Forest chimpanzees (Pan troglodytes verus) remember the location of numerous fruit trees

It is assumed that spatial memory contributes crucially to animal cognition since animals’ habitats entail a large number of dispersed and unpredictable food sources. Spatial memory has been investigated under controlled conditions, with different species showing and different conditions leading to varying performance levels. However, the number of food sources investigated is very low compared to what exists under natural conditions, where food resources are so abundant that it is difficult to precisely identify what is available. By using a detailed botanical map containing over 12,499 trees known to be used by the Taï chimpanzees, we created virtual maps of all productive fruit trees to simulate potential strategies used by wild chimpanzees to reach resources without spatial memory. First, we simulated different assumptions concerning the chimpanzees’ preference for a particular tree species, and, second, we varied the detection field to control for the possible use of smell to detect fruiting trees. For all these assumptions, we compared simulated distance travelled, frequencies of trees visited, and revisit rates with what we actually observed in wild chimpanzees. Our results show that chimpanzees visit rare tree species more frequently, travel shorter distances to reach them, and revisit the same trees more often than if they had no spatial memory. In addition, we demonstrate that chimpanzees travel longer distances to reach resources where they will eat for longer periods of time, and revisit resources more frequently where they ate for a long period of time during their first visit. Therefore, this study shows that forest chimpanzees possess a precise spatial memory which allows them to remember the location of numerous resources and use this information to select the most attractive resources.     

Acute effects of viloxazine HCl and flurazepam when given alone and in combination on sleep EEG: A double-blind interaction study with normals

Viloxazine, an aryl-oxypropanolamine type β-adreno-receptor antagonist, has been used in the treatment of depression. In a double-blind drug interaction study with flurazepam, a commonly used benzodiazepine hypnotic, viloxazine administered alone decreased the amount of time spent in REM sleep, increased the amount of time in the “light” stages of sleep, and increased the number of transitions to awake. However, no interactive effects of the combined administration of viloxazine and flurazepam could be detected.     

Conditioning in the prediction of therapeutic outcome in depressions

Predictions of clinical responsiveness to tricyclic anti-depressants were studied in 25 depressed patients. A well-preserved external inhibition at the commencement of treatment was found to be the best single indicator of therapeutic success.     

Relationship between implicit false belief understanding and role play: Longitudinal study

Pretend play is one of the earliest forms of children’s imagination. While social pretend play (role play) may facilitate the development of theory of mind – including false belief understanding – theoretically, the reverse may be true; theory of mind may facilitate the development of role play. To clarify this relationship, the present longitudinal study examined whether toddler’s implicit understanding of false beliefs predicted their role play during preschool years. We examined 18-month-old toddlers’ looking time in an implicit false-belief task (Time 1). When the children were 4/5 years old (Time 2), children’s parents answered a questionnaire on their child’s engagement in role play, such as playing with an imaginary companion and impersonating an imagined character. Toddlers’ looking time in the false-belief task at Time 1 predicted impersonation scores at Time 2. The results suggest that early theory of mind skills can facilitate children’s role play.     

Transference,discrimination and reversal

A total of 68 subjects-17 normal volunteers, 17 hospitalized paranoid schizophrenics, 17 non-paranoid schizophrenics, and 17 patients with organic brain syndrome-were compared on their performance on the different phases of a specially devised conditioning procedure. This procedure is composed of (1) acquistion of the conditional reflex,i.e., squeezing a rubber bulb to the presentation of white light; (2) transference from a visual conditional stimulus to a verbal conditional stimulus and back to the visual conditional stimulus; (3) conditional stimulus differentiation; and (4) conditional stimulus reversal. Performance profiles of the normal and of the pathological groups were established and the statistically significant differences among the sub-groups of the experimental population were described. The clinical significance of these findings is discussed.     

Effects of psychoactive agents on the conditioning of the microcirculation in the rat

Normal vascular tonus and permeability of the microcirculatory network is mediated by catecholamines, histamine and serotonin. Following electroconvulsive treatment (ECT), histamine did not provoke local vasodilatation. The inhibition was further potentiated by drugs which prevent the enzymatic or physical inactivarion of free catecholamines and by locally administered norepinephrine. This system became conditioned to a visual stimulus when rats were presented in six consecutive occasions with the visual stimulus preceedingly coincided with the administration of ECT. In the conditioned rats, light alone inhibited the histamine-induced vasodilatation, and this inhibition was potentiated by sub-effective doses of injected norepinephrine and by drugs which prevent the enzymatic or physical inactivation of catecholamines. Sedatives, antidepressants, MAO inhibitors and the chlorpromazine-type agents as well as the psychotomimetic drugs characteristically influence either the acquisition or the extinction of the conditioned reflex. Results suggest that the obtained conditioning of the microcirculatory functions are mediated by tie centrally released catecholamines.