— Motivated Cognition Lab

Different effects of spatial and temporal attention on the integration and segregation of stimuli in time

Poppy Sharp, David Melcher, and Clayton Hickey

in press, Attention, Perception and Psychophysics

 

Having expectations about when and where relevant stimuli will appear engenders endogenous temporal and spatial orienting, and can provide vital benefits to visual processing. Whilst more is known about how each of these forms of orienting affect spatial processing, comparatively little is understood about their influence on temporal integration and segregation of rapid sequential stimuli. A critical question is whether the influence of spatial cueing on temporal processing involves independent spatial and temporal orienting effects or a synergistic spatiotemporal impact. Here, we delineate between temporal and spatial orienting engendered by endogenous cues by using a paradigm with identical visual stimulation when the goal is to integrate or segregate stimuli in separate blocks of trials. We find strong effects of spatial orienting on both integration and segregation performance. In contrast, temporal orienting engendered only an invalid cueing cost, for integration trials only. This clear differentiation between spatial and temporal cueing effects provides constraints to inform arbitration between theories of how attention biases the visual processing stream and influences the organization of visual perception in time.

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From a fruitful ongoing collaboration with Daniel Schneider and Edmund Wascher in Dortmund.

Working memory contents can be prioritized by retroactively deploying attention within memory. This is broadly interpreted as evidence of a concentration of memory resources to the attended, to-be-remembered stimulus. However, online attentional selection is known to additionally depend on distractor inhibition, raising the viable alternative that attentional deployment in working memory involves inhibitory control processes. Here, we demonstrate that active inhibition plays a central role in the deployment of attention in working memory. We do so using a retroactive cueing paradigm, where a briefly presented memory array is followed by a cue indicating a to-be-remembered target (Experiment 1) or a to-be-forgotten distractor (Experiment 2). We identify discrete indices of target selection and distractor inhibition in lateralized oscillatory activity over visual areas. When a retroactive cue identifies the location of a target, results show rapid decrease of lateral, target-elicited alpha band activity, representing attentional orienting toward the target. This is followed only later by emergence of an increase in distractor-elicited alpha activity, reflecting distractor inhibition. In contrast, when the retroactive cue identifies a distractor, evidence of distractor inhibition emerges first, only later followed by target selection. These results thus demonstrate that separate excitatory and inhibitory processes underlie the deployment of attention on the level of working memory representations.

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    Poppy presented her exciting MEG data at ECVP in Trieste.

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    I have been awarded a 2018 ERC Starting Grant for the INSENSE project to investigate human
    incentive salience in health and disorder.

    I am very interested in hearing from potential postdoctoral fellows and PhD students to work on this project!

     

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    Electrophysiological indices of attentional selection in naturalistic vision. 

    Daniele Pollicino

     

    110 cum laude! Complimenti Daniele!

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    On September 1st, 2018, I will leave my post at the University of Trento to take up a position as Senior Lecturer at the University of Birmingham, UK.

    As always, I am very interested in hearing from potential PhD students and postdoctoral scholars and in supporting applications for funding.

    In particular, applications for the Marie Cure Individual Fellowship are accepted from April 12th, 2018 (with a September 12 deadline). I would be very happy to talk with applicants about potential projects and the possibility of carrying this grant at Birmingham.

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    Poppy’s first first-authored paper! Congratulations Poppy!

    Sharp, Melcher, & Hickey (2018). Endogenous attention modulates the temporal window of integration. Attention, Perception, & Psychophysics.

    Constructing useful representations of our visual environment requires the ability to selectively pay attention to particular locations at specific moments. Whilst there has been much investigation on the influence of selective attention on spatial discrimination, less is known about its influence on temporal discrimination. In particular, little is known about how endogenous attention influences two fundamental and opposing temporal processes: segregation – the parsing of the visual scene over time into separate features, and integration – the binding together of related elements. In four experiments, we tested how endogenous cueing to a location influences each of these opposing processes. Results demonstrate a strong cueing effect on both segregation and integration. These results are consistent with the hypothesis that endogenous attention can influence both of these opposing processes in a flexible manner. The finding has implications for arbitrating between accounts of the multiple modulatory mechanisms comprising selective attention.

     

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    Attentional bias for substance-related stimuli in addictive behaviours: An ERP study on tobacco users.

    Marco Pario

     

    Nt or Pd?: Analysis of the N2pc component describes the process of attentional allocation with respect to angry or neutral facial expressions.

    Leonardo Pimpini

     

    Congratulations Marco and Leo!

    Leo is beginning a PhD with Anne Roefs at the University of Maastricht. Good luck Leo!

     

     

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    A long one representing years of work from Ludwig.

    Barbaro, L., Peelen, M.V., & Hickey, C  (in press). Valence, not utility, underlies reward-driven prioritization in human vision. Journal of Neuroscience. <link>

    Objects associated with reward draw attention and evoke enhanced activity in visual cortex. What is the underlying mechanism? One possibility is that reward’s impact on vision is mediated by unique circuitry that modulates sensory processing, selectively increasing the salience of reward-associated stimuli. Alternatively, effects of reward may be part of a more general mechanism that prioritizes the processing of any beneficial object, importantly including stimuli that are associated with the evasion of loss. Here, we test these competing hypotheses by having male and female humans detect naturalistic objects associated with monetary reward, the evasion of equivalent loss, or neither of these. If vision is economically normative, processing of objects associated to reward and evasion of loss should be prioritized relative to neutral stimuli. Results from fMRI and behavioural experiments show that this is not the case: while objects associated with reward were better detected and represented in ventral visual cortex, detection and representation of stimuli associated with the evasion of loss was degraded. Representations in parietal cortex reveal a notable exception to this pattern, showing enhanced encoding of both reward- and loss-associated stimuli. Experience-driven visual prioritization can thus be economically irrational, driven by valence rather than objective utility.

     

     

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    110 cum laude! Complimenti Nicholas!

    How reward modulates visually guided and internally guided force. 

    Nicholas Menghi
    Advisors: Clayton Hickey and Giorgio Coricelli.

     

    IMG-20170725-WA0001

     

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