Kurylo Daniel D, Yeturo Sowmya, Lanza Joseph, Bukhari Farhan
Department of Psychology, Brooklyn College CUNY, Brooklyn, NY, 11210, United States.
Department of Psychology, Brooklyn College CUNY, Brooklyn, NY, 11210, United States.
Behav Brain Res. 2017 Sep 29;335:1-7. doi: 10.1016/j.bbr.2017.07.046. Epub 2017 Aug 5.
Changes in target visibility may be produced by additional stimulus elements at adjacent locations. Such contextual effects may reflect lateral interactions of stimulus representations in early cortical areas. It has been reported that the organization of orientation preference found in primates and cats visual cortex differs from that found in rodents, suggesting functional distinctions across species. In order to examine effects of lateral interactions at a perceptual level, contrast sensitivity in rats was measured for Gabor patches masked by two additional patches. Rats responded to target onset, and perceptual indices were based upon reaction time distributions across levels of luminance contrast. It was found that contrast sensitivity of targets without lateral masks corresponded to levels previously reported. For all measurements, the presence of sustained lateral masks systematically reduced sensitivity to targets, demonstrating interference by adjacent elements across levels of contrast. Effects of mask orientation or separation were not observed. These results may reflect reported non-systematic topography of orientation tuning across the cortex in rodents. Results suggest that intrinsic lateral connections in early processing areas play a minimal role in stimulus integration for rats.
目标可见性的变化可能由相邻位置的额外刺激元素产生。这种上下文效应可能反映了早期皮层区域中刺激表征的侧向相互作用。据报道，在灵长类动物和猫的视觉皮层中发现的方向偏好组织与在啮齿动物中发现的不同，这表明不同物种之间存在功能差异。为了在感知水平上研究侧向相互作用的影响，测量了大鼠对被另外两个斑块掩盖的Gabor斑块的对比敏感度。大鼠对目标出现做出反应，感知指标基于不同亮度对比度水平下的反应时间分布。发现没有侧向掩蔽的目标的对比敏感度与先前报道的水平相对应。对于所有测量，持续侧向掩蔽的存在系统地降低了对目标的敏感度，表明相邻元素在不同对比度水平上产生了干扰。未观察到掩蔽方向或间隔的影响。这些结果可能反映了啮齿动物皮层中方向调谐的非系统性地形学。结果表明，早期处理区域中的内在侧向连接在大鼠的刺激整合中起最小作用。
