Acetylcholine dynamically controls spatial integration in Marmoset primary visual cortex

Roberts , M. J. and Zinke, W. and Guo, K. and Robertson , R. and McDonald, J. S. and Thiele, A. (2005) Acetylcholine dynamically controls spatial integration in Marmoset primary visual cortex. Journal of Neurophysiology, 93 (4). pp. 2062-2072. ISSN 0022-3077

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Acetylcholine dynamically controls spatial integration in Marmoset primary visual cortex
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Official URL: http://jn.physiology.org/content/93/4/2062

Abstract

Recent in vitro studies have shown that acetylcholine (ACh)
selectively reduces the efficacy of lateral cortical connections via a muscarinic mechanism, while boosting the efficacy of thalamocortical/feed-forward connections via a nicotinic mechanism. This suggests that high levels of ACh should reduce center-surround interactions of neurons in primary visual cortex, making cells more reliant on
feed-forward information. In line with this hypothesis, we show that local iontophoretic application of ACh in primate primary visual cortex reduced the extent of spatial integration, assessed by recording a neurons’ length tuning. When ACh was externally applied, neurons’
preferred length shifted toward shorter bars, showing reduced impact of the extra-classical receptive field. We fitted a difference and a ratio of Gaussian model to these data to determine the underlying mechanisms of this dynamic change of spatial integration. These models assume overlapping summation and suppression areas with different
widths and gains to be responsible for spatial integration and size tuning. ACh significantly reduced the extent of the summation area, but had no significant effect on the extent of the suppression area. In line with previous studies, we also show that applying ACh enhanced
the response in the majority of cells, especially in the later (sustained) part of the response. These findings are similar to effects of attention on neuronal activity. The natural release of ACh is strongly linked with states of arousal and attention. Our results may therefore be
relevant to the neurobiological mechanism of attention.

Item Type:Article
Additional Information:Recent in vitro studies have shown that acetylcholine (ACh) selectively reduces the efficacy of lateral cortical connections via a muscarinic mechanism, while boosting the efficacy of thalamocortical/feed-forward connections via a nicotinic mechanism. This suggests that high levels of ACh should reduce center-surround interactions of neurons in primary visual cortex, making cells more reliant on feed-forward information. In line with this hypothesis, we show that local iontophoretic application of ACh in primate primary visual cortex reduced the extent of spatial integration, assessed by recording a neurons’ length tuning. When ACh was externally applied, neurons’ preferred length shifted toward shorter bars, showing reduced impact of the extra-classical receptive field. We fitted a difference and a ratio of Gaussian model to these data to determine the underlying mechanisms of this dynamic change of spatial integration. These models assume overlapping summation and suppression areas with different widths and gains to be responsible for spatial integration and size tuning. ACh significantly reduced the extent of the summation area, but had no significant effect on the extent of the suppression area. In line with previous studies, we also show that applying ACh enhanced the response in the majority of cells, especially in the later (sustained) part of the response. These findings are similar to effects of attention on neuronal activity. The natural release of ACh is strongly linked with states of arousal and attention. Our results may therefore be relevant to the neurobiological mechanism of attention.
Keywords:Acetylcholine, Spatial Integration, Marmoset, Primary Visual Cortex, bmjdoi
Subjects:C Biological Sciences > C800 Psychology
C Biological Sciences > C850 Cognitive Psychology
C Biological Sciences > C830 Experimental Psychology
C Biological Sciences > C860 Neuropsychology
Divisions:College of Social Science > School of Psychology
ID Code:5878
Deposited By: Alison Wilson
Deposited On:16 Jun 2012 19:16
Last Modified:13 Mar 2013 09:11

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