All Outputs (49)

Ventral extra-striate cortical areas are required for human visual texture segmentation (2009)
Journal Article
Allen, H. A., Humphreys, G. W., Colin, J., & Neumann, H. (2009). Ventral extra-striate cortical areas are required for human visual texture segmentation. Journal of Vision, 9(9), Article 2. https://doi.org/10.1167/9.9.2

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
Allen, H. A., & Humphreys, G. W. (2009). Direct tactile stimulation of dorsal occipito-temporal cortex in a visual agnosic. Current Biology, 19(12), https://doi.org/10.1016/j.cub.2009.04.057

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
Mavritsaki, E., Allen, H. A., & Humphreys, G. W. (2009). Model based analysis of fMRI-data: Applying the sSoTS framework to the neural basic of preview search. In L. Paletta, & J. K. Tsotsos (Eds.), Attention in Cognitive Systems : 5th International Workshop on Attention in Cognitive Systems, WAPCV 2008, Fira, Santorini, Greece, May 12, 2008 : revised selected papers. Springer. https://doi.org/10.1007/978-3-642-00582-4_10

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
Mavritsaki, E., Allen, H. A., & Humphreys, G. W. (2008). Decomposition of neural circuits of human attention using a model based analysis: sSoTs model application to fMRI data. https://doi.org/10.1142/9789812834232_0033

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
Allen, H. A., & Humphreys, G. W. (2007). Previewing distracters reduces their effective contrast. Vision Research, 47(23), https://doi.org/10.1016/j.visres.2007.07.019

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.

Ventral extra-striate cortical areas are required for optimal orientation averaging (2007)
Journal Article
Allen, H. A., Humphreys, G. W., & Bridge, H. (2007). Ventral extra-striate cortical areas are required for optimal orientation averaging. Vision Research, 47(6), https://doi.org/10.1016/j.visres.2006.10.018

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.

A psychophysical investigation into the preview benefit in visual search (2007)
Journal Article
Allen, H. A., & Humphreys, G. W. (2007). A psychophysical investigation into the preview benefit in visual search. Vision Research, 47(6), https://doi.org/10.1016/j.visres.2006.11.007

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.

Poor encoding of position by contrast-defined motion (2004)
Journal Article
Allen, H. A., Ledgeway, T., & Hess, R. F. (2004). Poor encoding of position by contrast-defined motion. Vision Research, 44(17), https://doi.org/10.1016/j.visres.2004.03.025

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
Derrington, A., Allen, H. A., & Delicato, L. (2003). Visual mechanisms of motion analysis and motion perception. Annual Review of Psychology, 55, https://doi.org/10.1146/annurev.psych.55.090902.141903

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.