- Email: [email protected]
Simultaneous selectivity to color and motion direction of neurons in V2 of macaque monkeys
e154
Abstracts / Neuroscience Research 68S (2010) e109–e222
P1-h21 Interaction between the lateral geniculate nucleus and the perigeniculate nucleus of the cat Hironobu Osaki 1 , Tomoyuki Naito 1 , Shogo Soma 2 , Hiromichi Sato 1 1
Grad Sch of Medicine, Osaka Univ, Osaka 2 Grad sch of Front Sci, Osaka Univ, Osaka The perigeniculate nucleus (PGN) is a layer of inhibitory GABAergic neurons lying over the dorsal surfaces of the lateral geniculate nucleus (LGN). It receives axon-collateral input from the principal cells of LGN and axon-collaterals of cortico-geniculate projections. PGN neuron sends back inhibitory projection to the LGN. It is known that these projections are organized in retinotopic manner. However, little is known about the relationship between visual receptive field properties of the PGN and LGN neurons, which are connected each other. To explore this point, we conducted a crosscorrelation analysis of single neuronal activity simultaneously recorded from the PGN and LGN neurons in anesthetized cats. For 15 pairs of functionally connected PGN and LGN neurons, we compared the receptive field properties, such as the spatial frequency tuning and temporal frequency tuning, of each neuron. Correlated firings were observed only in neuron pairs whose receptive fields were partially or entirely overlapped. We found a pattern of connection between these neurons, that is, the receptive field properties of the PGN neurons and the LGN neurons are similar when there is only excitatory connection from LGN to PGN (4 pairs), but different when the PGN neurons send inhibitory inputs to the LGN neurons (8 pairs). We also found that the inhibitory input from PGN neuron serves for sharpening the orientation selectivity of LGN neuron, which shows the orientation preference different from that of PGN neuron. These results suggest the inhibitory role of PGN neurons on the elaboration of the receptive field properties of LGN neurons. doi:10.1016/j.neures.2010.07.2254
P1-h22 Responses of disparity selective neurons in V3/V3A to anti-correlated random-dot stereograms Yasutaka Okazaki Grad Sch. Frontier Biosci, Osaka Univ, Osaka Binocular disparity is a strong cue for depth perception. Most visual areas in the primate brain process binocular disparity. Recent studies by using functional magnetic resonance imaging have demonstrated that among the visual areas, V3/V3A (in macaque monkeys) and V3A (in human subjects) are especially selective for binocular disparity, suggesting V3/V3A is important for stereoscopic depth perception. However, only few electrophysiological studies have examined the characteristics of binocular disparity tuning in V3/V3A neurons. The aim of this study is to characterize the extent to which disparity selective responses in V3/V3A neurons are relevant to depth perception. To examine this, we used correlated and anti-correlated random-dot sterograms (cRDSs and aRDSs, respectively). aRDSs, in which the luminance contrast is inverted in one eye, do not give rise to perception of a plane-indepth. Therefore, in this case, perceptually relevant neurons should attenuate their disparity selectivity. We recorded extracellular activity from 117 visually responsive single neurons in V3/V3A of two awake, fixating monkeys. Of these, Ninety five (81%) showed significant selectivity for binocular disparity in cRDSs (KruskalWallis; P < 0.05). We fitted Gabor functions to the data to calculate the ratio of disparity dependent modulation amplitudes between aRDSs and cRDSs. The median ratio for V3/V3A neurons was 0.29, indicating that the modulation by disparity in aRDSs was smaller than that in cRDSs. We compared our results with the ratios obtained for other visual areas. The ratio for V3/V3A was lower than that for V1 (median, 0.39; Cumming & Parker, 1997) (MannWhitney test, P = 0.0005) and for V2 (median, 0.33) (P = 0.02), but similar to that for V4 (median, 0.24; Tanabe et al, 2004) (P = 0.74). The results suggest that V3/V3A is situated at a more advanced stage of stereo processing than V1 and V2, but is comparable to V4. doi:10.1016/j.neures.2010.07.2255
P1-h23 Functional roles of GABAa- and GABAb- receptor on the surround suppression in the cat lateral geniculate nucleus Satoshi Shimegi 1 , Akihiro Kimura 1 , Shin-ichiro Hara 2 , Masahiro Okamoto 3 , Hiromichi Sato 1 1
Graduate School of Medicine, Osaka University 2 Graduate School of Frontier Biosciences, Osaka University 3 School of Medicine, Fukushima Medical University In neurons of the lateral geniculate nucleus (LGN), response to a stimulation of the classical center-surround receptive field (CRF) is suppressed by a stimulation of the extraclassical receptive field (ECRF) (surround suppression, SS). To examine how intrathalamic GABAergic inhibition is responsible for SS, we performed exracellular single-unit recordings from LGN neurons of anesthetized and paralyzed cats, and tested the effects of a blockade of GABAergic inhibition with a microiontophoresis of bicuculline methiodide (BIC), GABAa receptor specific antagonist, and CGP52432 (CGP), GABAb receptor specific antagonist, on stimulus-size tuning property of response to drifting sinusoidal gratings. Each antagonist increased spontaneous discharges and visual responses to CRF stimulation. Stimuli larger than CRF caused a reduction of response (SS), and BIC antagonized the SS induced by a stimulation of narrow area of ECRF near CRF (near ECRF) more strongly than the SS induced by a stimulation of wide and distal area of ECRF (far ECRF). CGP caused the effect similar to that of BIC but the antagonizing effects were weaker even on near ECRF comparing to BIC, suggesting that intrathalamic GABAergic inhibition does not contribute to SS induced by an stimulation of far ECRF. When both BIC and CGP were administered simultaneously, the blocking effects on the SS from near ECRF was summed in a sublinear fashion in some cells, but, unexpectedly, in another population of cells, the SS became stronger than that where only BIC was administered (enhanced SS), implying that the enhanced SS is due to a reduction of excitatory inputs to LGN neurons from neuronal circuits beyond LGN but not due to enhanced intrathalamic GABAergic inhibition. Thus, a stimulation of ECRF exerts suppressive effect on neuronal response in LGN via various receptor subtypes, and also via network- mechanisms. doi:10.1016/j.neures.2010.07.2256
P1-h24 Simultaneous selectivity to color and motion direction of neurons in V2 of macaque monkeys Kousuke Aratono , Hiroshi Tamura Grad Sch Front Bio, Osaka Univ, Osaka Anatomical, neurophysiological, and psychophysical studies suggested that each visual submodality, such as color, shape, or motion direction, is processed in parallel and independent pathways that originate from the retina to the prefrontal cortices. We, however, generally experience unified coherent percept of the surrounding environment. To achieve the unified visual experience, information that is processed in the parallel pathways should be integrated or bounded together. This is so called “binding problem”. One possible solution of the problem is that single neurons integrate information from different pathways. Indeed some of the studies suggested that the information is less segregated than originally thought. For example, in V2, neurons selective to both color and motion direction were reported. However, it is not certain whether they are detecting the conjunction of visual features, which is required to solve the binding problem at the single neurons level. In the present experiments, we devised a set of 181–349 visual stimuli that consist of a variety of conjunction of isoluminant colors and motion directions, and searched for neurons selectively activated by a feature conjunction in V2 of analgesized macaque monkeys. Neurons detecting feature conjunction are sparsely active. Multi-probe multiple single-unit recording techniques are suitable for the recording of sparsely active neurons, because the sampling of conventional single-probe single-unit recording techniques is biased to densely active neurons. We have recorded 642 neurons from V2 and found that some neurons were selectively activated by a stimulus with a color moving to a direction, indicating that they can detect a conjunction of stimulus color and motion direction. The results suggested that single neurons in V2 or neurons in the preceding stages integrate information from different pathways. Such integration contributes to solving the binding problem. doi:10.1016/j.neures.2010.07.2257
Abstracts / Neuroscience Research 68S (2010) e109–e222
P1-h21 Interaction between the lateral geniculate nucleus and the perigeniculate nucleus of the cat Hironobu Osaki 1 , Tomoyuki Naito 1 , Shogo Soma 2 , Hiromichi Sato 1 1
Grad Sch of Medicine, Osaka Univ, Osaka 2 Grad sch of Front Sci, Osaka Univ, Osaka The perigeniculate nucleus (PGN) is a layer of inhibitory GABAergic neurons lying over the dorsal surfaces of the lateral geniculate nucleus (LGN). It receives axon-collateral input from the principal cells of LGN and axon-collaterals of cortico-geniculate projections. PGN neuron sends back inhibitory projection to the LGN. It is known that these projections are organized in retinotopic manner. However, little is known about the relationship between visual receptive field properties of the PGN and LGN neurons, which are connected each other. To explore this point, we conducted a crosscorrelation analysis of single neuronal activity simultaneously recorded from the PGN and LGN neurons in anesthetized cats. For 15 pairs of functionally connected PGN and LGN neurons, we compared the receptive field properties, such as the spatial frequency tuning and temporal frequency tuning, of each neuron. Correlated firings were observed only in neuron pairs whose receptive fields were partially or entirely overlapped. We found a pattern of connection between these neurons, that is, the receptive field properties of the PGN neurons and the LGN neurons are similar when there is only excitatory connection from LGN to PGN (4 pairs), but different when the PGN neurons send inhibitory inputs to the LGN neurons (8 pairs). We also found that the inhibitory input from PGN neuron serves for sharpening the orientation selectivity of LGN neuron, which shows the orientation preference different from that of PGN neuron. These results suggest the inhibitory role of PGN neurons on the elaboration of the receptive field properties of LGN neurons. doi:10.1016/j.neures.2010.07.2254
P1-h22 Responses of disparity selective neurons in V3/V3A to anti-correlated random-dot stereograms Yasutaka Okazaki Grad Sch. Frontier Biosci, Osaka Univ, Osaka Binocular disparity is a strong cue for depth perception. Most visual areas in the primate brain process binocular disparity. Recent studies by using functional magnetic resonance imaging have demonstrated that among the visual areas, V3/V3A (in macaque monkeys) and V3A (in human subjects) are especially selective for binocular disparity, suggesting V3/V3A is important for stereoscopic depth perception. However, only few electrophysiological studies have examined the characteristics of binocular disparity tuning in V3/V3A neurons. The aim of this study is to characterize the extent to which disparity selective responses in V3/V3A neurons are relevant to depth perception. To examine this, we used correlated and anti-correlated random-dot sterograms (cRDSs and aRDSs, respectively). aRDSs, in which the luminance contrast is inverted in one eye, do not give rise to perception of a plane-indepth. Therefore, in this case, perceptually relevant neurons should attenuate their disparity selectivity. We recorded extracellular activity from 117 visually responsive single neurons in V3/V3A of two awake, fixating monkeys. Of these, Ninety five (81%) showed significant selectivity for binocular disparity in cRDSs (KruskalWallis; P < 0.05). We fitted Gabor functions to the data to calculate the ratio of disparity dependent modulation amplitudes between aRDSs and cRDSs. The median ratio for V3/V3A neurons was 0.29, indicating that the modulation by disparity in aRDSs was smaller than that in cRDSs. We compared our results with the ratios obtained for other visual areas. The ratio for V3/V3A was lower than that for V1 (median, 0.39; Cumming & Parker, 1997) (MannWhitney test, P = 0.0005) and for V2 (median, 0.33) (P = 0.02), but similar to that for V4 (median, 0.24; Tanabe et al, 2004) (P = 0.74). The results suggest that V3/V3A is situated at a more advanced stage of stereo processing than V1 and V2, but is comparable to V4. doi:10.1016/j.neures.2010.07.2255
P1-h23 Functional roles of GABAa- and GABAb- receptor on the surround suppression in the cat lateral geniculate nucleus Satoshi Shimegi 1 , Akihiro Kimura 1 , Shin-ichiro Hara 2 , Masahiro Okamoto 3 , Hiromichi Sato 1 1
Graduate School of Medicine, Osaka University 2 Graduate School of Frontier Biosciences, Osaka University 3 School of Medicine, Fukushima Medical University In neurons of the lateral geniculate nucleus (LGN), response to a stimulation of the classical center-surround receptive field (CRF) is suppressed by a stimulation of the extraclassical receptive field (ECRF) (surround suppression, SS). To examine how intrathalamic GABAergic inhibition is responsible for SS, we performed exracellular single-unit recordings from LGN neurons of anesthetized and paralyzed cats, and tested the effects of a blockade of GABAergic inhibition with a microiontophoresis of bicuculline methiodide (BIC), GABAa receptor specific antagonist, and CGP52432 (CGP), GABAb receptor specific antagonist, on stimulus-size tuning property of response to drifting sinusoidal gratings. Each antagonist increased spontaneous discharges and visual responses to CRF stimulation. Stimuli larger than CRF caused a reduction of response (SS), and BIC antagonized the SS induced by a stimulation of narrow area of ECRF near CRF (near ECRF) more strongly than the SS induced by a stimulation of wide and distal area of ECRF (far ECRF). CGP caused the effect similar to that of BIC but the antagonizing effects were weaker even on near ECRF comparing to BIC, suggesting that intrathalamic GABAergic inhibition does not contribute to SS induced by an stimulation of far ECRF. When both BIC and CGP were administered simultaneously, the blocking effects on the SS from near ECRF was summed in a sublinear fashion in some cells, but, unexpectedly, in another population of cells, the SS became stronger than that where only BIC was administered (enhanced SS), implying that the enhanced SS is due to a reduction of excitatory inputs to LGN neurons from neuronal circuits beyond LGN but not due to enhanced intrathalamic GABAergic inhibition. Thus, a stimulation of ECRF exerts suppressive effect on neuronal response in LGN via various receptor subtypes, and also via network- mechanisms. doi:10.1016/j.neures.2010.07.2256
P1-h24 Simultaneous selectivity to color and motion direction of neurons in V2 of macaque monkeys Kousuke Aratono , Hiroshi Tamura Grad Sch Front Bio, Osaka Univ, Osaka Anatomical, neurophysiological, and psychophysical studies suggested that each visual submodality, such as color, shape, or motion direction, is processed in parallel and independent pathways that originate from the retina to the prefrontal cortices. We, however, generally experience unified coherent percept of the surrounding environment. To achieve the unified visual experience, information that is processed in the parallel pathways should be integrated or bounded together. This is so called “binding problem”. One possible solution of the problem is that single neurons integrate information from different pathways. Indeed some of the studies suggested that the information is less segregated than originally thought. For example, in V2, neurons selective to both color and motion direction were reported. However, it is not certain whether they are detecting the conjunction of visual features, which is required to solve the binding problem at the single neurons level. In the present experiments, we devised a set of 181–349 visual stimuli that consist of a variety of conjunction of isoluminant colors and motion directions, and searched for neurons selectively activated by a feature conjunction in V2 of analgesized macaque monkeys. Neurons detecting feature conjunction are sparsely active. Multi-probe multiple single-unit recording techniques are suitable for the recording of sparsely active neurons, because the sampling of conventional single-probe single-unit recording techniques is biased to densely active neurons. We have recorded 642 neurons from V2 and found that some neurons were selectively activated by a stimulus with a color moving to a direction, indicating that they can detect a conjunction of stimulus color and motion direction. The results suggested that single neurons in V2 or neurons in the preceding stages integrate information from different pathways. Such integration contributes to solving the binding problem. doi:10.1016/j.neures.2010.07.2257