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Takamitsu Hanamori

Publications and source records attributed to Takamitsu Hanamori.

3 recordsLinked to original sources
PubMed2005

Fluctuations of the spontaneous discharge in the posterior insular cortex neurons are associated with changes in the cardiovascular system in rats.

Extracellular neuronal responses were recorded from the posterior insular cortex. In three of 20 neurons, fluctuations in their spontaneous discharge were observed during recording without stimulation. In these recordings, fluctuations were also observed in arterial blood pressure (BP) and heart rate (HR) recorded simultaneously. For 3 neurons, the relationships among the fluctuations in the spontaneous discharge of the insular cortex neuron (INSneu), mean arterial pressure (MAP), and HR were analyzed using Pearson's correlation coefficient (r). In unit A, there was a negative correlation between INSneu and MAP (r = -0.30). The r between INSneu and HR was -0.02. In unit B, the data were divided into two groups according to HR (HR < 400 and HR > or = 400). The differential results in the correlations for INSneu-MAP were obtained in the two groups (r = -0.2, HR < 400; r = 0.51, HR > or = 400). For unit C, the INSneu was positively correlated with BP (r = 0.31) and HR (r = 0.36). From the correlation analysis concerning the time, changes in INSneu seem to precede (or delay) changes in BP. These results showed that fluctuations in neuronal activity in the posterior insular cortex are positively or negatively correlated with BP (or HR). The data suggest that some of the neurons in the posterior insular cortex may play a role in the homeostatic (and/or regulatory) control of the autonomic system.

Action Potentials↗
PubMed2003

Chemical stimulation of the thalamic reticular nucleus inhibits the neuronal activity of the posterior insular cortex in rats.

Extracellular neuronal responses were recorded from the posterior insular cortex following electrical and chemical stimulation of the thalamic reticular nucleus (Rt) regions. In the present study, most neurons (29/32) were first characterized for their responses to electrical stimulation of the superior laryngeal (SL) nerve or glossopharyngeal (IXth) nerve. In the first experiment, 15 neurons in the posterior insular cortex were examined for their responses to electrical stimulation of the Rt regions. It was found that effective stimulation sites to evoke action potentials in the posterior insular cortex were the ventromedial portion of the Rt and its adjacent regions. In the second experiment, 17 neurons in the posterior insular cortex were examined for their responses by pressure injection of glutamate (Glu) into the Rt regions. Of the 17 neurons, 13 were inhibited in the spontaneous discharge rate following injection of Glu into the Rt, and the remaining four were unaffected. Histologically, it was demonstrated that Glu injection sites for the case of inhibition were located near or within the Rt. On the other hand, the injection sites for all four non-responsive neurons were located outside of the Rt. These data suggest that excitation of the Rt (GABAergic neurons) causes depression of the neuronal activity in the thalamic relay nucleus and then this may in turn induce depressed neuronal activity in the posterior insular cortex. The results here indicate that neuronal activity in the posterior insular cortex is controlled by the Rt, which has been reported in other sensory systems.

Animals↗