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Putamen neuron activity during visually-triggered, self-paced, and memory-guided movements in the monkey
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R RHYTHMIC FIRING IN UR TANTIA >JIGRA DOPAMINERGIC AND STEPYEN T. KITAI*3 , ? Department of Anatomy and eurobiology, College of Medicine, The university of Tennessee, Memphis, Memphis, TN 38163 and YDepartment of Physiology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan. Dopamine (DA) neurons in substantia nigra compacta (SNc) in in vitro slice preparations are known to fire in a regular pacemaker pattern with preceding pacemaker-like slow depolarization (PLSD) similar to the cardiac muscle cell. The underlying electrophysiological membrane properties responsible for rhythmic firing in SNc DA neurons were studied in a" in vitro slice preparation from the rat. Intracellular potentials were recorded from SNc DA neurons. Biocytin was intracellularly injected and tyrosine hydroxylase immunocytochemistry was performed to identify the transmitter phenotype of the recorded neurons. In the presence of TTX, membrane potential oscillation (between -50 and -35 mV) characterized by PLSD followed by prompt repolarization was seen. PLSD was found to be mediated by a calcium conductance and to have the characteristics of a spike potential. However, the rising time course of PLSD was extremely slower (up to 1400 msec) than that of Ca-dependent low threshold spikes (LTS) and the threshold of PLSD (-60 to -40 mV) lay between those of LTS and high threshold spikes (9TS), suggesting that the responsible Ca conductance for PLSD is different from LTS and HTS. Ca-dependent PLSD may be termed a medium threshold spike (MTS) which can be activated at "ear the resting membrane potential without preceding hyperpolarization. Thus, MTS may be the basis for rhythmic firing in SNc DA neurons.
PATTERNS OF EMG ACTIVITIES OF CAT NECK MUSCLES RELATED TO THE INITIATION OF CAUDATE-INDUCED HEAD TURNING. TADAO OHNO and HIROSHI TSUBOKAWA*, Deuartment of Physiology, Institute of BasicMedicalSciences,Universitv of Tsukuba,Tsuku~,Ibara~ 305,Ispan. Although it is well known that electrical stimulation of the unilateral caudate nucleus (Cd) induces contraversive head turning (HTJ, the contribution of individual neck muscles to the generation of this I-lT has not been analyzed in detail. Hence, we examined which neck muscles participate in the initiation of the Cd-induced HT. Experiments were carried out using awake unrestrained cats. EMGs of the following neck muscles on both sides were recorded through chronically implanted wire electrodes: splenius (Sp), longissimus capitis (LCa), longissimus cervicis (LCe), obliquus capitis cranialis (OCCr), obliquus capitis caudalis (OCCa), occipitoscapularis (0~1, complexus (Co), biventer cervicis (BC), and scalenus cervicis and cervical multifidus. Sp, LCa, LCe, CCCr, and OCCa on the flexion side increased in activity before the onset of I-IT in most cases, while Sp, LCe, and OCCa activity on the opposite side mostly decreased. Activities of Oc, Co, and BC decreased on both sides around the onset of I-IT in most cases. Therefore, it is assumed that increased activities in Sp, LCa, LCe, OcCr, and OCCa can contribute to the initiation of the Cd-induced HT. Furthermore, similar analysis made on non-Cd-induced lateral flexion of the neck revealed similar patterns of EMG activities suggesting that the Cd-induced I-IT is initiated via those muscular systems which are utilized for the initiation of non-Cd-induced lateral flexlon of the neck in freely moving cats.
PUTAMEN NEURON ACTIVITY DURING VISUALLY-TRIGGERED, SELF-PACED, AND MEMORY-TIDED AND MOVEMENTS IN THE MONSFY. MINORIJ KIMURA, YINGAN HU , TOSHIHIKO AOSAKI KATSUSHIGE WATANABE , Oepartment 22 Physiology, Jichi Medical School. Minamikawachi-machi, Kawachi-gun, Tochigi 329-04. Japan. Putamen neuron activity was examined duringlearned arm movements initiated pushed in 3 distinct behavioral contexts. A monkey (Macaca fuscata) sequentially 3 buttons in an instructed order with theright= either l)visuallyThe push buttons were 3) memory-guided modes. triggered, 2) self-paced, or placed 50 cm in front of layed out 9 cm apart in a triangular form on a panel The EMG patterns of prime movers in the forearm and upper arm were the animal. Single neuron not significantly different across these 3 modes of movements. activity was recorded in the putamen on the side contralateral to the arm. The putamen neuron activity was related to either movement per se (55/104 cells), out of 50 anticipation /preparation of movement (25/104), or both (24/104). examined during more than 2 modes of cells in which neuron activity was movements, 64 % of the cells were selectively activated during either visually(6 cells) modes of (11 cells), or memory-guided triggered (15 cells), self-paced The present result that about two-thirds of putamen neurons are movement. selective to the context in which a movement is initiated strongly suggests that the basal ganglia play a role in the initiation of movement through selection of a particular mode of movement.
R RHYTHMIC FIRING IN UR TANTIA >JIGRA DOPAMINERGIC AND STEPYEN T. KITAI*3 , ? Department of Anatomy and eurobiology, College of Medicine, The university of Tennessee, Memphis, Memphis, TN 38163 and YDepartment of Physiology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan. Dopamine (DA) neurons in substantia nigra compacta (SNc) in in vitro slice preparations are known to fire in a regular pacemaker pattern with preceding pacemaker-like slow depolarization (PLSD) similar to the cardiac muscle cell. The underlying electrophysiological membrane properties responsible for rhythmic firing in SNc DA neurons were studied in a" in vitro slice preparation from the rat. Intracellular potentials were recorded from SNc DA neurons. Biocytin was intracellularly injected and tyrosine hydroxylase immunocytochemistry was performed to identify the transmitter phenotype of the recorded neurons. In the presence of TTX, membrane potential oscillation (between -50 and -35 mV) characterized by PLSD followed by prompt repolarization was seen. PLSD was found to be mediated by a calcium conductance and to have the characteristics of a spike potential. However, the rising time course of PLSD was extremely slower (up to 1400 msec) than that of Ca-dependent low threshold spikes (LTS) and the threshold of PLSD (-60 to -40 mV) lay between those of LTS and high threshold spikes (9TS), suggesting that the responsible Ca conductance for PLSD is different from LTS and HTS. Ca-dependent PLSD may be termed a medium threshold spike (MTS) which can be activated at "ear the resting membrane potential without preceding hyperpolarization. Thus, MTS may be the basis for rhythmic firing in SNc DA neurons.
PATTERNS OF EMG ACTIVITIES OF CAT NECK MUSCLES RELATED TO THE INITIATION OF CAUDATE-INDUCED HEAD TURNING. TADAO OHNO and HIROSHI TSUBOKAWA*, Deuartment of Physiology, Institute of BasicMedicalSciences,Universitv of Tsukuba,Tsuku~,Ibara~ 305,Ispan. Although it is well known that electrical stimulation of the unilateral caudate nucleus (Cd) induces contraversive head turning (HTJ, the contribution of individual neck muscles to the generation of this I-lT has not been analyzed in detail. Hence, we examined which neck muscles participate in the initiation of the Cd-induced HT. Experiments were carried out using awake unrestrained cats. EMGs of the following neck muscles on both sides were recorded through chronically implanted wire electrodes: splenius (Sp), longissimus capitis (LCa), longissimus cervicis (LCe), obliquus capitis cranialis (OCCr), obliquus capitis caudalis (OCCa), occipitoscapularis (0~1, complexus (Co), biventer cervicis (BC), and scalenus cervicis and cervical multifidus. Sp, LCa, LCe, CCCr, and OCCa on the flexion side increased in activity before the onset of I-IT in most cases, while Sp, LCe, and OCCa activity on the opposite side mostly decreased. Activities of Oc, Co, and BC decreased on both sides around the onset of I-IT in most cases. Therefore, it is assumed that increased activities in Sp, LCa, LCe, OcCr, and OCCa can contribute to the initiation of the Cd-induced HT. Furthermore, similar analysis made on non-Cd-induced lateral flexion of the neck revealed similar patterns of EMG activities suggesting that the Cd-induced I-IT is initiated via those muscular systems which are utilized for the initiation of non-Cd-induced lateral flexlon of the neck in freely moving cats.
PUTAMEN NEURON ACTIVITY DURING VISUALLY-TRIGGERED, SELF-PACED, AND MEMORY-TIDED AND MOVEMENTS IN THE MONSFY. MINORIJ KIMURA, YINGAN HU , TOSHIHIKO AOSAKI KATSUSHIGE WATANABE , Oepartment 22 Physiology, Jichi Medical School. Minamikawachi-machi, Kawachi-gun, Tochigi 329-04. Japan. Putamen neuron activity was examined duringlearned arm movements initiated pushed in 3 distinct behavioral contexts. A monkey (Macaca fuscata) sequentially 3 buttons in an instructed order with theright= either l)visuallyThe push buttons were 3) memory-guided modes. triggered, 2) self-paced, or placed 50 cm in front of layed out 9 cm apart in a triangular form on a panel The EMG patterns of prime movers in the forearm and upper arm were the animal. Single neuron not significantly different across these 3 modes of movements. activity was recorded in the putamen on the side contralateral to the arm. The putamen neuron activity was related to either movement per se (55/104 cells), out of 50 anticipation /preparation of movement (25/104), or both (24/104). examined during more than 2 modes of cells in which neuron activity was movements, 64 % of the cells were selectively activated during either visually(6 cells) modes of (11 cells), or memory-guided triggered (15 cells), self-paced The present result that about two-thirds of putamen neurons are movement. selective to the context in which a movement is initiated strongly suggests that the basal ganglia play a role in the initiation of movement through selection of a particular mode of movement.