Lankow Benjamin S, Usrey W Martin
Center for Neuroscience, University of California, Davis, Davis, CA, United States.
Front Syst Neurosci. 2022 Feb 1;16:818633. doi: 10.3389/fnsys.2022.818633. eCollection 2022.
Throughout the brain, parallel processing streams compose the building blocks of complex neural functions. One of the most salient models for studying the functional specialization of parallel visual streams in the primate brain is the lateral geniculate nucleus (LGN) of the dorsal thalamus, through which the parvocellular and magnocellular channels, On-center and Off-center channels, and ipsilateral and contralateral eye channels are maintained and provide the foundation for cortical processing. We examined three aspects of neural processing in these streams: (1) the relationship between extraclassical surround suppression, a widespread visual computation thought to represent a canonical neural computation, and the parallel channels of the LGN; (2) the magnitude of binocular interaction in the parallel streams; and (3) the magnitude of suppression elicited by perceptual competition (binocular rivalry) in each stream. Our results show that surround suppression is almost exclusive to Off channel cells; further, we found evidence for two different components of monocular surround suppression-an early-stage suppression exhibited by all magnocellular cells, and a late-stage suppression exhibited only by Off cells in both the parvocellular and magnocellular pathways. This finding indicates that stream-specific circuits contribute to surround suppression in the primate LGN and suggests a distinct role for suppression in the Off channel to the cortex. We also examined the responses of LGN neurons in alert macaque monkeys to determine whether neurons that supply the cortex with visual information are influenced by stimulation of both eyes. Our results demonstrate that LGN neurons are not influenced by stimulation of the non-dominant eye. This was the case when dichoptic stimuli were presented to classical receptive fields of neurons, extraclassical receptive fields of neurons, and when stimuli were appropriate to produce the perception of binocular rivalry.
在整个大脑中，并行处理流构成了复杂神经功能的基石。研究灵长类大脑中并行视觉流功能特化的最显著模型之一是背侧丘脑的外侧膝状体核（LGN），通过该核，小细胞和大细胞通道、中心开和中心关通道以及同侧和对侧眼通道得以维持，并为皮层处理提供基础。我们研究了这些流中神经处理的三个方面：（1）超经典周围抑制（一种被认为代表典型神经计算的广泛视觉计算）与LGN并行通道之间的关系；（2）并行流中双眼相互作用的程度；（3）每个流中由感知竞争（双眼竞争）引起的抑制程度。我们的结果表明，周围抑制几乎只存在于关通道细胞中；此外，我们发现了单眼周围抑制的两种不同成分的证据——所有大细胞都表现出的早期抑制，以及在小细胞和大细胞通路中仅由关细胞表现出的晚期抑制。这一发现表明，特定流的电路有助于灵长类LGN中的周围抑制，并暗示了关通道中抑制对皮层的独特作用。我们还研究了清醒猕猴中LGN神经元的反应，以确定向皮层提供视觉信息的神经元是否受到双眼刺激的影响。我们的结果表明，LGN神经元不受非优势眼刺激的影响。当向神经元的经典感受野、神经元的超经典感受野呈现双眼视差刺激时，以及当刺激适合产生双眼竞争感知时，都是如此。
