Overstimulation, occipital/somesthetic cerebral cortical depth, and cortical asymmetry in mice

Autoradiography of hypothalamic regions after acute hyperosmolarity in mice

Many regions around the third ventricle of the brain are thought to participate in the regulation of water intake. In this study we have visualized in acutely hyperosmolar mice the hypothalamic regions by using autoradiography and [14C]deoxyglucose as marker. By applying a recently published, inexpensive, calibrated photographic method for the analysis of the autoradiographs, we can show that the medial parts of the hypothalamus near the third ventricle increased their uptake of deoxyglucose in comparison with the lateral parts. Densitometric measurements confirmed the results. The results also indicate that parts of the medial hypothalamus, even those that are more caudal than the paraventricular nuclei, react to hyperosmolarity.

Social intelligence, a neurological system?

Social intelligence has been researched for almost 70 yr. without definitive findings. During this period almost no attempts have been made to consider the complexity of the brain's anatomy and functions responsible for social competence. An ecological model focusing on social abilities within a biopsychosocial context is discussed along with supporting literature and an hypothesis for research. This argument invokes social intelligence as an independent brain system. It is suggested that neurological structures and chemical activities controlling social skills are directly influenced by the environment, individual beliefs, personal goals, and physiology.

Ontogenesis of transcallosal responses in cats: II. Formation of interhemispheric asymmetry

Experiments were performed on 59 kittens of both sexes at the age of 1 to 30 days after birth, anaesthesized by nembutal and immobilized by diplacinum, using the technique of multiple topographical TCR recording. TCRs being recorded from symmetrical points of the right and left hemispheres, interhemispheric asymmetry of their amplitude time parameters was revealed, which arose immediately following TCR appearance. In the kittens' sensorimotor cortex TCR asymmetry was individual, whereas in the parietal cortex it was species-specific. One-hemisphere dominance in kittens possessed a partial character. During interhemispheric asymmetry formation, the callosal and the extracallosal systems participated. Asymmetry dynamism was revealed in asymmetry changing with kittens' age according to form (individual/species-specific) and magnitude (intensification/weakening up to changing its sign), and it was conditioned by differences in mechanisms of hemispheric interaction in the course of the cat's ontogenesis. The process of TCR asymmetry formation was characterized by zonal specificity. The general tendency of asymmetry development during ontogenesis in the cat was intensification, with age, of the integrative interaction of those systems which supported it.

Impoverished rearing conditions increase stress-induced irritability in mice

Irritability was tested in mice reared in four environmental conditions: impoverished (IC), impoverished + overstimulated (ICS), enriched (EC), and enriched + overstimulated (ECS) conditions. The test used was a modified "bottle brush" test. Both overstimulations and individual housing increased irritability interacting positively with each other. Individual housing but not overstimulation decreased avoidance behavior in the mice.