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At least 1,081 records · Page 60Linked to original sources
PubMed1984

Comparison of brain structure volumes in insectivora and primates. IV. Non-cortical visual structures.

The relative size of the eyes, optic nerves, chiasms and tracts, and of the dorsal nucleus of the lateral geniculate body is distinctly larger in Primates than in (theoretically) isoponderous Insectivora. Within Insectivora, the relative size is lowest in moles, medium in shrews and hedgehog-like tenrecs, and largest in hedgehogs. Within Primates, all relative sizes are on the average larger in simians than in prosimians: the eyes to a small degree, the lateral geniculate bodies moderately and the optic nerves considerably larger. The ratio between eyes and optic nerves is large in night-active primates and distinctly smaller in day-active forms, with no overlap. The only night-active simian (Aotus trivirgatus) is in line with night-active prosimians. The relative size of the non-cortical visual structures in man is in line with that of day-active simians, whereas two of the great apes (orang-utan and gorilla) are relatively low. The size of the visual structures appears to depend mainly on functional requirements and is not, or is distinctly less, related to differences in the evolutionary level. The size of the visual structures of tree-shrews (Scandentia) shows special features which are not found in Insectivora and Primates and is compatible with their separation from these orders.

Animals↗
PubMedDate not supplied

[Bioelectric activity and metabolism of individual brain structures at different times after administration of synthetic tetrapeptidamide].

Complex study of the opioid tetrapeptide amid (TPA) effect on metabolism and neurophysiological processes of different cortical areas, caudate nucleus n. accumbens allowed to detect prolonged (several days) specific action on these structures. The influence was manifested in certain changes of transmitter metabolism, background bioelectric activity, as well as in changes of EEG reactions to adequate afferent signals. The duration of the detected changes significantly exceeded the duration of anti-pain TPA effect.

Acetylcholinesterase↗
PubMed1983

Comparison of brain structure volumes in Insectivora and Primates. III. Main olfactory bulb (MOB).

Volumes of the main olfactory bulb (MOB) in 76 species of Insectivora, Scandentia, Primates and Macroscelidea, and some of the laminar components in 34 species were measured. No statistically significant differences were found (1) between the two sides in the 162 individuals and (2) between males and females in the 19 species in which both sexes were examined. In interspecific comparisons the relative size (expressed by size indices) shows a definite tendency to decrease from Insectivora through prosimians and simians to man. The average indices were 100-64-10-3.6, respectively. Scandentia and Macroscelidea have the highest average MOB indices (135 and 166). The relative MOB size is discussed in relation to feeding and social behaviour. It was shown that MOB development is largely linked to dietary adaptations but that its importance in feeding behaviour is paralleled by a similar importance in social behaviour. Within each dietary type, MOB development is associated with the different characteristics of the occupied niche. Among Insectivora, ground-dwelling species occupy the upper, and semiaquatic species the lower positions in the size scale for the MOB. Among Primates, in closely related species, the nocturnal species have in general better developed MOBs than the diurnal species. The composition of the MOB is relatively stable, i.e. the laminar components (layers 1 + 2, 3, and 4-6) show no clear change in their percentage size from well developed to strongly reduced MOBs. Only in the diurnal simians are layers 4-6 relatively small. This corresponds with the general observation (obtained from light-microscopy) that the granular layer (layer 6) is reduced and decomposed in higher Primates, and especially in man.

Animals↗
PubMed1984

[Effect of microwaves on work capacity and impedance of the brain structures of rats].

Adaptive processes occurring in white rats in response to microwave irradiation with non-thermogenic density, were studied as well as the maximal working ability of the animals, the impedance of their sensomotor cortex, hypothalamic nuclei and cerebral tissues, skeletal muscles and liver. Probable physiological mechanism of the observed effects is discussed.

Adaptation, Physiological↗
PubMedDate not supplied

[Effect of microionophoretic administration of met-enkephalin into various brain structures on secretion of luteinizing and thyrotropic hormones].

The influence of local microiontophoretic met-enkephalin injections upon luteinizing and thyrotropic hormone (LH and TTH) secretion and spontaneous electric neuron activity was studied. It was shown that opioid injection into the hypothalamic arcuate nucleus (HAN) decreases 3-fold the blood LH concentration and its injection into the hypothalamic paraventricular nucleus (HPN) inhibits similarly the TTH secretion. Both effects are completely blocked by nalorphin--a concurrent opiate antagonist. Nalorphin alone has no pronounced endocrine effect. Met-enkephalin exerts a dose-dependent neurotropic action. Nalorphin blocks mainly the pentapeptide inhibiting effects. A direct correlation between endocrine and neurotropic opioid action was not observed. It appears to be due to polyfunctions of the structures studied and to a wide spectrum of met-enkephalin biological activity.

Action Potentials↗
PubMed1980

[Suppression of epileptiform activity by micropolarizing brain structures].

Penicillin administration elicited epileptiform responses whereas micropolarization (MCP) affected the epileptogenic foci in cats with indwelled electrodes and chemotrodes. Three types of experimental epilepsy models were obtained: focal petit mal seizures, adversive, and grand mal seizures. The MCP of amygdala and caudate nucleus completely suppressed all three types of seizures whereas MCP of hippocampus enhanced the pathology. Two mechanisms of seizure suppression seem to exist: the inhibitory and the activating ones.

Amygdala↗
PubMed1982

Comparison of brain structure volumes in Insectivora and Primates. I. Neocortex.

Based on volume measurements the total neocortex increases enormously from the lower ('basal') Insectivora, through prosimians, monkeys and apes up to man. In man it is about 132 times larger than in the average basal Insectivora of (theoretical) equal body weight and 232 times larger than in the insectivoran species which has the least developed neocortex. Within the neocortex the white matter increases more markedly than the grey matter. For man the white matter reaches a value 298 times that of the basal Insectivora and the grey matter reaches a value 198 times greater. Within the grey matter the cell dense layers (laminae 2-6) increase distinctly more than the molecular layer (lamina 1). Thus in man the volume of layers 2-6 is 272 times greater than that in basal Insectivora and the molecular layer is 68 times greater. When related to the total grey matter the percentage of the molecular layer clearly decreases from about 32% in the lower Insectivora to 12% in higher primates.

Animals↗