The timing of feature-based attentional effects during object perception

Department of Psychology, University of Toronto at Scarborough, Toronto, Ontario, Canada.
Neuropsychologia (Impact Factor: 3.3). 08/2011; 49(12):3406-18. DOI: 10.1016/j.neuropsychologia.2011.08.017
Source: PubMed


Allocating attention to basic features such as colour enhances perception of the respective features throughout the visual field. We have previously shown that feature-based attention also plays a role for more complex features required for object perception. To investigate at which level object perception is modulated by feature-based attention we recorded high-density event-related potentials (ERPs). Participants detected contour-defined objects or motion, and were informed to expect each feature dimension. Participants perceived contour-defined objects and motion better when they expected the congruent feature. This is consistent with modulation of the P1 when attending to lower-level features. For contours, modulation occurred at 290 ms, first at frontal electrodes and then at posterior sites, associated with sources in ventral visual areas accompanied by greater signal strength. This pattern of results is consistent with what has been observed in response to illusory contours. Our data provide novel insights into the contribution of feature-based attention to object perception that are associated with higher tier brain areas.

Download full-text


Available from: Bobby (Boge) Stojanoski, Mar 11, 2014
1 Follower
14 Reads
  • Source
    • "The difference in feature-based attention is arguably seen in the small HI/LO effect during the late P1 phase, likely because the lower spatial frequencies were less salient (Singh et al., 2011) and required more attentional effort. An influence of feature-based attention is consistent with the timing of the effect (Stojanoski & Niemeier, 2011; Zhang & Luck, 2009) and with source localization, estimating that the effect originated from the dorsal parietal cortex (Liu, Hospadaruk, Zhu, & Gardner, 2011). It showed a trend of left-sided activation, perhaps due to a task-specific larger P1 amplitude and better signal-to-noise ratio on the left. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Major clues to the human brain mechanisms of spatial attention and visual awareness have come from the syndrome of neglect, where patients ignore one half of space. A longstanding puzzle, though, is that neglect almost always comes from right-hemisphere damage, which suggests that the two sides of the brain play distinct roles. But tests of attention in healthy people have revealed only slight differences between the hemispheres. Here we show that major differences emerge if we look at the timing of brain activity in a task optimized to identify attentional functions. Using EEG to map cortical activity on a millisecond timescale, we found transient (20-30 ms) periods of interhemispheric competition, followed by short phases of marked right-sided activity in the ventral attentional network. Our data are the first to show interhemispheric interactions that, much like a toggle switch, quickly allocate neural resources to one or the other hemisphere.
    Cortex 11/2014; 64. DOI:10.1016/j.cortex.2014.09.015 · 5.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: ABSTRACT: A mysterious disease affecting calves, named bovine neonatal pancytopenia (BNP), emerged in 2007 in several European countries. Epidemiological studies revealed a connection between BNP and vaccination with an inactivated vaccine against bovine virus diarrhea (BVD). Alloantibodies reacting with blood leukocytes of calves were detected in serum and colostrum of dams, which have given birth to calves affected by BNP. To understand the linkage between vaccination and the development of alloantibodies, we determined the antigens reacting with these alloantibodies. Immunoprecipitation of surface proteins from bovine leukocytes and kidney cells using sera from dams with a confirmed case of BNP in their gestation history reacted with two dominant protein species of 44 and 12 kDa. These proteins were not detected by sera from dams, free of BVDV and not vaccinated against BVD, and from sera of animals vaccinated with a different inactivated BVD vaccine. The 44 kDa protein was identified by mass spectrometry analysis as MHC I, the other as β-2-microglobulin. The presence of major histocompatibility complex class I (MHC I) in the vaccine was confirmed by Western blot using a MHC I specific monoclonal antibody. A model of BNP pathogenesis is proposed.
    Veterinary Research 08/2011; 42(1):97. DOI:10.1186/1297-9716-42-97 · 2.82 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigated the influence of dimensional set on report of object feature information using an immediate memory probe task. Participants viewed displays containing up to 36 coloured geometric shapes which were presented for several hundred milliseconds before one item was abruptly occluded by a probe. A cue presented simultaneously with the probe instructed participants to report either about the colour or shape of the probe item. A dimensional set towards the colour or shape of the presented items was induced by manipulating task probability - the relative probability with which the two feature dimensions required report. This was done across two participant groups: One group was given trials where there was a higher report probability of colour, the other a higher report probability of shape. Two experiments showed that features were reported most accurately when they were of high task probability, though in both cases the effect was largely driven by the colour dimension. Importantly the task probability effect did not interact with display set size. This is interpreted as tentative evidence that this manipulation influences feature processing in a global manner and at a stage prior to visual short term memory.
    Acta psychologica 05/2013; 143(3):261-268. DOI:10.1016/j.actpsy.2013.04.007 · 2.19 Impact Factor
Show more