Evaluation of prenatal androgen and ovarian secretions on receptivity in female and male rats

Offspring of rats infected daily from Day 16 through Day 20 of gestation with either 2 mg of testosterone propionate (TP) in .1 ml of sesame oil or oil alone were tested for sexual receptivity following injections of 3.3 microgram of estradiol benzoate (EB) and .5 mg of progesterone (P) beginning at 40, 80, or 120 days of age. At each age, neonatally gonadectomized males and females from TP-injected litters exhibited less receptivity than corresponding oil-injected controls. Prenatally androgenized females were similar to neonatally castrated oil-injected males at all ages. Ovarian implants from birth to 35 days of age significantly increased receptivity in neonatally castrated males and androgenized females. Increasing the age at which testing was initiated systematically reduced receptivity in all groups.     

Positive and negative behavioral contrast in the rat

Three groups of rats received either 8, 23, or 53 sessions of multiple variable-interval variable-interval baseline training before being shifted to a multiple extinction variable-interval schedule. The rate of responding during the unaltered component was higher for the groups shifted to multiple extinction variable-interval than for control groups remaining on multiple variable-interval variable-interval (positive contrast). Furthermore, when the multiple variable-interval variable-interval schedule was re-instated, stable negative contrast was found in the groups that had received 23 or 53 baseline sessions, but not for the group that had received only eight sessions. Positive and negative contrast were also demonstrated in the eight and 23-session groups when the multiple extinction variable-interval and multiple variable-interval variable-interval schedules were re-administered in further phases of the experiment. These results suggest that both positive and negative behavioral contrast can be obtained reliably in a species other than the pigeon.     

Sexual reinforcement in the female rat.

Sexual reinforcement in the female rat was studied in a preparation that allowed continuous operant responding for access to a male rat leading to intromission. Experiment 1 used a high operant level nose-poke response to test the possible reinforcing effects of some components of access to a male. A simple tone stimulus used as a conditioned reinforcer and two odor stimuli, target male bedding and emulsified preputial gland, were tested. None of these contingent events altered responding above or below operant level. Access to the male, which was always accompanied by intromission, immediately increased response rate when it was made contingent upon the nose-poke response. Performance on fixed-ratio schedules was erratic, and response rate was low in comparison to typical food-reinforced responding. An interresponse-time analysis indicated, however, that some effect of the ratio contingency may have been present. In Experiment 2, several modifications of the procedure were tested with the objective of creating a more tractable preparation for behavior analysis. Response type and the hormone delivery method were changed, and 2 target males were used instead of 1. The latter tripled the average number of reinforcers earned in a single session. Differences between sexual and other reinforcers are discussed in terms of procedural, quantitative, and motivational aspects of the sexual reinforcement procedure.     

Antagonism of behavioral effects of bromocriptine by prolactin in female cats

The effects of the dopaminergic agonist bromocriptine (BC) and exogenously administered prolactin (PRL) on the spontaneous behavior of female cats were investigated. The objective was to test whether BC-induced behavioral effects may be antagonized by PRL. BC (6 mg/kg ip) administration induced abnormal behaviors such as limb flicks, abortive grooms, head/body shakes, and hallucinatory-like behavior/escape as well as excessive grooming. PRL (5 mg/kg ip) administration induced biphasic changes in grooming. The first change was an increase in grooming frequency averaging 256% of baseline control values and lasting for 1 h. This change was followed by reductions in grooming of 75 and 82.5% below baseline during Hours 2 and 3 postinjection, respectively. Combined BC and PRL treatment antagonized the frequency of BC-induced motor effects such as limb flicks, abortive grooms, and head/body shakes. Limb flicks occurred nine times more often 2 h after BC alone than after BC and PRL. The combined treatment also antagonized the excessive grooming observed after separate administrations of BC and PRL. The observed interactions between PRL and BC behavioral effects support the notion that PRL may be an important modulator of dopamine-dependent motor behavior in female cats.     

Effects of selective forebrain noradrenaline loss on behavioral inhibition in the rat.

Virtually total depletion of cortical and hippocampal noradrenaline by stereotaxic injection of 6-hydroxydopamine into the fibers of the dorsal noradrenergic bundle produced no impairment in acquisition learning of a runway response for food reward. Extinction of this response, once learned, was markedly slower in the treated group than in controls, the treated animals perseverating in rapid running to the goal box even with no food present there. Similarly, no impairment was found on acquisition of a continuously reinforced lever-pressing response for food. Extinction of this response, however, was again slower in the treated group. Subsequent acquisition of a successive light-dark discrimination task was also slower in the treated group, with these animals perseverating in responding to the negative stimulus. Although selective forebrain noradrenaline loss does not impair the acquisition of appetitive responses, the suppression of responses in the absence of reward is impeded. A parallel is drawn with those effects found classically after surgical lesion to the hippocampus.     

Proactive behavioral effects of theta-blocking septal stimulation in the rat

The induction of hippocampal theta rhythm using low-frequency septal stimulation has been shown to proactively (1) facilitate the acquisition and (2) increase resistance to extinction of a food-rewarded fixed-ratio (FR) bar-press response (Holt & Gray, Quarterly Journal of Experimental Psychology, 35B, 97-118, 1983). Both (1) and (2) are also seen after septal lesions. This suggests that Holt and Gray's (1983) results may have been due either to stimulation-produced theta waves (the "theta" hypothesis), or a small septal lesion produced by the stimulating current (the "lesion" hypothesis). Both hypotheses were tested in the present experiment using high-frequency septal stimulation. In one of two treatment conditions male Sprague-Dawley rats, chronically implanted with a bilateral septal stimulating electrode and a unilateral bipolar hippocampal recording electrode, received (1) trains of continuous pulses at 77 Hz which blocked the hippocampal theta rhythm, or (2) trains of pulses at 100 Hz interrupted by a 30-msec interval at a frequency of 7.7 Hz. Control animals were implanted but not stimulated. Acquisition of a discrete-trial bar-press response on a fixed ratio 5 reinforcement schedule immediately followed the treatment phase. After 15 days' acquisition all animals were extinguished over the subsequent 12 days. Results indicated that both types of septal stimulation reduced resistance to extinction of barpressing; theta-blocking stimulation produced the greater effect. Theta-blocking stimulation retarded the acquisition of bar-pressing in the early stages of training. These overall results are exactly opposite to those produced by low-frequency (7.7 Hz) theta-driving septal stimulation (Holt & Gray, 1983) and contrary to the predictions of the lesion hypothesis. Furthermore, these findings support the idea that long-term changes in behavior may depend on stimulation-produced changes in the hippocampal theta rhythm.     

Future and potentiality in the psychoanalytic process

A perspective is delineated on the dimension of the future in the psychoanalytic situation. Clinical manifestations are presented of the tension between actuality and potentiality that characterizes the treatment situation. This tension, an aspect of the intersubjective field that exists between patient and analyst, involves the analyst's hopes, expectations, anticipations, sense of purpose, and therapeutic intent, facets of the analyst's subjectivity that affect the clinical process. The question of the patient's individuality and autonomy is raised in the context of the notion of the "true self." To understand potentiality in the clinical situation, it is argued, the intersubjective emphasis on the inevitable mutual influence between analyst and patient must be complemented by a view of the self as emerging from within and gaining coherence through the unfolding of inherent dispositions and potentialities.     

Effect of behavioral inhibition on interactions in mixed-sex dyads

The present studies assessed the effect of behavioral inhibition on interactions of college students in mixed-sex groups. In Study 1, 20 participants were arranged into two dyadic groups based on self-rated measures of approach/withdrawal behavior. These dyads (inhibited men/uninhibited women; inhibited women/uninhibited men) were videotaped during an unstructured 5-min. interaction in a laboratory. Time series analysis indicated greater behavioral covariation in the inhibited men/uninhibited women dyads and less behavioral covariation in the inhibited women/uninhibited men dyads. Additional analyses indicated a relationship between inhibition and comfort experienced during the interaction. Inhibited participants, particularly women, reported feeling uncomfortable while interacting with an uninhibited male partner. A second study corroborated the findings reported in Study 1 and also noted elevated heart rate in the inhibited women. This increased discomfort in women appeared to be related to heightened self-consciousness during the interaction.     

Age-dependent changes in olfactory-mediated behavioral investigations in the male rat.

In the present experiment male Sprague-Dawley rats at three different ages (young, middle-aged, and old) were tested in a series of olfactory-mediated behavioral tests. The amount of ano-genital investigation directed to receptive females by old rats was significantly reduced compared to that of young and middle-aged animals. In contrast, general body investigation of receptive females was similar among the three age groups. The amount of anogenital investigation directed to nonreceptive females or immature male rats indicated significant differences only between young and old rats, with values from middle-aged rats being intermediate and not significantly different from either of the two extreme groups. General body investigation of nonreceptive females and immature males did not differ among the three age groups. Old rats showed the best performance in a location of buried food test with latencies to locate food approximately one-half that obtained from young and middle-aged rats. Measures of general locomotor activity indicated significantly greater values from young compared to middle-aged and old rats, with the latter two showing very similar levels. These results demonstrate clear discriminatory differences in olfactory-mediated behavioral performance of the male rat as a function of the specific test and age of the animal. Overall, the results suggest that olfactory-mediated behaviors related to reproduction appear more sensitive to age-related declines, while behavior related to food procurement is more minimally affected.     

Modeling behavioral recovery following lesion induction in the rat dentate gyrus

Unilateral entorhinal lesions have enjoyed immense popularity as a model of recovery from damage. In part, the popularity has been supported the laminar organization of the hippocampal formation, which allows for the dissection of the contribution of individual afferent pathways to the recovery process. The commissural/associational pathway is of particular interest, since electrophysiological and gross anatomical data, although limited, have correlated sprouting in this pathway with behavioral recovery. Unfortunately, information relating recovery to synaptic structure is lacking. Addressing this issue, two analyses were conducted. Initially, a quantitative review of the literature reporting behavioral recovery following this type of lesion was conducted using meta-analytic techniques. Using this detailed information across decades of research, multiple linear regression analysis was conducted to address whether the morphological correlates of recovery could predict behavioral recovery. This resulted in an equation relating morphology and recovery that stood up well to several diagnostic tests. Moreover, this model suggests that synapse structure (in particular, synapse size and curvature, as well as terminal compartmentalization and the density of multi-synaptic terminals) holds a greater potential to predict behavioral recovery than increases in synapse number, which is typically seen as the optimal anatomical measure of recovery. This initial attempt to identify, quantify, and validate a model of lesion recovery is an important initial step in understanding how synaptic morphology may help mediate recovery of function.