Bolzon Douglas M, Nordström Karin, O'Carroll David C
Discipline of Physiology, The University of Adelaide, Adelaide, South Australia 5005, Australia.
J Neurosci. 2009 Nov 11;29(45):14143-50. doi: 10.1523/JNEUROSCI.2857-09.2009.
Lateral inhibition is perhaps the most ubiquitous of neuronal mechanisms, having been demonstrated in early stages of processing in many different sensory pathways of both mammals and invertebrates. Recent work challenges the long-standing view that assumes that similar mechanisms operate to tune neuronal responses to higher order properties. Scant evidence for lateral inhibition exists beyond the level of the most peripheral stages of visual processing, leading to suggestions that many features of the tuning of higher order visual neurons can be accounted for by the receptive field and other intrinsic coding properties of visual neurons. Using insect target neurons as a model, we present unequivocal evidence that feature tuning is shaped not by intrinsic properties but by potent spatial lateral inhibition operating well beyond the first stages of visual processing. In addition, we present evidence for a second form of higher-order spatial inhibition--a long-range interocular transfer of information that we argue serves a role in establishing interocular rivalry and thus potentially a neural substrate for directing attention to single targets in the presence of distracters. In so doing, we demonstrate not just one, but two levels of spatial inhibition acting beyond the level of peripheral processing.
侧抑制可能是最为普遍存在的神经元机制，在哺乳动物和无脊椎动物的许多不同感觉通路的早期处理阶段都得到了证实。最近的研究对长期以来的观点提出了挑战，该观点认为类似的机制用于调节神经元对高阶特性的反应。在视觉处理最外周阶段之外，几乎没有侧抑制的证据，这导致有人提出，高阶视觉神经元调谐的许多特征可以通过视觉神经元的感受野和其他内在编码特性来解释。我们以昆虫目标神经元为模型，提供了明确的证据表明，特征调谐不是由内在特性塑造的，而是由远超视觉处理第一阶段的强大空间侧抑制塑造的。此外，我们还提供了第二种高阶空间抑制形式的证据——一种远距离的眼间信息传递，我们认为这种传递在建立眼间竞争中发挥作用，因此可能是在存在干扰物的情况下将注意力引向单个目标的神经基础。通过这样做，我们不仅证明了一种，而且证明了两种作用于外周处理水平之上的空间抑制水平。
