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Identification of amacrine cells involved in motion detection in the rat retina
S204
Abstracts
P3-b08 Dendritic stratification of RGCs and immunoreactive lamination of calcium binding proteins in the inner plexiform layer of the chick retina Jumpei Naito 1 , Taiki Tamura 2 1
Dept Animarl Sci, Teikyo Univ of Sci & Tech, Uenohara, Japan; of Sci and Tech, Uenohara, Japan
2
Teikyo Univ
There are two plexuses of neural processes, outer and inner plexiform layers (IPL), in the vertebrate retina. Both plexiform layers processes visual information into the physiological properties expressed by x-, y-, and w-cells and finally conveyed them to the retinal ganglion cells (RGCs). Cajal divided the IPL of the vertebrate retina into 5 sublayers based on the stratification of bipolar, amacrine, and ganglion cell processes. Recent immunohistochemical studies showed some immunoreactive laminae of calcium binding proteins in the IPL of mammalian retina. Recently, we proposed that chick RGCs formed 8 dendritic strata in the IPL. Then, we investigated the relationship between immunoreactivity of calcium binding proteins and dendritic strata of the RGCs in the chick retina. Corresponding to the dendritic strata, calretinin immunoreactivity was found to form three strata and calbindin and parvalbumin formed a single immunoreactive stratum in the outmost of the IPL.
We investigated variance of neural activities in the visual cortex of awake mice using transcranial flavoprotein fluorescence imaging. Fluorescence signals in the visual cortex were spontaneously variable in the absence of visual stimuli. Large variability and inconsistency were also observed in stimulus-evoked responses. The averaged response amplitudes to repeated familiar stimuli were smaller than those recorded in anesthetized mice. However, awake mice showed larger responses to novel visual stimuli mixed in a series of familiar stimuli. When the intervals of stimulus presentation were fixed at 20 s, some activities in the visual cortex were observed 1–2 s before the stimulus onset. These activities before the stimulus onset disappeared when the intervals of stimulus presentation were randomized. These variability and dynamic properties of fluorescence responses in the visual cortex, which were not observed in anesthetized mice, were eliminated in awake mice with a lesion in the frontal association cortex. doi:10.1016/j.neures.2009.09.1120
P3-b12 Properties of higher visual cortices visualized based on the differential stimulus selectivity in mice Manavu Tohmi 1 , Reiko Meguro 2 , Kentaro Nagami 1 , Ryuichi Hishida 1 , Masao Norita 2 , Takeshi Yagi 3 , Katsuei Shibuki 1 1
doi:10.1016/j.neures.2009.09.1117
P3-b09 Dopamine reduces an h current in human rod photoreceptors via a D2 receptor Fusao Kawai 1 , Masayuki Horiguchi 2 , Ei-Ichi Miyachi 1 1
Dept Physiol, Fujita Health University, Aichi, Japan; Fujita Health University, Aichi, Japan
2
Dept Ophthalmol,
A hyperpolarization-activated current, an h current (Ih), contributes to the rod responses induced by light stimuli by bringing the membrane potential back toward the dark level in the presence of continued light in lower vertebrate retinas. Here we report that Ih in human rods is reduced by dopamine. We used the whole-cell patch-clamp recording technique on surgically excised human retina to examine how dopamine modulates Ih in human rods. Bath application of dopamine reversibly decreased the amplitude of Ih induced by hyperpolarizing voltage steps from a holding potential of −60 mV. At the voltage step of −100 mV, 20 mM dopamine decreased the amplitude of Ih. The D2 dopamine agonist quinpirole (20 mM) inhibited Ih, whereas the D1 agonist SKF-38393 (100 mM) had no effect on Ih. Dopamine-induced reduction of the Ih amplitude was blocked by the D2 dopamine antagonist sulpiride (20 mM). These suggest that dopamine reduces the amplitude of Ih in human rods via a D2 receptor.
2
KOKORO-Biology
We have reported that cortical depression was induced by intermodal space mismatch in the primaryvisual cortex of young divergent strabismic mice wearing a monocular prism goggle. This depression was not induced in strabismic mice with trimmed whiskers. Lesion in the association area or geneticablation of protocadherin-␣ constant region blocked cortical depression in strabismic mice but not ocular dominance plasticity after monocular deprivation. Visual cortical depression was also observed in mice with curled whiskers wearing no goggle. Mice recognize nearby space using vision and somatosensation. Therefore, visual space has to be matched with somatosensory space. We found that the retinotopic maps obtained by the stimuli via the strabismic eye was medially shifted so that intermodal space mismatch was compensated. The medial shift of the retinotopic maps was not observed in strabismic mice with trimmed whiskers, while comparable shift was found in mice with curled whiskers wearing no goggle. doi:10.1016/j.neures.2009.09.1119
P3-b11 Variance of visual cortical responses in awake mice is eliminated by a lesion in the frontal association cortex Hiroaki Tsukano, Kentaro Nagami, Manavu Tohmi, Ryuichi Hishida, Katsuei Shibuki Dept of Neurophysiol, Brain Res Inst, Niigata Univ, Japan
doi:10.1016/j.neures.2009.09.1121
P3-b13 Postnatal development of endocannabinoid system in mouse visual cortex Taisuke Yoneda 1 , Masahiko Watanabe 2 , Yoshio Hata 1 Div Integrative Biosci, Tottori Univ Grad Sch Med Sci Yonago Japan; 2 Dept Anatomy and Embryology, Hokkaido Univ Grad Sch Med Sapporo Japan
P3-b10 Experience-dependent positional shift of retinotopic maps in the mouse visual cortex Kohei Yoshitake 1 , Kenji Watanabe 1 , Manavu Tohmi 1 , Ryuichi Hishida 1 , Takeshi Yagi 2 , Katsuei Shibuki 1 Dept Neurophysiol, Brain Res Inst, Niigata Univ, Japan; Group, Osaka Univ, Japan
We investigated higher visual cortices using transcranial flavoprotein fluorescence imaging in mice. When the speed of drifting grating patterns was increased, fluorescence signals were increased in area LM, AL and RL, while they were decreased in V1. A decrease in the drifting speed produced signal increases in V1 and decreases in higher areas, suggesting that each area had preferred drifting speeds of grating patterns. Similar preferences in drifting speeds were confirmed by unit recordings. The preferences to higher drifting speeds in higher areas were not observed in mice reared under continual flash light illumination. Histological studies using tracers verified that V1 received afferent inputs from LGN while higher areas from the nuclei surrounding LGN such as area LP, which received visual inputs from superior colliculus. Abnormal activities of higher visual areas were found in protocadherin-alpha KO mice.
1
doi:10.1016/j.neures.2009.09.1118
1
Dept Neurophysiol, Brain Res Inst, Niigata Univ, Niigata, Japan; 2 Dept Sensory and Integrative Med, Niigata Univ, Niigata, Japan; 3 Osaka Univ, Osaka, Japan
Mammalian visual system exhibits significant experience-induced plasticity during development. Evidences suggest a role of endocannnabinoid system in the plasticity of central nervous system. To explore a possible role of endocannnabinoid system in the visual cortical plasticity, we examined the expression of an endocannabinoid receptor CB1 and DGL-␣, which synthesizes a major endocannabinoid 2-AG, in visual cortex of mice at various ages by immunohistochemistry and western blot analysis.CB1 immunoreactivity was rather faint at P10 and mainly observed in layer II/III and VI of the primary visual cortex (V1) from P20 to adult. CB1 immunopositive signal was mainly observed in inhibitory nerve terminals containing VGAT rather than excitatory ones containing VGluT. Monocular region of V1 showed significantly higher CB1 immunoreactivity than binocular region. On the other hand, DGL-␣ immunoreactivity showed slightly different laminar distribution in V1 with the strongest signal at the lower part of layer II/III and IV. doi:10.1016/j.neures.2009.09.1122
P3-b14 Identification of amacrine cells involved in motion detection in the rat retina Mie Gangi 1 , Yoshiyuki Yamazaki 2 , Teiko Kuroda 2 , Michiko Imanishi 2 , Masao Tachibana 1 , Masahiko Takada 2 1 2
Dept Psychol, Grad Sch of Hum and Sociol, Univ of Tokyo, Tokyo, Japan; Dept System Neurosci, Tokyo Metropolitan Inst for Neurosci, Tokyo, Japan
Computation of motion direction of visual objects is basic and essential for information processing in the visual system. However, local circuits for motion direction are yet to be elucidated. In the retina, some types of ganglion cells (GC) show direction selectivity. It has been shown that ON direction-selective GCs project their axons to the terminal nuclei of the accessory optic system (AOS). Thus, we examined which types of amacrine cells were connected to the ON direction-selective GCs in the rat retina. We injected rabies virus, a retrograde transneuronal tracer, into the
Abstracts medial terminal nucleus (MTN) of the AOS, and then analyzed immunohistochemically the distribution of labeled retinal neurons. Double labeling with rabies virus and amacrine cell markers revealed that the MTN-projecting direction-selective GCs received major input from inhibitory amacrine cells except cholinergic (starburst) amacrine cells. doi:10.1016/j.neures.2009.09.1123
P3-b15 Localization of histamine H2 receptor in the gerbil retina Mahito Ohkuma, Hideki Imada, Ei-ichi Miyachi Dept of Physiol, Sch of Med, Fujita Health Univ, Aichi, Japan Histaminergic signal transduction system exists in the vertebrate retina. This system has been considered to participate in the efferent innervation. Although histamine H1 receptor and/or histamine H3 receptor were involved this visual function, the histamine H2 receptor (H2R) was excluded because it expressed glial cells. However, we found that H2R expressed on the retinal ganglion cells in the premature gerbil. Furthermore, some retinal ganglion cells were excited by dimaprit, an agonist of the H2R. While expression of H2R became maximum at about 14 to 21 postnatal days, decreased according to mature and disappeared at postmature gerbil. These results suggest functional H2R transduction system exists at the premature retina. Since the gerbil opens the eyes at 3 weeks old, it is considered that the H2R plays specific role at the formation of the early optical signal transduction system. doi:10.1016/j.neures.2009.09.1124
P3-b16 Inhibitory stabilization of the cortical network underlies visual surround suppression Hirofumi Ozeki 1,2 , Ian M. Finn 2 , Evan S. Schaffer 3 , Kenneth D. Miller 3 , David Ferster 2 1
RIKEN BSI, Wako, Saitama, Japan; 2 Northwestern Univ, Evanston, IL, USA; 3 Columbia Univ, New York, NY, USA
In what regime does the cortical circuit operate? Our intracellular studies of surround suppression in cat primary visual cortex (V1) provide strong evidence on this question. Although suppression has been thought to arise from an increase in lateral inhibition, we find that the inhibition that cells receive is reduced, not increased, by a surround stimulus. Instead, suppression is mediated by a withdrawal of excitation. Thalamic recordings and previous work show that these effects cannot be explained by a withdrawal of thalamic input. We find in theoretical work that this behavior can only arise if V1 operates as an inhibition-stabilized network (ISN), in which excitatory recurrence alone is strong enough to destabilize visual responses but feedback inhibition maintains stability. We confirm two strong tests of this scenario experimentally, and show through simulation that observed cell-to-cell variability in surround effects, from facilitation to suppression, can arise naturally from variability in the ISN. doi:10.1016/j.neures.2009.09.1125
P3-b17 Robust preservation of altered orientation maps in the visual cortex of kittens reared with discordant goggles Toshiki Tani, Shigeru Tanaka RIKEN Brain Science Institute, Japan The marked over-representation of an exposed orientation is induced by 1- or 2week single-orientation exposure in the two eyes with head-mounted goggles in early life. After prolonged goggle rearing, however, the over-representation of the exposed orientation gradually decreases towards a moderate level. In the present study, to examine interocular cortical inhibition working between the left- and righteye dominance patches on altered orientation maps, we performed optical imaging of intrinsic signals in the visual cortex of kittens reared with discordant goggles which exposed animals to orthogonal orientations in the respective eyes. In these kittens, the representations of the vertical and horizontal orientations separately occupied cortical patches of opposite ocular dominance. The overrepresentation of the exposed orientation for each eye tended to be robustly preserved even after prolonged discordant-goggle rearing. These findings suggest that interocular cortical inhibition enhanced by concordant-goggle rearing moderates the initially induced over-representation of the exposed orientation. doi:10.1016/j.neures.2009.09.1126
S205
P3-b18 Saccade-related signals in V1 change within the sequence of eye-movements during natural vision Junji Ito 1 , Pedro Maldonado 2 , Sonja Gruen 1 1
RIKEN Brain Science Inst, Wako-shi, Japan;
2
Univ de Chile, Santiage, Chile
In our previous studies of V1 activity of freely viewing monkeys, we found that visually induced spikes during fixations are phase-locked to LFP beta-oscillations evoked by preceding saccades. These signals may be instrumental during selfinitiated eye movements enabling precise temporal relationships within the neural network involved in visual processing. Studies in humans that freely view natural images have reported changes in the durations of the saccades and fixations as a function of the sequence order of sucessive eye movements (EM). Thus, here we reexamine our monkey neuronal activity to determine whether the order in EMsequences influences saccade-evoked LFP and phase locking of spikes. We found an EM-sequence dependent modulation of the amplitude of the saccade-evoked LFP oscillations, along with changes of the phase locking of visually induced early spikes. These results suggest that different types of visual processing are involved during early and late EMs in visual exploration. doi:10.1016/j.neures.2009.09.1127
P3-b19 A mathematical model of color map formation in macaque V1 and V2 Masanobu Miyashita 1,2 , Shigeru Tanaka 2 1
Numazu National College of Technology, Japan; RIKEN, Japan
2
Brain Science Institute,
In macaque V1 and V2, some portions of neurons are selective for color information. However, the spatial organizations of color representation are different between V1 and V2: in V1, color cells in response to red/green or blue/yellow are located in CO blobs and bridges linking nearest neighbor CO blobs; and in V2, color responsive cells, which are mainly confined in the CO thin stripes, are rather regularly arranged according to hue. Thus far, few models have not successfully explained such organization about color representation. In this study, we built a self-organization model to explain cortical color representation in V1 and V2 in a unified manner. Changing the values of coefficients of response biases, we reproduced basic structure of color blobs and bridges in V1 and alternating achromatic (thick and pale) stripes and chromatic (thin) stripes in which hue is regularly represented. doi:10.1016/j.neures.2009.09.1128
P3-b20 Organization of multisynaptic inputs from LGN to MT and V4 of macaques Taihei Ninomiya 1,2 , Hiromasa Sawamura 1,3 , Ken-ichi Inoue 1 , Masahiko Takada 1 1
System Neurosci, Tokyo Met Inst Neurosci, Tokyo, Japan; 2 Grad Sch Frontier Biosci, Osaka Univ, Osaka, Japan; 3 Dept Opthal, Tokyo Univ, Tokyo, Japan The primate visual system is composed of multisynaptic pathways connecting the lateral geniculate nucleus (LGN) and higher cortical areas via the primary visual cortex. To investigate the architecture of the dorsal and ventral visual pathways, we injected rabies virus into the middle temporal area (MT) and visual area 4 (V4) of macaque monkeys and compared the patterns of transneuronal labeling in the LGN. The neuronal labeling in the LGN occurred 3 days after the MT injection, whereas the labeling appeared 4 days after V4. In these cases, labeled neurons were observed in both magno- and parvocellular layers of the LGN. The present results suggest that the MT and V4 receive the second- or third-order multisynaptic inputs, respectively, from the LGN with convergent signals originating in magno- and parvocellular layers. doi:10.1016/j.neures.2009.09.1129
P3-b21 Face identity decoding by population activity in macaque inferotemporal cortex face-selective region Naohisa Miyakawa 1,2 , Manabu Tanifuji 1 1
Integrative Neural Systems, RIKEN BSI, Saitama, Japan; sity, Niigata, Japan
2
Niigata Univer-
Primates can recognize faces invariantly even when they view the faces from different viewing angles. Inferotemporal (IT) cortex is the latest stage of the ventral visual stream, and is widely accepted to be a crucial area for visual recognition. It has been shown that in IT cortex, there are multiple face-responsive regions, which have strong selectivity to face images. These face-selective regions are considered to contribute to face detection, however, it is still unclear how identification of view-invariant face identification is realized. We recorded population activities
Abstracts
P3-b08 Dendritic stratification of RGCs and immunoreactive lamination of calcium binding proteins in the inner plexiform layer of the chick retina Jumpei Naito 1 , Taiki Tamura 2 1
Dept Animarl Sci, Teikyo Univ of Sci & Tech, Uenohara, Japan; of Sci and Tech, Uenohara, Japan
2
Teikyo Univ
There are two plexuses of neural processes, outer and inner plexiform layers (IPL), in the vertebrate retina. Both plexiform layers processes visual information into the physiological properties expressed by x-, y-, and w-cells and finally conveyed them to the retinal ganglion cells (RGCs). Cajal divided the IPL of the vertebrate retina into 5 sublayers based on the stratification of bipolar, amacrine, and ganglion cell processes. Recent immunohistochemical studies showed some immunoreactive laminae of calcium binding proteins in the IPL of mammalian retina. Recently, we proposed that chick RGCs formed 8 dendritic strata in the IPL. Then, we investigated the relationship between immunoreactivity of calcium binding proteins and dendritic strata of the RGCs in the chick retina. Corresponding to the dendritic strata, calretinin immunoreactivity was found to form three strata and calbindin and parvalbumin formed a single immunoreactive stratum in the outmost of the IPL.
We investigated variance of neural activities in the visual cortex of awake mice using transcranial flavoprotein fluorescence imaging. Fluorescence signals in the visual cortex were spontaneously variable in the absence of visual stimuli. Large variability and inconsistency were also observed in stimulus-evoked responses. The averaged response amplitudes to repeated familiar stimuli were smaller than those recorded in anesthetized mice. However, awake mice showed larger responses to novel visual stimuli mixed in a series of familiar stimuli. When the intervals of stimulus presentation were fixed at 20 s, some activities in the visual cortex were observed 1–2 s before the stimulus onset. These activities before the stimulus onset disappeared when the intervals of stimulus presentation were randomized. These variability and dynamic properties of fluorescence responses in the visual cortex, which were not observed in anesthetized mice, were eliminated in awake mice with a lesion in the frontal association cortex. doi:10.1016/j.neures.2009.09.1120
P3-b12 Properties of higher visual cortices visualized based on the differential stimulus selectivity in mice Manavu Tohmi 1 , Reiko Meguro 2 , Kentaro Nagami 1 , Ryuichi Hishida 1 , Masao Norita 2 , Takeshi Yagi 3 , Katsuei Shibuki 1 1
doi:10.1016/j.neures.2009.09.1117
P3-b09 Dopamine reduces an h current in human rod photoreceptors via a D2 receptor Fusao Kawai 1 , Masayuki Horiguchi 2 , Ei-Ichi Miyachi 1 1
Dept Physiol, Fujita Health University, Aichi, Japan; Fujita Health University, Aichi, Japan
2
Dept Ophthalmol,
A hyperpolarization-activated current, an h current (Ih), contributes to the rod responses induced by light stimuli by bringing the membrane potential back toward the dark level in the presence of continued light in lower vertebrate retinas. Here we report that Ih in human rods is reduced by dopamine. We used the whole-cell patch-clamp recording technique on surgically excised human retina to examine how dopamine modulates Ih in human rods. Bath application of dopamine reversibly decreased the amplitude of Ih induced by hyperpolarizing voltage steps from a holding potential of −60 mV. At the voltage step of −100 mV, 20 mM dopamine decreased the amplitude of Ih. The D2 dopamine agonist quinpirole (20 mM) inhibited Ih, whereas the D1 agonist SKF-38393 (100 mM) had no effect on Ih. Dopamine-induced reduction of the Ih amplitude was blocked by the D2 dopamine antagonist sulpiride (20 mM). These suggest that dopamine reduces the amplitude of Ih in human rods via a D2 receptor.
2
KOKORO-Biology
We have reported that cortical depression was induced by intermodal space mismatch in the primaryvisual cortex of young divergent strabismic mice wearing a monocular prism goggle. This depression was not induced in strabismic mice with trimmed whiskers. Lesion in the association area or geneticablation of protocadherin-␣ constant region blocked cortical depression in strabismic mice but not ocular dominance plasticity after monocular deprivation. Visual cortical depression was also observed in mice with curled whiskers wearing no goggle. Mice recognize nearby space using vision and somatosensation. Therefore, visual space has to be matched with somatosensory space. We found that the retinotopic maps obtained by the stimuli via the strabismic eye was medially shifted so that intermodal space mismatch was compensated. The medial shift of the retinotopic maps was not observed in strabismic mice with trimmed whiskers, while comparable shift was found in mice with curled whiskers wearing no goggle. doi:10.1016/j.neures.2009.09.1119
P3-b11 Variance of visual cortical responses in awake mice is eliminated by a lesion in the frontal association cortex Hiroaki Tsukano, Kentaro Nagami, Manavu Tohmi, Ryuichi Hishida, Katsuei Shibuki Dept of Neurophysiol, Brain Res Inst, Niigata Univ, Japan
doi:10.1016/j.neures.2009.09.1121
P3-b13 Postnatal development of endocannabinoid system in mouse visual cortex Taisuke Yoneda 1 , Masahiko Watanabe 2 , Yoshio Hata 1 Div Integrative Biosci, Tottori Univ Grad Sch Med Sci Yonago Japan; 2 Dept Anatomy and Embryology, Hokkaido Univ Grad Sch Med Sapporo Japan
P3-b10 Experience-dependent positional shift of retinotopic maps in the mouse visual cortex Kohei Yoshitake 1 , Kenji Watanabe 1 , Manavu Tohmi 1 , Ryuichi Hishida 1 , Takeshi Yagi 2 , Katsuei Shibuki 1 Dept Neurophysiol, Brain Res Inst, Niigata Univ, Japan; Group, Osaka Univ, Japan
We investigated higher visual cortices using transcranial flavoprotein fluorescence imaging in mice. When the speed of drifting grating patterns was increased, fluorescence signals were increased in area LM, AL and RL, while they were decreased in V1. A decrease in the drifting speed produced signal increases in V1 and decreases in higher areas, suggesting that each area had preferred drifting speeds of grating patterns. Similar preferences in drifting speeds were confirmed by unit recordings. The preferences to higher drifting speeds in higher areas were not observed in mice reared under continual flash light illumination. Histological studies using tracers verified that V1 received afferent inputs from LGN while higher areas from the nuclei surrounding LGN such as area LP, which received visual inputs from superior colliculus. Abnormal activities of higher visual areas were found in protocadherin-alpha KO mice.
1
doi:10.1016/j.neures.2009.09.1118
1
Dept Neurophysiol, Brain Res Inst, Niigata Univ, Niigata, Japan; 2 Dept Sensory and Integrative Med, Niigata Univ, Niigata, Japan; 3 Osaka Univ, Osaka, Japan
Mammalian visual system exhibits significant experience-induced plasticity during development. Evidences suggest a role of endocannnabinoid system in the plasticity of central nervous system. To explore a possible role of endocannnabinoid system in the visual cortical plasticity, we examined the expression of an endocannabinoid receptor CB1 and DGL-␣, which synthesizes a major endocannabinoid 2-AG, in visual cortex of mice at various ages by immunohistochemistry and western blot analysis.CB1 immunoreactivity was rather faint at P10 and mainly observed in layer II/III and VI of the primary visual cortex (V1) from P20 to adult. CB1 immunopositive signal was mainly observed in inhibitory nerve terminals containing VGAT rather than excitatory ones containing VGluT. Monocular region of V1 showed significantly higher CB1 immunoreactivity than binocular region. On the other hand, DGL-␣ immunoreactivity showed slightly different laminar distribution in V1 with the strongest signal at the lower part of layer II/III and IV. doi:10.1016/j.neures.2009.09.1122
P3-b14 Identification of amacrine cells involved in motion detection in the rat retina Mie Gangi 1 , Yoshiyuki Yamazaki 2 , Teiko Kuroda 2 , Michiko Imanishi 2 , Masao Tachibana 1 , Masahiko Takada 2 1 2
Dept Psychol, Grad Sch of Hum and Sociol, Univ of Tokyo, Tokyo, Japan; Dept System Neurosci, Tokyo Metropolitan Inst for Neurosci, Tokyo, Japan
Computation of motion direction of visual objects is basic and essential for information processing in the visual system. However, local circuits for motion direction are yet to be elucidated. In the retina, some types of ganglion cells (GC) show direction selectivity. It has been shown that ON direction-selective GCs project their axons to the terminal nuclei of the accessory optic system (AOS). Thus, we examined which types of amacrine cells were connected to the ON direction-selective GCs in the rat retina. We injected rabies virus, a retrograde transneuronal tracer, into the
Abstracts medial terminal nucleus (MTN) of the AOS, and then analyzed immunohistochemically the distribution of labeled retinal neurons. Double labeling with rabies virus and amacrine cell markers revealed that the MTN-projecting direction-selective GCs received major input from inhibitory amacrine cells except cholinergic (starburst) amacrine cells. doi:10.1016/j.neures.2009.09.1123
P3-b15 Localization of histamine H2 receptor in the gerbil retina Mahito Ohkuma, Hideki Imada, Ei-ichi Miyachi Dept of Physiol, Sch of Med, Fujita Health Univ, Aichi, Japan Histaminergic signal transduction system exists in the vertebrate retina. This system has been considered to participate in the efferent innervation. Although histamine H1 receptor and/or histamine H3 receptor were involved this visual function, the histamine H2 receptor (H2R) was excluded because it expressed glial cells. However, we found that H2R expressed on the retinal ganglion cells in the premature gerbil. Furthermore, some retinal ganglion cells were excited by dimaprit, an agonist of the H2R. While expression of H2R became maximum at about 14 to 21 postnatal days, decreased according to mature and disappeared at postmature gerbil. These results suggest functional H2R transduction system exists at the premature retina. Since the gerbil opens the eyes at 3 weeks old, it is considered that the H2R plays specific role at the formation of the early optical signal transduction system. doi:10.1016/j.neures.2009.09.1124
P3-b16 Inhibitory stabilization of the cortical network underlies visual surround suppression Hirofumi Ozeki 1,2 , Ian M. Finn 2 , Evan S. Schaffer 3 , Kenneth D. Miller 3 , David Ferster 2 1
RIKEN BSI, Wako, Saitama, Japan; 2 Northwestern Univ, Evanston, IL, USA; 3 Columbia Univ, New York, NY, USA
In what regime does the cortical circuit operate? Our intracellular studies of surround suppression in cat primary visual cortex (V1) provide strong evidence on this question. Although suppression has been thought to arise from an increase in lateral inhibition, we find that the inhibition that cells receive is reduced, not increased, by a surround stimulus. Instead, suppression is mediated by a withdrawal of excitation. Thalamic recordings and previous work show that these effects cannot be explained by a withdrawal of thalamic input. We find in theoretical work that this behavior can only arise if V1 operates as an inhibition-stabilized network (ISN), in which excitatory recurrence alone is strong enough to destabilize visual responses but feedback inhibition maintains stability. We confirm two strong tests of this scenario experimentally, and show through simulation that observed cell-to-cell variability in surround effects, from facilitation to suppression, can arise naturally from variability in the ISN. doi:10.1016/j.neures.2009.09.1125
P3-b17 Robust preservation of altered orientation maps in the visual cortex of kittens reared with discordant goggles Toshiki Tani, Shigeru Tanaka RIKEN Brain Science Institute, Japan The marked over-representation of an exposed orientation is induced by 1- or 2week single-orientation exposure in the two eyes with head-mounted goggles in early life. After prolonged goggle rearing, however, the over-representation of the exposed orientation gradually decreases towards a moderate level. In the present study, to examine interocular cortical inhibition working between the left- and righteye dominance patches on altered orientation maps, we performed optical imaging of intrinsic signals in the visual cortex of kittens reared with discordant goggles which exposed animals to orthogonal orientations in the respective eyes. In these kittens, the representations of the vertical and horizontal orientations separately occupied cortical patches of opposite ocular dominance. The overrepresentation of the exposed orientation for each eye tended to be robustly preserved even after prolonged discordant-goggle rearing. These findings suggest that interocular cortical inhibition enhanced by concordant-goggle rearing moderates the initially induced over-representation of the exposed orientation. doi:10.1016/j.neures.2009.09.1126
S205
P3-b18 Saccade-related signals in V1 change within the sequence of eye-movements during natural vision Junji Ito 1 , Pedro Maldonado 2 , Sonja Gruen 1 1
RIKEN Brain Science Inst, Wako-shi, Japan;
2
Univ de Chile, Santiage, Chile
In our previous studies of V1 activity of freely viewing monkeys, we found that visually induced spikes during fixations are phase-locked to LFP beta-oscillations evoked by preceding saccades. These signals may be instrumental during selfinitiated eye movements enabling precise temporal relationships within the neural network involved in visual processing. Studies in humans that freely view natural images have reported changes in the durations of the saccades and fixations as a function of the sequence order of sucessive eye movements (EM). Thus, here we reexamine our monkey neuronal activity to determine whether the order in EMsequences influences saccade-evoked LFP and phase locking of spikes. We found an EM-sequence dependent modulation of the amplitude of the saccade-evoked LFP oscillations, along with changes of the phase locking of visually induced early spikes. These results suggest that different types of visual processing are involved during early and late EMs in visual exploration. doi:10.1016/j.neures.2009.09.1127
P3-b19 A mathematical model of color map formation in macaque V1 and V2 Masanobu Miyashita 1,2 , Shigeru Tanaka 2 1
Numazu National College of Technology, Japan; RIKEN, Japan
2
Brain Science Institute,
In macaque V1 and V2, some portions of neurons are selective for color information. However, the spatial organizations of color representation are different between V1 and V2: in V1, color cells in response to red/green or blue/yellow are located in CO blobs and bridges linking nearest neighbor CO blobs; and in V2, color responsive cells, which are mainly confined in the CO thin stripes, are rather regularly arranged according to hue. Thus far, few models have not successfully explained such organization about color representation. In this study, we built a self-organization model to explain cortical color representation in V1 and V2 in a unified manner. Changing the values of coefficients of response biases, we reproduced basic structure of color blobs and bridges in V1 and alternating achromatic (thick and pale) stripes and chromatic (thin) stripes in which hue is regularly represented. doi:10.1016/j.neures.2009.09.1128
P3-b20 Organization of multisynaptic inputs from LGN to MT and V4 of macaques Taihei Ninomiya 1,2 , Hiromasa Sawamura 1,3 , Ken-ichi Inoue 1 , Masahiko Takada 1 1
System Neurosci, Tokyo Met Inst Neurosci, Tokyo, Japan; 2 Grad Sch Frontier Biosci, Osaka Univ, Osaka, Japan; 3 Dept Opthal, Tokyo Univ, Tokyo, Japan The primate visual system is composed of multisynaptic pathways connecting the lateral geniculate nucleus (LGN) and higher cortical areas via the primary visual cortex. To investigate the architecture of the dorsal and ventral visual pathways, we injected rabies virus into the middle temporal area (MT) and visual area 4 (V4) of macaque monkeys and compared the patterns of transneuronal labeling in the LGN. The neuronal labeling in the LGN occurred 3 days after the MT injection, whereas the labeling appeared 4 days after V4. In these cases, labeled neurons were observed in both magno- and parvocellular layers of the LGN. The present results suggest that the MT and V4 receive the second- or third-order multisynaptic inputs, respectively, from the LGN with convergent signals originating in magno- and parvocellular layers. doi:10.1016/j.neures.2009.09.1129
P3-b21 Face identity decoding by population activity in macaque inferotemporal cortex face-selective region Naohisa Miyakawa 1,2 , Manabu Tanifuji 1 1
Integrative Neural Systems, RIKEN BSI, Saitama, Japan; sity, Niigata, Japan
2
Niigata Univer-
Primates can recognize faces invariantly even when they view the faces from different viewing angles. Inferotemporal (IT) cortex is the latest stage of the ventral visual stream, and is widely accepted to be a crucial area for visual recognition. It has been shown that in IT cortex, there are multiple face-responsive regions, which have strong selectivity to face images. These face-selective regions are considered to contribute to face detection, however, it is still unclear how identification of view-invariant face identification is realized. We recorded population activities