TMS to V1 spares discrimination of emotive relative to neutral body postures

This study used TMS to examine the role played by striate cortex (V1) in processing the emotional content of visual stimuli. Participants learned to discriminate two sets of body posture images. For half of each set, the posture's emotional significance (threat versus pleasant) provided a redundant cue for the discrimination; the other half were emotionally neutral. An image was briefly presented at a lateral location in the visual field where a TMS pulse produced a phosphene, or at a control location in the opposite hemifield. A TMS pulse 70-140 ms after stimulus presentation at the phosphene location impaired discrimination of neutral stimuli with little effect on discrimination of emotional stimuli; the two classes of stimuli were equally discriminable when presented at the control location. The results are consistent with the proposal that emotionally salient patterns, such as social threat, can be discriminated independently of the geniculo-striate pathway.