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Optical imaging of neuronal activity in rat primary motor cortex evoked by stimulation of the ventral tegmental area
Abstracts / Neuroscience Research 71S (2011) e108–e415
pathway itself plays a critical role for stabilization of vocal patterns with auditory-independent manners. doi:10.1016/j.neures.2011.07.1101
P3-j02 Learned heterospecific song patterns were limitedly produced at juvenile stage but finally restricted by species-specific manners in songbird Raimu
Imai 1
, Kazuhiro
Wada 1,2
1
Grad. Sch. of Life Science, Hokkaido Univ., Sapporo, Japan 2 Fac. of Sci., Dep. of Biol. Sci., Hokkaido Univ., Sapporo, Japan
e253
using non-dopamine neurotransmitters. Further investigation is necessary to understand the functional roles of non-dopamine systems, as well as dopamine systems, in the VTA-M1 mesocortical pathway. Research fund: This work was partially supported by KAKENHI (22500375). doi:10.1016/j.neures.2011.07.1103
P3-j04 Long-lasting aftereffects of prism adaptation with abrupt versus gradual exposure to visual displacement in the monkey Motoaki Uchimura , Masato Inoue, Shigeru Kitazawa Dep. of Neurophysiology, Sch. of Med., Juntendo Univ., Tokyo, Japan
Animals transfer information to other individuals by various types of communication. Vocal communication represented by human language is one of the most important ways of communication observed in various animals. Songbirds learn their songs that consist of species-specific combinations of syllables. It has been considered that acquisition of species-specific song patterns is allowed by both effects not only from nature but also from nurture. A large number of behavioral studies of song learning have been reported. In most of studies, those mainly focused on development of acoustic structure of syllables but not of syllable sequences. How each species of songbirds develops species-specific song patterns is not well understood. To analyze process of developing species-specific song patterns, we devised a novel method called Syllable Similarity Matrix (SSM) method to analyze development of structure of syllable sequences in songs. Using the SSM method, first, we thoroughly analyzed development of zebra finch (ZF) songs from immature juvenile songs to crystallized adult songs. We also performed cross-fostering experiment to examine how ZFs learn songs from a heterospecies, Bengalese finch (BF) which sings a song with different structure of syllable sequences, including many repetition and chunks of syllables. The ZFs which were tutored by BF learned syllable structure from tutor songs well, but failed to acquire BF-like syllable sequences when they have crystallized songs at adult stage. However, some of cross-fostered birds succeeded to produce BF-like syllable sequences at the early stage of song learning. These results suggest that ZF could learn and vocalize various acoustic structures and rule of syllable sequences from a hetero-species, BF, at the early stage of song learning. However, their ability for learning syllable sequences is genetically restricted to form automatically own species-specific song patterns even they had never heard own species songs. Research fund: Grant-in-Aid for JSPS Fellows.
The errors in target-reaching that are produced by laterally displacing vision with wedge prisms decrease with trials (prism adaptation). When the prisms are removed, errors in the opposite direction are observed (aftereffect). We previously reported in monkeys that the aftereffect disappeared at 24 h after a repetition of 250 trials with prisms, but remained as large for 72 h after 500 trials, when the visual displacement was introduced in a single step (Yin and Kitazawa, 2001). In the present study, we examined if the long-lasting aftereffect is enhanced by introducing the visual displacement gradually in multi-steps. Two monkeys were trained to make rapid reaching movements toward a visual target. Experiments were designed in a two (abrupt/gradual) by two (short/long) factorial manner. In the abrupt condition, a visual displacement of 30 mm was introduced abruptly and the monkeys repeated the task for 250 (short) or 500 (long) trials. In the gradual condition, visual displacement was gradually increased from 0 to 30 mm in 490 trials, and the task was continued for additional 10 (short) or 260 (long) trials. Cumulative exposure to displacement in the long exposure conditions (30 mm × 500 trials or (490/2 + 260) trials) was twice as large as that in the short exposure conditions (3 cm × 250 or (490/2 + 10) trials). The size of aftereffect at 24 h was 2.7 ± 5.3 mm (mean ± SEM, n = 8) in the abrupt × short condition, 14 ± 3.3 mm in the abrupt × long condition, 3.9 ± 1.1 mm in the gradual × short condition and 15 ± 3.3 mm in the gradual × long condition. A two way ANOVA revealed that the main effect of cumulative exposure was significant (short/long; F(1, 25), p < 0.005) but the way of exposure (abrupt/gradual) or their interaction was not. These results indicate that the size of aftereffect depended simply on the cumulative exposure to visual shift, irrespective of whether the displacement was introduced abruptly or increased gradually over trials. Research fund: HFSP.
doi:10.1016/j.neures.2011.07.1102 doi:10.1016/j.neures.2011.07.1104
P3-j03 Optical imaging of neuronal activity in rat primary motor cortex evoked by stimulation of the ventral tegmental area
P3-j05 Effect of mirror visual feedback on human motor plasticity
1
Grad. Sch. of Comp. Human Sci., Tsukuba Univ., Tsukuba, Japan 2 Human Tech RI, AIST, Tsukuba, Japan 3 Biomed RI, AIST, Tsukuba, Japan
1
Midbrain dopamine neurons of the ventral tegmental area (VTA) project broadly to the prefrontal cortex (PFC) and at least part of this projection terminates in primary motor cortex (M1). Recent studies revealed that dopaminergic terminals in M1 contribute to M1 synaptic plasticity and motor skill learning. In the present study, the spatiotemporal pattern of M1 neuronal activity evoked by VTA stimulation was analyzed by using a voltage-sensitive dye imaging technique. Single electrical pulse stimulation of VTA induced transient depolarization of neurons followed by hyperpolarization in M1. The depolarization occurred 12 ms after VTA stimulation around the caudal-lateral region of M1 and propagated toward the rostral-medial direction. After 90 ms, the excitatory response became weak and a long-lasting inhibitory response developed (90–680 ms poststimulation) more medially compared to the preceding depolarization. In order to confirm the anatomical connections between VTA and M1, we injected retrograde tracer into the M1 where neuronal activity was observed. Three days after injection, retrogradely labeled neurons were identified in the VTA, some of which (∼10%) were confirmed as Tyrosine-Hydroxylase positive. Considering previous reports indicating the co-release of glutamate and dopamine from VTA dopaminergic neurons, the fast excitatory response in M1 observed in our imaging study seems to be produced by the activation of dopaminergic neurons in VTA. We speculate that inhibitory responses in M1 may reflect GABAergic projection from VTA, since several tract-tracing studies have identified substantial GABA-containing neurons in VTA that send axons to the PFC. In this study, it was shown that VTA activation elicits fast excitatory-inhibitory neuronal activities in M1, probably
Hemiparesis is one of the most common and disabling sequelae of stroke. A new rehabilitation technique using mirror visual feedback (MVF), called mirror therapy firstly introduced to alleviate phantom pain, was recently introduced for these patients. However, the neural substrate of MVF-induced motor recovery has not been fully understood. One possible mechanism is the plasticity of the human primary motor cortex (M1), which has been proposed as a neural basis of motor learning. Here, to test that the M1 plasticity is the physiologic substrate of the motor behavioral improvement induced by MVF, we investigated the M1 function before and after MVF in healthy volunteers by using transcranial magnetic stimulation (TMS), and found the improvement of the motor behavior and enhancement of the excitatory functions of M1. Moreover, these behavioral and physiologic measures of MVF-induced changes were positively correlated with each other. In addition, we tested whether continuous theta burst stimulation (cTBS) over M1, which is a procedure to suppress local cortical function, can disrupt the behavioral and electrophysiological motor improvement induced by MVF. The beneficial effects of MVF were disrupted by cTBS over M1 but not over the control site in the occipital cortex and suggested the cause–effect link between the M1 plasticity and behavioral improvement in MVF-induced motor learning. Our findings indicate that the M1 plasticity, especially in its excitatory system, is one of the essential components of MVF-based therapies.
Nobuo Kunori 1,2 , Riichi Kajiwara 3 , Fumihiro Shuto 1 , Setsuji Hisano 1 , Ichiro Takashima 2
Ippei Nojima 1 , Satoko Koganemaru 2 , Hidenao Fukuyama 2 , Toshio Kawamata 1 , Tatsuya Mima 2 Rehabil. Grad. Sch. of Health Sciences, Kobe Univ., Hyogo, Japan 2 Human Brain Research Center, Grad. Sch. of Med., Kyoto Univ., Kyoto, Japan
doi:10.1016/j.neures.2011.07.1105
pathway itself plays a critical role for stabilization of vocal patterns with auditory-independent manners. doi:10.1016/j.neures.2011.07.1101
P3-j02 Learned heterospecific song patterns were limitedly produced at juvenile stage but finally restricted by species-specific manners in songbird Raimu
Imai 1
, Kazuhiro
Wada 1,2
1
Grad. Sch. of Life Science, Hokkaido Univ., Sapporo, Japan 2 Fac. of Sci., Dep. of Biol. Sci., Hokkaido Univ., Sapporo, Japan
e253
using non-dopamine neurotransmitters. Further investigation is necessary to understand the functional roles of non-dopamine systems, as well as dopamine systems, in the VTA-M1 mesocortical pathway. Research fund: This work was partially supported by KAKENHI (22500375). doi:10.1016/j.neures.2011.07.1103
P3-j04 Long-lasting aftereffects of prism adaptation with abrupt versus gradual exposure to visual displacement in the monkey Motoaki Uchimura , Masato Inoue, Shigeru Kitazawa Dep. of Neurophysiology, Sch. of Med., Juntendo Univ., Tokyo, Japan
Animals transfer information to other individuals by various types of communication. Vocal communication represented by human language is one of the most important ways of communication observed in various animals. Songbirds learn their songs that consist of species-specific combinations of syllables. It has been considered that acquisition of species-specific song patterns is allowed by both effects not only from nature but also from nurture. A large number of behavioral studies of song learning have been reported. In most of studies, those mainly focused on development of acoustic structure of syllables but not of syllable sequences. How each species of songbirds develops species-specific song patterns is not well understood. To analyze process of developing species-specific song patterns, we devised a novel method called Syllable Similarity Matrix (SSM) method to analyze development of structure of syllable sequences in songs. Using the SSM method, first, we thoroughly analyzed development of zebra finch (ZF) songs from immature juvenile songs to crystallized adult songs. We also performed cross-fostering experiment to examine how ZFs learn songs from a heterospecies, Bengalese finch (BF) which sings a song with different structure of syllable sequences, including many repetition and chunks of syllables. The ZFs which were tutored by BF learned syllable structure from tutor songs well, but failed to acquire BF-like syllable sequences when they have crystallized songs at adult stage. However, some of cross-fostered birds succeeded to produce BF-like syllable sequences at the early stage of song learning. These results suggest that ZF could learn and vocalize various acoustic structures and rule of syllable sequences from a hetero-species, BF, at the early stage of song learning. However, their ability for learning syllable sequences is genetically restricted to form automatically own species-specific song patterns even they had never heard own species songs. Research fund: Grant-in-Aid for JSPS Fellows.
The errors in target-reaching that are produced by laterally displacing vision with wedge prisms decrease with trials (prism adaptation). When the prisms are removed, errors in the opposite direction are observed (aftereffect). We previously reported in monkeys that the aftereffect disappeared at 24 h after a repetition of 250 trials with prisms, but remained as large for 72 h after 500 trials, when the visual displacement was introduced in a single step (Yin and Kitazawa, 2001). In the present study, we examined if the long-lasting aftereffect is enhanced by introducing the visual displacement gradually in multi-steps. Two monkeys were trained to make rapid reaching movements toward a visual target. Experiments were designed in a two (abrupt/gradual) by two (short/long) factorial manner. In the abrupt condition, a visual displacement of 30 mm was introduced abruptly and the monkeys repeated the task for 250 (short) or 500 (long) trials. In the gradual condition, visual displacement was gradually increased from 0 to 30 mm in 490 trials, and the task was continued for additional 10 (short) or 260 (long) trials. Cumulative exposure to displacement in the long exposure conditions (30 mm × 500 trials or (490/2 + 260) trials) was twice as large as that in the short exposure conditions (3 cm × 250 or (490/2 + 10) trials). The size of aftereffect at 24 h was 2.7 ± 5.3 mm (mean ± SEM, n = 8) in the abrupt × short condition, 14 ± 3.3 mm in the abrupt × long condition, 3.9 ± 1.1 mm in the gradual × short condition and 15 ± 3.3 mm in the gradual × long condition. A two way ANOVA revealed that the main effect of cumulative exposure was significant (short/long; F(1, 25), p < 0.005) but the way of exposure (abrupt/gradual) or their interaction was not. These results indicate that the size of aftereffect depended simply on the cumulative exposure to visual shift, irrespective of whether the displacement was introduced abruptly or increased gradually over trials. Research fund: HFSP.
doi:10.1016/j.neures.2011.07.1102 doi:10.1016/j.neures.2011.07.1104
P3-j03 Optical imaging of neuronal activity in rat primary motor cortex evoked by stimulation of the ventral tegmental area
P3-j05 Effect of mirror visual feedback on human motor plasticity
1
Grad. Sch. of Comp. Human Sci., Tsukuba Univ., Tsukuba, Japan 2 Human Tech RI, AIST, Tsukuba, Japan 3 Biomed RI, AIST, Tsukuba, Japan
1
Midbrain dopamine neurons of the ventral tegmental area (VTA) project broadly to the prefrontal cortex (PFC) and at least part of this projection terminates in primary motor cortex (M1). Recent studies revealed that dopaminergic terminals in M1 contribute to M1 synaptic plasticity and motor skill learning. In the present study, the spatiotemporal pattern of M1 neuronal activity evoked by VTA stimulation was analyzed by using a voltage-sensitive dye imaging technique. Single electrical pulse stimulation of VTA induced transient depolarization of neurons followed by hyperpolarization in M1. The depolarization occurred 12 ms after VTA stimulation around the caudal-lateral region of M1 and propagated toward the rostral-medial direction. After 90 ms, the excitatory response became weak and a long-lasting inhibitory response developed (90–680 ms poststimulation) more medially compared to the preceding depolarization. In order to confirm the anatomical connections between VTA and M1, we injected retrograde tracer into the M1 where neuronal activity was observed. Three days after injection, retrogradely labeled neurons were identified in the VTA, some of which (∼10%) were confirmed as Tyrosine-Hydroxylase positive. Considering previous reports indicating the co-release of glutamate and dopamine from VTA dopaminergic neurons, the fast excitatory response in M1 observed in our imaging study seems to be produced by the activation of dopaminergic neurons in VTA. We speculate that inhibitory responses in M1 may reflect GABAergic projection from VTA, since several tract-tracing studies have identified substantial GABA-containing neurons in VTA that send axons to the PFC. In this study, it was shown that VTA activation elicits fast excitatory-inhibitory neuronal activities in M1, probably
Hemiparesis is one of the most common and disabling sequelae of stroke. A new rehabilitation technique using mirror visual feedback (MVF), called mirror therapy firstly introduced to alleviate phantom pain, was recently introduced for these patients. However, the neural substrate of MVF-induced motor recovery has not been fully understood. One possible mechanism is the plasticity of the human primary motor cortex (M1), which has been proposed as a neural basis of motor learning. Here, to test that the M1 plasticity is the physiologic substrate of the motor behavioral improvement induced by MVF, we investigated the M1 function before and after MVF in healthy volunteers by using transcranial magnetic stimulation (TMS), and found the improvement of the motor behavior and enhancement of the excitatory functions of M1. Moreover, these behavioral and physiologic measures of MVF-induced changes were positively correlated with each other. In addition, we tested whether continuous theta burst stimulation (cTBS) over M1, which is a procedure to suppress local cortical function, can disrupt the behavioral and electrophysiological motor improvement induced by MVF. The beneficial effects of MVF were disrupted by cTBS over M1 but not over the control site in the occipital cortex and suggested the cause–effect link between the M1 plasticity and behavioral improvement in MVF-induced motor learning. Our findings indicate that the M1 plasticity, especially in its excitatory system, is one of the essential components of MVF-based therapies.
Nobuo Kunori 1,2 , Riichi Kajiwara 3 , Fumihiro Shuto 1 , Setsuji Hisano 1 , Ichiro Takashima 2
Ippei Nojima 1 , Satoko Koganemaru 2 , Hidenao Fukuyama 2 , Toshio Kawamata 1 , Tatsuya Mima 2 Rehabil. Grad. Sch. of Health Sciences, Kobe Univ., Hyogo, Japan 2 Human Brain Research Center, Grad. Sch. of Med., Kyoto Univ., Kyoto, Japan
doi:10.1016/j.neures.2011.07.1105