Microcomputer servo-controlled bicycle ergometer system for psychophysiological research.

Steady state exercise is widely used for psychophysiological studies in which a constant heart rate at a predetermined level is desired. We have developed a microcomputer servo-controlled bicycle ergometer system that can be used for administering steady state exercise. Fourteen healthy male subjects, with a wide range of fitness levels (measured by VO2max) were exercised to either a fixed workload (130 watts) or a predetermined heart rate level (servo-heart rate) of 122 bpm (i.

Lateral subthalamic area as mediator of classically conditioned bradycardia in rabbits.

This study was conducted to examine whether a central efferent pathway passing through the lateral zona incerta (LZI) of the subthalamus selectively mediates the bradycardia conditioned response (CR) in rabbits. Electrodes were implanted bilaterally in LZI or in control sites just dorsal or ventral to LZI. Two days following surgery, animals were subjected to Pavlovian conditioning or to pseudoconditioning.

A description and analysis of the operation and validity of the psychological stress evaluator.

A detailed description and analysis are presented of the psychological stress evaluator (PSE), an instrument purported to measure accurately and to portray graphically differential levels of stress in human speech. In addition, two studies are presented that attempt to validate this instrument against better known measures of stress or A-state anxiety. The PSE measures were compared with heart rate and State Trait Anxiety Inventory (STAI) A-state scores obtained under conditions where the level of stress was experimentally manipulated through threat of shock or the presentation of taboo words.

Instrumental conditioning of human heart rate during free and controlled respiration.

The effect of respiratory constraint on heart rate control was assessed in a biofeedback situation with feedback consisting of changes in both illumination level and intensity of pre-recorded baby's cry. Subjects were reinforced for alternately increasing and decreasing heart rate on each of seven days during which respiration was unconstrained (Phase 1). This phase was followed by eight days when respiration was constrained during training sessions with a control respirator (Phase 2).