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Environmental enrichment enhances neuropsin mRNA in the hippocampus
Abstracts respectively, and compared the difference of the multisynaptic inputs to the DG along the septotemporal axis. doi:10.1016/j.neures.2009.09.1320
P3-i04 Self-organization process of network structure in a STDP neural network model Norihiro Katayama, Shohei Yamada, Akihiro Karashima, Mitsuyuki Nakao Tohoku University, Japan The spike-timing-dependent plasticity (STDP) of synapse is believed to play an essential role in self-organization of neural network in the brain. In this study, we explored the process of self-organization of network structure in a STDP neural network model. The neural network model was constructed by the Hodgkin–Huxley type model neurons coupled with chemical synapses with a fixed time delay. Computer simulations showed that a few groups of synchronously firing neurons were autonomously organized when random perturbations were applied to the network. The neuron groups fired in a fixed order. The number of neuron group was dependent on the time delay. We found that the neuron groups were hierarchically organized during the process of self-organization.
S235
P3-i07 Spatial working memory deficits are shown in the rat with abnormal hippocampal neurogenesis, but not in the rat with abnormal cerebellar neurogenesis Kozo Sugioka 1 , Tomiyoshi Setsu 2 , Toshio Terashima 2 1 Dept. Functional Anat., Facul. Pharmac. Sci., Himeji Dokkyo Univ., Himeji, Japan; 2 Div. Anat. & Dev. Neurobiol., Department Physiol. & Cell Biol., Kobe Univ. Grad. Sch. Med., Kobe, Japan
We examined spatial working memory in rats with abnormal morphogenesis of the hippocampus or cerebellum. Jcl:Wistar pregnant rats were i.p. injected with saline or 25 mg/kg methylazoxymethanol (MAM) on gestational day 15 (M-15) or 19 (M19). Offspring were trained to reach a hidden escape platform in a water maze using delayed-matching-to-place task which consisted of two trials (a forced and a test trial) for 24 days (one session per day) during adult period. The forced trial taught the rat the daily correct section in which the escape platform was placed. In the test trial, the rat was required to enter to the platform section learned in the preceding forced trial. Spatial working memory deficits are shown in the M15 rat which had an abnormal hippocampal neurogenesis (disruption of the CA1 pyramidal layer and ectopic neuron mass), but not in the M-19 rat which had an abnormal anterior cerebellar foliation. doi:10.1016/j.neures.2009.09.1324
doi:10.1016/j.neures.2009.09.1321
P3-i05 Effect of alcohol (ethanol) administration on hippocampal CA1 neuron activity in conscious rats Momoka Tanji 1 , Atsuko Ito 1 , Sachie Tajima 1 , Chiaki Megumi 2 , Takuya Hamano 2 , Nobuaki Tsuge 2 , Kenju Miki 1 1
Dept. Integrative Physiol., Nara Women’s Univ., Nara, Japan; Center, House Foods Co., Chiba, Japan
2
Somatech
The present study was designed to examine the time course of a response of hippocampal CA1 neuron activity to alcohol administration in conscious rats. Wistar male rats were instrumented chronically with multiple electrodes (100 micrometer stainless steal wire) for the measurement of the hippocampal CA1 neuron activity and bipolar electrodes for measurement of electroencephalogram (EEG) and electromyogram. 20% of ethanol (2 g/kg body weight) in saline solution was infused intravenously over 5 min after the 60 min control period. The hippocampal CA1 neuron activity was decreased immediately after start of the infusion, and it was remained lowered over 180 min thereafter. The theta power of EEG was decreased immediately after start of the infusion, but it returned to the control level at 180 min after the infusion. It is therefore suggested that alcohol (ethanol) suppressed hippocampal CA1 neuron and cerebral cortex activity in regionally different manner.
P3-i08 Dependence on the cerebellum and the medial prefrontal cortex in mouse eyeblink conditioning Shigenori Kawahara, Keisuke Matoba Dept. Life Sci. and Bioeng., Fac. Engineering, Univ. of Toyama, Toyama, Japan We previously reported that bilateral cerebellar ablation does not impair eyeblink conditioning in C57BL/6 mice, while DBA/2 mice, which have several deficits in the forebrain, showed a significant impairment by cerebellar ablation ipsilateral to the trained eye. Based on these results, we hypothesized that C57 mice have another or compensative learning mechanism that does not necessarily require the cerebellum but depends on the forebrain. In the present study, we examined the medial prefrontal cortex (mPFC) as a candidate. We ablated the ipsilateral cerebellum (CB group), the bilateral mPFC (mPFC group), or both of them (CB-mPFC group). Mice were trained in delay eyeblink conditioning paradigm with a tone and a periorbital shock. We found that CB-mPFC group showed a significant impairment, while mPFC and CB groups learned as well as intact mice. These results indicate that mice require either the ipsilateral cerebellum or mPFC for a successful learning, suggesting that mPFC is involved in the extra-cerebellar mechanism for delay eyeblink conditioning in mice. doi:10.1016/j.neures.2009.09.1325
doi:10.1016/j.neures.2009.09.1322
P3-i06 Environmental enrichment enhances neuropsin mRNA in the hippocampus Dai Kanagawa, Yasuyuki Ishikawa, Sadao Shiosaka Nara Institute of Science and Technology, Japan Environmental enrichment is known to induce neural development and plasticity in the hippocampus. Several investigators demonstrated that environmental enrichment induced improvements of memory performances in rodents, and the improvements correlates to the increased neurogenesis, synaptic density, and gene expression such as neurotrophic factors, neurotransmitter receptors, and synthesizing enzymes for neurotransmitters. In the present study, we analyzed an effect of environmental enrichment on mRNA expression of synaptic plasticity relating serine proteases (neuropsin, neurotrypsin, tPA) and cell adhesion molecules (L1CAM, NCAM, N-cadherin) in the hippocampus by real-time RT-PCR. Our data showed that neuropsin mRNA significantly increased in the hippocampus of enriched mice compared to control mice. Our result suggests that molecular changes relating to the structural plasticity may induce a synaptic modulation and rearrangement through environmental enrichment.
P3-i09 Image analysis of the trace eyeblink conditioning in mice Koji Usui, Airi Mizukami, Shigenori Kawahara Dept. Life Sci. and Bioeng., Fac. Engineering, Univ. of Toyama, Toyama, Japan We previously developed an image-analysis system for studying eyeblink conditioning in mice with their head fixed, and found that DBA/2 mice, which have several abnormalities in the forebrain, learned delay eyeblink conditioning as well as C57BL/6 mice. In the present work, we further examined whether these mice learn trace eyeblink conditioning, in which the forebrain, including the hippocampus, plays an important role. The neural activities in hippocampus were also recorded. During the conditioning, DBA mice showed a significant impairment compared to C57 mice, which is consistent with our previous data in free-moving mice. An analysis of temporal pattern of the conditioned response revealed that there was a significant difference in the onset latency but not in the peak latency of the conditioned response between these mice: C57 mice began to blink earlier. Combined with the results from the cerebellar lesion study in delay eyeblink conditioning, these results suggest that the learning mechanism underlying the trace eyeblink conditioning may be different between C57BL/6 and DBA/2 mice. doi:10.1016/j.neures.2009.09.1326
doi:10.1016/j.neures.2009.09.1323
P3-i10 The influence of interrupting a memory-guided sequential motor task on prefrontal neuronal activity Toshi Nakajima 1 , Atsushi Miyazaki 1 , Keisetsu Shima 1 , Jun Tanji 2 , Hajime Mushiake 1 1
Dept. Physiol., Tohoku Univ. Sch. Med., Sendai, Japan; Cent., Tamagawa Univ. Res. Inst., Machida, Japan
2
Brain Sci. Res.
We often need to keep an internal action plan against external perturbation in order to obtain a certain behavioral goal. To investigate how the brain maintains and recalls
P3-i04 Self-organization process of network structure in a STDP neural network model Norihiro Katayama, Shohei Yamada, Akihiro Karashima, Mitsuyuki Nakao Tohoku University, Japan The spike-timing-dependent plasticity (STDP) of synapse is believed to play an essential role in self-organization of neural network in the brain. In this study, we explored the process of self-organization of network structure in a STDP neural network model. The neural network model was constructed by the Hodgkin–Huxley type model neurons coupled with chemical synapses with a fixed time delay. Computer simulations showed that a few groups of synchronously firing neurons were autonomously organized when random perturbations were applied to the network. The neuron groups fired in a fixed order. The number of neuron group was dependent on the time delay. We found that the neuron groups were hierarchically organized during the process of self-organization.
S235
P3-i07 Spatial working memory deficits are shown in the rat with abnormal hippocampal neurogenesis, but not in the rat with abnormal cerebellar neurogenesis Kozo Sugioka 1 , Tomiyoshi Setsu 2 , Toshio Terashima 2 1 Dept. Functional Anat., Facul. Pharmac. Sci., Himeji Dokkyo Univ., Himeji, Japan; 2 Div. Anat. & Dev. Neurobiol., Department Physiol. & Cell Biol., Kobe Univ. Grad. Sch. Med., Kobe, Japan
We examined spatial working memory in rats with abnormal morphogenesis of the hippocampus or cerebellum. Jcl:Wistar pregnant rats were i.p. injected with saline or 25 mg/kg methylazoxymethanol (MAM) on gestational day 15 (M-15) or 19 (M19). Offspring were trained to reach a hidden escape platform in a water maze using delayed-matching-to-place task which consisted of two trials (a forced and a test trial) for 24 days (one session per day) during adult period. The forced trial taught the rat the daily correct section in which the escape platform was placed. In the test trial, the rat was required to enter to the platform section learned in the preceding forced trial. Spatial working memory deficits are shown in the M15 rat which had an abnormal hippocampal neurogenesis (disruption of the CA1 pyramidal layer and ectopic neuron mass), but not in the M-19 rat which had an abnormal anterior cerebellar foliation. doi:10.1016/j.neures.2009.09.1324
doi:10.1016/j.neures.2009.09.1321
P3-i05 Effect of alcohol (ethanol) administration on hippocampal CA1 neuron activity in conscious rats Momoka Tanji 1 , Atsuko Ito 1 , Sachie Tajima 1 , Chiaki Megumi 2 , Takuya Hamano 2 , Nobuaki Tsuge 2 , Kenju Miki 1 1
Dept. Integrative Physiol., Nara Women’s Univ., Nara, Japan; Center, House Foods Co., Chiba, Japan
2
Somatech
The present study was designed to examine the time course of a response of hippocampal CA1 neuron activity to alcohol administration in conscious rats. Wistar male rats were instrumented chronically with multiple electrodes (100 micrometer stainless steal wire) for the measurement of the hippocampal CA1 neuron activity and bipolar electrodes for measurement of electroencephalogram (EEG) and electromyogram. 20% of ethanol (2 g/kg body weight) in saline solution was infused intravenously over 5 min after the 60 min control period. The hippocampal CA1 neuron activity was decreased immediately after start of the infusion, and it was remained lowered over 180 min thereafter. The theta power of EEG was decreased immediately after start of the infusion, but it returned to the control level at 180 min after the infusion. It is therefore suggested that alcohol (ethanol) suppressed hippocampal CA1 neuron and cerebral cortex activity in regionally different manner.
P3-i08 Dependence on the cerebellum and the medial prefrontal cortex in mouse eyeblink conditioning Shigenori Kawahara, Keisuke Matoba Dept. Life Sci. and Bioeng., Fac. Engineering, Univ. of Toyama, Toyama, Japan We previously reported that bilateral cerebellar ablation does not impair eyeblink conditioning in C57BL/6 mice, while DBA/2 mice, which have several deficits in the forebrain, showed a significant impairment by cerebellar ablation ipsilateral to the trained eye. Based on these results, we hypothesized that C57 mice have another or compensative learning mechanism that does not necessarily require the cerebellum but depends on the forebrain. In the present study, we examined the medial prefrontal cortex (mPFC) as a candidate. We ablated the ipsilateral cerebellum (CB group), the bilateral mPFC (mPFC group), or both of them (CB-mPFC group). Mice were trained in delay eyeblink conditioning paradigm with a tone and a periorbital shock. We found that CB-mPFC group showed a significant impairment, while mPFC and CB groups learned as well as intact mice. These results indicate that mice require either the ipsilateral cerebellum or mPFC for a successful learning, suggesting that mPFC is involved in the extra-cerebellar mechanism for delay eyeblink conditioning in mice. doi:10.1016/j.neures.2009.09.1325
doi:10.1016/j.neures.2009.09.1322
P3-i06 Environmental enrichment enhances neuropsin mRNA in the hippocampus Dai Kanagawa, Yasuyuki Ishikawa, Sadao Shiosaka Nara Institute of Science and Technology, Japan Environmental enrichment is known to induce neural development and plasticity in the hippocampus. Several investigators demonstrated that environmental enrichment induced improvements of memory performances in rodents, and the improvements correlates to the increased neurogenesis, synaptic density, and gene expression such as neurotrophic factors, neurotransmitter receptors, and synthesizing enzymes for neurotransmitters. In the present study, we analyzed an effect of environmental enrichment on mRNA expression of synaptic plasticity relating serine proteases (neuropsin, neurotrypsin, tPA) and cell adhesion molecules (L1CAM, NCAM, N-cadherin) in the hippocampus by real-time RT-PCR. Our data showed that neuropsin mRNA significantly increased in the hippocampus of enriched mice compared to control mice. Our result suggests that molecular changes relating to the structural plasticity may induce a synaptic modulation and rearrangement through environmental enrichment.
P3-i09 Image analysis of the trace eyeblink conditioning in mice Koji Usui, Airi Mizukami, Shigenori Kawahara Dept. Life Sci. and Bioeng., Fac. Engineering, Univ. of Toyama, Toyama, Japan We previously developed an image-analysis system for studying eyeblink conditioning in mice with their head fixed, and found that DBA/2 mice, which have several abnormalities in the forebrain, learned delay eyeblink conditioning as well as C57BL/6 mice. In the present work, we further examined whether these mice learn trace eyeblink conditioning, in which the forebrain, including the hippocampus, plays an important role. The neural activities in hippocampus were also recorded. During the conditioning, DBA mice showed a significant impairment compared to C57 mice, which is consistent with our previous data in free-moving mice. An analysis of temporal pattern of the conditioned response revealed that there was a significant difference in the onset latency but not in the peak latency of the conditioned response between these mice: C57 mice began to blink earlier. Combined with the results from the cerebellar lesion study in delay eyeblink conditioning, these results suggest that the learning mechanism underlying the trace eyeblink conditioning may be different between C57BL/6 and DBA/2 mice. doi:10.1016/j.neures.2009.09.1326
doi:10.1016/j.neures.2009.09.1323
P3-i10 The influence of interrupting a memory-guided sequential motor task on prefrontal neuronal activity Toshi Nakajima 1 , Atsushi Miyazaki 1 , Keisetsu Shima 1 , Jun Tanji 2 , Hajime Mushiake 1 1
Dept. Physiol., Tohoku Univ. Sch. Med., Sendai, Japan; Cent., Tamagawa Univ. Res. Inst., Machida, Japan
2
Brain Sci. Res.
We often need to keep an internal action plan against external perturbation in order to obtain a certain behavioral goal. To investigate how the brain maintains and recalls