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Measurement of the size and number of the sensory fibers in three branches of the trigeminal nerve in the mouse
S160
Abstracts / Neuroscience Research 58S (2007) S1–S244
P2-f26 c-fos expression in the catecholaminergic neurons of the brainstem after eccentric rotation of rats
P2-f31 Orexin modulates neuronal activities in rat mesencephalic trigeminal sensory neurons
Yulin Dong, F.X. Zhang, Y.Q. Li Department of Anatomy, The Fourth Military Medical University, Japan
Kiyomi Nakayama, Shiro Nakamura, Tomio Inoue Department of Physiology, Showa University School Dent., Tokyo, Japan
The expression of c-fos gene in catecholaminergic neurons within the brainstem was examined immunohistochemically. Conscious animals were subjected to eccentric rotation on the horizontal plane. Neuronal activation was defined by Fos protein expression. After stimulation, the Fos protein were mainly distributed in the vestibular nucleus complex (VNC), parabrachial nucleus (PBN), nucleus of the solitary tract (NTS), locus coeruleus (LC), substantia nigra (SN), caudo- or rostro-ventrolateral reticular formation (CVL, RVL), etc. Double immunofluorescent staining showed that most of catecholaminergic neurons in the NTS were activation (double labeled Fos/TH neurons) after eccentric rotation. Double labeled Fos/TH neurons were also observed in LC, CVL, RVL, and other regions related to sympathetic activities of the brainstem. However, there were no double labeled Fos/TH neurons in the SN. Our findings suggest that the catecholaminergic neurons in the brainstem may contribute to the changes of the sympathetic activities induced by the gravity-related spatial information during head movements.
Orexin is a regulatory peptide involved in the control of feeding, motivation and adaptive behaviors. To examine the role of orexin in mastication, whole cell patch-clamp recordings from mesencephalic trigeminal sensory neurons (Mes V), which are critical components of the circuits controlling oral-motor activity, were performed on brainstem slice preparations from Wistar rats aged between postnatal days (P) 0–17. By bath-application of orexin-A (100–500 nM), small membrane depolarizations <3 mV with decreases of the input resistance were observed at the resting potential in the presence of tetrodotoxin (1 M). In rats older than P7 or P8, it is known that the burst discharges are induced by a depolarizing step pulse at a holding potential of about −40 to −50 mV in Mes V neurons. Such conditional burst discharges in Mes V neurons were reduced to 61% of control by bath-application of orexin-A. Persistent sodium currents, which contribute to production of such conditional burst discharges, were also reduced by orexin-A. These results suggest that orexin modulates oral-motor behavior via Mes V neurons.
P2-f28 Measurement of the size and number of the sensory fibers in three branches of the trigeminal nerve in the mouse
P2-f32 Neurons that become active during hand and mouth
Masami Yoshimoto, Nayuki Yamamoto, Hitoshi Ozawa Department of Anatomy and Neurobiology, Nippon Medical School, Tokyo, Japan The sensory part of trigeminal nerve is divided into three main branches, ophthalmic (V1), maxillary (V2) and mandibular nerves (V3). We investigated the number and size of the sensory fibers in the three branches in the mouse. The animals were perfused with 2% paraformaldehyde and 2% glutaraldehyde in 0.1 M phosphate buffer (pH 7.4). Each branch was embedded in the epoxy resin, then semi-thin sections were cut. The microphotographs were taken in a computer and the cross-sectional areas and number of fibers were measured by a computer software (Image-Pro Plus, Planetron, Inc.). The cross-sectional areas of fibers were 6.11 ± 0.11 m2 (mean ± S.E.M.) for V1 fibers, 8.93 ± 0.05 m2 for V2 fibers, and 6.01 ± 0.06 m2 for V3 fibers. Total number of the sensory fibers was about 36,000 (per one side), of which 7% were V1, 82% were V2, and 11% were V3 fibers. The large size and number of V2 fibers may reflect well-developed vibrissae in the maxillary part and a wide area innervated by this branch.
movements in the hand region of the secondary somatosensory cortex of the macaque monkey Miki Taoka 1 , Michio Tanaka 1 , Hisayuki Ojima 1 , Sayaka Hihara 1,2 , Atsushi Iriki 1,2 1 Sec. Cognitive Neurobiology, Tokyo Medical Dental University, Tokyo, Japan; 2 Lab. Symbolic Cognitive Development, RIKEN BSI, Wako, Japan Neuronal activities during a simple feeding task were investigated in the hand region of the secondary somatosensory cortex (SII) using an unanesthetized macaque monkey. The monkey was trained to pick up a small piece of food from the experimenter’s hand and ate it. Among 704 isolated neurons from both sides of SII, 557 were active during retrieval of food. Most of them (54%) discharged when the ipsilateral as well as contralateral hand was used (bilateral activities). We found 61 neurons that were active during eating as well as retrieving food (hand/mouth neurons). Almost all of the hand/mouth neurons (92%) showed the bilateral activities suggesting that integration of information about the movements of the hand and mouth occurs among the neurons showing bilateral activities during hand movements. We believe that integrated information of these hand/mouth neurons contributes to the coordination of the hand and mouth movements. Research funds: KAKENHI (17500205)
Inhibitory input from the interpolar nucleus of the spinal P2-f30 trigeminal complex to the principal trigeminal nucleus Takahiro Furuta 1 , Elena Timofeeva 2 , Keiko Okamoto-Furuta 1 , Martin Deschenes 2 , Kouichi Nakamura 1,3 , Takeshi Kaneko 1,3 1 Department Morphological Brain Science, Graduate school of Medicine, Kyoto University, Kyoto, Japan; 2 Centre de Recherche Universite Laval Robert-Giffard, Quebec, Canada; 3 CREST The brainstem trigeminal complex is the first relay stations in the vibrissal system. The lemniscal pathway which arises from the principal trigeminal nucleus and the paralemniscal pathway which arises from interpolar nucleus of the spinal trigeminal complex convey information to the somatosensory cortices. In the principal nucleus neurons, discharges were evoked by the motion of one vibrissa (the principal whisker), while inhibition was induced by deflection of adjacent whiskers. Since very few GABAergic neurons are distributed in the principal nucleus, it is unlikely that the inhibition comes from local cells in the principal nucleus. Using tract tracing technique, we revealed that a subgroup of the interpolar nucleus neurons send GABAergic afferents to the principal nucleus. This suggest that those two parallel pathways coordinately act even in the brainstem. Research funds: KAKENHI 18019017, 18700342
P2-f33 Behavioral inference based on hippocampal multineuronal activities of rats
Masaki Nomura 1,2 , Yoshio Sakurai 1,3 , Toshio Aoyagi 1,2 1 CREST, JST, Japan; 2 Kyoto University Graduate School of Informatics, Kyoto, Japan; 3 Kyoto University Graduate School of Letters, Kyoto, Japan We tried to infer behaviors of rats from multi-neuronal spike data of the hippocampus. The rats were conditioned to poke the right (left) hole when they heard a high (low) tone. We recorded the neuronal activities from the hippocampus CA1 region of the rats, and we obtained the multineuronal spike activities applying the spike sorting technique to the data. Next, we measured a similarity among multi-neuronal spike activities. The similarity we used is defined by the kernel function termed by Spikernel. Performing the kernel k-means clustering and the kernel PCA with the similarity matrices, we classified the multi-neuronal spike activities into two groups, each of which is in good agreement with the discrimination behavior. Our results suggest that the sequence of spike activities plays a crucial role in the better inference.
Abstracts / Neuroscience Research 58S (2007) S1–S244
P2-f26 c-fos expression in the catecholaminergic neurons of the brainstem after eccentric rotation of rats
P2-f31 Orexin modulates neuronal activities in rat mesencephalic trigeminal sensory neurons
Yulin Dong, F.X. Zhang, Y.Q. Li Department of Anatomy, The Fourth Military Medical University, Japan
Kiyomi Nakayama, Shiro Nakamura, Tomio Inoue Department of Physiology, Showa University School Dent., Tokyo, Japan
The expression of c-fos gene in catecholaminergic neurons within the brainstem was examined immunohistochemically. Conscious animals were subjected to eccentric rotation on the horizontal plane. Neuronal activation was defined by Fos protein expression. After stimulation, the Fos protein were mainly distributed in the vestibular nucleus complex (VNC), parabrachial nucleus (PBN), nucleus of the solitary tract (NTS), locus coeruleus (LC), substantia nigra (SN), caudo- or rostro-ventrolateral reticular formation (CVL, RVL), etc. Double immunofluorescent staining showed that most of catecholaminergic neurons in the NTS were activation (double labeled Fos/TH neurons) after eccentric rotation. Double labeled Fos/TH neurons were also observed in LC, CVL, RVL, and other regions related to sympathetic activities of the brainstem. However, there were no double labeled Fos/TH neurons in the SN. Our findings suggest that the catecholaminergic neurons in the brainstem may contribute to the changes of the sympathetic activities induced by the gravity-related spatial information during head movements.
Orexin is a regulatory peptide involved in the control of feeding, motivation and adaptive behaviors. To examine the role of orexin in mastication, whole cell patch-clamp recordings from mesencephalic trigeminal sensory neurons (Mes V), which are critical components of the circuits controlling oral-motor activity, were performed on brainstem slice preparations from Wistar rats aged between postnatal days (P) 0–17. By bath-application of orexin-A (100–500 nM), small membrane depolarizations <3 mV with decreases of the input resistance were observed at the resting potential in the presence of tetrodotoxin (1 M). In rats older than P7 or P8, it is known that the burst discharges are induced by a depolarizing step pulse at a holding potential of about −40 to −50 mV in Mes V neurons. Such conditional burst discharges in Mes V neurons were reduced to 61% of control by bath-application of orexin-A. Persistent sodium currents, which contribute to production of such conditional burst discharges, were also reduced by orexin-A. These results suggest that orexin modulates oral-motor behavior via Mes V neurons.
P2-f28 Measurement of the size and number of the sensory fibers in three branches of the trigeminal nerve in the mouse
P2-f32 Neurons that become active during hand and mouth
Masami Yoshimoto, Nayuki Yamamoto, Hitoshi Ozawa Department of Anatomy and Neurobiology, Nippon Medical School, Tokyo, Japan The sensory part of trigeminal nerve is divided into three main branches, ophthalmic (V1), maxillary (V2) and mandibular nerves (V3). We investigated the number and size of the sensory fibers in the three branches in the mouse. The animals were perfused with 2% paraformaldehyde and 2% glutaraldehyde in 0.1 M phosphate buffer (pH 7.4). Each branch was embedded in the epoxy resin, then semi-thin sections were cut. The microphotographs were taken in a computer and the cross-sectional areas and number of fibers were measured by a computer software (Image-Pro Plus, Planetron, Inc.). The cross-sectional areas of fibers were 6.11 ± 0.11 m2 (mean ± S.E.M.) for V1 fibers, 8.93 ± 0.05 m2 for V2 fibers, and 6.01 ± 0.06 m2 for V3 fibers. Total number of the sensory fibers was about 36,000 (per one side), of which 7% were V1, 82% were V2, and 11% were V3 fibers. The large size and number of V2 fibers may reflect well-developed vibrissae in the maxillary part and a wide area innervated by this branch.
movements in the hand region of the secondary somatosensory cortex of the macaque monkey Miki Taoka 1 , Michio Tanaka 1 , Hisayuki Ojima 1 , Sayaka Hihara 1,2 , Atsushi Iriki 1,2 1 Sec. Cognitive Neurobiology, Tokyo Medical Dental University, Tokyo, Japan; 2 Lab. Symbolic Cognitive Development, RIKEN BSI, Wako, Japan Neuronal activities during a simple feeding task were investigated in the hand region of the secondary somatosensory cortex (SII) using an unanesthetized macaque monkey. The monkey was trained to pick up a small piece of food from the experimenter’s hand and ate it. Among 704 isolated neurons from both sides of SII, 557 were active during retrieval of food. Most of them (54%) discharged when the ipsilateral as well as contralateral hand was used (bilateral activities). We found 61 neurons that were active during eating as well as retrieving food (hand/mouth neurons). Almost all of the hand/mouth neurons (92%) showed the bilateral activities suggesting that integration of information about the movements of the hand and mouth occurs among the neurons showing bilateral activities during hand movements. We believe that integrated information of these hand/mouth neurons contributes to the coordination of the hand and mouth movements. Research funds: KAKENHI (17500205)
Inhibitory input from the interpolar nucleus of the spinal P2-f30 trigeminal complex to the principal trigeminal nucleus Takahiro Furuta 1 , Elena Timofeeva 2 , Keiko Okamoto-Furuta 1 , Martin Deschenes 2 , Kouichi Nakamura 1,3 , Takeshi Kaneko 1,3 1 Department Morphological Brain Science, Graduate school of Medicine, Kyoto University, Kyoto, Japan; 2 Centre de Recherche Universite Laval Robert-Giffard, Quebec, Canada; 3 CREST The brainstem trigeminal complex is the first relay stations in the vibrissal system. The lemniscal pathway which arises from the principal trigeminal nucleus and the paralemniscal pathway which arises from interpolar nucleus of the spinal trigeminal complex convey information to the somatosensory cortices. In the principal nucleus neurons, discharges were evoked by the motion of one vibrissa (the principal whisker), while inhibition was induced by deflection of adjacent whiskers. Since very few GABAergic neurons are distributed in the principal nucleus, it is unlikely that the inhibition comes from local cells in the principal nucleus. Using tract tracing technique, we revealed that a subgroup of the interpolar nucleus neurons send GABAergic afferents to the principal nucleus. This suggest that those two parallel pathways coordinately act even in the brainstem. Research funds: KAKENHI 18019017, 18700342
P2-f33 Behavioral inference based on hippocampal multineuronal activities of rats
Masaki Nomura 1,2 , Yoshio Sakurai 1,3 , Toshio Aoyagi 1,2 1 CREST, JST, Japan; 2 Kyoto University Graduate School of Informatics, Kyoto, Japan; 3 Kyoto University Graduate School of Letters, Kyoto, Japan We tried to infer behaviors of rats from multi-neuronal spike data of the hippocampus. The rats were conditioned to poke the right (left) hole when they heard a high (low) tone. We recorded the neuronal activities from the hippocampus CA1 region of the rats, and we obtained the multineuronal spike activities applying the spike sorting technique to the data. Next, we measured a similarity among multi-neuronal spike activities. The similarity we used is defined by the kernel function termed by Spikernel. Performing the kernel k-means clustering and the kernel PCA with the similarity matrices, we classified the multi-neuronal spike activities into two groups, each of which is in good agreement with the discrimination behavior. Our results suggest that the sequence of spike activities plays a crucial role in the better inference.