Spatial frequency selectivity of the human visual cortex estimated with pseudo-random visual evoked cortical potential (VECP).

Spatial frequency selectivity of the human visual cortex estimated with pseudo-random visual evoked cortical potential (VECP). Vision Res. 2019 Oct 11;165:13-21 Authors: Martins ICVS, Brasil A, Miquilini L, Goulart PRK, Herculano AM, Silveira LCL, Souza GS Abstract Single-cell recordings in the primary visual cortex (V1) show neurons with spatial frequency (SF) tuning, which had different responses to chromatic and luminance stimuli. Visually evoked cortical potential (VECP) investigations have reported different spatial profiles. The current study aimed to investigate the spatial selectivity of V1 to simultaneous stimulus of chromatic and luminance contrasts. Compound stimuli temporally driven by m-sequences at 8 SFs were utilized to generate VECP records from thirty subjects (14 trichromats and 16 colorblind subjects). We extracted the second-order kernel, first and second slices (K2.1 and K2.2, respectively). Optimal SF, SF bandwidth, and high SF cut-off were estimated from the best-fitted functions to the VECP amplitude vs SF. For trichromats, K2.1 waveforms had a negative component (N1 K2.1) at 100 ms followed by a positive component (P1 K2.1). K2.2 waveforms also had a negative component (N1 K2.2) at 100 ms followed by a positive deflection (P1 K2.2). SF tuning of N1 K2.1 and N1 K2.2 had a band-pass profile, while the P1 K2.1 was low-pass tuned. P1 K2.1 optimal SF differed significantly from both other negative responses an...
Source: Vision Research - Category: Opthalmology Authors: Tags: Vision Res Source Type: research