Fast and slow dynamics in learning and attending to objects: Transient Where and sustained What stream inputs explain individual differences

摘要

How are spatial and object attention coordinated to achieve invariant object learning and recognition during eye movement search? How do prefrontal priming and parietal spatial mechanisms interact to determine the reaction time costs of intra-object attention shifts, inter-object attention shifts, and shifts between visible objects and covertly cued locations and their effects on individual differences (Brown and Denny, 2007; Roggeveen et al., 2009)? The current work builds on the ARTSCAN model (Fazl, Grossberg, and Mingolla, 2009) of how spatial attention in the Where cortical stream coordinates stable, view-invariant object category learning in the What cortical stream under free viewing conditions. The earlier model predicted how a??attentional shroudsa?? (Tyler and Konsevich, 1995) are formed when surface representations in cortical area V4 resonate with spatial attention in posterior parietal cortex (PPC), and how active surface-shroud resonances support conscious surface perception. Our work clarifies how interactions of fast transient Where stream inputs from cortical area MT and slow sustained What stream inputs from V4 influence both PPC and prefrontal cortex (PFC), whose interactions with V4 explain psychological data about covert attention switching and multifocal attention without eye movements. The relative strength of transient and sustained attention-enhancing inputs explains all cases in the experiments cited above, including individual differences in reaction time for invalid cues. Moreover, volitional control of the strength of inhibition between shrouds simulates performance differences in useful-field-of-view tasks (Green and Bavelier, 2003), and separated left and right cortically magnified hemifield representations simulates allocation of independent attention resources in left and right visual hemifields (Alvarez and Cavanagh, 2005).