M Miura

Bio: M Miura is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 265 citations.

Termination and secondary projections of carotid sinus nerve in the cat brain stem.

Abstract: MIURA, MITSUHIKO, AND DONALD J, REXS. Tmmktzb~ and secondary projections of carotid sinus nerve in the cat brain stem. Am. J. Physiol. 217(I): 142-153. 1969.-Field responses and unit activity evoked by electrical stimulation of the carotid sinus nerve (CSN) were recorded with microelectrodes in the medulla and pons of anesthetized, paralyzed cats. A short-latency (0.7-I .4 msec), monosynaptic, “early” response, triggered by myelinated CSN fibers, was found in the intermediate portion of the nucleus tractus solitarii (NTS) and in the paramedial reticular formation of the medulla, especially in n, paramedian reticularis; a paucisynaptic “intermediate” response (1.7 msec mean latency) was localized within the intermediate portion of the NTS; and polysynaptic “late” responses (peak > 5 msec) were found in specific subnuclei of the medullary and pontine reticular formation. We conclude that myelinated CSN fibers terminate in both the intermediate portion of the NTS and on large neurons of the paramedial reticular formation of the medulla, that integration of CSN activity occurs in the intermediate portion of the NTS, and that specific reticular nuclei receive multisynaptic CSN projections.

Taste pathways to hypothalamus and amygdala

Abstract: The projections of a third order gustatory relay in the dorsal pons of rats have been traced using tritiated proline autoradiography and antidromic activation of pontine neurons from electrodes in the thalamus and amygdala. Labelled axons collect in the central tegmental tract and ascend to the thalamic taste area in the medial extension of the ventrobasal complex. The majority of the fibers remain ipsilateral, but a few cross in the rostral pons and midbrain. The largest crossing occurs at the level of the thalamic termination. Many fascicles of fibers continue rostrally by passing beneath the thalamic taste area, piercing the medial lemniscus, and spreading out along the dorsomedial corner of the internal capsule (IC). The terminal field at this level caps IC from the subthalamic nucleus down into the far-lateral hypothalamus. Labelled axons grandually penetrate through the internal capsule, and ramify throughout the underlying substantia innominata. This terminal zone extends laterally into the rostral end of the central nucleus of the amygdala, which is densely labelled to its caudal exremity. At the caudal end of the amygdala labelled fibers are visible in one component of the stria terminalis. These fibers can be followed over the dorsal thalamus into a smaller, but equally dense terminal area in the dorsolateral bed nucleus of the stria terminalis. The electrophysiological data demonstrate that pontine gustatory units can be antidromically activated by electrodes located in or near the central nucleus of the amygdala. Since many of the same units can also be driven from the thalamic taste area, at least some of the axons traced autoradiographically probably convey gustatory information to the hypothalamus and amygdala.

Hypothalamic integration of central and peripheral clocks

Abstract: During sleep, our biological clock prepares us for the forthcoming period of activity by controlling the release of hormones and the activity of the autonomic nervous system. Here, we review the history of the study of circadian rhythms and highlight recent observations indicating that the same mechanisms that govern our central clock might be at work in the cells of peripheral organs. Peripheral clocks are proposed to synchronize the activity of the organ, enhancing the functional message of the central clock. We speculate that peripheral visceral information is then fed back to the same brain areas that are directly controlled by the central clock. Both clock mechanisms are proposed to have a complementary function in the organization of behaviour and hormone secretion.