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S Aou

Publications and source records attributed to S Aou.

72 records · Page 4Linked to original sources
PubMed1986

Feeding-related activity of glucose- and morphine-sensitive neurons in the monkey amygdala.

Feeding-related neuronal activity of monkey amygdalar glucose-sensitive and morphine-sensitive cells was investigated during a task that required bar-pressing to obtain food. Both glucose-sensitive and morphine-sensitive cells, located mostly in the centromedial part of the amygdala, decreased firing during the bar-press period more often than insensitive cells. Naloxone attenuated the decrease in activity during the bar press period. The results suggest involvement of these glucose- and morphine-sensitive cells in the control of food acquisition behavior.

Amygdala↗
PubMed1986

Opiate mechanism in reward-related neuronal responses during operant feeding behavior of the monkey.

Reward-related neuronal activity and its modulation by morphine and naloxone was investigated by extracellular single neuron recording and electrophoretic application of drugs in the lateral hypothalamus, during operant feeding of the monkey. Morphine-sensitive neurons responded more often during bar press and ingestion-reward phases. Naloxone blocked only ingestion-reward responses, especially the inhibitory ones. The results suggest that the central opiate system can be involved in reward-related neuronal responses in the lateral hypothalamic area of the monkey.

Animals↗
PubMed1986

Responsiveness of monkey preoptic thermosensitive neurons to non-thermal emotional stimuli.

Responsiveness of 143 preoptic neurons to changes in hypothalamic temperature and to non-thermal emotional stimuli were investigated while rewarding (foods) and aversive objects (hypertonic saline, a toy snake, an air puffer) were given. About 71% of thermosensitive neurons and 32% of thermally insensitive neurons changed the activity when emotional stimuli were shown to and/or tasted by the monkey. Such responses were modulated by satiety/hunger state and were dependent on the degree of perturbation of emotional state. About half of the neurons tested responded when the monkey opened the mouth and protruded the tongue or moved fingers in trying to obtain foods with strong motivation, but did not when the animal made such movements less readily or reluctantly with the progress of satiation. This response was most frequently found among warm-units. The results raise a possibility that preoptic thermosensitive neurons, besides their postulated thermoregulatory functions, might be involved in the response of coordination with thermal and non-thermal emotional behaviors controlled in the hypothalamus.

Animals↗
PubMed1985

Reward related neuronal activity in monkey dorsolateral prefrontal cortex during feeding behavior.

Extracellular single neuron activity was recorded in the dorsolateral prefrontal cortex (DL) during bar pressing for food reward. Most of the reward-related neurons were located around the rostral end of the principal sulcus. Neuronal activity was diminished, abolished, or reversed when quinine adulterated food (aversive food) was given as a reinforcement. Cue-related neurons tended to be located more caudally in the DL. The activity of these neurons was not modulated by the nature of the reward as much as that of the reward-related neurons. The results suggest that DL neurons are not functionally homogeneous.

Animals↗
PubMed1985

A computerized control system for a bar-press feeding task initiated by monkey vocalization.

Computerized control of a bar-press feeding task initiated by a monkey's vocalization was designed to study the motivational roles of brain regions in feeding behavior. In this paradigm, the monkey was required to vocalize in order to initiate the task and then press the bar 30 times to obtain the reward. A microcomputer was used to sense the vocalization and to control the task. Using this system, changes in single neuron activity in the orbitofrontal cortex and the lateral hypothalamic area preceding the time of the vocalization were observed. The entire system including interface and control program is described.

Animals↗
PubMed1985

Driven shield for multi-barrel electrode.

A driven shield for a nine-barrel micropipette containing a carbon fiber recording electrode in the center barrel is described. Two of the nine surrounding micropipettes were used as a driven shield channel to reduce capacitance between the recording electrode and the brain tissue. This method facilitates recording of single neuron activity, even in deep areas of the monkey brain, such as the amygdala and lateral hypothalamic area.

Amygdala↗
PubMed1984

Behavioral significance of monkey hypothalamic glucose-sensitive neurons.

Feeding-related neuronal activity of lateral hypothalamic glucose-sensitive and glucose-insensitive neurons was investigated in behaving monkeys. The behavioral paradigm was a high fixed ratio of bar pressing for food reward signaled by light and tone cues. Twenty-seven percent of the neurons tested were glucose-sensitive. The population of neurons which changed in firing rate during the feeding task was higher among glucose-sensitive cells than among glucose-insensitive cells. The activity of many glucose-sensitive neurons decreased during the bar pressing and reward periods. A small population of glucose-sensitive neurons responded to cue stimuli. The results suggest that glucose-sensitive neurons are mainly involved in the drive and/or reward mechanism of feeding behavior, and that these cells may have specific roles in neural control of hunger-motivated food acquisition.

Animals↗
PubMed1984

Medial preoptic neuronal responses to connatural females in sexually inactive male monkeys (Macaca fuscata).

Neuronal responses to a connatural female were investigated in the medial preoptic area of two sexually inactive male monkeys. Of 72 neurons tested, the presence of the female elicited a phasic excitatory response in 11 neurons and a tonic excitatory response in 5 neurons. These findings suggest that a small number of medial preoptic neurons are involved in coding the presence of the female in the sexually inactive male monkey.

Animals↗
PubMed1984

Neuronal activity in the medial orbitofrontal cortex of the behaving monkey: modulation by glucose and satiety.

To investigate neuronal responses to interoceptive information, single neuron activity of the orbitofrontal cortex (OBF) of the behaving monkey was recorded during glucose injection, natural feeding and an operant bar press feeding task. Intravenous glucose injection had almost no effect on rates of spontaneous firing, but tended to attenuate neuronal responses during the bar press and reward periods. In about half of the neurons tested, the spontaneous firing rate changed for a relatively long period after the animal ate to satiety. The results suggest that blood glucose concentration is a modulatory factor in neuronal processing for feeding, but other interoceptive information generated by satiety strongly affects the activity of OBF neurons.

Animals↗
PubMed1984

Monkey orbitofrontal neuron activity during emotional and feeding behaviors.

Long term, single neuron activity was recorded in the monkey orbitofrontal cortex (OBF) through chronic platinum-iridium microwire electrodes. Tonic as well as phasic changes in neuronal activity occurred upon presentation of palatable (food) and aversive stimuli during bar pressing for food. Lesions in this region are known to induce changes in emotional behavior. Therefore, the results suggest that the OBF neurons are involved in processing emotion.

Animals↗
PubMed1984

A telemetry system for single neuronal discharge recording from behaving monkey.

A telemetry system for neuronal discharge recording from behaving monkeys positioned in a primate chair is described. Using FM telemetry system single neuronal activity was recorded from the monkey brain through five teflon-coated platinum-iridium microwire electrodes (25 mu in dia.). This system permits stable long term neuronal discharge recording during feeding behavior with minimal artifacts even during mastication. The system has a broadcasting distance of more than 30 m. The frequency response and the S/N ratio obtained from this system is almost comparable with that of the usual direct wire procedures, and the elimination of artifacts is superior. This report describes the procedure for constructing the microelectrode assembly and FM telemetry system.

Animals↗
PubMed1983

Cholinergic role in monkey dorsolateral prefrontal cortex during bar-press feeding behavior.

Cholinergic involvement in the neuronal activity of the dorsolateral (DL) prefrontal cortex in the monkey was investigated during bar-press feeding behavior. Iontophoretic application of ACh increased the firing rate of more than half of the cells through muscarinic receptors. Activity of ACh-sensitive cells did not correlate with any particular event during the feeding task. Continuous application of ACh markedly enhanced increases in response to events during the feeding task, and application of an ACh antagonist diminished response levels. This indicates that ACh release may occur during the feeding task and affect cortical cells to improve the signal-to-noise ratio of the excitatory input. Decreased responses to events during the feeding task diminished during ACh application. Driven discharges in the cells were evoked by stimulation of the basal nucleus of Meynert (BNM) where ACh containing cells are localized. This response was specifically blocked by iontophoretic application of atropine. In conclusion, cholinergic inputs arising from the BNM are distributed profusely among the cortical cells and modulate their excitability during bar-press feeding behavior.

Acetylcholine↗
PubMed1983

Influence of acetylcholine on neuronal activity in monkey orbitofrontal cortex during bar press feeding task.

Cholinergic involvement in feeding-related neuronal activity was investigated in the orbitofrontal cortex (OBF) of the behaving monkey by means of a microiontophoretic application of acetylcholine (ACh) and atropine. The activity of ACh sensitive cells did not correlate with any particular event during the bar press feeding task. Atropine blocked the excitatory response to ACh and task events. The results suggest that the cholinergic system in the monkey OBF regulates excitatory neuronal responses in several phases of motivated behavior.

Acetylcholine↗
PubMed1983

Influence of catecholamines on reward-related neuronal activity in monkey orbitofrontal cortex.

Reward-related neuronal activity and its regulation by catecholaminergic input were investigated in the orbitofrontal cortex of the behaving monkey by means of extracellular unit recording and microiontophoretic application of drugs. Neuronal activity was modulated by reward situations and catecholamines. The activity of a majority of the noradrenaline-sensitive cells decreased and of the dopamine sensitive cells increased during food acquisition behavior. The results suggest that catecholamines could be involved in reward-related neuronal activity in the monkey orbitofrontal cortex.

Animals↗
PubMed1983

Medial preoptic and hypothalamic neuronal activity during sexual behavior of the male monkey.

Neuronal activity changes in the medial preoptic area of the male monkey were related to the commencement of sexual behavior, penile erection and the refractory period following ejaculation. Increased neuronal activity in the dorsomedial hypothalamic nucleus was found to be synchronized to each mating act. The involvement of medial preoptic neurons in sexual arousal, initial penile erection and that of dorsomedial hypothalamic neurons in the copulatory act are suggested by the present findings.

Animals↗
PubMed1983

Functional heterogeneity of single neuronal activity in the monkey dorsolateral prefrontal cortex.

Extracellular single unit recording during high fixed ratio bar press behavior, guided by multimodal cue stimuli for food intake, revealed functional heterogeneity in the monkey dorsolateral prefrontal cortex. Cells were found significantly more often in the ventral arcuate concavity, the dorsal arcuate concavity, the principal sulcal area and the inferior convexity which responded, respectively, to visual events, auditory events, visual plus auditory events and bar press.

Animals↗
PubMedDate not supplied

Functional heterogeneity of the monkey lateral hypothalamus in the control of feeding.

Regional differences in the effects of electrical (ES) and chemical stimulation on execution of a bar-press feeding task, and in neuronal activity related to feeding, glucose sensitivity, and odor responsiveness were examined in the lateral hypothalamic area (LHA) of monkeys. In satiated animals, ES of the far lateral and ventral LHA induced bar-press feeding. In hungry animals, ES of the dorsal LHA suppressed the feeding task only during the stimulation period, but prolonged feeding suppression that occurred after ES of the ventromedial LHA. Microinjection of Na-glutamate into LHA sites where ES was effective in suppressing feeding had no effect, but it was effective in the medial hypothalamus. Glucose-sensitive (GS) neurons decreased in activity during bar pressing and/or during the ingestion period. Glucose-insensitive (GIS) neurons showed a cue-related excitation more often than GS neurons. Odor-responding GS and GIS cells were localized in ventromedial and lateral LHA sites, respectively. The present study suggests the regional heterogeneity of the LHA in feeding regulation, depending on both hunger and satiety states.

Animals↗