A FUNCTIONAL-ROLE OF CHOLINERGIC INNERVATION TO NEURONS IN THE CAT VISUAL-CORTEX
A FUNCTIONAL-ROLE OF CHOLINERGIC INNERVATION TO NEURONS IN THE CAT VISUAL-CORTEX
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DOI：
10.1152/jn.1987.58.4.765
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发表时间：
1987-10-01
影响因子：
2.5
通讯作者：
TSUMOTO, T
中科院分区：
文献类型：
--
作者：
SATO, H;HATA, Y;TSUMOTO, T
在猫纹状体皮层研究了乙酰胆碱（ACh）及其拮抗剂对视觉刺激和电刺激外侧膝状体神经元反应的影响。视觉和电引起的反应，促进乙酰胆碱在74%的细胞测试，而反应被抑制在16%。这些ACh的影响被阻断的毒蕈碱拮抗剂，阿托品，但不是由烟碱拮抗剂，六甲双铵，表明ACh的影响是通过毒蕈碱受体介导的。单次应用阿托品抑制ACh易化的细胞的视觉反应，而增强ACh抑制的细胞的视觉反应，表明内源性ACh可能对皮层神经元的视觉反应性进行紧张性调节。在大多数细胞的易化ACh的效果，单峰电刺激的反应变得更加一致，往往与双峰，在ACh的应用。乙酰胆碱的抑制作用最常见于对电刺激外侧膝状体反应潜伏期较长的细胞。在大多数易化细胞的自发活动保持零或非常低的过程中ACh的应用，尽管显着增强的视觉反应，表明ACh可能会提高皮层神经元活动的信噪比（S/N）。为了证实这一建议，我们通过计算反应（S）和刺激周时间直方图（S + N）中的尖峰总数来计算S/S + N指数，发现在ACh应用期间，大约一半的细胞得到改善，而大约五分之一的细胞变得更糟。在大多数易化细胞中，ACh不仅增强了对最佳刺激的视觉反应，而且增强了对非最佳刺激的视觉反应，导致方向选择性没有改善甚至恶化。刺激运动方向的选择性也是如此。的层状位置的促进细胞偏向于层V和VI的皮质，虽然他们也弥补了大多数在层II + III和约一半的测试细胞在层IVab和IVc。根据最近对皮层神经回路的认识，这些结果提示，胆碱能神经支配皮层神经元可能在提高纹状皮层信息处理的信噪比和促进将处理后的信息传送到其他视觉中枢方面起作用。
Effects of microionophoretic application of acetylcholine (ACh) and its antagonists on neuronal responses to visual stimuli and to electrical stimulation of the lateral geniculate nucleus were studied in the cat striate cortex. Responses elicited visually and electrically were facilitated by ACh in 74% of the cells tested, whereas the responses were suppressed in 16%. These ACh effects were blocked by a muscarinic antagonist, atropine, but not by a nicotinic antagonist, hexamethonium, indicating that the ACh effects are mediated through muscarinic receptors. A single application of atropine suppressed visual responses of cells facilitated by ACh, whereas it enhanced those of cells inhibited by ACh, suggesting that endogenous ACh may tonically modulate visual responsivity of cortical neurons. In most cells with the facilitatory ACh effect, responses with single spikes to the electrical stimulation became more consistent, often with double spikes, during the ACh application. The suppressive effects of ACh were noted most often in cells with a longer response latency to electrical stimulation of lateral geniculate nucleus. In most of the facilitated cells the spontaneous activity remained null or very low during ACh application, in spite of marked enhancement of visual responses, suggesting that ACh may improve the signal-to-noise ratio (S/N) of cortical neuron activity. To confirm this suggestion, we calculated a S/S + N index by counting the total number of spikes in the responses (S) and that in peristimulus time histogram (S + N) and found that it was improved during the ACh application in about a half of the cells, whereas it became worse in about one-fifth. In most of the facilitated cells, ACh enhanced visual responses not only to optimal but also to nonoptimal stimuli, resulting in no improvement or even worsening of the orientation selectivity. This was also the case in the selectivity of directon of stimulus movement. The laminar location of the facilitated cells was biased toward layers V and VI of the cortex, although they also made up the majority in layers II + III and about half the tested cells in layers IVab and IVc. In the light of recent understanding of cortical circuitry, these results suggest that the cholinergic innervation to cortical neurons may play a role in improvement of the S/N ratio of information processing in the striate cortex and in facilitation of sending processed informations to other visual centers.