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Biomedical subjects

K Jinnai

Publications and source records attributed to K Jinnai.

At least 73 records · Page 4Linked to original sources
PubMed1988

Projection on the motor cortex of thalamic neurons with pallidal input in the monkey.

The cortical projection areas of thalamic neurons with basal ganglia and/or cerebellar inputs were studied electrophysiologically in unanesthetized monkeys. Thalamic neurons which receive inhibition from the pallidum were found to project to the motor cortex (area 4) as well as to premotor cortex. The neurons with pallidal input and motor cortical projection were located mainly in VLo. This result indicates that the basal ganglia innervate the motor cortex through the thalamus. Thus the basal ganglia can modify the cortical output for controlling movements directly through this pathway as compared with its influence through the prefrontal and premotor cortices.

Action Potentials↗
PubMed1987

Thalamic afferents to layer I of anterior sigmoid cortex originating from the VA-VL neurons with entopeduncular input.

Seventy seven thalamic neurons in the VA-VL nuclear complex of the cat which projected to the anterior sigmoid gyrus (ASG) were studied extracellularly, and their responses to stimulation of both the cerebellar nuclei (CN) and the entopeduncular nucleus (ENT) were examined. Forty two neurons were inhibited by ENT-stimulation but were not excited by CN-stimulation, while 27 neurons were excited by CN-stimulation but were not inhibited by ENT-stimulation. Eight neurons were inhibited by ENT-stimulation and also excited by CN-stimulation. Distribution of axons in each layer of ASG was examined by means of antidromic activation of the thalamic neurons by microstimulation at various depths of ASG. Almost all (13/14) of the ENT-inhibited neurons examined were antidromically activated by microstimulation in layer I with currents less than 35 microA. On the other hand, most (11/13) of CN-excited neurons were antidromically activated by weak microstimulation in layers deeper than the second, but were not activated by microstimulation in layer I with currents less than 40 microA. VA-VL neurons with inhibitory input from ENT were considered to project mainly to layer I of ASG.

Action Potentials↗
PubMed1987

Neuropathological changes of the brain in myotonic dystrophy--some new observations.

Brain autopsy materials from 2 patients with myotonic dystrophy (MyD) were studied. The results obtained in these 2 cases were quite similar. Besides thalamic inclusion bodies and minor abnormalities in gyral architecture with a disordered cortical cellular arrangement, some new observations have been made. First, no more than one intracytoplasmic inclusion body per cell was present in the cerebral cortex, the thalamus, the caudate nucleus and the putamen; this inclusion body was oval or elongated with smooth, sharply defined contours and was usually located at the periphery of the cell. Second, irregular intracytoplasmic inclusion bodies, often multiple and not surrounded by a halo, were found at the periphery or within accumulations of neuromelanin granules in the pigmented cells of the substantia nigra. All the bodies described above stained highly eosinophilic with hematoxylin-eosin and the ultrastructure of the bodies in the thalamus and the substantia nigra was almost the same; these bodies were composed of stacks of alternating parallel, light and dark rectilinear profiles oriented perpendicularly to the longitudinal axis of the bodies. Third, Marinesco bodies were observed with a very high frequency in the pigmented cells of the substantia nigra.

Aged↗
PubMed1986

Enhancement of spontaneous acetylcholine release from motor nerve terminal by calmodulin inhibitors.

The role of calmodulin (CaM) in neuromuscular transmission in the rat diaphragm was electrophysiologically investigated using a microelectrode technique with two different CaM inhibitors, trifluoperazine (TFP) and N-(6-aminohexyl)-5-chrolo-1-naphthalene-sulfonamide HC1 (W-7). These inhibitors in the perfusate decreased the amplitude of miniature endplate potentials and increased the frequency dose dependently without any changes occurring in the resting membrane potentials. These effects were abolished in a Ca2+-free perfusate. The acetylcholine (ACh) quantal size and content were not affected by the reagents. The effects of TFP and W-7 were thought to result from their specific inhibition of calmodulin. It is suggested that accumulated intracellular Ca2+ and cyclic AMP, due to inhibition of calmodulin, had enhanced the frequency of spontaneous ACh release from the nerve terminal, and the decrease in the amplitude might be attributed to inhibition of the postsynaptic action of CaM.

Acetylcholine↗
PubMed1986

Hypoplasty of the breast due to x-ray irradiation.

We treated five women with hypoplasty of the breast induced by radiation. Only one of these women underwent mammaplasty with the use of a latissimus dorsi muscle flap and prosthesis. Hypoplasty of the breast is considered a result of imprudent utilization of x-ray irradiation of young patients with benign skin diseases. To prevent underdevelopment and hypoplasty, attention must be directed to the risk involved in radiation therapy for benign diseases.

Adolescent↗
PubMed1986

Respiratory myoclonus. Report of a case with electromyographic study.

A case of respiratory myoclonus in a 45 year-old male was studied by electromyography. He complained of anorexia, involuntary swinging movement of the thorax and trunk, and epigastric pulsation. Electromyographic studies showed synchronous rhythmic grouped discharges at the of 2 to 3 Hz from the bilateral 8th to 10th intercostal muscles, the right iliocostalis lumborum muscle, and the left hemidiaphragm only during the expiratory phase. They disappeared on inspiration and forced expiration. Anesthetic block of the left phrenic nerve abolished both the voluntary and myoclonic movements of the left hemidiaphragm. Abnormal excitation of the central nervous system and possible irritation of the afferent pathways were postulated.

Afferent Pathways↗
PubMed1984

Electrophysiological study on the corticoreticular projection neurons of the cat.

Thirty-two motor cortical neurons of the cat which project on medullary reticular formation (RF) were electrophysiologically classified into 3 groups, i.e., 22 slow PT-RF neurons (collateral projections to RF from slow pyramidal tract (PT) neurons), 6 fast PT-RF neurons (those from fast PT neurons) and 4 RF (non-PT) neurons without any relation to PT neurons. Firings of slow PT-RF and RF (non-PT) neurons elicited by thalamic stimulation showed close correlation to the surface negative component of cortical evoked potentials. It was suggested that activities of these neurons are controlled mainly by excitatory thalamic inputs onto the distal and superficial part of their apical dendrites.

Animals↗
PubMed1981

Thalamocaudate projection neurons with a branching axon to the cerebral motor cortex.

Sixty-nine thalamocaudate projection neurons in ventroanterior (VA: 32 cells), centrolateral (CL: 12 cells) and centrum medianum or parafascicular (CM-Pf: 25 cells) nuclei of the cat were identified by antidromic response to stimulation of the caudate nucleus (CD). Twenty-two VA and 3 CL neurons in this sample were proved to have a branching axon projecting on both CD and the cerebral motor cortex (Mcx). Most of the branching VA neurons showed repetitive discharges synchronous with the cortical recruiting response elicited by repetitive stimulation (6-10/sec) of the pallidum. Such activities of the VA neuron which would induce the motor cortical recruiting response, were proved to be conveyed to CD.

Animals↗
PubMed1981

Cervical input to vestibulocollic neurons.

Extracellular responses of vestibulospinal neurons projecting to neck segments (vestibulocollic neurons) to stimulation of cervical afferents were studied in decerebellate cats anesthetized with chloralose or decerebrated intercollicularly. These neurons were antidromically activated by microstimulation in the C2 ventral horn ipsilateral or contralateral to the vestibular nuclei. Contralateral neck afferents produce in vestibulocollic neurons the same responses they produce in other vestibulo-spinal neurons, although the response (early excitation, inhibition) which predominates varies with type of preparation. In intercollicular decerebrate cats, the main effect of stimulating the contralateral C2 ganglion was inhibition (latency greater than or equal to 6 msec), often followed by late excitation. Early excitation, at a latency less than 6 msec, was rarely seen, although it occurred in half the vestibulospinal neurons projecting to the cervical enlargement. In contrast to the results in decerebrate cats, stimulation of the contralateral C2 ganglion produced early excitation in over one-third of the vestibulocollic neurons studied in chloralose-anesthetized cats. Results on vestibulocollic neurons were similar whether the cells projected ipsilaterally or contralaterally, or whether or not the cells also projected to the cervical enlargement (branching neurons). The influence of cervical afferents on vestibulocollic neurons demonstrates supraspinal paths by which cervical afferents may act upon the neck and might modify vestibular reflexes of the neck.

Afferent Pathways↗
PubMed1979

The parieto-rubro-olivary pathway in the cat.

Stimulation of the parietal association cortex as well as the frontal motor cortex elicited clearly extracellular unitary activities or field potentials in the ipsilateral inferior olive in the cat. The parietal-induced responses came out generally at a longer and more variable latency than the frontal-induced ones. This suggested the existence of an indirect pathway from the parietal association cortex to the inferior olive. The recording sites for the parietal-induced responses were located not only in the dorsal lamella but also in the ventral lamella of the principal olive and in the medial accessory olive. Such olivary sites were exclusively in the rostral half of the inferior olive, and these areas in the olive were considered to give projection fibres predominantly to the hemispherical parts of the cerebe-lar cortex (neocerebellum). Small neuronal cells were labelled with horseradish peroxidase (HRP) homolaterally in the midbrain tegmentum, after HRP was injected through recording glass microelectrodes into the inferior olive where only the parietal-induced responses were evidently recorded. These small cells were distributed in the rostral one-third of the red nucleus and/or around the adjacent midbrain reticular formation close to the lateral border of the red nucleus. In referring to recent anatomical and physiological data, such small neurones labelled with HRP could be identified as the parvocellular red nucleus neurones. The present results indicate the existence of the parieto-rubro-olivary pathway system in the cat and suggest, in association with our previous studies, that the parvocellular red nucleus neurones participate in control of highly co-ordinated posture and movement predominantly through the neocerebellum.

Animals↗
PubMed1979

Projection of the cerebellar dentate nucleus onto the frontal association cortex in monkeys.

Stimulation of the cerebellar dentate nucleus in monkeys elicited responses in the frontal association cortex (area 9) on the contralateral side to the stimulation, in addition to those in the motor (area 4) and premotor (area 6) cortices which were reported previously. The responses in the frontal association cortex were characterized by surface positive-deep negative field potentials in the cortex. They contrasted with surface negative-deep positive potentials in the motor and premotor cortices on the same dentate nucleus stimulation. In the rostral part of the premotor cortex (area 6) on the border of area 9, both types of responses were induced and admixed. The relay nucleus of the thalamus was suggested for the dentate-induced responses in the frontal association cortex.

Animals↗
PubMed1979

Neurons of the motor cortex projecting commonly on the caudate nucleus and the lower brain stem in the cat.

The cortico-caudate projections due to collateral axons of cortico-spinal and/or cortico-bulbar fibers were explored. In 34 cats, 59 neurons in the motor cortex were extracellularly identified to be antidromically activated by stimulation of the caudate nucleus (Cd). Thirty four neurons responded antidromically only to Cd-stimulation, and they were irresponsive to thalamic stimulation. Contrarily, 25 neurons responded antidromically not only to Cd-stimulation but also to stimulation of the cerebral peduncle and/or the medullary pyramid. 40% of the latter were orthodromically activated by thalamic stimulations. They were considered to be important in coordinating the cerebellum and the basal ganglia system.

Animals↗
PubMed1978

Common projection of the motor cortex to the caudate nucleus and the cerebellum.

1. Stimulation of the caudate nucleus (Cd) was found to evoke early mossy fibre (MF) and late climbing fibre (CF) responses in fairly wide areas of the cerebellar cortex in cats. Points capable of eliciting the cerebellar responses were situated exclusively in the head portion of the nucleus. These responses showed a close resemblance to those induced by stimulation of the medial part of the anterior sigmoid gyrus (ASG) both in their contours and in their distributions. 2. There was a remarkable interaction between the Cd- and the medial ASG-induced field potentials in the pontine nuclei. When conditioned by the Cd stimulation at significantly short time intervals, the field potentials evoked by the medial ASG stimulation were more remarkably suppressed than those by the lateral ASG stimulation. 3. Field potentials or extracellular unitary activities in the inferior olive elicited by the Cd stimulation were closely related to those evoked by the medial ASG stimulation both in their responsiveness and in their topographical localizations. 4. When the cortical motor area had been ablated 10--14 days previously, the Cd stimulation elicited no responses in the cerebellar cortex. 5. From these findings, it was indicated that the Cd receives collaterals of the cortico-pontine and/or the cortico-olivary axons that originated almost exclusively from the neurones in the medial ASG (area 6). This suggested the existence of a common innervation of the basal ganglia and the cerebellar systems by the premotor area of the cerebral cortex.

Animals↗