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Biomedical subjects

C Ohye

Publications and source records attributed to C Ohye.

At least 109 records · Page 6Linked to original sources
PubMed1979

Physiological study of presumed ventralis intermedius neurons in the human thalamus.

Unitary or a group of unitary responses recorded extracellularly in the rostral part of the thalamic sensory nucleus during the course of thalamotomy for parkinsonian and other kinds of tremor were studied. They were the first sensory neurons encountered in the frontocaudal approach of the stereotaxic needle to the therapeutic target at the lower border of the ventralis intermedius nucleus. The spike discharges, isolated from high neural noise background, responded to passive and/or active movement of joint or muscle on the contralateral extremity but never to light tactile stimuli. In five cases, electrical stimulation of the corresponding peripheral nerves elicited the same spike discharge at short and fixed latency of about 12 msec. Weak electrical stimulation given to each thalamic point produced paresthetic or electric sensation around the receptive field, and stronger stimulation induced tremor-like movement in the area involving the receptive field. Finally, a small coagulation lesion in this thalamic point resulted in immediate relief of tremor without any sensory deficit. From these findings, the possibility is considered that in the human, this particular thalamic zone could be the ventralis intermedius nucleus, which is separable from the surrounding nuclei and is related to tremor mechanism.

Action Potentials↗
PubMed1978

Estimation of neural noise. Functional anatomy of the human thalamus.

In the course of stereotactic thalamotomy, the neural noise level of subcortical structures was estimated quantitatively with the aid of two semimicro-electrodes. The neural noise showed several characteristic features in terms of its amplitude and discharge pattern so that it was correlated with the possible anatomical substrate, thus providing the functional anatomy of the subcortical structures. The study on saggital plane revealed a systematic difference of the noise level between VL and Vim-Vc that could be explained by the different cell size in respective nucleus. Several exceptional cases were also presented, emphasizing the neural noise study in stereotactic surgery.

Adult↗
PubMed1977

Physiologically controlled selective thalamotomy for the treatment of abnormal movement by Leksell's open system.

In the course of stereotaxic thalamotomy by Leksell's open system in 20 cases of abnormal movement, recording and stimulation of the subcortical structures have been performed by means of two semimicro-electrodes introduced parallel to the frontal plane. Taking advantage of simultaneous recording and electrical stimulation through these two electrodes, several critical points in the caudate nucleus and thalamus have been clearly delineated. Thus in each individual case an outline of the thalamic configuration in the frontal plane could be obtained, so that the final therapeutic lesion was placed with good precision at the lower-most border of VL or Vim nucleus. It has been shown that the physiologically determined minimum lesion resulted in satisfactory alleviation of the abnormal movements without notable untoward effects.

Electroencephalography↗
PubMed1976

Responses of subthalamic and pallidal neurons to striatal stimulation: an extracellular study on awake monkeys.

The unitary activity of subthalamic neurons (corpus Luysii) and of GP neurons was recorded extracellularly on awake monkeys (Macaca cynomolgus). Striatal stimulation induces in subthalamic (Sth) neurons a short latency spike discharge (10-15 msec) followed by a long lasting depression of the spontaneous activity. As, according to anatomical studies, the subthalamic nucleus is principally connected to the globus pallidus (GP), electrophysiological relations between striatal and GP neurons and between GP and Sth neurons were studied. Striatal stimulation induced an inhibitory-excitatory sequence in GP neurons and pallidal stimulation induced only a depression of the activity of Sth neurons. Since no GP neurons are excited at short latency by striatal stimulation, possible events along a striato-subthalamic pathway are discussed.

Animals↗
PubMed1975

[Changes in cellular activity in corpus Luysi after stimulation of monkey corpus striatum].

In a chronic experiment on three awake Macaca Cynomolgus, the activity of 27 neurons localized in the Corpus Luysi was recorded. Their spontaneous activity is continuous without rhythmicity or bursts. All neurons responded to a stimulation of the Striatum by an initial activation followed by an inhibition. These facts reveal the occurrence of a double projection from the Putamen and also from the head of the Caudate Nucleus to the Corpus Luysi.

Animals↗