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2242 Functional expression of NMDA receptors in cerebellum and their contribution to eyeblink classical conditioning
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2242
FUNCTIONAL EXPRESSION OF NMDA RECEPTORS IN CEREBELLUM AND THEIR CONTRIBUTION TO EYEBLINK CLASSICAL CONDITIONING Laboratory of Neurobiophysics, School of Pharmace utical Sciences, The University of Tokyo, Tokyo,ll3, Japan.‘, Department of Biological Sciences, Kyoto University Facluty of Medicine, Kyoto, 606-01, Japan2, Department of Mol. Neurobiol., School of Human Sciences, Waseda University, Tokorozawa, 359, Japan.3 YASUSHI KISHIMOTO’, SHIGENORI KAWAHARA’, YUTAKA KIIUNO’ , HIROSHI KADOTAN12, SHIGETADA NAKANISH12, YUKIHIRO NAKAMURA3, MASAYUKI IKEDA3, TOHRU YOSHIOKA3 NMDA receptors are thought to be essential in various kinds of synaptic plasticity underlying learning and memory, especially in spatial learning involving hippocampus. But some of this receptor subunit isoforms are expressed in cerebellum. Eyeblink conditioning is a kind of motor learning known as a Pavlovian conditioning, and its engram is known to be localized mainly in cerebellum. To study functions of the isoforms NRZA and NR2C that are expressed in cerebellum, we investigated eyeblink conditioning in knockout mice deficient in these isoforms. The deficiency was confirmed by Ca imaging of the slice preparations. For conditioning, a tone (conditioned stimulus) was paired with a periocular shock (unconditioned stimulus). Animals received 100 paired stimuli a day. As a result, knockout mice deficient in NR2A or deficient in NR2A and NR2C showed some impairments in learning at an early stage of training. These results suggest the involvement of NRZA in synaptic plasticity in cerebellum.
2243 Department Japan
LONG-LASTING DEPRESSION OF MAUTHNER CELL-INITIATED ESCAPE RESPONSE PRODUCED BY INHIBITORY LONG-TERM POTENTIATION of Biophysical Engineering, Osaka University, Machikaneyama l-3, Toyonaka, Osaka 560,
HARUKO,MATSUI,
KEISUKE
KAWASAKI,
YOICHI
ODA
Mauthner (M) cell in the goldfish hindbrain initiates a startle response away from an abrupt sound. The M cell activity is controlled by monosynaptic excitation and disynaptic inhibition from the auditory nerve. Previously we demonstrated that application of repeated sound induced a long-term potentiation (LTP) at the inhibitory connection and a long-lasting depression of the escape response. In the present study, we further analyzed relationship between the LTP and the behavioral modification. The sound with frequency ranging from 500 to 800Hz is effective to induce both the cellular and behavioral modifications (pO.l), indicating that the behavioral kinetics were unaffected. These findings suggest that the LTP of inhibitory connection onto the M-cell underlies the long-lasting depression of the behavior.
2244
Classical conditioning
between light and vestibular stimulus in pond snail Lymneee
Tokai Univ., Dept. Biol. Sci. and Tech. Ryo Kawai, Tetsuro Horikoshi, Manabu Sakakibara Conditioned withdrawal behavior was characterized in the pond snail Lynaneae. Using light as the conditioned stimulus and high-speed orbital rotation as the unconditioned stimulus, experimental animals were trained with 30 paired presentations of light and vibration per day for 3 days. All experimental animals responded to light with withdrawal behavior. Control animals exposed to the same number of explicitly unpaired presentation of light and vibration, light alone, or no stimulation did not respond to light. Thirty paired presentations per day for 2 days resulted in a partial association of the two stimuli. Neither 45 paired presentation per day for 2 days nor 90 paired presentations for 1 day resulted in complete acquisition of the conditioned withdrawal response. The conditioned withdrawal response observed following 30 paired presentation per day for 3 to 5 days persisted to Day 10. After the conditioned withdrawal response was extinguished, only 2 to 5 paired presentation of light and vibration were required for reacquisition for most animals. This study further establishes Lymneae as an animal model of basic associative learning.
2242
FUNCTIONAL EXPRESSION OF NMDA RECEPTORS IN CEREBELLUM AND THEIR CONTRIBUTION TO EYEBLINK CLASSICAL CONDITIONING Laboratory of Neurobiophysics, School of Pharmace utical Sciences, The University of Tokyo, Tokyo,ll3, Japan.‘, Department of Biological Sciences, Kyoto University Facluty of Medicine, Kyoto, 606-01, Japan2, Department of Mol. Neurobiol., School of Human Sciences, Waseda University, Tokorozawa, 359, Japan.3 YASUSHI KISHIMOTO’, SHIGENORI KAWAHARA’, YUTAKA KIIUNO’ , HIROSHI KADOTAN12, SHIGETADA NAKANISH12, YUKIHIRO NAKAMURA3, MASAYUKI IKEDA3, TOHRU YOSHIOKA3 NMDA receptors are thought to be essential in various kinds of synaptic plasticity underlying learning and memory, especially in spatial learning involving hippocampus. But some of this receptor subunit isoforms are expressed in cerebellum. Eyeblink conditioning is a kind of motor learning known as a Pavlovian conditioning, and its engram is known to be localized mainly in cerebellum. To study functions of the isoforms NRZA and NR2C that are expressed in cerebellum, we investigated eyeblink conditioning in knockout mice deficient in these isoforms. The deficiency was confirmed by Ca imaging of the slice preparations. For conditioning, a tone (conditioned stimulus) was paired with a periocular shock (unconditioned stimulus). Animals received 100 paired stimuli a day. As a result, knockout mice deficient in NR2A or deficient in NR2A and NR2C showed some impairments in learning at an early stage of training. These results suggest the involvement of NRZA in synaptic plasticity in cerebellum.
2243 Department Japan
LONG-LASTING DEPRESSION OF MAUTHNER CELL-INITIATED ESCAPE RESPONSE PRODUCED BY INHIBITORY LONG-TERM POTENTIATION of Biophysical Engineering, Osaka University, Machikaneyama l-3, Toyonaka, Osaka 560,
HARUKO,MATSUI,
KEISUKE
KAWASAKI,
YOICHI
ODA
Mauthner (M) cell in the goldfish hindbrain initiates a startle response away from an abrupt sound. The M cell activity is controlled by monosynaptic excitation and disynaptic inhibition from the auditory nerve. Previously we demonstrated that application of repeated sound induced a long-term potentiation (LTP) at the inhibitory connection and a long-lasting depression of the escape response. In the present study, we further analyzed relationship between the LTP and the behavioral modification. The sound with frequency ranging from 500 to 800Hz is effective to induce both the cellular and behavioral modifications (p
2244
Classical conditioning
between light and vestibular stimulus in pond snail Lymneee
Tokai Univ., Dept. Biol. Sci. and Tech. Ryo Kawai, Tetsuro Horikoshi, Manabu Sakakibara Conditioned withdrawal behavior was characterized in the pond snail Lynaneae. Using light as the conditioned stimulus and high-speed orbital rotation as the unconditioned stimulus, experimental animals were trained with 30 paired presentations of light and vibration per day for 3 days. All experimental animals responded to light with withdrawal behavior. Control animals exposed to the same number of explicitly unpaired presentation of light and vibration, light alone, or no stimulation did not respond to light. Thirty paired presentations per day for 2 days resulted in a partial association of the two stimuli. Neither 45 paired presentation per day for 2 days nor 90 paired presentations for 1 day resulted in complete acquisition of the conditioned withdrawal response. The conditioned withdrawal response observed following 30 paired presentation per day for 3 to 5 days persisted to Day 10. After the conditioned withdrawal response was extinguished, only 2 to 5 paired presentation of light and vibration were required for reacquisition for most animals. This study further establishes Lymneae as an animal model of basic associative learning.