Experiments from Daniele’s masters and Giacomo’s internship will appear in a paper in the Journal of Cognitive Neuroscience!
Ultrafast object detection in naturalistic vision relies on ultrafast distractor suppression.
Hickey, Pollicino, Bertazzoli, and Barbaro
People are quicker to detect examples of real-world object categories in natural scenes than is predicted by classic attention theories. One explanation for this puzzle suggests that experience renders the visual system sensitive to mid-level features diagnosing target presence. These are detected without the need for spatial attention, much as occurs for targets defined by low-level features like color or orientation. The alternative is that naturalistic search relies on spatial attention but is highly efficient because global scene information can be used to quickly reject non-target objects and locations. Here, we use ERPs to differentiate between these possibilities. Results show that hallmark evidence of ultrafast target detection in frontal brain activity is preceded by an index of spatially-specific distractor suppression in visual cortex. Naturalistic search for heterogenous targets therefore appears to rely on spatial operations that act on neural object representations, as predicted by classic attention theory. Participants appear able to rapidly reject non-target objects and locations in order to constrain naturalistic search and increase search efficiency, possibly reflecting the use of global scene information.
Read MoreClayton has moved to the brand-new Center for Human Brain Health. His office is on the ground floor, room G04.
Read More
Poppy successfully defended her PhD at the CIMEC in Rovereto, Italy, on April 5th, 2019.
Poppy’s work examines the role of spatial attention on temporal processing of visual stimuli. Two papers are available here on the website and another is in preparation.
Poppy clearly impressed her committee, resulting in a prestigious cum laude notation to her PhD!
Poppy’s dissertation work was co-supervised by Clayton Hickey and David Melcher, and we look suitably proud in the attached photo.
Congratulations Poppy!
Read More
Jackie Dell has won a prestigious Fulbright award! This will support her PhD research on addiction and incentive salience at the University of Birmingham.
Jackie is finishing her Masters at the University of South Florida with Jennifer O’Brien and will begin at the University of Birmingham in the fall of 2019.
Congratulations Jackie!
Read MoreDifferent 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.
Read MoreFrom 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.
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!
Read More
Electrophysiological indices of attentional selection in naturalistic vision.
Daniele Pollicino
110 cum laude! Complimenti Daniele!
Read More