- Email: [email protected]
Thalamocortical projections of the anteroventral thalamic nucleus in the rabbit
e376
Abstracts / Neuroscience Research 71S (2011) e108–e415
P4-n10 Fear conditioning changes responsiveness of fearrelated neurons to conditioned stimulus Ayako Nonaka , Norio Matsuki, Hiroshi Nomura Lab. Chem. Pharmacol., Grad. Sch. Pharm. Sci., Univ. of Tokyo, Tokyo, Japan Fear conditioning is a form of associative learning in which subjects learn the relationship between a neutral conditioned stimulus (CS) and an aversive unconditioned stimulus (US). After conditioning, the subjects come to express fear responses to CS as if there is US. Neural circuitry underlying fear conditioning is hypothesized as follows: fear-related neurons are not responsive to CS; when the neurons receive CS-relevant input and US-relevant one, the neurons become responsive to CS through synaptic potentiation; thus, CS-evoked activation of fear-related neurons induces fear responses. However, there is no clear evidence to confirm this hypothesis. To establish this, we identified active neurons during fear conditioning. We used Arc and Homer1a mRNA, a kind of immediate early genes (IEGs) which appears in the neuron immediately after activation. Mice were placed in the conditioning chamber before conditioning. They were returned to their homecage and 36 min later, they were conditioned with footshocks in the chamber. They were returned to the homecage again and 20 min later, they were reexposed to the chamber to recall the fear memory. Immediately after the retrieval, their brains were removed and Arc and Homer1a mRNA in the lateral amygdala were detected by fluorescence in situ hybridization. The activity of individual neurons during each behavioral task was determined by subcellular localization of Arc and Homer1a mRNA. Some neurons were not activated during the first CS-exposure but were activated during conditioning. More than half of these fear-related neurons were activated during second CSexposure. The proportion of neurons that changed their responsiveness to CS through conditioning was higher than that of control level. These findings indicate that fear-related neurons become responsive to CS through conditioning. CS-induced activation of fear-related neurons may produce fear responses. doi:10.1016/j.neures.2011.07.1650
P4-n11 Cholinergic activation is required for learningdependent AMPA receptor delivery into the CA3-CA1 synapses Dai Mitsushima , Takuya Takahashi Dept. Physiol., Yokohama City Univ., Grad. Sch. of Med. We previously reported that contextual learning requires AMPA receptor delivery in CA1 synapses. Since acetylcholine release increases during the period of learning in behaving rats, we hypothesized that cholinergic activation triggers learning-dependent plasticity in CA1 neurons in vivo. By combining in vivo gene delivery with in vitro patch-clamp recordings, we found that hippocampal-dependent inhibitory avoidance (IA) learning drives recombinant GluR1-containing AMPA receptors into synapses formed between CA3 and CA1 pyramidal neurons. Pretreatment of scopolamine (2 mg/kg), a muscarinic receptor antagonist, not only impaired the IA learning, but also blocked the synaptic delivery of reconmbinant GluR1containig AMPA receptors. Moreover, scopolamine pretreatment blocked the learning-induced increase in AMPA/NMDA ratio, suggesting acetylcholinemediated synaptic delivery of endogenous AMPA receptors. Moreover, in paired-recording study, scopolamine pretreatment successfully blocked the effect of mutated fragment of GluR1 cytoplasmic tail (MPR-DD), a construct that inhibits learning-dependent synaptic delivery of endogenous AMPA receptors. In contrast, neither learning nor scopolamine pretreatment affect the synaptic delivery in neurons expressed control fragment (MPR-AA). Further, using in vivo microdialysis technique, we monitored local acetylcholine release at CA1 region in behaving animals. The acetylcholine release significantly increased during IA learning, and the increase was sustained after the task for 60 min. Acetylcholine release transiently increased in some control animals (such as naive, shock only, or walk through rats), but the increase was not sustained. These results suggest that cholinergic activation is required for learning-dependent AMPA receptor delivery into the CA3-CA1 synapses. Research fund: KAKENHI 20590232. doi:10.1016/j.neures.2011.07.1651
P4-n12 Molecular mechanisms of circadian regulation of the memory for novel objects Kimiko Shimizu , Yodai Kobayashi, Yoshitaka Fukada Dept. Biophys. and Biochem., Grad. Sch. of Sci., Univ. of Tokyo, Tokyo, Japan Evidence from several studies demonstrates that circadian rhythm affects memory formation. However it is not yet clear if the internal clock regulates
the efficiency of memory formation, and there is no molecular-based evidence that connects memory and circadian rhythm. We tested novel object recognition memory over the circadian time. Long-term memory varied in a circadian manner and hence it seems to be controlled by endogenous circadian clock. In fact, clock mutant mouse did not show the circadian oscillation of long-term memory for novel object. We are focusing on SCOP and related molecules to find a molecular process between circadian rhythm and memory formation. SCOP/PHLPP is expressed in a circadian manner in the suprachiasmatic nucleus (SCN) that is the center for circadian rhythm. SCOP negatively regulates K-Ras function and its downstream ERK/MAPK pathway. In the hippocampus, SCOP is critical for long-term memory formation for novel objects. These data indicate that SCOP-ERK pathway could be a key for circadian control for long-term memory formation in the hippocampus. We found that SCOP protein level in raft fraction in the hippocampus oscillates in a circadian manner. SCOP knockdown by shRNA expression lentivirus attenuated circadian oscillation of long-term memory for objects. Now we are examining detailed molecular mechanisms of circadian regulation system of memory formation in in vivo and in vitro. Research fund: Asahi Glass Foundation. doi:10.1016/j.neures.2011.07.1652
P4-n13 Calcineurin in the hippocampus and amygdala is required for destabilization and extinction of retrieved contextual fear memory Ryang Kim 1 , Karim Nader 2 , Satoshi Kida 1,3 1
Dep. of Bioscience, Tokyo Univ. of Agriculture, Tokyo, Japan 2 Dep. of Psychology, McGill Univ., Kanada 3 JST, CREST, Saitama, Japan
Retrieval of conditioned fear memory by re-exposure to the context (conditioned stimulus; CS) initiates reconsolidation and extinction. We previously found that reconsolidation and extinction of contextual fear memory requires activation of CREB through phosphorylation at Serine 133 in the hippocampus/amygdala or amygdala/medial prefrontal cortex, respectively (Kida et al., 2002; Mamiya et al., 2009). Interestingly, we observed that short re-exposure (3 min) to the CS inducing reconsolidation increase in CREB phosphorylation in hippocampus, whereas the prolonged re-exposure (30 min) inducing extinction prevented this CREB phosphorylation. These observations suggest that regulations of phosphorylation and dephosphorylation of CREB by CREB-kinases and phosphatases, respectively, play critical roles in the determination for the fate of fear memory; reconsolidation or extinction. In this study, we tried to understand roles of calcineurin (Protein Phosphatase 2B; PP2B) in reconsolidation and extinction of contextual fear memory. Infusion of calcineurin inhibitor FK506 into hippocampus after 3 min re-exposure to the CS prevented the disruption of reactivated memory by protein synthesis inhibitor anisomycin (ANI). This prevention of amnesic ANI-effect by FK506 was also observed when FK506 was infused into amygdala. These observations suggest that calcineurin in the hippocampus and amygdala is required for destabilization of retrieved contextual fear memory. On the other hand, hippocampal FK506-infusion just before, but not after, 30 min re-exposure to the CS impaired acquisition of extinction. In contrast, amgdaloid FK506-infusion inhibited consolidation but not acquisition of extinction, indicating that calcineurin in the hippocampus and amygdala plays distinct roles in extinction of contextual fear. Collectively, these results suggest that calcineurin in the hippocampus and amygdala plays essential roles in destabilization and extinction of retrieved contextual fear memory. doi:10.1016/j.neures.2011.07.1653
P4-n14 Thalamocortical projections of the anteroventral thalamic nucleus in the rabbit Hideshi Shibata 1 , Yoshiko Honda 2
1 Lab. of Vet. Anat., Inst. of Agri., Tokyo Univ. of Agri. & Tech., Fuchu, Tokyo, Japan 2 Dept. of Anat., Tokyo Women’s Med. Univ., Tokyo, Japan
The anteroventral nucleus (AV), which is part of the anterior thalamic nuclei, has been implicated in behavioral learning such as discriminative avoidance conditioning in the rabbit. Although the interactions between AV and the cortex are important for such learning, it is not yet known the neural connections between AV and the cortex in the rabbit. In the present study, we demonstrated the areal and laminar distributions of the thalamocortical projections of AV, using anterograde axonal transport of biotinylated dextran amine (BDA). An injection of BDA restricted to the magnocellular division of AV (AVm) labeled massive terminals in superficial layer I of areas 29a-c. In contrast, an injection restricted to the parvocellular division of AV (AVp) labeled massive terminals in layer IV and deep layer I of areas 29a-c, lay-
Abstracts / Neuroscience Research 71S (2011) e108–e415
ers I and IV of area 30, and layers I and VI of the presubiculum. The results show that in the rabbit AVm and AVp provide different thalamocortical projections, suggesting that each division may play different functional roles in behavioral learning. Research fund: The Japan Pet Care Association (to H.S.). doi:10.1016/j.neures.2011.07.1654
P4-n15 Hippocampal afferents to the rabbit presubiculum Yoshiko Honda 1 , Hideshi Shibata 2 1
Dept. of Anat., Scl. of Med., Tokyo Women’s Med. Univ., Tokyo, Japan 2 Lab. of Vet. Anat, Inst. Agri., Tokyo Univ. Agri. & Tech., Tokyo, Japan Connections between the hippocampal formation and its adjoining parahippocampal areas are crucial for memory formation in many species. In the rat, the presubiculum (Pre), a part of the parahippocampal areas, is known to be responsible for processing spatial information. In the rabbit, the parahippocampal areas are more differentiated than in the rat, so that its Pre seems to have more extended function. However, little is known about the connectivity of Pre in the rabbit. In the present study, cells of origin of hippocampal afferents to Pre are investigated in the rabbit by in vivo injection of choleratoxin B subunit as a retrograde tracer. We found that rabbit Pre receives strong hippocampal inputs from both CA1 and the subiculum (Sub). Such strong hippocampal input from CA1 is characteristic in rabbit Pre, because rat Pre receives major inputs from Sub, but not from CA1. Our results show that rabbit Pre receives afferents from broader regions in the hippocampus, suggesting more complex memory information processing than in the rat. doi:10.1016/j.neures.2011.07.1655
P4-n16 Increase of hippocampal BDNF is essential for consolidation of spatial memory in spontaneous place recognition test in rats Takaaki Ozawa , Kazuo Yamada, Yukio Ichitani Dept. of Behav. Neurosci., Univ. of Tsukuba, Ibaraki, Japan It has been broadly accepted that after the acquisition of memory, shortterm memory is transferred to long-term memory via consolidation process in a protein synthesis-dependent manner. In the present study, we investigated roles of brain-derived neurotrophic factor (BDNF) as a possible product of protein synthesis required for consolidation process. For this purpose, the causal relationship between the increase of hippocampal BDNF and establishment of long-term memory was examined using spontaneous place recognition (SPR) test in rats. SPR test utilizes rats’ innate tendency to explore the object in a novel place, and it consists of a sample phase, delay period, and a test phase. In experiment 1, the effect of combined hippocampal administration of anisomycin (ANI, 100 g/1 l/side), a protein synthesis inhibitor, and/or BDNF (0.25 g/1 l/side) on the SPR performance was examined. The sample phase length was 20 min and the delay period was 24 h. The administration of ANI before the sample phase extinguished the preference for the object in a novel place in the test phase. However, this impairment was rescued by BDNF treatment immediately after the sample phase. On the other hand, BDNF treatment itself did not improve the performance. In experiment 2, facilitative effect of BDNF on the SPR performance was further investigated. The administration of BDNF immediately after the sample phase provided rats’ significant preference for the object in a novel place even in a shorter sample phase condition (5 min) in which control rats did not show any preference. In conclusion, these results suggest that (1) the increase of hippocampal BDNF is necessary for consolidation of spatial memory in SPR test, and (2) BDNF is a possible product of protein synthesis required for memory consolidation. doi:10.1016/j.neures.2011.07.1656
P4-n17 Marmosets can retain their memories on abstract symbols with an interval of 3 years Ikuko Tanaka , Keiko Moriya-ito, Hironobu Tokuno Labo. of Brain Structure, Tokyo Met. Inst. of Med. Sci., Tokyo, Japan To assess the semantic memory retention in the common marmoset, we tested the memory of correct visual symbol in simple visual discrimination tasks twice at an interval of 3 years, using an open circle and a cross as symbols. Correct symbol was randomly determined for each individual at the first session. One task block was constructed by a total of 50 trials in 5 serial days (10 trials per 1 day). At the first session of 3 blocks, all marmosets (5 female, 5 male, 1–5 years old) could learn how to perform the task easily.
e377
Calculated Success Rate of Task (SRT) was increased in every block. At the second session after 3 years, the correct symbol was the same for 6 animals, whereas the correct symbol was opposite to the previous one for the other 4 animals. In the correct-symbol-maintained group, SRT was higher than that of the first session. In contrast, marmosets in the correct-symbol-opposed group preferred to choose incorrect symbol that had been correct in the first session. They showed lower SRT. The learning ability of each marmoset group was confirmed by a further visual discrimination task using completely different symbols. These data suggested that marmosets in both groups have memorized the correct symbols as long as 3 years, indicating their splendid capacity of semantic memory retention. doi:10.1016/j.neures.2011.07.1657
P4-n18 Characteristics of timing learning in delayed eyelid conditioning tested with an amplitude-modulated tone as a conditioned stimulus Kazuki Uchino 1 , Moritoshi Hirono 2 , Takeru Honda 2,3 , Tadashi Yamazaki 4 , Mari Anzai 2 , Hiromasa Kitazawa 5 , Masahiro Nakagawa 1 , Soichi Nagao 2 1
Dept. Elect. Eng, Nagaoka Univ. Tech 2 Lab. for Motor Learning Control, RIKEN BSI, Wako, Japan 3 EC, Univ. of Electro-Communications, Tokyo, Japan 4 BTCC, RIKEN BSI, Wako, Japan 5 Dept. Histol. and Neuroanat., Tokyo Med. Univ., Tokyo, Japan Pavlovian eyelid conditioning has been used widely as an experimental paradigm for cerebellar motor learning. The animal learns to close eyelid to the tone after training with repeated presentations of a conditioned stimulus (CS), a tone, with an unconditioned stimulus (US), an air-puff to the eye. Usually, a tone with a constant sound pressure, frequency and duration is used for CS, unlike the adaptation of vestibulo-ocular reflex, in which sinusoidal modulated turntable oscillation is used commonly for training stimuli. Here we setup a recording system for nictitating membrane movement of rabbits, and examined the characteristics of timing learning in eyelid conditioning when an amplitude-modulated (AM) tone was used for CS. Nictitating membrane movements were recorded from chronically prepared male New Zealand albino rabbits using a CCD-camera and a real-time X-Y analyzer (Percept Scope), and stored in the personal computer to measure the onsets of nictitating membrane movements using a MATLAB software. The AM tone (maximum sound intensity, 80 dB SPL; sound frequency, 4 kHz) with the duration of either 1 s or 0.5 s was used for CS. At the time when the sound intensity reached maximum, an air-puff (pressure, 0.015 MPa; duration, 0.1 s) was applied to the eyelid for US. The rabbits were trained with 250 presentations of CS + US, daily for 4 days. Both the 1 s and 0.5 s AM sounds successfully induced around the peak sound intensity after the end of 4-day training, which were extinguished by similar time course. When the rabbits conditioned with 0.5 s AM sounds were tested with 1 s AM sounds after the end of training, the CR started earlier than the time of peak sound intensity. These results suggest that the CNS learns the time of passage after the start of CS, rather than the time of maximum sound intensity, in eyelid conditioning. doi:10.1016/j.neures.2011.07.1658
P4-n19 Social reward facilitates off-line improvement of procedural motor memory Shou Sugawara 1,2 , Satoshi Tanaka 2 , Shuntaro Okazaki 2 , Katsumi Watanabe 3,4 , Norihiro Sadato 2 1 Dep. of Physio. Sci., Sch of Life Sci., Grad. Univ. Advanced Studies, Okazaki, Japan 2 Division of Cerebral Integration, National Institute for Physiological Sciences, Okazaki, Japan 3 Research Center for Advanced Science and Technology, Univ. of Tokyo, Tokyo, Japan 4 Japan Science and Technology Agency, Kawaguchi, Japan
Recent studies have suggested that social reward activates the dopaminergic system in humans, which has an important role for motor learning and memory. However, it has not been empirically examined whether social reward could facilitate the process of the motor memory. Here, we tested the hypothesis that praise of performance after a procedural motor training could facilitate its consolidation. Participants were trained in a sequential finger-tapping task with their non-dominant hand (Walker et al., 2002). Immediately after the training, participants were divided into three groups according to the type of feedback of their performance: (A) participants who watched a movie in which the evaluators praised participants for their performance during the training (self-praised group, n = 12), (B) participants who watched a movie in which the evaluators praised other persons for their performance (other-praised
Abstracts / Neuroscience Research 71S (2011) e108–e415
P4-n10 Fear conditioning changes responsiveness of fearrelated neurons to conditioned stimulus Ayako Nonaka , Norio Matsuki, Hiroshi Nomura Lab. Chem. Pharmacol., Grad. Sch. Pharm. Sci., Univ. of Tokyo, Tokyo, Japan Fear conditioning is a form of associative learning in which subjects learn the relationship between a neutral conditioned stimulus (CS) and an aversive unconditioned stimulus (US). After conditioning, the subjects come to express fear responses to CS as if there is US. Neural circuitry underlying fear conditioning is hypothesized as follows: fear-related neurons are not responsive to CS; when the neurons receive CS-relevant input and US-relevant one, the neurons become responsive to CS through synaptic potentiation; thus, CS-evoked activation of fear-related neurons induces fear responses. However, there is no clear evidence to confirm this hypothesis. To establish this, we identified active neurons during fear conditioning. We used Arc and Homer1a mRNA, a kind of immediate early genes (IEGs) which appears in the neuron immediately after activation. Mice were placed in the conditioning chamber before conditioning. They were returned to their homecage and 36 min later, they were conditioned with footshocks in the chamber. They were returned to the homecage again and 20 min later, they were reexposed to the chamber to recall the fear memory. Immediately after the retrieval, their brains were removed and Arc and Homer1a mRNA in the lateral amygdala were detected by fluorescence in situ hybridization. The activity of individual neurons during each behavioral task was determined by subcellular localization of Arc and Homer1a mRNA. Some neurons were not activated during the first CS-exposure but were activated during conditioning. More than half of these fear-related neurons were activated during second CSexposure. The proportion of neurons that changed their responsiveness to CS through conditioning was higher than that of control level. These findings indicate that fear-related neurons become responsive to CS through conditioning. CS-induced activation of fear-related neurons may produce fear responses. doi:10.1016/j.neures.2011.07.1650
P4-n11 Cholinergic activation is required for learningdependent AMPA receptor delivery into the CA3-CA1 synapses Dai Mitsushima , Takuya Takahashi Dept. Physiol., Yokohama City Univ., Grad. Sch. of Med. We previously reported that contextual learning requires AMPA receptor delivery in CA1 synapses. Since acetylcholine release increases during the period of learning in behaving rats, we hypothesized that cholinergic activation triggers learning-dependent plasticity in CA1 neurons in vivo. By combining in vivo gene delivery with in vitro patch-clamp recordings, we found that hippocampal-dependent inhibitory avoidance (IA) learning drives recombinant GluR1-containing AMPA receptors into synapses formed between CA3 and CA1 pyramidal neurons. Pretreatment of scopolamine (2 mg/kg), a muscarinic receptor antagonist, not only impaired the IA learning, but also blocked the synaptic delivery of reconmbinant GluR1containig AMPA receptors. Moreover, scopolamine pretreatment blocked the learning-induced increase in AMPA/NMDA ratio, suggesting acetylcholinemediated synaptic delivery of endogenous AMPA receptors. Moreover, in paired-recording study, scopolamine pretreatment successfully blocked the effect of mutated fragment of GluR1 cytoplasmic tail (MPR-DD), a construct that inhibits learning-dependent synaptic delivery of endogenous AMPA receptors. In contrast, neither learning nor scopolamine pretreatment affect the synaptic delivery in neurons expressed control fragment (MPR-AA). Further, using in vivo microdialysis technique, we monitored local acetylcholine release at CA1 region in behaving animals. The acetylcholine release significantly increased during IA learning, and the increase was sustained after the task for 60 min. Acetylcholine release transiently increased in some control animals (such as naive, shock only, or walk through rats), but the increase was not sustained. These results suggest that cholinergic activation is required for learning-dependent AMPA receptor delivery into the CA3-CA1 synapses. Research fund: KAKENHI 20590232. doi:10.1016/j.neures.2011.07.1651
P4-n12 Molecular mechanisms of circadian regulation of the memory for novel objects Kimiko Shimizu , Yodai Kobayashi, Yoshitaka Fukada Dept. Biophys. and Biochem., Grad. Sch. of Sci., Univ. of Tokyo, Tokyo, Japan Evidence from several studies demonstrates that circadian rhythm affects memory formation. However it is not yet clear if the internal clock regulates
the efficiency of memory formation, and there is no molecular-based evidence that connects memory and circadian rhythm. We tested novel object recognition memory over the circadian time. Long-term memory varied in a circadian manner and hence it seems to be controlled by endogenous circadian clock. In fact, clock mutant mouse did not show the circadian oscillation of long-term memory for novel object. We are focusing on SCOP and related molecules to find a molecular process between circadian rhythm and memory formation. SCOP/PHLPP is expressed in a circadian manner in the suprachiasmatic nucleus (SCN) that is the center for circadian rhythm. SCOP negatively regulates K-Ras function and its downstream ERK/MAPK pathway. In the hippocampus, SCOP is critical for long-term memory formation for novel objects. These data indicate that SCOP-ERK pathway could be a key for circadian control for long-term memory formation in the hippocampus. We found that SCOP protein level in raft fraction in the hippocampus oscillates in a circadian manner. SCOP knockdown by shRNA expression lentivirus attenuated circadian oscillation of long-term memory for objects. Now we are examining detailed molecular mechanisms of circadian regulation system of memory formation in in vivo and in vitro. Research fund: Asahi Glass Foundation. doi:10.1016/j.neures.2011.07.1652
P4-n13 Calcineurin in the hippocampus and amygdala is required for destabilization and extinction of retrieved contextual fear memory Ryang Kim 1 , Karim Nader 2 , Satoshi Kida 1,3 1
Dep. of Bioscience, Tokyo Univ. of Agriculture, Tokyo, Japan 2 Dep. of Psychology, McGill Univ., Kanada 3 JST, CREST, Saitama, Japan
Retrieval of conditioned fear memory by re-exposure to the context (conditioned stimulus; CS) initiates reconsolidation and extinction. We previously found that reconsolidation and extinction of contextual fear memory requires activation of CREB through phosphorylation at Serine 133 in the hippocampus/amygdala or amygdala/medial prefrontal cortex, respectively (Kida et al., 2002; Mamiya et al., 2009). Interestingly, we observed that short re-exposure (3 min) to the CS inducing reconsolidation increase in CREB phosphorylation in hippocampus, whereas the prolonged re-exposure (30 min) inducing extinction prevented this CREB phosphorylation. These observations suggest that regulations of phosphorylation and dephosphorylation of CREB by CREB-kinases and phosphatases, respectively, play critical roles in the determination for the fate of fear memory; reconsolidation or extinction. In this study, we tried to understand roles of calcineurin (Protein Phosphatase 2B; PP2B) in reconsolidation and extinction of contextual fear memory. Infusion of calcineurin inhibitor FK506 into hippocampus after 3 min re-exposure to the CS prevented the disruption of reactivated memory by protein synthesis inhibitor anisomycin (ANI). This prevention of amnesic ANI-effect by FK506 was also observed when FK506 was infused into amygdala. These observations suggest that calcineurin in the hippocampus and amygdala is required for destabilization of retrieved contextual fear memory. On the other hand, hippocampal FK506-infusion just before, but not after, 30 min re-exposure to the CS impaired acquisition of extinction. In contrast, amgdaloid FK506-infusion inhibited consolidation but not acquisition of extinction, indicating that calcineurin in the hippocampus and amygdala plays distinct roles in extinction of contextual fear. Collectively, these results suggest that calcineurin in the hippocampus and amygdala plays essential roles in destabilization and extinction of retrieved contextual fear memory. doi:10.1016/j.neures.2011.07.1653
P4-n14 Thalamocortical projections of the anteroventral thalamic nucleus in the rabbit Hideshi Shibata 1 , Yoshiko Honda 2
1 Lab. of Vet. Anat., Inst. of Agri., Tokyo Univ. of Agri. & Tech., Fuchu, Tokyo, Japan 2 Dept. of Anat., Tokyo Women’s Med. Univ., Tokyo, Japan
The anteroventral nucleus (AV), which is part of the anterior thalamic nuclei, has been implicated in behavioral learning such as discriminative avoidance conditioning in the rabbit. Although the interactions between AV and the cortex are important for such learning, it is not yet known the neural connections between AV and the cortex in the rabbit. In the present study, we demonstrated the areal and laminar distributions of the thalamocortical projections of AV, using anterograde axonal transport of biotinylated dextran amine (BDA). An injection of BDA restricted to the magnocellular division of AV (AVm) labeled massive terminals in superficial layer I of areas 29a-c. In contrast, an injection restricted to the parvocellular division of AV (AVp) labeled massive terminals in layer IV and deep layer I of areas 29a-c, lay-
Abstracts / Neuroscience Research 71S (2011) e108–e415
ers I and IV of area 30, and layers I and VI of the presubiculum. The results show that in the rabbit AVm and AVp provide different thalamocortical projections, suggesting that each division may play different functional roles in behavioral learning. Research fund: The Japan Pet Care Association (to H.S.). doi:10.1016/j.neures.2011.07.1654
P4-n15 Hippocampal afferents to the rabbit presubiculum Yoshiko Honda 1 , Hideshi Shibata 2 1
Dept. of Anat., Scl. of Med., Tokyo Women’s Med. Univ., Tokyo, Japan 2 Lab. of Vet. Anat, Inst. Agri., Tokyo Univ. Agri. & Tech., Tokyo, Japan Connections between the hippocampal formation and its adjoining parahippocampal areas are crucial for memory formation in many species. In the rat, the presubiculum (Pre), a part of the parahippocampal areas, is known to be responsible for processing spatial information. In the rabbit, the parahippocampal areas are more differentiated than in the rat, so that its Pre seems to have more extended function. However, little is known about the connectivity of Pre in the rabbit. In the present study, cells of origin of hippocampal afferents to Pre are investigated in the rabbit by in vivo injection of choleratoxin B subunit as a retrograde tracer. We found that rabbit Pre receives strong hippocampal inputs from both CA1 and the subiculum (Sub). Such strong hippocampal input from CA1 is characteristic in rabbit Pre, because rat Pre receives major inputs from Sub, but not from CA1. Our results show that rabbit Pre receives afferents from broader regions in the hippocampus, suggesting more complex memory information processing than in the rat. doi:10.1016/j.neures.2011.07.1655
P4-n16 Increase of hippocampal BDNF is essential for consolidation of spatial memory in spontaneous place recognition test in rats Takaaki Ozawa , Kazuo Yamada, Yukio Ichitani Dept. of Behav. Neurosci., Univ. of Tsukuba, Ibaraki, Japan It has been broadly accepted that after the acquisition of memory, shortterm memory is transferred to long-term memory via consolidation process in a protein synthesis-dependent manner. In the present study, we investigated roles of brain-derived neurotrophic factor (BDNF) as a possible product of protein synthesis required for consolidation process. For this purpose, the causal relationship between the increase of hippocampal BDNF and establishment of long-term memory was examined using spontaneous place recognition (SPR) test in rats. SPR test utilizes rats’ innate tendency to explore the object in a novel place, and it consists of a sample phase, delay period, and a test phase. In experiment 1, the effect of combined hippocampal administration of anisomycin (ANI, 100 g/1 l/side), a protein synthesis inhibitor, and/or BDNF (0.25 g/1 l/side) on the SPR performance was examined. The sample phase length was 20 min and the delay period was 24 h. The administration of ANI before the sample phase extinguished the preference for the object in a novel place in the test phase. However, this impairment was rescued by BDNF treatment immediately after the sample phase. On the other hand, BDNF treatment itself did not improve the performance. In experiment 2, facilitative effect of BDNF on the SPR performance was further investigated. The administration of BDNF immediately after the sample phase provided rats’ significant preference for the object in a novel place even in a shorter sample phase condition (5 min) in which control rats did not show any preference. In conclusion, these results suggest that (1) the increase of hippocampal BDNF is necessary for consolidation of spatial memory in SPR test, and (2) BDNF is a possible product of protein synthesis required for memory consolidation. doi:10.1016/j.neures.2011.07.1656
P4-n17 Marmosets can retain their memories on abstract symbols with an interval of 3 years Ikuko Tanaka , Keiko Moriya-ito, Hironobu Tokuno Labo. of Brain Structure, Tokyo Met. Inst. of Med. Sci., Tokyo, Japan To assess the semantic memory retention in the common marmoset, we tested the memory of correct visual symbol in simple visual discrimination tasks twice at an interval of 3 years, using an open circle and a cross as symbols. Correct symbol was randomly determined for each individual at the first session. One task block was constructed by a total of 50 trials in 5 serial days (10 trials per 1 day). At the first session of 3 blocks, all marmosets (5 female, 5 male, 1–5 years old) could learn how to perform the task easily.
e377
Calculated Success Rate of Task (SRT) was increased in every block. At the second session after 3 years, the correct symbol was the same for 6 animals, whereas the correct symbol was opposite to the previous one for the other 4 animals. In the correct-symbol-maintained group, SRT was higher than that of the first session. In contrast, marmosets in the correct-symbol-opposed group preferred to choose incorrect symbol that had been correct in the first session. They showed lower SRT. The learning ability of each marmoset group was confirmed by a further visual discrimination task using completely different symbols. These data suggested that marmosets in both groups have memorized the correct symbols as long as 3 years, indicating their splendid capacity of semantic memory retention. doi:10.1016/j.neures.2011.07.1657
P4-n18 Characteristics of timing learning in delayed eyelid conditioning tested with an amplitude-modulated tone as a conditioned stimulus Kazuki Uchino 1 , Moritoshi Hirono 2 , Takeru Honda 2,3 , Tadashi Yamazaki 4 , Mari Anzai 2 , Hiromasa Kitazawa 5 , Masahiro Nakagawa 1 , Soichi Nagao 2 1
Dept. Elect. Eng, Nagaoka Univ. Tech 2 Lab. for Motor Learning Control, RIKEN BSI, Wako, Japan 3 EC, Univ. of Electro-Communications, Tokyo, Japan 4 BTCC, RIKEN BSI, Wako, Japan 5 Dept. Histol. and Neuroanat., Tokyo Med. Univ., Tokyo, Japan Pavlovian eyelid conditioning has been used widely as an experimental paradigm for cerebellar motor learning. The animal learns to close eyelid to the tone after training with repeated presentations of a conditioned stimulus (CS), a tone, with an unconditioned stimulus (US), an air-puff to the eye. Usually, a tone with a constant sound pressure, frequency and duration is used for CS, unlike the adaptation of vestibulo-ocular reflex, in which sinusoidal modulated turntable oscillation is used commonly for training stimuli. Here we setup a recording system for nictitating membrane movement of rabbits, and examined the characteristics of timing learning in eyelid conditioning when an amplitude-modulated (AM) tone was used for CS. Nictitating membrane movements were recorded from chronically prepared male New Zealand albino rabbits using a CCD-camera and a real-time X-Y analyzer (Percept Scope), and stored in the personal computer to measure the onsets of nictitating membrane movements using a MATLAB software. The AM tone (maximum sound intensity, 80 dB SPL; sound frequency, 4 kHz) with the duration of either 1 s or 0.5 s was used for CS. At the time when the sound intensity reached maximum, an air-puff (pressure, 0.015 MPa; duration, 0.1 s) was applied to the eyelid for US. The rabbits were trained with 250 presentations of CS + US, daily for 4 days. Both the 1 s and 0.5 s AM sounds successfully induced around the peak sound intensity after the end of 4-day training, which were extinguished by similar time course. When the rabbits conditioned with 0.5 s AM sounds were tested with 1 s AM sounds after the end of training, the CR started earlier than the time of peak sound intensity. These results suggest that the CNS learns the time of passage after the start of CS, rather than the time of maximum sound intensity, in eyelid conditioning. doi:10.1016/j.neures.2011.07.1658
P4-n19 Social reward facilitates off-line improvement of procedural motor memory Shou Sugawara 1,2 , Satoshi Tanaka 2 , Shuntaro Okazaki 2 , Katsumi Watanabe 3,4 , Norihiro Sadato 2 1 Dep. of Physio. Sci., Sch of Life Sci., Grad. Univ. Advanced Studies, Okazaki, Japan 2 Division of Cerebral Integration, National Institute for Physiological Sciences, Okazaki, Japan 3 Research Center for Advanced Science and Technology, Univ. of Tokyo, Tokyo, Japan 4 Japan Science and Technology Agency, Kawaguchi, Japan
Recent studies have suggested that social reward activates the dopaminergic system in humans, which has an important role for motor learning and memory. However, it has not been empirically examined whether social reward could facilitate the process of the motor memory. Here, we tested the hypothesis that praise of performance after a procedural motor training could facilitate its consolidation. Participants were trained in a sequential finger-tapping task with their non-dominant hand (Walker et al., 2002). Immediately after the training, participants were divided into three groups according to the type of feedback of their performance: (A) participants who watched a movie in which the evaluators praised participants for their performance during the training (self-praised group, n = 12), (B) participants who watched a movie in which the evaluators praised other persons for their performance (other-praised