Relationship between VEP kernels and the visual responses on magnocellular and parvocellular pathways

Abstract

Abstract: : Purpose: To investigate the correlation of the first and second–order binary kernels with the visual responses on parvocellular (P) and magnocellular (M) pathways. Methods: The VEPs elicited by checkerboard pattern alternating based on pseudorandom binary sequence were measured, and their nonlinear parameters (binary kernels) were calculated. VEPs to black–white checkerboard pattern with 0.5, 1.0, 2.0 and 4.0 [c/d] were measured from four normal volunteers. First and second–order binary kernels were compared with steadystate VEPs (S–VEPs) to pattern reversal stimulation with a constant temporal frequency (4, 8, 12, 16, and 32 Hz). Results: Positive peak latency at 150 ms of second–order first slice was correlated with S–VEP amplitude for 32 Hz (r = –0.71), indicating that first slice reflected the responses on magnocellular pathway. Amplitudes of second slice were well correlated with S–VEPs to 4, 8, 12, and 16 Hz stimuli (r = 0.62, 0.77, 0.61, and 0.72), and their latencies of positive peak around 150 ms was also correlated with S–VEPs to 32 Hz (r = –0.65), indicating that second slice reflected the responses on both parvo– and magnocellular pathway. Amplitudes and latencies of third slices were correlated with S–VEP to 4–16 Hz and 8Hz, respectively, indicating that third slice reflected the responses on parvocellular pathway. These results support the previously reported observations that the second–order kernel slices could be indices of the parvocellular and magnocellular pathways responses. Conclusions: Results indicated that the first and second slice response functions reflect the response of the M– and P–pathways in the human visual system, respectively.

Keywords: electrophysiology: non–clinical • contrast sensitivity