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Biomedical subjects

G Crescimanno

Publications and source records attributed to G Crescimanno.

At least 37 records · Page 2Linked to original sources

Electrophysiological relationship between claustrum and contralateral area 4 and 6 pyramidal tract neurons.

The connections between the claustrum and the contralateral motor areas were electrophysiologically investigated in cats under chloralose anesthesia. The extracellular unitary activity of 81 pyramidal tract neurons (PTNs) was recorded; 22 PTNs were inhibited by activation of the contralateral claustrum; inhibition was preceded by an early activation of 4 out of the 22 inhibited PTNs. Section of the corpus callosum abolished the contralateral claustrum effect, while the action of the ipsilateral homologous structure persisted.

Animals↗

Effects of substantia nigra stimulation on hypothalamic rage reaction in cats.

The effects of substantia nigra (SN) (pars compacta) stimulation on the rage reaction elicited by ventromedial hypothalamic nucleus (VMH) were investigated in the cat. The studied parameters of the rage reaction were: the current and the frequency threshold for the appearance of the hissing and the hissing latency. A facilitatory effect induced by the SN on the hypothalamic rage reaction was observed in the form of a decrease in the hypothalamic stimulus threshold for the hissing appearance and a decrease in the hissing latency. Moreover, when the VMH was stimulated with parameters below the threshold for the hissing display, simultaneous nigral activation determined its appearance. The excitatory influence exerted by the SN on the affective component of the aggressive behavior is discussed.

Aggression↗

Stimulation of the ventral tegmental area (A10 region) enhances the hypothalamic attack behavior in the cat.

The influence of the A10 region of the ventral tegmental area (VTA) on the quiet biting attack evoked by stimulation of the lateral hypothalamic nucleus (LH) was studied. The latency of the biting was considered as reference value and measured with stop-watches; it remained constant when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of the A10 neuron group induced a facilitation of the aggression in the form of a decrease in the biting latency or a display of the attack pattern when LH was stimulated with parameters below the threshold for biting appearance. The facilitatory effect of the A10 neurons of the VTA is discussed.

Aggression↗

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation, in the cat.

The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.

Aggression↗

The control exerted by the substantia nigra on the quiet biting attack elicited by hypothalamic stimulation in the cat.

The effects of substantia nigra (SN) (pars compacta) stimulation on the quiet biting attack evoked by hypothalamic activation in the cat were studied. The measure of the aggressive behavior was the latency of the biting which did not greatly change from one animal to another when hypothalamic stimulation was performed with the same parameters. Concurrent activation of the SN determined an inhibitory effect on the studied behavior in the form of an increase in the biting latency or loss of the attack pattern. The inhibitory role of the SN on predatory attack behavior is discussed.

Aggression↗

[Effects of stimulation of the substantia nigra on the rage reaction evoked in the cat by hypothalamic stimulation].

The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease of the hissing latency. The influence of the substantia nigra on the affective components of the aggressive behaviour in underlined.

Anger↗

[Effects of stimulation of the claustrum on the spontaneous activity of pyramidal neurons of the contralateral motor areas 4 and 6 in the cat].

In order to investigate the functional meaning of the connections between the claustrum and the controlateral motor areas, the extracellular spontaneous activity of 81 PTNs was recorded. Single shock controlateral claustrum stimulation inhibited twenty-two out of the 81 PTNs. On four of the twenty-two PTNs the inhibition was preceded by an early activation. The split of the corpus callosum was performed in 5 cats in order to study the pathway followed by claustrum fibers to the controlateral motor cortex. It is ipothesized that the relationship between the claustrum and controlateral area 4 and 6 PTNs might have the purpose of giving the pyramidal output the bilateral contribution of a plurisensory structure.

Animals↗

[An optoelectronic apparatus for the registration of stepping activity in small mammals].

In order to record the stepping activity in little size mammals, it was planned a set able to transform the stepping activity of the animals in electrical signals displayed on a polygraph. The set is formed by a complex transmitter-receiver, and transformer-recorder, that allow to record also high frequency stepping activity and its time variations.

Animals↗

[Induced facilitation in the ventral tegmentum area on the latency of biting evoked by hypothalamic stimulation in the cat].

The effects of VTA stimulation on the quiet biting attack evoked by hypothalamic activation in the cat, were studied. The reference value of the aggressive behaviour was the latency of the biting. Concurrent activation of both the hypothalamus and VTA determined a decrease of the biting latency, which depended on the parameters of VTA stimuli. The facilitatory effect of the dopaminergic mesolimbic system on the attack behaviour is emphasized.

Aggression↗

[The substantia nigra in quiet attack induced by hypothalamic stimulation in the cat].

The role of the substantia nigra on the quiet biting attack evoked by hypothalamic stimulation was investigated. Simultaneous activation of the hypothalamus and of the s. nigra determined a significant increase of the biting latency or in some case the disappearance of the attack pattern. The inhibitory role of the s. nigra on the quiet biting attack evoked by hypothalamic stimulation is discussed.

Aggression↗

[Functional aspects of the relation between the claustrum and motor cortex in the cat].

In order to study the relationships between the claustrum and motor cortex neurons both of area 4 and area 6 in the cat, an experiment was performed in which the effect of claustral stimulation on pyramidal tract neurons was investigated. Single shock electrical activation of the claustrum caused an inhibition of the spontaneous activity of the neurons, or an inhibition preceded by short activation, or no effect. These evidences lead to the conclusion that the claustrum exerts a role in movement organization.

Animals↗

Functional relationship between claustrum and pyramidal tract neurons, in the cat.

Electrophysiological relationships between the claustrum and the motor cortex were studied in cats preliminarily anesthetized with ketamine and then with chloralose. Single shock electrical activation of the claustrum induced a decrease of the spontaneous unitary activity of the pyramidal tract neurons (PTNs) both in area 4 and in area 6. Eighty percent of the total number of PTNs was inhibited whereas the remaining 20% was unaffected. The inhibitory effect lasted about 200 msec and appeared about 19 msec after claustrum activation. The results show a functional linkage between the claustrum and the efferent cells of the motor cortex. This relationship suggests the hypothesis that the claustrum, a multisensory structure, may be involved in motor activity integration.

Afferent Pathways↗

Effects of claustrum stimulation on spontaneous bioelectrical activity of motor cortex neurons in the cat.

Electrophysiologic interactions between claustrum and motor cortex neurons were investigated in the cat. A total of 136 neurons was recorded from the motor cortex in area 4 (90 cells) and in area 6 (46 cells). Ninety-eight of the total neurons were identified as pyramidal tract neurons (PTNs). Stimulation of the claustrum by single shocks or by trains of stimuli imposed on the tested PTNs a pure long-lasting inhibition, or a long-lasting inhibition preceded by a short early activation, or no effect. No functional localization of the effects of claustrum activation were found within the motor areas. The observed results are consistent with the hypothesis that the claustrum may play a role in movement organization.

Action Potentials↗

Modifications induced on the amygdaloid paroxysmal activity by entopeduncolar or nigral injection of kainic acid, in the cat.

Entopeduncolar or nigral injection of kainic acid determines an early decrease of the evoked amygdaloid paroxysmal activity and a later increase of the after discharge duration. This biphasic effect is likely due to the structural analogy of the drug with monosodium glutamate, a neuroexcitant amino acid. The data suggest that the basal ganglia exert a tonic control on the amygdaloid activity.

Amygdala↗

[Time course analysis of the effects of intrapeduncular injection of kainic acid on amygdaloid paroxysmal activity].

Intrapeduncolar intrapeduncolar entopeduncolar injection of kainic acid determines an early decrease of the evoked amygdaloid paroxysmal activity, and a later increase of the AD length. The diphasic effect of the injection of kainic acid into the entopeduncular nucleus is likely due to the structural analogy of this drug with a neuroexcitant amino acid, monosodium glutamate. The inhibitory role of the entopeduncolar nucleus on the paroxysmal phenomena evoked in the amygdala is emphasized.

Animals↗