Donald M. Krus

The effects of p-chlorophenylalanine, a depletor of brain serotonin, on behavior: I. facilitation of discrimination learning

Abstract Rats were given either position discrimination and discrimination reversal, simultaneous brightness discrimination, or successive brightness discrimination tasks. Half of the subjects were injected with p-chlorophenylalanine (p-CIPhe) in Steroid Suspension Vehicle and half were injected with the vehicle only. Rats given p-CIPhe learned the two brightness discriminations with fewer errors than the control animals. No differences were found between groups given the position discrimination and discrimination reversal task. Since p-CIPhe severely depletes brain serotonin with only a slight reduction of brain catechol amines, it is likely that reduction of brain serotonin was responsible for the facilitation of learning found in previous experiments where both serotonin and catechol amines were reduced.

The influence of progesterone on behavioral changes induced by lysergic acid diethylamide (LSD-25) in normal males

SummaryThe influence of a steroid, progesterone, in altering the effects of LSD-25 on psychological behavior in normal male humans was investigated in this study. Some evidence was found that the magnitude of changes found to occur under LSD-25 in. behavior representing sensori-motor, perceptual and conceptual levels of organization, was reduced when LSD ingestion was preceded by progesterone ingestion.

Effect of LSD on Pace of Performing a Variety of Tasks

During the past few years, as part of a program of research evaluating the behavioral effects of lysergic acid diethylamide (LSD-25), a number of studies have been reported which involved a formal analysis of changes in the spacial properties of objects. These changes were considered relatively independent of their occurrence in the course of time (Liebert, et al., 1957, 195s; Krus & Wapner, 1959; Wapner & G u s , 1959). While convenient for purposes of analysis, this focus does not fully describe the behavioral operations of the organism in its transactions with environmental objects; rather, a more comprehensive analysis must, of necessity, consider spatio-temporal aspects of the organisms activity. A step in rhis direction is taken in the present paper which considers temporal aspects of behavior, in rhis case, the pace of carrying out n variety of tasks. The tasks selected to assess LSD-induced changes in pace were drawn from some situacions utilized in a larger unpublished study whose purpose was co inquire into the interrelationships becween the races of activity manifested in operations representative of various levels of organization, e.g., physiological, sensori-motor, perceptual, and concepn~al. The principal criterion for selecting situations from the larger battery was that the task be reliable. The six tasks so chosen had uncorrected test-retest reliabilities ranging from + .91 to + .96, and sampled the routine activities of rapping, psychomotor line-drawing, card sorting, handwriting, and addition.