- Email: [email protected]
Relationship between prefrontal and hippocampal neuronal spike activities in anesthetized rats
S112
Abstracts / Neuroscience Research 58S (2007) S1–S244
A cooperative dynamics of network of neural oscillaP1-g40 tors between the neuronal activity and the synatptic weight
P1-g44 Relationship between prefrontal and hippocampal neu-
Takaaki Aoki 1,2 , Toshio Aoyagi 1 1 Graduate School of Informatics, Kyoto University, Kyoto, Japan; 2 CREST, JST, Kyoto, Japan
Sei-etsu Fujiwara, Yoshinori Izaki, Tatsuo Akema Department of Physiology, St. Marianna University, Kawasaki, Japan
In general, the activity of neurons highly depends on the structure of neural network, namely, the synaptic connections among the neurons. On the other hand, this network structure is also gradually changing, because the synaptic connection is modulated by its plasticity depending on the current neuronal activity. This cooperative dynamics between the neuronal activity and the synaptic connection is essential for realizing high adaptability in brain. However, it is almost unclear what type of functional network structure is organized through such a cooperative dynamics. Thus, we investigate this issue in the modeling study. Considering an oscillatory activity of neurons, we show that the system can be described by the both dynamics of the general phase oscillators and synaptic weights. This system exhibits various types of dynamical behaviors according to the rule of synaptic plasticity.
The prefrontal cortex (PFC) and hippocampus (Hip) are important brain regions for learning and memory. The anatomical connection between both regions is well known. The aim of this study was to investigate possible functional connections between these regions based on the correlation of neuronal activities. A cross-correlation histogram was constructed based on each pair of PFC and Hip neuronal spike trains which were simultaneously recorded in urethane-anesthetized rats. The pattern of cross-correlogram changed depending on the location of the electrodes. The cross-correlogram corresponding to monosynaptic projection from Hip to PFC was also seen. These results suggest the neuronal connectivity is reflected in the cross-correlogram changes and could be analyzed based on spontaneous firing patterns of PFC and Hip. The method using the present study may be useful in investigating neuronal connectivity between the PFC and Hip for learning and memory in conscious animals.
ronal spike activities in anesthetized rats
Research funds: KAKENHI (18047014, 18019019, 18300079), CREST
P1-g41 Involvement of the Calcineurin B2 gene in Drosophila courtship memory Yasuhiro Nakai, Toshiro Aigaki, Takaomi Sakai Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan Courtship conditioning is a classical conditioning paradigm in Drosophila that involves only physiological stimuli and is able to induce long-term memory (LTM) lasting several days. Since the activation of transcriptional factors or new protein synthesis is required for LTM-formation, it is possible that expression level of genes regulating LTM-formation increases after the conditioning. We have performed DNA microarray analyses to compare transcriptional changes induced by courtship conditioning in wild-type males, and identified a Calcineurin B2 (CanB2) that encodes regulatory subunit of calcineurin. Calcineurin is a Ca2+ /calmodulin dependent serine/threonine protein phosphatase and affects various behavior or neuronal plasticity in animal. We measured LTM of CanB2 homozygous mutants by courtship conditioning, and confirmed that the homozygous mutants show the defective LTM but the LTM in heterozygous mutants are normal. Taken together, our study suggests that the formation of long-term courtship memory depends on the expression level of CanB2.
P1-g42 Singing-related activity in basal ganglia of juvenile songbird Shin Yanagihara, Neal Hessler BSI, RIKEN, Saitama, Japan Although the striatal nucleus Area X is clearly required for normal song learning, its function in this process remains unclear. As a first step toward understanding the role of the basal ganglia in this easily quantified form of motor learning, we have begun to characterize the activity patterns of Area X neurons in juvenile songbirds during the sensorimotor learning period. We recorded single-unit activity from Area X of male juvenile zebra finches (from 50 to 70 days of age) when the birds produce immature and highly variable ‘plastic’ songs. We found that the level of activity of Area X neurons was consistently increased during singing. This increase began before initiation of singing. These neurons did not respond to playback of the bird’s own song, or to hearing the tutor sing in awake condition. Some neurons that were active during singing also showed occasional phasic increases of activity during sleep, possibly similar to previously described ‘replay’ of song-generation activity in song system motor nuclei.
P1-g45 Nitric oxide synthase dsRNA interfere with long-term memory formation in an insect Toshifumi Takahashi 1 , Hisayo Kunitou 2 , Asuka Hamada 2 , Yukihisa Matsumoto 1 , Taro Mito 2 , Sumihare Noji 2 , Makoto Mizunami 1 1 Graduate School of Life Sciences, Tohoku University, Sendai, Japan; 2 Department of Life Systems, Institute of Science and Technology, University of Tokushima, Tokushima, Japan Cyclic AMP pathway plays an essential role in long-term memory (LTM) formation. In insects, nitric oxide (NO)/cyclic GMP (cGMP) pathway is also involved in LTM formation. We suggested NO/cGMP pathway is upstream of cAMP/PKA pathway in pharmacological study in crickets (Matsumoto et al. 2006). We attempted to use dsRNA to investigate signaling cascade underlying the formation of LTM, and show that nitric oxide synthase (NOS) dsRNA is effective to interfere with LTM formation. Nympal crickets were injected with dsRNA before conditioning. At 30 min and 24 h after conditioning, we performed preference test. We found that NOS dsRNA interfered with LTM formation, without affecting short-term memory retention.
P1-g46 Relationship between hippocampal and prefrontal local field potential power changes related to neuronal connectivity in anesthetized rats Yoshinori Izaki, Sei-etsu Fujiwara, Tatsuo Akema Department of Physiology, St. Marianna University School of Medicine, Kawasaki, Japan To investigate whether neural connectivity between the hippocampus (Hip) and prefrontal cortex (PFC) is reflected in the relationship between power changes in these local field potentials (LFPs), we recorded Hip and PFC extracellular spike activities (spikes) and LFPs simultaneously in urethane-anesthetized rats. The cross-correlation (CC) histogram between the Hip and PFC spikes was analyzed for each pair of recording sites. Recorded LFPs were filtered with 8–16, 16–32, 32–64, 64–128, and 128–256 Hz band-pass filters, and then the CC between the Hip and PFC LFP power changes was analyzed in each frequency band. These analyses revealed that the features of the CC histogram for neuronal spikes were similar to those of the CC for the 32–64 or 64–128 Hz LFP power changes. These results suggest that the neuronal connectivity is also reflected in the feature of the CC for the gamma-band power changes between the Hip and PFC. Similar methods may be useful for learning and memory studies on LFPs.
Abstracts / Neuroscience Research 58S (2007) S1–S244
A cooperative dynamics of network of neural oscillaP1-g40 tors between the neuronal activity and the synatptic weight
P1-g44 Relationship between prefrontal and hippocampal neu-
Takaaki Aoki 1,2 , Toshio Aoyagi 1 1 Graduate School of Informatics, Kyoto University, Kyoto, Japan; 2 CREST, JST, Kyoto, Japan
Sei-etsu Fujiwara, Yoshinori Izaki, Tatsuo Akema Department of Physiology, St. Marianna University, Kawasaki, Japan
In general, the activity of neurons highly depends on the structure of neural network, namely, the synaptic connections among the neurons. On the other hand, this network structure is also gradually changing, because the synaptic connection is modulated by its plasticity depending on the current neuronal activity. This cooperative dynamics between the neuronal activity and the synaptic connection is essential for realizing high adaptability in brain. However, it is almost unclear what type of functional network structure is organized through such a cooperative dynamics. Thus, we investigate this issue in the modeling study. Considering an oscillatory activity of neurons, we show that the system can be described by the both dynamics of the general phase oscillators and synaptic weights. This system exhibits various types of dynamical behaviors according to the rule of synaptic plasticity.
The prefrontal cortex (PFC) and hippocampus (Hip) are important brain regions for learning and memory. The anatomical connection between both regions is well known. The aim of this study was to investigate possible functional connections between these regions based on the correlation of neuronal activities. A cross-correlation histogram was constructed based on each pair of PFC and Hip neuronal spike trains which were simultaneously recorded in urethane-anesthetized rats. The pattern of cross-correlogram changed depending on the location of the electrodes. The cross-correlogram corresponding to monosynaptic projection from Hip to PFC was also seen. These results suggest the neuronal connectivity is reflected in the cross-correlogram changes and could be analyzed based on spontaneous firing patterns of PFC and Hip. The method using the present study may be useful in investigating neuronal connectivity between the PFC and Hip for learning and memory in conscious animals.
ronal spike activities in anesthetized rats
Research funds: KAKENHI (18047014, 18019019, 18300079), CREST
P1-g41 Involvement of the Calcineurin B2 gene in Drosophila courtship memory Yasuhiro Nakai, Toshiro Aigaki, Takaomi Sakai Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan Courtship conditioning is a classical conditioning paradigm in Drosophila that involves only physiological stimuli and is able to induce long-term memory (LTM) lasting several days. Since the activation of transcriptional factors or new protein synthesis is required for LTM-formation, it is possible that expression level of genes regulating LTM-formation increases after the conditioning. We have performed DNA microarray analyses to compare transcriptional changes induced by courtship conditioning in wild-type males, and identified a Calcineurin B2 (CanB2) that encodes regulatory subunit of calcineurin. Calcineurin is a Ca2+ /calmodulin dependent serine/threonine protein phosphatase and affects various behavior or neuronal plasticity in animal. We measured LTM of CanB2 homozygous mutants by courtship conditioning, and confirmed that the homozygous mutants show the defective LTM but the LTM in heterozygous mutants are normal. Taken together, our study suggests that the formation of long-term courtship memory depends on the expression level of CanB2.
P1-g42 Singing-related activity in basal ganglia of juvenile songbird Shin Yanagihara, Neal Hessler BSI, RIKEN, Saitama, Japan Although the striatal nucleus Area X is clearly required for normal song learning, its function in this process remains unclear. As a first step toward understanding the role of the basal ganglia in this easily quantified form of motor learning, we have begun to characterize the activity patterns of Area X neurons in juvenile songbirds during the sensorimotor learning period. We recorded single-unit activity from Area X of male juvenile zebra finches (from 50 to 70 days of age) when the birds produce immature and highly variable ‘plastic’ songs. We found that the level of activity of Area X neurons was consistently increased during singing. This increase began before initiation of singing. These neurons did not respond to playback of the bird’s own song, or to hearing the tutor sing in awake condition. Some neurons that were active during singing also showed occasional phasic increases of activity during sleep, possibly similar to previously described ‘replay’ of song-generation activity in song system motor nuclei.
P1-g45 Nitric oxide synthase dsRNA interfere with long-term memory formation in an insect Toshifumi Takahashi 1 , Hisayo Kunitou 2 , Asuka Hamada 2 , Yukihisa Matsumoto 1 , Taro Mito 2 , Sumihare Noji 2 , Makoto Mizunami 1 1 Graduate School of Life Sciences, Tohoku University, Sendai, Japan; 2 Department of Life Systems, Institute of Science and Technology, University of Tokushima, Tokushima, Japan Cyclic AMP pathway plays an essential role in long-term memory (LTM) formation. In insects, nitric oxide (NO)/cyclic GMP (cGMP) pathway is also involved in LTM formation. We suggested NO/cGMP pathway is upstream of cAMP/PKA pathway in pharmacological study in crickets (Matsumoto et al. 2006). We attempted to use dsRNA to investigate signaling cascade underlying the formation of LTM, and show that nitric oxide synthase (NOS) dsRNA is effective to interfere with LTM formation. Nympal crickets were injected with dsRNA before conditioning. At 30 min and 24 h after conditioning, we performed preference test. We found that NOS dsRNA interfered with LTM formation, without affecting short-term memory retention.
P1-g46 Relationship between hippocampal and prefrontal local field potential power changes related to neuronal connectivity in anesthetized rats Yoshinori Izaki, Sei-etsu Fujiwara, Tatsuo Akema Department of Physiology, St. Marianna University School of Medicine, Kawasaki, Japan To investigate whether neural connectivity between the hippocampus (Hip) and prefrontal cortex (PFC) is reflected in the relationship between power changes in these local field potentials (LFPs), we recorded Hip and PFC extracellular spike activities (spikes) and LFPs simultaneously in urethane-anesthetized rats. The cross-correlation (CC) histogram between the Hip and PFC spikes was analyzed for each pair of recording sites. Recorded LFPs were filtered with 8–16, 16–32, 32–64, 64–128, and 128–256 Hz band-pass filters, and then the CC between the Hip and PFC LFP power changes was analyzed in each frequency band. These analyses revealed that the features of the CC histogram for neuronal spikes were similar to those of the CC for the 32–64 or 64–128 Hz LFP power changes. These results suggest that the neuronal connectivity is also reflected in the feature of the CC for the gamma-band power changes between the Hip and PFC. Similar methods may be useful for learning and memory studies on LFPs.