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Biomedical subjects

R Houdart

Publications and source records attributed to R Houdart.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

[Affectivity in the nervous system].

Affectivity is an ambiguous term, related altogether to, mood, well-being, ill-being, emotional states, and at the same time to individual sensitivity, capacity to feel moved, as well as feelings and passions. We want to show that those states, as different as they may seem, belong to the perception by the central nervous system of past or present modifications, of an organism reacting to situations it has to cope with. Opposite to common opinion, this affectivity is not "generated" by the cerebral cortex but by the central brain. It results from memory input by the limbic system and from information processing by the hypothalamus and the reticular system, and from processing of mood and emotional rates provoked by self reactions in order to perpetuate survival, protection or one's own species. Considered as "favourable" or "unfavourable" after analyses by the limbic cortex, those states become in the central brain "pleasure" or "aversion", and generate motivation for action, to follow-on or to stop. From the limbic cortex, those motivations are transmitted to the contiguous prefrontal cortex. The prefrontal cortex is a center for action imitation. One may imagine it as a center for conscious cortical activity and for affective memory. This organisation of affectivity and affective memory settings in 2 different centers and at two different levels of the nervous system: the limbic cortex and the prefrontal neo-cortex. The prefrontal neo-cortex only is conscious, but the limbic cortex, although unconscious, is a source of motivation. One is led to describe an unconscious affectivity. It is impossible to talk about this affectivity without mentioning Freud's unconscious.

Functional Laterality↗
PubMedDate not supplied

[Memory: a view of the history of central nervous system].

In order to stress the role and importance of memory in human nervous system, this first paper intends to show how it appeared during evolution with the cortex of brain hemispheres and how its significant growth is the cause (and not consequence) of hominization. This growth seems related to a discontinuation of the fetal period during gestation. It leads to birth before the brain is mature, substituting a genetic maturation by an epigenetic maturation through learning. This discontinuation of pregnancy is related to a purely mechanical and obstetrical cause, depending on maternal pelvis. Evolution from quadrupedia to bipedia transformed the pelvis, obliging the newborn to make his way not downward but forward, through a narrow inextensible pass. This history of memory, showing its role in human species evolution, may lead to a reflection on its role in the evolution of all the species possessing a cortex. Above all, it will allow to understand how and in which way human brain is a sort of machine totally associated with memory.

Animals↗
PubMedDate not supplied

[Memory, brain, a machine for learning and rememberingy].

Following a previous paper describing how memory appeared in the nervous system in mammalians, during evolution, and how its significant growth led to hominization, the present paper intends to show the prevailing place it occupies in human brain. Memory, an attribute of cortex, is an engraving of neuronal circuits created during information analysis of data input in the cortex. It is created either by repetition of information or by increase in brain activity, under the influence of a central brain system. In the brain of human newborns, immature and unprogrammed, but endowed with a great capacity for learning, the whole organization and programming will be possible through learning and remembering. Communication pathways between functions are memory pathways. Brain becomes a memory machine and every cortical area is a memory territory. Its lesion results in a disturbance corresponding exactly to forgetting what has been stored in that territory.

Adolescent↗
PubMedDate not supplied

[Arteriography in pituitary tumors. Pseudotumoral aneurysm].

In the presence of any "expansive process" of the sellar region, one must recall that in I % of the instances there may be the possibility of a pseudo-tumoral aneurysm. In a number of cases, neither the clinical study, nor the roentgenologic and tomographic balance of the sellar region, will allow to differentiate an aneurysm and a pituitary tumor. Only the carotid arteriography makes possible a diagnosis of certainty under the condition to make a bilateral study (compression being insufficient). This kind of investigation will therefore be systematic, particularly in those cases in which a sphenoid route of access is considered for the management of the expansive process of the sellar region.

Carotid Arteries↗