Taosheng Liu

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A network of fronto-parietal cortical areas is known to be involved in the control of visual attention, but the representational scope and specific function of these areas remains unclear. Recent neuroimaging evidence has revealed the existence of both transient (attention-shift) and sustained (attention-maintenance) mechanisms of space-based and(More)
When a visual stimulus suddenly appears, it captures attention, producing a transient improvement of performance on basic visual tasks. We investigate the effect of transient attention on stimulus representations in early visual areas using rapid event-related fMRI. Participants discriminated the orientation of one of two gratings preceded or followed by a(More)
How does attention optimize our visual system for the task at hand? Two mechanisms have been proposed for how attention improves signal processing: gain and tuning. To distinguish between these two mechanisms we use the equivalent-noise paradigm, which measures performance as a function of external noise. In the present study we explored how spatial and(More)
Sequential sampling models provide a useful framework for understanding human decision making. A key component of these models is an evidence accumulation process in which information is accrued over time to a threshold, at which point a choice is made. Previous neurophysiological studies on perceptual decision making have suggested accumulation occurs only(More)
How does feature-based attention modulate neural responses? We used adaptation to quantify the effect of feature-based attention on orientation-selective responses in human visual cortex. Observers were adapted to two superimposed oblique gratings while attending to one grating only. We measured the magnitude of attention-induced orientation-selective(More)
During apparent motion, spatially distinct items presented in alternation cause the perception of a visual stimulus smoothly traversing the intervening space where no physical stimulus exists. We used fMRI to determine whether the perceptual 'filling-in' that underlies this phenomenon has an early or late cortical locus. Subjects viewed a display comprised(More)
PURPOSE To describe retinotopic mapping of the visual cortex when a central scotoma is present. DESIGN Single observational case report. METHODS Scanning laser ophthalmoscope perimetry was used to define the site and stability of fixation and the area of dense scotoma. Functional magnetic resonance imaging of the visual cortex was performed while the(More)
The ability to identify emotions from the human voice is a crucial aspect of social cognition. Currently, very little is known about the neural correlates of nonverbal emotional vocalizations processing. We used electrophysiological measures to examine the processing of emotional versus neutral vocalizations. Participants listened to nonverbal angry, happy,(More)
We investigated the time course of feature-based attention and compared it to the time course of spatial attention in an experiment with identical stimuli and task. Observers detected a speed increment in a compound motion stimulus preceded by cues that indicated either the target location or direction. The cue-target stimulus-onset-asynchrony (SOA) was(More)
Although both the object and the observer often move in natural environments, the effect of motion on visual object recognition ha not been well documented. The authors examined the effect of a reversal in the direction of rotation on both explicit and implicit memory for novel, 3-dimensional objects. Participants viewed a series of continuously rotating(More)