Poster A117, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Magnocellular-parvocellular pathway reciprocity in visual processing and the trait-like set point modulated by anxiety
Yuqi You1, Wen Li1; 1Florida State University
Human visual processing is carried out by separate magnocellular (M-) and parvocellular (P-) channels showing distinct sensitivities to distinct physical properties of incoming visual stimuli. The psychological/functional relevance and interrelationship of M/P pathways remain unclear. Combining visual event-related potentials (VEPs) with Gabor patches selectively activating M- vs. P-pathways (N=47), we identified a positive-going P1 and a negative-going C2 at around 100 ms in response to M- versus P-selective stimuli. There was a highly significant anticorrelation between the absolute amplitudes of P1 and C2, indicating a reciprocal relationship between the strengths of M and P pathways. Furthermore, this reciprocity was observed across three time points (r’s<-.71, p’s<.001), two weeks apart, suggesting a trait-like neural set point that relates to individual differences in low-level visual processing. Moreover, this M-P reciprocity was modulated by trait anxiety measured by the Behavioral Inhibition Scale (BIS) at three time points: BIS scores correlated negatively with P1 amplitude (r’s<-.36, p’s<=.026), positively with C2 absolute amplitude (r’s>.37, p’s<=.01), and negatively with a M-P preference index (calculated as P1-C2; r’s>-.27, p’s<.068). In a follow-up experiment (N=49), we replicated this relationship between trait anxiety and M-P preference (r=-.35, p=.014) using low-spatial-frequency/low-contrast and high-spatial-frequency/high-contrast achromatic gratings as M- and P-selective stimuli. These findings together suggest that given threat can be differentially encoded via M/P pathways, the M-P set point may have evolved for maximal threat detection. Our data further indicate a potential neural marker for trait anxiety, characterized by a heightened P-over-M preference that promotes visual hypersensitivity to threat.
Topic Area: PERCEPTION & ACTION: Vision