Behavioral biology最新文献

Wallnau and Gallup (L. B. Wallnau and G. G. Gallup, 1977, Biobehav. Rev. 1, 35–43) recently proposed a serotonergic midbrain raphé model of tonic immobility (TI), wherein there is an inverse relationship between raphé activity and the duration of TI. In part, this model was based on the results of central and peripheral injections of serotonin in chickens which increase and decrease TI, respectively. In rats, centrally administered serotonin depresses raphé firing (G. K. Aghajanian, 1972, Fed. Proc. 31, 91–96) while peripherally administered serotonin potentiates raphé firing (S. Mosko and B. L. Jacobs, 1974, Brain Res. 79, 315–320). The present investigation examined the effect of central and peripheral injections of serotonin on the duration of TI in rabbits. The results were not in agreement with Wallnau and Gallup's predictions. The data suggest that serotonergic influences on TI vary across species.

The effect of handling-induced seizures on passive avoidance behavior was investigated in the gerbil. In the first experiment, ictal activity immediately before Day 1 training significantly impaired retention on Day 2; after additional training on Day 2, retention was normal on Day 3. In the second experiment, a 24-hr interval was allowed between seizure testing and passive avoidance training. No difference between seizing and nonseizing groups was seen during the Day 2 training or Day 3 retention trials. Therefore, the Day 2 impairment in the first experiment was attributed to the immediate effect of the seizure on Day 1 learning. It was suggested that the poor performance of some gerbils in passive avoidance may be attributed to pretraining ictal activity.

Olfactory-related behaviors were observed in social groups of Guyanese squirrel monkeys (Saimiri sciureus) during three distinct phases of the annual reproductive cycle. Olfactory investigation of females and environmental objects by males showed marked increases in frequency from the nonmating to the mating season and intermediate levels during a period of transition from mating to nonmating. Olfactory investigation by females also showed evidence of seasonality, though females engaged in investigatory behaviors less frequently than did males. Females sniffed environmental objects and the anogenital area of other females more often during the mating season than during either of the other two observation periods. The frequency of three probable scent-marking behaviors (rump rubbing, back rubbing, and urine washing) showed no evidence of seasonal variation. Overall, females rump-rubbed more than males, and males back-rubbed more than females. These data suggest that olfactory investigation of females by males is an important component of reproductive activities in the squirrel monkey. The seasonal pattern of male investigatory behavior does not appear to result from an increase in female scent marking during the mating season. Rather, it seems likely that female odors change during this phase of the reproductive cycle so as to provoke increased investigation by males.

Rats received an intraperitoneal injection of naloxone prior to an intraventricular infusion of etonitazene or morphine. The rigidity produced by etonitazene was antagonized by naloxone (10 mg/kg). In contrast to the results of a previous study, all doses of naloxone up to 160 mg/kg failed to attenuate the explosive motor behavior resulting from an intraventricular infusion of morphine. The results of the present study indicate that all actions of opiates and opioids are not mediated by the naloxone-blocked opiate receptor.

Rats were tested in a large, open field with 16 small holes in the floor. Locomotion, exploration, rearing, and grooming were measured during each 10-min testing session. When tested after injection of intraventricular saline, locomotion, exploration, and rearing were the most frequently observed behaviors. Grooming occurred only infrequently. When tested after intraventricular injection of ACTH_1–24, locomotion, exploration, and rearing were greatly reduced, while grooming was markedly increased. These results indicate that the induction of excessive grooming by ACTH_1–24 is not restricted to the small testing chambers usually used in such experiments and that the effect of the ACTH fragment is specific to grooming. Its effect is not an enhancement of the most prominent response being made in a particular situation.

The present series of experiments was designed (1) to determine the nature of the associative learning processes which occur during conditioning in a one-trial step-through passive avoidance paradigm commonly used to assess the effects of a variety of agents on memory processes and (2) to determine whether or not postconditioning electrical stimulation of the dorsal hippocampal formation, at current levels subthreshold for the production of afterdischarge activity, produces memory deficits as a function of the nature of the associative learning processes which occur during conditioning. Using noncontingent and response-contingent footshock conditioning procedures, a behavioral analysis demonstrated that both classical fear conditioning and instrumental punishment conditioning contribute to retention test response suppression in rats trained in the step-through passive avoidance paradigm. Postconditioning hippocampal stimulation produces retention deficits in animals trained in the response-contingent conditioning procedure but not in animals trained in the noncontingent conditioning procedure. The data suggest that the effects of postconditioning hippocampal stimulation on retention depend upon the nature of the associative learning processes which occur during conditioning and which are dictated by the procedural details of the conditioning paradigm.

Common crows received baseline training on an equal-valued multiple variable-interval variable-interval schedule of food reinforcement. When the schedule was subsequently changed to a multiple variable—interval variable-time schedule, in which reinforcement was delivered independently of responding in the latter component, this resulted in negative induction. That is, responding decreased in both components. After a return to the baseline schedule, a change to a multiple variable—interval extinction schedule, resulted in decreased responding in the extinction component. Accompanying this change was an increase in responding during the unaltered variable—interval component, i.e., positive behavioral contrast. Differences between these findings and predictions derived from several theories of behavioral contrast are discussed.

The aggressive tendencies of territorial male redwinged blackbirds were tested using playback of conspecific songs and presentation of a male redwing mount. Factor analysis of overt aggressive responses generated three orthogonal indices of aggressive tendencies. These indices were named (1) Distant Approach (rate of flights over, and proportion of time spent within 5 m of, the mount), (2) Proximity (proportions of time spent within radii of 5, 3, and 1 m of the mount), and (3) Attack Latency (latency to perch beside and attack the mount), and were tested for correlation with the threat displays and other behavior of territorial males to assess their aggressive motivation. In addition, the behavior and time budget variables were used in a linear discriminant function analysis of males that attacked the mount during the testing periods and males that did not attack. The Distant Approach factor was negatively correlated with the proportion of time foraging. The Proximity factor was positively correlated with mean Song Spread display intensity and the proportion of time singing and defending, and negatively correlated with proportion of time foraging. Attack Latency was positively correlated with low Song Spread rate and negatively correlated with medium Song Spread rate given by the territorial males when more than 5 m from the mount. Attacking the nonattacking males could be discriminated on the basis of their (1) proportions of time spent foraging and singing and defending the territory; (2) mean Song Spread (intensity) and incipient Song Spread rate when less than 5 m from the mount; and (3) low Song Spread rate when more than 5 m from the mount. These results suggest that the extent or intensity of the Song Spread indicates the level of aggressive motivation in situations where attack is inhibited, and that threat display and other behavior have signal value and indicate to an intruder the probability of attack.

Hamsters, housed in groups composed of one, two, four, or six females, with two males per group, were observed for a period of 60 days. The effect of such groupings on reproductive success was assessed by determining interference with pregnancy, lactation, maternal behavior, and litter survival. While there was little interference with the onset or course of pregnancy, a marked effect of group size on nursing behavior and litter survival occurred. These effects increased over the course of the experiment so that second litters were less likely to be nursed and to survive in the larger groups. The results appeared to be attributable to a breakdown in maternal behavior as well as to the killing of pups by nonlactating female hamsters. It is significant that the outcome of this experiment, reduced litter survival, parallels the effects that have been reported for other rodents, since different mechanisms are involved in the case of the hamster.

For 35 days male Syrian hamsters were exposed to food treated with aflatoxin, copper acetate, aflatoxin plus copper acetate, or a control diet. When tested in an open-field, the copper acetate and the control groups showed normal decreases in rears, squares entered, and escape attempts across trials. The two aflatoxin-treated groups, however, did not show a decrease across trials on these measures. In fact, the aflatoxin plus copper acetate group showed significant increases in rears and escape attempts. There seems to be a lack of habituation in all animals receiving aflatoxin, and concurrent copper treatment failed to alter this response. Thus, the open-field test revealed behavioral changes while the hamsters were still in a precancerous stage.