Contrast sensitivity of pattern transient VEP components: Contribution from M and P pathways.

Abstract

The purpose of this study was to compare contrast sensitivity estimated from transient visual evoked potentials (VEPs) elicited by achromatic pattern-reversal and pattern-onset/offset modes. The stimuli were 2-cpd, achromatic horizontal gratings presented either as a 1 Hz pattern reversal or a 300 ms onset/700 ms offset stimulus. Contrast thresholds were estimated by linear regression to amplitudes of VEP components vs. the logarithm of the stimulus contrasts, and these regressions were extrapolated to the zero amplitude level. Contrast sensitivity was defined as the inverse of contrast threshold. For pattern reversal, the relation between the P100 amplitude and log of the stimulus contrast was best described by two separate linear regressions. For the N135 component, a single straight line was sufficient. In the case of pattern onset/offset for both the C1 and C2 components, single straight lines described their amplitude vs. log contrast relations in the medium-to-low contrast range. Some saturation was observed for C2 components. The contrast sensitivity estimated from the low-contrast limb of the P100, from the N135, and from the C2 were all similar but higher than those obtained from the high-contrast limb of the P100 and C1 data, which were also similar to each other. With 2 cpd stimuli, a mechanism possibly driven by the M pathway appeared to contribute to the P100 component at medium-to-low contrasts and to the N135 and C2 components at all contrast levels, whereas another mechanism, possibly driven by the P and M pathways, appeared to contribute to the P100 component at high contrast and C1 component at all contrast levels.

Visual awareness negativity is an early neural correlate of awareness: A preregistered study with two Gabor sizes

“…Notably, confounding of various parameters occurs by necessity in this typical experimental design. Because size (Mihaylova et al, 2015 ; Pfabigan, Sailer, & Lamm, 2015 ), contrast (Souza et al, 2013 ), as well as duration affect the amplitude and latency of visual evoked potentials, there is a built-in confound when using this design.…”

Low-contrast Pattern-reversal Visual Evoked Potential in Different Spatial Frequencies

“…They have a high contrast sensitivity, high temporal resolution, and short impulse conduction time, whereas PC neurons with a smaller receptive field are sensitive to low temporal and high spatial frequencies. [1,8,12,35,42,[45][46][47][48][49] Therefore, MC signals (high SFs) are conveyed to V1 more rapidly than PC signals (low SFs). At high SFs, the optical properties of the eye noticeably reduce the retinal contrast, resulting in decreased amplitude and delayed latency.…”

Multi-Stage Cortical Plasticity Induced by Visual Contrast Learning

“…In the current study, we observed contrast-dependent gain change both in the latency and amplitude of early P1 component, which resembles a previous single-unit study that recorded the responses of V1 neurons in cats and found that training increased neuronal contrast gain ( Hua et al, 2010 ). P1 is a visually evoked exogenous response that reflected the encoding of sensory information in visual cortex ( Voorhis and Hillyard, 1977 ; Gonzalez et al, 1994 ; Woldorff et al, 1997 ; O’Shea et al, 2010 ; Souza et al, 2013 ). Moreover, we found there is little improvement in the latency and amplitude of P1 at the location and eye change control conditions, which is also indicative of learning specificity.…”