All Outputs (51)

The role of contrast sensitivity in global motion processing deficits in the elderly (2010)
Journal Article

This study compared the effects of age on the perception of translational, radial, and rotational global motion patterns. Motion coherence thresholds were measured for judging the direction of each motion type as a function of contrast (visibility) a... Read More about The role of contrast sensitivity in global motion processing deficits in the elderly.

Using biologically plausible neural models to specify the functional and neural mechanisms of visual search (2009)
Journal Article

We review research from our laboratory that attempts to pull apart the functional and neural mechanisms of visual search using converging, inter-disciplinary evidence from experimental studies with normal participants, neuropsychological studies with... Read More about Using biologically plausible neural models to specify the functional and neural mechanisms of visual search.

Ventral extra-striate cortical areas are required for human visual texture segmentation (2009)
Journal Article

A patient (HJA) with bilateral occipital lobe damage to ventral cortical areas V2, V3 and V4 was tested on a texture segmentation task involving texture bar detection in an array of oriented lines. Performance detecting a target shape was assessed as... Read More about Ventral extra-striate cortical areas are required for human visual texture segmentation.

Direct tactile stimulation of dorsal occipito-temporal cortex in a visual agnosic (2009)
Journal Article

The human occipito-temporal cortex is preferentially activated by images of objects as opposed to scrambled images [1]. Touching objects (versus textures) also activates this region [2–10]. We used neuropsychological fMRI to probe whether dorsal regi... Read More about Direct tactile stimulation of dorsal occipito-temporal cortex in a visual agnosic.

Model based analysis of fMRI-data: Applying the sSoTS framework to the neural basic of preview search. (2009)
Book Chapter

The current work aims to unveil the neural circuits under- lying visual search over time and space by using a model-based analysis of behavioural and fMRI data. It has been suggested by Watson and Humphreys [31] that the prioritization of new stimuli... Read More about Model based analysis of fMRI-data: Applying the sSoTS framework to the neural basic of preview search..

Decomposition of neural circuits of human attention using a model based analysis: sSoTs model application to fMRI data (2008)
Journal Article

The complex neural circuits found in fMRI studies of human attention were decomposed using a model of spiking neurons. The model for visual search over time and space (sSoTS) incorporates different synaptic components (NMDA, AMPA, GABA) and a frequen... Read More about Decomposition of neural circuits of human attention using a model based analysis: sSoTs model application to fMRI data.

Previewing distracters reduces their effective contrast (2007)
Journal Article

In a visual search task, when half the distracters are presented earlier than the remainder (‘previewed’), observers find the target item more efficiently than when all the items are presented together—the preview benefit. We measured psychometric fu... Read More about Previewing distracters reduces their effective contrast.

A psychophysical investigation into the preview benefit in visual search (2007)
Journal Article

In preview search, half of the distracters are presented ahead of the remaining distracters and the target. Search under these conditions is more efficient than when all the items appear together (Watson & Humphreys, 1997). We investigated the mechan... Read More about A psychophysical investigation into the preview benefit in visual search.

Ventral extra-striate cortical areas are required for optimal orientation averaging (2007)
Journal Article

We examined the ability of a previously well-studied patient with visual agnosia to compute the average orientation of elements in visual displays. In a structural MRI study, we show that the lesion is likely to involve a variety of ventral extra-str... Read More about Ventral extra-striate cortical areas are required for optimal orientation averaging.

Poor encoding of position by contrast-defined motion (2004)
Journal Article

Second-order (contrast-defined) motion stimuli lead to poor performance on a number of tasks, including discriminating form from motion and visual search. To investigate this deficiency, we tested the ability of human observers to monitor multiple re... Read More about Poor encoding of position by contrast-defined motion.

Visual mechanisms of motion analysis and motion perception (2003)
Journal Article

Psychophysical experiments on feature tracking suggest that most of our sensitivity to chromatic motion and to second-order motion depends on feature tracking. There is no reason to suppose that the visual system contains motion sensors dedicated to... Read More about Visual mechanisms of motion analysis and motion perception.