法国国家科研中心7日发表公报称，该机构与瑞士弗里德里希－米舍研究所合作，在哺乳动物的视网膜内发现了新的神经回路，能够帮助眼睛“捕获”不断接近的物体。

公报说，视网膜一直被视为构造简单的“过滤器”，其作用无非是在眼睛与大脑之间传递信息。但是近几年来，科学家们发现，视网膜对视觉信息并非“照单全收”，而是要经过精确的筛选，再将其传递到大脑。法国和瑞士的研究人员在仔细研究了老鼠的视网膜后，发现了一个新的神经回路，其用途非常单一，当有物体靠近时，神经回路就会被激活。

研究人员表示，这个神经回路的功能对捕食类动物至关重要，因为只有将猎物识别清楚，才能将其捕获。相关研究成果已发表在最新一期的英国《自然·神经科学》杂志上。

原始出处：

Nature Neuroscience 6 September 2009 | doi:10.1038/nn.2389

Approach sensitivity in the retina processed by a multifunctional neural circuit

Thomas A Münch1,3,4, Rava Azeredo da Silveira2,4, Sandra Siegert1, Tim James Viney1, Gautam B Awatramani1,3 & Botond Roska1

The detection of approaching objects, such as looming predators, is necessary for survival. Which neurons and circuits mediate this function? We combined genetic labeling of cell types, two-photon microscopy, electrophysiology and theoretical modeling to address this question. We identify an approach-sensitive ganglion cell type in the mouse retina, resolve elements of its afferent neural circuit, and describe how these confer approach sensitivity on the ganglion cell. The circuit's essential building block is a rapid inhibitory pathway: it selectively suppresses responses to non-approaching objects. This rapid inhibitory pathway, which includes AII amacrine cells connected to bipolar cells through electrical synapses, was previously described in the context of night-time vision. In the daytime conditions of our experiments, the same pathway conveys signals in the reverse direction. The dual use of a neural pathway in different physiological conditions illustrates the efficiency with which several functions can be accommodated in a single circuit.

1 Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
2 Department of Physics and Department of Cognitive Studies, école Normale Supérieure, Paris, France.
3 Present addresses: Laboratory for Retinal Circuits and Optogenetics, Centre for Integrative Neuroscience, Eberhard-Karls University Tübingen, Tübingen, Germany (T.A.M.); Department of Anatomy and Neurobiology, Dalhousie University, Halifax, Nova Scotia, Canada (G.B.A.).
4 These authors contributed equally to this work.