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The origin of spreading burst activities in the local circuit of the superior colliculus
S154
Abstracts / Neuroscience Research 58S (2007) S1–S244
P2-e33 An evaluation of 3-D binocular receptive fields in the early visual cortex
P2-e38 Dynamics of intrinsic optical signals in cat primary
Yuka Tabuchi 1 , Kota Sasaki 2 , Izumi Ohzawa 1,2 1 Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan; 2 Graduate School of Engineering Science, Osaka University, Osaka, Japan
Wataru Suzuki, Midori Nagai, Toshiyuki Ootsuka, Gang Wang Kagoshima University, Japan
A binocular receptive field (RF) is inherently a 3-D entity defined as a function of visual direction (x, y) and distance z. However, binocular RFs have conventionally been measured only in 2-D, because bar stimuli of optimal orientation are used. Therefore, it is not known whether binocular RF profiles are uniform along the length axis (parallel to the preferred orientations). Stimulating neurons in the early visual cortex by 2-D dynamic dense noise stimuli presented dichoptically, we examined 3-D binocular RFs, which now have the length axis in addition to the left-eye and right-eye position axes. These analyses showed many cells with uniform profiles along the length axis. However, some neurons exhibited gradual changes in structure, indicating non-uniformity of the binocular RFs. Our new method allows evaluation of the true 3-D forms of the binocular RFs and their internal structures of visual cortical neurons.
visual cortex
Although optical imaging based on intrinsic signals has been widely used in visualizing the brain functional organization, its property is not well known. The purpose of this study was to investigate the temporal property and visualize the signal dynamics over the cortical surface. We applied the intrinsic optical imaging to cat V1. Reflection images were taken under the illumination light tuned to 605 nm at 500 ms interval. The time-course model of signal was created by averaging the optical intensity values at active regions. We calculated the correlation coefficient, at each pixel, between the time-series of the response evoked by the visual stimulation and the model. The value was compared to the correlation coefficients to the model shifted every 500 ms in time scale. Aligned by the shift time of model, we observed that the area with higher correlation coefficient gradually shifted from the cortical region showing functional mapping signals to the region covered by relatively large blood vessels. The results demonstrate the dynamics in cat V1 and suggest the validity of the proposed method in extracting localized functional signals.
Research funds: MEXT(18020017), JSPS(13308048), COE21
P2-e34 Developmental changes in electrophysiological properties of layer III pyramidal neurons in macaque visual cortices
P2-e39 A new approach to estimating receptive fields from
Atsuko Maruyama 1 , Ayako Ishikawa 2 , Daisuke Hosoyama 2 , Yumiko Yoshimura 1,3 , Hiroshi Tamura 1,2 , Hiromichi Sato 2 , Ichiro Fujita 1,2 1 CREST, JST, Japan; 2 Osaka University, Japan; 3 Nagoya University, Japan
Nicolas A. Lesica 1 , Toshihiko Hosoya 2 1 Department of Biology II, Division of Neurobiology, Ludwig Maximilians University Munich, Martinsried, Germany; 2 RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan
We studied developmental changes of intrinsic membrane properties of layer III pyramidal neurons in the striate (V1) and inferior temporal (TE) cortices of macaque monkeys. Whole-cell patch-clamp techniques were applied to slices prepared from animals of different ages (10 days, 7–8 months, adult). The membrane time constant decreased with age in both V1 and TE. In V1, the value at 7–8 months was already close to that in adults, while in TE it gradually decreased up to adulthood. Inward rectification in response to hyperpolarization became stronger with age, and this change was more evident in V1 than in TE. In both areas, the maximal rate of firing in response to depolarizing current injection increased with age, and the duration of individual action potentials shortened. The results demonstrate that electrophysiological properties of cortical neurons in monkeys become matured over a prolonged period after birth, which may contribute to refinement of visual responsiveness during development.
responses to natural stimuli
The reasons for using natural stimuli to study sensory function are quickly mounting, but neurophysiologists have been slow to incorporate them, partly because of the difficulty of estimating receptive fields (RFs) from responses to stimuli with complex statistical properties. Natural stimuli typically contain strong correlations and often have skewed distributions of light intensity. These statistical complexities can bias the result of RF estimation when standard techniques such as spike-triggered averaging or reverse correlation are used. Here, we develop a method for RF estimation that accounts for both the correlations and the skewed intensity distributions. The method involves a transformation of the original stimulus to decrease correlations and skews, as well as an explicit correction for residual biases. The utility of the method is demonstrated by estimating RFs from the responses of retinal ganglion cells to natural stimuli and using these RFs to predict responses to novel stimuli.
Research funds: CREST
P2-e36 Neural dynamics involved in the 3-D object perception
P2-e40 The origin of spreading burst activities in the local
as assessed by MEG/fMRI integrated imaging technique
circuit of the superior colliculus
Sunao Iwaki 1 , Giorgio Bonmassar 2 , John W. Belliveau 2 1 AIST, Osaka, Japan; 2 MGH, Boston, USA
P. Phongphanphanee 1,2 , K. Kaneda 1,2 , T. Isa 1,2,3 1 Department of Devlopmental Physiology, National Institute for Physiological Sciences, Japan; 2 The Graduate University for Advanced Studies, Japan; 3 CREST, JST, Japan
Recent neuroimaging studies suggest the involvement of the parietooccipital (PO), the intraparietal (IP), and the inferior-temporal (IT) regions in the 3-D object perception from 2-D motion (3D-SFM: 3-D structure-from-motion), however, the neural dynamics underlying the 3D-SFM is not fully understood. Here, we used both MEG and fMRI measurements to visualize the brain dynamics during 3-D SFM. The coherence of the random-dot motion was parametrically controlled. The results of the fMRI analysis were used to impose plausible constraints on the MEG inverse calculation. IT, PO, and IP regions showed increased neural activity in the highly coherent motion conditions in which subjects perceived robust 3-D object structure at different latencies. These results are in agreement with the previous fMRI studies and add further insight into the temporal dynamics of the neural activities in the multiple brain regions along both the dorsal and the ventral visual processing streams during 3D-SFM. Research funds: JSPS, Magnetic Health Science Foundation, Suzuki Foundation
Our previous studies have shown that when slices of the superior colliculus (SC) are exposed to a solution containing 10 M bicuculline and low Mg2+ (0.1 mM), most neurons in deeper layers (dSC) and some neurons in the superficial layers (sSC) exhibited spontaneous depolarization and burst firing. In present study, we used this condition to study the mechanism of the spread of burst activity in the mice SC with the field potential recording from 64 multi-planar electrodes and the whole cell patch clamp recording. The burst originally occurred from the ventral portion of the sSC and then spread to the dSC. The current injection to a wide-field vertical (WFV) cell, mainly located in the ventral sSC, could evoke the burst response, which spread from the sSC to the dSC. The WFV cells uniquely exhibit large Ih currents among the SC cell groups and application of 50–100 M ZD7288, a Ih blocker, completely eliminated the spontaneous bursts. These findings supported the idea that WFV cells are the origin for the propagation of burst activity in the SC. Research funds: MEXT (No. 18200027)
Abstracts / Neuroscience Research 58S (2007) S1–S244
P2-e33 An evaluation of 3-D binocular receptive fields in the early visual cortex
P2-e38 Dynamics of intrinsic optical signals in cat primary
Yuka Tabuchi 1 , Kota Sasaki 2 , Izumi Ohzawa 1,2 1 Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan; 2 Graduate School of Engineering Science, Osaka University, Osaka, Japan
Wataru Suzuki, Midori Nagai, Toshiyuki Ootsuka, Gang Wang Kagoshima University, Japan
A binocular receptive field (RF) is inherently a 3-D entity defined as a function of visual direction (x, y) and distance z. However, binocular RFs have conventionally been measured only in 2-D, because bar stimuli of optimal orientation are used. Therefore, it is not known whether binocular RF profiles are uniform along the length axis (parallel to the preferred orientations). Stimulating neurons in the early visual cortex by 2-D dynamic dense noise stimuli presented dichoptically, we examined 3-D binocular RFs, which now have the length axis in addition to the left-eye and right-eye position axes. These analyses showed many cells with uniform profiles along the length axis. However, some neurons exhibited gradual changes in structure, indicating non-uniformity of the binocular RFs. Our new method allows evaluation of the true 3-D forms of the binocular RFs and their internal structures of visual cortical neurons.
visual cortex
Although optical imaging based on intrinsic signals has been widely used in visualizing the brain functional organization, its property is not well known. The purpose of this study was to investigate the temporal property and visualize the signal dynamics over the cortical surface. We applied the intrinsic optical imaging to cat V1. Reflection images were taken under the illumination light tuned to 605 nm at 500 ms interval. The time-course model of signal was created by averaging the optical intensity values at active regions. We calculated the correlation coefficient, at each pixel, between the time-series of the response evoked by the visual stimulation and the model. The value was compared to the correlation coefficients to the model shifted every 500 ms in time scale. Aligned by the shift time of model, we observed that the area with higher correlation coefficient gradually shifted from the cortical region showing functional mapping signals to the region covered by relatively large blood vessels. The results demonstrate the dynamics in cat V1 and suggest the validity of the proposed method in extracting localized functional signals.
Research funds: MEXT(18020017), JSPS(13308048), COE21
P2-e34 Developmental changes in electrophysiological properties of layer III pyramidal neurons in macaque visual cortices
P2-e39 A new approach to estimating receptive fields from
Atsuko Maruyama 1 , Ayako Ishikawa 2 , Daisuke Hosoyama 2 , Yumiko Yoshimura 1,3 , Hiroshi Tamura 1,2 , Hiromichi Sato 2 , Ichiro Fujita 1,2 1 CREST, JST, Japan; 2 Osaka University, Japan; 3 Nagoya University, Japan
Nicolas A. Lesica 1 , Toshihiko Hosoya 2 1 Department of Biology II, Division of Neurobiology, Ludwig Maximilians University Munich, Martinsried, Germany; 2 RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan
We studied developmental changes of intrinsic membrane properties of layer III pyramidal neurons in the striate (V1) and inferior temporal (TE) cortices of macaque monkeys. Whole-cell patch-clamp techniques were applied to slices prepared from animals of different ages (10 days, 7–8 months, adult). The membrane time constant decreased with age in both V1 and TE. In V1, the value at 7–8 months was already close to that in adults, while in TE it gradually decreased up to adulthood. Inward rectification in response to hyperpolarization became stronger with age, and this change was more evident in V1 than in TE. In both areas, the maximal rate of firing in response to depolarizing current injection increased with age, and the duration of individual action potentials shortened. The results demonstrate that electrophysiological properties of cortical neurons in monkeys become matured over a prolonged period after birth, which may contribute to refinement of visual responsiveness during development.
responses to natural stimuli
The reasons for using natural stimuli to study sensory function are quickly mounting, but neurophysiologists have been slow to incorporate them, partly because of the difficulty of estimating receptive fields (RFs) from responses to stimuli with complex statistical properties. Natural stimuli typically contain strong correlations and often have skewed distributions of light intensity. These statistical complexities can bias the result of RF estimation when standard techniques such as spike-triggered averaging or reverse correlation are used. Here, we develop a method for RF estimation that accounts for both the correlations and the skewed intensity distributions. The method involves a transformation of the original stimulus to decrease correlations and skews, as well as an explicit correction for residual biases. The utility of the method is demonstrated by estimating RFs from the responses of retinal ganglion cells to natural stimuli and using these RFs to predict responses to novel stimuli.
Research funds: CREST
P2-e36 Neural dynamics involved in the 3-D object perception
P2-e40 The origin of spreading burst activities in the local
as assessed by MEG/fMRI integrated imaging technique
circuit of the superior colliculus
Sunao Iwaki 1 , Giorgio Bonmassar 2 , John W. Belliveau 2 1 AIST, Osaka, Japan; 2 MGH, Boston, USA
P. Phongphanphanee 1,2 , K. Kaneda 1,2 , T. Isa 1,2,3 1 Department of Devlopmental Physiology, National Institute for Physiological Sciences, Japan; 2 The Graduate University for Advanced Studies, Japan; 3 CREST, JST, Japan
Recent neuroimaging studies suggest the involvement of the parietooccipital (PO), the intraparietal (IP), and the inferior-temporal (IT) regions in the 3-D object perception from 2-D motion (3D-SFM: 3-D structure-from-motion), however, the neural dynamics underlying the 3D-SFM is not fully understood. Here, we used both MEG and fMRI measurements to visualize the brain dynamics during 3-D SFM. The coherence of the random-dot motion was parametrically controlled. The results of the fMRI analysis were used to impose plausible constraints on the MEG inverse calculation. IT, PO, and IP regions showed increased neural activity in the highly coherent motion conditions in which subjects perceived robust 3-D object structure at different latencies. These results are in agreement with the previous fMRI studies and add further insight into the temporal dynamics of the neural activities in the multiple brain regions along both the dorsal and the ventral visual processing streams during 3D-SFM. Research funds: JSPS, Magnetic Health Science Foundation, Suzuki Foundation
Our previous studies have shown that when slices of the superior colliculus (SC) are exposed to a solution containing 10 M bicuculline and low Mg2+ (0.1 mM), most neurons in deeper layers (dSC) and some neurons in the superficial layers (sSC) exhibited spontaneous depolarization and burst firing. In present study, we used this condition to study the mechanism of the spread of burst activity in the mice SC with the field potential recording from 64 multi-planar electrodes and the whole cell patch clamp recording. The burst originally occurred from the ventral portion of the sSC and then spread to the dSC. The current injection to a wide-field vertical (WFV) cell, mainly located in the ventral sSC, could evoke the burst response, which spread from the sSC to the dSC. The WFV cells uniquely exhibit large Ih currents among the SC cell groups and application of 50–100 M ZD7288, a Ih blocker, completely eliminated the spontaneous bursts. These findings supported the idea that WFV cells are the origin for the propagation of burst activity in the SC. Research funds: MEXT (No. 18200027)