Lester R. Aronson

The influence of experience on behavioural effects of androgen in prepuberally castrated male cats

Abstract Thirteen male kittens were castrated at the age of 4 months. When tested in adulthood with oestrous females they performed very little sexual behaviour. Only one of these males mounted the female, but stepping, thrusting and intromission were absent. When the above tests were completed, 11 of the males were treated with testosterone propionate by injection and pellet implantation. Six males (Group I) were permitted sexual experiences during the period of hormone administration. Of these, four showed the complete sexual pattern after relatively large doses of androgen. The other two never approached the female even after receiving over 3 gr. of hormone. Five other males (Group II) were denied access to the female during the period of androgen therapy. After the hormone treatment was terminated, these animals were tested with a female. Three of these showed no advances in sexual performance over their low levels before androgen therapy started; two made definite advances during the period of testing, pointing to the importance of the experiences gained during the early tests after hormone therapy terminated. Also, the persistence of sexual behaviour after hormone withdrawal was much greater among the maximally experienced males of Group I than among the minimally experienced males of Group II. An analysis of the data from these experiments emphasises the distinction between initiation of sexual behaviour during ontogenesis, and the persistence of the organised sexual pattern when the androgen level is reduced. The data also favour the interpretation of an indirect influence of male hormone when sexual behaviour is being initiated. Androgen causes a variety of critical organic changes, but in addition, stimuli must be present in the environment which elicit behaviour tending to the development of the mating pattern. Once organised through hormones and experience, this behaviour remains for a time relatively independent of the hormone until such time as regressive morphological and physiological changes disrupt it.

Seasonal Variation in Mating Behavior in Cats after Desensitization of Glans Penls

The glans penis in 14 sexually experienced cats was desensitized by section of the nerves dorsalis penis. These males mounted the estrous female readily but they were so disoriented that they could not achieve intromission. Reduced sensory feedback resulting from the operation and from lack of intromissions caused a decided drop in sexual activity in the fall with recovery in early winter. A latent sexual cycle in male cats is revealed, which corresponds in time to the established female cycle.

Amygdaloid hypersexuality in male cats re-examined

Abstract It is widely believed that amygdaloid lesions induce hypersexuality in certain mammals including humans. However, the evidence is so confused as to obscure the real nature of the purported changes. Twelve sexually experienced male cats were given two series of quantitative tests, the conventional sex test and a new selection test in which the animals were presented sequentially with a small stuffed toy panda, moving toy, tranquilized rabbit, tranquilized male and estrous female. Lesions in 8 experimental males were largely confined to the basolateral nuclei and periamygdaloid cortex. In the standard test and in the response to the female in the selection tests, the only significant postoperative change in the major measurements of sexual behavior was a decline in initial mount latency. However, in the selection tests, the major change was an increased tendency to mount less appropriate objects. There was no evidence of hypersexuality, in the sense of a higher level of sexual performance. This change was not interpreted as the disruption of an amygdaloid mechanism directly regulating sexual behavior, but rather as interference with a system which normally modulates approach and withdrawal behavior in response to stimuli that are salient with respect to an existing behavioral setting and set.

Effects of castration on neural afferent responses from the penis of the domestic cat

Abstract To determine the effects of androgen on penile mechanoreceptor activity and sensitivity, first-order afferent responses, evoked by quantified tactile stimulation of the penis, were measured in sexually experienced intact and castrated cats. The results indicate that, in adult animals, testicular androgen has no role in maintaining genital sensory fields, sensory thresholds, initiation of neural responses, conduction velocity, or amount of neural activity evoked by a particular stimulus; therefore, peripheral sensory effects of castration seem not to be the cause of the decline of sexual behavior following gonadectomy. Under some stimulus conditions, mean neural responses and intragroup variability were greater in the castrate group. A possible interpretation is that decreases in androgen level affect the physical properties of the penile integument, making it more flaccid. The function of the cats penile spines, which are androgen dependent, was investigated also, and the results lend some support to the idea that these spines act as accessory sensory structures. The possible role of androgen on central nervous mechanisms is also discussed.

Olfactory deprivation and mating behavior in sexually experienced male cats

The effects of bilateral olfactory bulbectomy (sodium pentobarbital anesthesia) upon mating behavior was studied in sexually experienced adult male cats. In the first experiment preoperative and postoperative behavior of eight animals were compared. After bulbectomy there were no decrements in mating behavior; rather, small but significant increases in sexual activity occurred, e.g., increased frequency and duration of intromission, decreased initial and intromissive mount latencies. A second experiment was designed to test the hypothesis that this increase in sexual activity resulted from a decrease in the amount of test time that the desensitized animals spent in related activities, especially sniffing. Here sniffing, grooming and scratching were measured in five bulbectomized and four sham operates. They were tested preoperatively, postoperatively in the usual test room and later in a strange test room. The same increase in sexual behavior appeared in the bulbectomized animals as in the first experiment. Additionally, there were significant decreases in frequency and duration of sniffing the room and sniffing the female. The sham operates remained unchanged. When tested in a strange room the shams reacted with a decrease in frequency of intromission and an increase in initial mount and intromissive mount latencies. Sniffing the room rose to well above preoperative levels. Under similar conditions the bulbectomized males showed some increase in frequency of intromission, increased latencies and an increase in sniffing of the room, but not to preoperative levels. The probability that complete anosmia was achieved in these experiments is supported by detailed histological examination of the brains which demonstrated that the glomeruli in remaining bulbar fragments were all markedly degenerate. Other important histological changes are described. The results are discussed in relation to the pronounced decrements following bulbectomy in several species of rodents.

Mating behaviour in sexually inexperienced cats after desensitization of the glans penis

Abstract 1. 1. Only three out of eleven sexually inexperienced adult male cats in which the glans penis was desensitized by resection of the dorsal nerve of the penis developed sexual behaviour. These males showed the typical behavioural abnormalities reported previously for sexually experienced, adult males. The abnormalities seen were: (a) genital disorientation while mounting the female causing loss of intromission; (b) a cyclical low period in sexual arousal in the fall of each year; and (c) a non-seasonal decline in sexual behaviour during the third and fourth years of testing. 2. 2. Five out of eight prepuberally nerve-cut males developed sexual behaviour and had similar behavioural abnormalities, except that the seasonal cycles did not appear until the third year. Intromission occurred occasionally during the first 1 1 2 years of testing, but ceased completely thereafter.

The case ofThe Case of the Midwife Toad

The facts concerning Kammerers case are reviewed. Koestlers view that Kammerer was unjustly accused is presented and shown to be incorrect.

CENTRAL VERSUS PERIPHERAL GENITAL DESENSITIZATION AND MATING BEHAVIOR IN MALE CATS: TONIC AND PHASIC EFFECTS*

Tonic concepts have long been associated with descriptions of sexual behavior. Characterization of this behavior in terms of sexual excitement or sexual arousal was a common practice well before it was incorporated into the analytical literature. More than three decades ago Frank Beach5 formalized the conceptual framework by developing a series of hypotheses concerning the interrelationships of sensory input with the hormonal, neural and experiential factors mediating sexual behavior in mammals. These hypotheses revolved around the unifying concept of a sexual arousal system that Beach modeled after Sherrington and called the central excitatory mechanism. Although the model was based primarily on rat studies, Beach used data from other animals to the extent then available, and it was assumed that the model would be applicable to many or most mammals. In brief: 1. The sensory input for sexual behavior in males is nonspecific, multimodal, and additive. Accordingly, major sensory deprivations of many kinds lead to proportional decreases in sexual arousal. Conversely, increased stimulation increases sexual arousal, as, for example, when a highly receptive female rat is introduced into a chamber with a sexually sluggish male, the latter often increases its sexual responsiveness. 2. The central excitatory mechanism (CEM), which Beachs later called the sexual arousal mechanism (SAM), receives the various sensory inputs, summates them, and if the copulatory threshold is reached, the male approaches and mounts the female. At this point a second set of mechanisms is activated, namely the intromission and ejaculatory mechanisms (IEM) , which completes the copulatory pattern. Even nonsexual stimuli will increase the SAM. Thus Beach noted that male rats can sometimes be aroused to renewed copulatory aotivity by batting them sharply about the cage. 3. The mechanism maintains a central tonus that is independent of peripheral stimulation. Beach suggests that individual differences in sexual excitability are correlated with the extent or intensity of this tonus. 4. Levels of gonadal hormones increase the excitability of the SAM and at the same time lower the thresholds for the copulatory responses. Social and sexual experience affect the activity of the SAM.

Effects of experience on optomotor performance in the cichlid fish Aequidens latifrons

Laboratory-bred cichlid fishes, Aequidens latifrons, were tested individually in a modified optomotor apparatus in which the rotation of the vertically striped drum changed direction every 56 sec. Over a period of five consecutive daily tests, quantitative changes in optomotor behavior that are characterized as more efficient responding occurred. That is, the fish followed the moving stripes more accurately in all the measures that we used to define it. Retesting some subjects on Days 11–15, 43–47, and 89–93 showed that these changes in behavior persisted and are therefore characterized as a learning phenomenon. A hypothesis is presented concerning the ontogeny of optomotor behavior based on the experience gained by juveniles in viewing the conspicuous vertical stripes of other members of the school when following them.