Biomedical subjects

Nobuhiko Hatanaka

Publications and source records attributed to Nobuhiko Hatanaka.

6 recordsLinked to original sources

PubMed2005

Input-output organization of jaw movement-related areas in monkey frontal cortex.

The brain mechanisms underlying mastication are not fully understood. To address this issue, we analyzed the distribution patterns of cortico-striatal and cortico-brainstem axon terminals and the origin of thalamocortical and intracortical fibers by injecting anterograde/retrograde tracers into physiologically and morphologically defined jaw movement-related cortical areas. Four areas were identified in the macaque monkey: the primary and supplementary orofacial motor areas (MIoro and SMAoro) and the principal and deep parts of the cortical masticatory area (CMaAp and CMaAd), where intracortical microstimulation produced single twitch-like or rhythmic jaw movements, respectively. Tracer injections into these areas labeled terminals in the ipsilateral putamen in a topographic fashion (MIoro vs. SMAoro and CMaAp vs. CMaAd), in the lateral reticular formation and trigeminal sensory nuclei contralaterally (MIoro and CMaAp) or bilaterally (SMAoro) in a complex manner of segregation vs. overlap, and in the medial parabranchial and Kölliker-Fuse nuclei contralaterally (CMaAd). The MIoro and CMaAp received thalamic projections from the ventrolateral and ventroposterolateral nuclei, the SMAoro from the ventroanterior and ventrolateral nuclei, and the CMaAd from the ventroposteromedial nucleus. The MIoro, SMAoro, CMaAp, and CMaAd received intracortical projections from the ventral premotor cortex and primary somatosensory cortex, the ventral premotor cortex and rostral cingulate motor area, the ventral premotor cortex and area 7b, and various sensory areas. In addition, the MIoro and CMaAp received projections from the three other jaw movement-related areas. Our results suggest that the four jaw movement-related cortical areas may play important roles in the formation of distinctive masticatory patterns.

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PubMed2004

Input-output organization of the rostral part of the dorsal premotor cortex, with special reference to its corticostriatal projection.

Until recently, little was known about the rostral part of the dorsal premotor cortex (PMdr). In the present study, somatotopical representations of the PMdr were electrophysiologically identified in the macaque monkey, and the distribution of corticostriatal input from the forelimb region of the PMdr was analyzed in relation to its thalamocortical and intracortical (with the frontal lobe) connections. Results have revealed that (1) the forelimb is represented predominantly in the PMdr, while only a few sites representing other body parts are distributed as embedded within the forelimb representation; (2) the corticostriatal input zone is located in the striatal cell bridges and their surroundings; (3) the cells of origin of the thalamocortical projections to the PMdr are located mainly in the parvicellular division of the ventroanterior nucleus, the oral divison of the ventrolateral nucleus, area X, the caudal divison of the ventrolateral nucleus, the mediodorsal nucleus, and the intralaminar nuclear group; (4) the PMdr is interconnected primarily with higher-order motor-related areas and dorsal area 46. These data indicate that the input-output pattern of the PMdr resembles those of the presupplementary motor area and the rostral cingulate motor area, and that the PMdr may play critical roles in higher-order motor functions.

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PubMed2003

Cytochrome oxidase activity in the monkey globus pallidus and subthalamic nucleus after ablation of striatal interneurons expressing substance P receptors.

To understand functional roles of striatal interneurons in primate basal ganglia circuitry, we ablated interneurons expressing substance P (SP) receptors (SPR) in the putamen with SP-saporin, a SPR selective neurotoxin. The effect of SP-saporin injection into the putamen was evaluated by examining the loss of cholinergic interneurons and NADPHd-positive (nicotinamide adenine dinucleotide phosphate diaphorase positive) interneurons. We then analyzed regional metabolic changes using cytochrome oxidase (CO) histochemistry. CO activity in some regions of the internal and external segments of the globus pallidus (GP) in the lesioned hemisphere was lower than that in the contralateral or surrounding GP regions. CO activity in the subthalamic nucleus, however, showed no significant change. The present findings suggest that striatopallidal projection neurons exert enhanced inhibitory influence on the GP without modulatory control by the striatal SPR-expressing interneurons.

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PubMed2003

Thalamocortical and intracortical connections of monkey cingulate motor areas.

Although there has been an increasing interest in motor functions of the cingulate motor areas, data concerning their input organization are still limited. To address this issue, the patterns of thalamic and cortical inputs to the rostral (CMAr), dorsal (CMAd), and ventral (CMAv) cingulate motor areas were investigated in the macaque monkey. Tracer injections were made into identified forelimb representations of these areas, and the distributions of retrogradely labeled neurons were analyzed in the thalamus and the frontal cortex. The cells of origin of thalamocortical projections to the CMAr were located mainly in the parvicellular division of the ventroanterior nucleus and the oral division of the ventrolateral nucleus (VLo). On the other hand, the thalamocortical neurons to the CMAd/CMAv were distributed predominantly in the VLo and the oral division of the ventroposterolateral nucleus-the caudal division of the ventrolateral nucleus. Additionally, many neurons in the intralaminar nuclear group were seen to project to the cingulate motor areas. Except for their well-developed interconnections, the corticocortical projections to the CMAr and CMAd/CMAv were also distinctively preferential. Major inputs to the CMAr arose from the presupplementary motor area and the dorsal premotor cortex, whereas inputs to the CMAd/CMAv originated not only from these areas but also from the supplementary motor area and the primary motor cortex. The present results indicate that the CMAr and the caudal cingulate motor area (involving both the CMAd and the CMAv) are characterized by distinct patterns of thalamocortical and intracortical connections, reflecting their functional differences.

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PubMed2003

Fluorescence digital photomacrography.

Low-power photographs of brain sections have been needed for neuroanatomical studies. This paper describes a setup for fluorescence digital photomacrography. High-resolution digital images were obtained with commercially available digital cameras combined with an oblique fluorescence illumination and filters for excitation and emission. The image of an entire coronal section of the macaque brain could be taken with a single exposure. The present photographic system would be useful not only for neuroanatomical, but also for histological, embryological or pathological studies that require low-magnification fluorescence images.

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PubMed2002

An improved method with a long-shanked glass micropipette and ultrasonography for drug injection into deep brain structure of the monkey.

We describe an improved method to inject drug into deep brain structure of the macaque monkey. A Teflon-coated tungsten wire for extracellular recording was passed through a long-shanked (4-5 cm) glass micropipette, which was then attached to a microsyringe with dental impression material. The surface of the micropippete was coated with Teflon to reduce acoustic artifact in ultrasound imaging. Thereby, it was possible to identify the micropipette in the brain with B-mode ultrasonography. Extracellular recording combined with electrical stimulation in the input source of the target nucleus was also helpful to determine the location of the micropipette. Here, we demonstrate injection of a neuronal tracer, wheat germ agglutinin conjugated to horseradish peroxidase, into the medial mammillary nucleus of the Japanese monkey.

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