both groups, and animals were killed on Day 6. Glucocorticoid receptor (GR), and mineralocorticoid (MR) mRNA levels were determined using in-situ hybridization techniques. Five days of restraint stress caused an habituation of the plasma corticosterone response to stress measured 60 and 90 min post-stress initiation; this pattern of corticosterone secretion was not observed in the animals subjected to unpredictable stress. Five days of either stress paradigm did not alter MR mRNA levels measured within the hippocampus or GR mRNA levels within the hippocampus or the medial parvocellular division of the paraventricular nucleus of the hypothalamus (mpPVN). However, an individual's GR mRNA levels measured within the CA1/2 region of the hippocampus and the mpPVN were significantly correlated with the degree of habituation of the corticosterone response to stress measured on Day 5. This suggests that an increase in the rate of termination of the stress response and levels of GR within the hippocampus and mpPVN may be functionally related.     

The effects of multiphasic prepulses on automatic and attention-modulated prepulse inhibition

Prepulse inhibition (PPI) is widely viewed as an operational measure of sensorimotor gating. Previous research has shown that sensorimotor gating can occur automatically and also can be influenced by selective attention. The present research investigated the relationship of the transient detection response (TDR) with automatic and attention-modulated PPI using a novel “multiphasic” prepulse stimulus. Experiment 1 compared discrete versus multiphasic prepulse types in a no-task PPI protocol to validate multiphasic prepulses as effective elicitors of automatic sensorimotor gating. Results revealed that the two prepulse types elicited equivalent levels of PPI. Experiment 2 compared the effectiveness of continuous monophasic versus continuous multiphasic prepulses within a task-based PPI protocol using a lead interval of 120 ms. Results revealed a significant attention effect for monophasic prepulses only. However, robust PPI was produced by the multiphasic prepulses independent of attention as well as over time. These results suggest that multiple influences on PPI can be assessed concurrently depending on prepulse parameters designed to active the TDR when used in a PPI protocol capable of assessing the effects of selective attention on prepulse processing.     

Aging, selective attention, and inhibitory processes: a psychophysiological approach.

The present study investigated the efficiency with which younger and older adults allocate attention to relevant and irrelevant stimuli. The model of attention guiding this research links the orienting response with the allocation of attention and habituation with the inhibition of the allocation of attention. We adapted a paradigm developed by Iacono and Lykken (1983) in which subjects are instructed unambiguously either to attend to or to ignore a series of innocuous tones, and the skin conductance orienting response elicited by each tone is measured. Results revealed that young subjects instructed to ignore the tones habituated more quickly than did those instructed to attend to the tones. However, older adults exhibited nondifferential orienting across the 2 instruction conditions. These results suggest an age-related deficit in the ability to inhibit attention to irrelevant stimuli.     

Effort expenditure during proportionally reinforced responding

A bar-pressing experiment was carried out in which laboratory rats were reinforced approximately in direct proportion to the level of time integral of force (“effort”) exerted per response. Over the course of training, the subjects increased in efficiency, as measured by amount of food obtained per unit effort exerted. It was not demonstrated, however, that the animals learned to take advantage of the effort-proportional reinforcement contingency.     

Obsessive Passion: A Compensatory Response to Unsatisfied Needs

The present research investigated the role of two sources of psychological need satisfaction (inside and outside a passionate activity) as determinants of harmonious (HP) and obsessive (OP) passion. Four studies were carried out with different samples of young and middle‐aged adults (e.g., athletes, musicians; total N = 648). Different research designs (cross‐sectional, mixed, longitudinal) were also used. Results showed that only a rigid engagement in a passionate activity (OP) was predicted by low levels of need satisfaction outside the passionate activity (in an important life context or in life in general), whereas both OP and a more favorable and balanced type of passion, HP were positively predicted by need satisfaction inside the passionate activity. Further, OP led to negative outcomes, and HP predicted positive outcomes. These results suggest that OP may represent a form of compensatory striving for psychological need satisfaction. It appears important to consider two distinct sources of need satisfaction, inside and outside the passionate activity, when investigating determinants of optimal and less optimal forms of activity engagement.     

Self-report and startle-based measures of emotional reactions to body image cues as predictors of Drive for Thinness and Body Dissatisfaction in female college students

The purpose was to compare self-report and psychophysiological assessment techniques in the measurement of emotional response to body image cues. Female college students (n=53; % Caucasian=53.6; M body mass index=26.1 kg/m2) completed the Eating Disorder Inventory (EDI-3) and viewed photos of themselves both unaltered and morphed to simulate weight gain. Response to the photos was assessed by self-report and the affect modulated startle paradigm. EDI-3 Drive for Thinness (DT) and Body Dissatisfaction (BD) scale scores were correlated with startled amplitude for the largest simulated weight gain photo. Startle eye blink amplitude predicted more variance in DT and BD subscales than self-reported response to the image. The affect modulated startle paradigm may provide unique information in the assessment of eating disorder symptomatology that cannot be captured via self-report techniques, and has potential to inform evaluation of treatment outcomes of eating and body image disorders.