Causal evidence for adaptive recruitment of subcortical and cortical pathways in rapid fear processing

This study addresses the long-standing debate on whether the subcortical or cortical visual pathway underlies rapid transmission of threat-related information. Using a single-pulse transcranial magnetic stimulation protocol to transiently disrupt V1/V2 function at various time points, we examined the necessity of early visual cortices at different phases of fear processing. Our results showed that early disruption of V1/V2 had no effect on fearful emotion recognition under conditions of limited visual accessibility (N = 28 adults), but significantly impaired fear recognition when visual accessibility was increased (N = 28 adults). Notably, the impairment occurred as early as 30 ms poststimulus onset and was specific to low spatial frequency information, in stark contrast to the impairment on nonaffective content of the stimuli. These findings suggest a dual-pathway system in the human brain that flexibly engages either the subcortical or cortical pathway, depending on the availability of threat information in the environment. (PsycInfo Database Record (c) 2025 APA, all rights reserved).