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Biomedical subjects

J M Delgado

Publications and source records attributed to J M Delgado.

At least 55 records · Page 3Linked to original sources
PubMed1977

Cerebral blood flow and behavior during brain stimulation in the goat.

Cerebral blood flow, heart rate, arterial blood pressure, and behavior were studied in conscious goats during electrical stimulation of the diencephalon and mesencephalon. Stimulation of the subthalamic area produced a considerable increase in ipsilateral cerebral blood flow and heart rate, accompanied by either a small or a large increase in systemic arterial blood pressure. Cardiovascular effects were associated with changes in alertness. The increase in cerebral blood flow was partially abolished by previous administration of atropine directly into the internal maxillary artery. Stimulation of the mesencephalic reticular formation caused a marked increase in blood pressure with no change or with some decrease in cerebral blood flow. After administration of phentolamine into the internal maxillary artery, stimulation produced increase in cerebral blood flow. The behavioral response consisted of restlessness and attempted flight. These results suggest the existence of cholinergic vasodilator and adrenergic vasoconstrictor pathways to cerebral blood vessels that may be stimulated electrically.

Animals↗
PubMed1976

Neurobiology of aggressive behavior.

Causality, neurological mechanisms, and behavioral manifestations may be heterogeneous in different forms of aggressive behavior, but some elements are shared by all forms of violence, including the necessity of sensory inputs, the coding and decoding of information according to acquired frames of reference, and the activation of pre-established patterns of response. Understanding and prevention of violence requires a simultaneous study of its social, cultural, and economic aspects, at parity with an investigation of its neurological mechanisms. Part of the latter information may be obtained through animal experimentation, preferably in non-human primates. Feline predatory behavior has no equivalent in man, and therefore its hypothalamic representation probably does not exist in the human brain. Codes of information, frames of reference for sensory perception, axis to evaluate threats, and formulas for aggressive performance are not established genetically but must be learned individually. We are born with the capacity to learn aggressive behavior, but not with established patterns of violence. Mechanisms for fighting which are acquired by individual experience may be triggered in a similar way by sensory cues, volition, and by electrical stimulation of specific cerebral areas. In monkeys, aggressive responses may be modified by changing the hierarchical position of the stimulated animal, indicating the physiological quality of the neurological mechanisms electrically activated.

Acoustic Stimulation↗
PubMed1976

Ultradian rhythms in the mobility and behavior of rhesus monkeys.

The presence of ultradian rhythms in the mobility and behavior of rhesus monkeys was explored in eleven animals equipped with mobility FM transmitters and placed alone or in pairs in laboratory cage situated in a sound proof, temperature controlled room, with food and water ad libitum. After an habituation period of 3 to 7 days, telemetric recordings of the mobility of the animals showed ultradian rhythms with a periodicity of 70 min during the daily 12-h light period. During the corresponding 12-h dark period, there were two dominant cycles of 103-144 min and 48 min respectively. Restriction of food and water to 1h/day did not change the duration of these cycles, and the presence of random noise also had little effect. Spontaneous behavior occurred in regular sequences within each cycle. Social relationships were found to affect rhythmicity of behavior, since pairs of monkeys synchronized their cycles. The lever press response recorded during auto-shaping showed the same rhythmicity found in mobility, demonstrating the influence of ultradian rhythms on learned behavior.

Animals↗