Abstract
Purpose: To probe for contributions from the parvocellular (P) and magnocellular (M) pathways to location based inhibition of return (IOR) we manipulated cue and target spatial frequency (SF), the visual field they appeared in, and whether they were presented alone or in 3-D objects. Earlier evidence (Brown, 2006) suggested conditions favoring P relative to M activity should produce greater IOR magnitude and vice versa. Thus, greater IOR was expected to higher SF targets presented in 3-D objects in the upper visual field. Conversely, less IOR was expected to lower SF targets presented alone in the lower visual field. Method: Cues and targets were gabor patches presented in the left/right or upper/lower visual fields, alone or in 3-D objects, using cue-to-target timing known to produce location-based IOR. Simple RT to target onset was measured. Different SF pairings were tested (1+12cpd; 1+4cpd; 4+12cpd). Results: The absolute SF of the cue and target and the relative frequency difference between them influenced IOR magnitude. When presented alone, the lowest frequency tested (1 cpd) always produced less IOR compared to its higher frequency counterpart, whether 4 cpd or 12 cpd. The results indicate greater P activity is associated with greater IOR magnitude and greater M activity is associated with less. This relationship was further supported by the changes in the patterns of IOR magnitude for the different SF targets when attention shifted between the upper (P dominant) and lower (M dominant) visual fields, and whether they appeared alone or in 3-D objects. P on M inhibition related to attention was also evident (Yeshurun, 2004). Conclusions: The differences in location-based IOR magnitude related to P and M activity support a close link between attentive processing, object processing and the P pathway (Yeshurun, 2004), and between inattentive processing and the M pathway (Srinivasan & Brown, 2006).