Professor Charles Heywood
(email at email@example.com)
My research is chiefly concerned with the perception of visual attributes such as form and motion and surface properties, such as colour and texture, in both neurological patients and normal observers. Using fMRI, we have identified the location of a region specialised for the processing of texture and established its relative independence from brain areas concerned with colour and form. These and other visual properties can be selectively disturbed as a result of brain damage, consistent with the notion of modularity of cortical visual processing. Nevertheless, the selectivity of impairments is far from clear. For example, my early work established that damage to the so-called ‘colour centre’ renders a person phenomenally blind to colour yet, surprisingly, with spared abilities to use wavelength variation to process colour-defined form and motion. More recently, my colleagues and I have extended this work to examine other cortical contributions to the perception of surfaces, including those which account for their constant appearance under changes in illuminant.
A moment of serendipity during the testing of a ‘blindsight’ patient (where he claimed that had he had the opportunity to attend to a location in his blind field, his performance would have improved) led to a number of further studies in normal observers which questioned the then prevailing view of an inextricable link between attention and awareness.
The most frequent consequence of damage to the visual brain is a homonymous field defect. Hemianopia, the loss of a half-field, has debilitating effects on reading and visual exploration. With colleagues from the Ludwig-Maximilian University, Munich, we have conducted a number of studies assessing the efficacy of rehabilitative techniques and examined the basis of the disorders by simulating homonymous hemianopia by using eye-movement contingent displays in normal observers.
- Cortical processes in colour vision
- Visual disorders after brain damage
Chapter in book
- Heywood, C.A. & Cowey, A (2003). Colour vision and its disturbance after cortical lesions. In The Neuropsychology of Vision. Fahle, M. & Greenlee, M. Oxford: Oxford University Press. 259-282.
- Zihl, J. & Heywood, C.A. (2016). The contribution of single case studies to the neuroscience of vision. PsyCh Journal 5(1): 5-17.
- Norman, L.J., Heywood, C.A. & Kentridge, R.W. (2015). Direct encoding of orientation variance in the visual system. Journal of Vision 15(4): 3, 1-14.
- Norman, L.J., Heywood, C.A. & Kentridge, R.W. (2015). Exogenous attention to unseen objects?. Consciousness & Cognition 35: 319-329.
- Zihl, J. & Heywood, C.A. (2015). The contribution of LM to the neuroscience of movement vision. Frontiers in Integrative Neuroscience 9: 6.
- Norman, L.J., Akins, K., Heywood, C.A. & Kentridge, R.W. (2014). Colour constancy for an unseen surface. Current Biology 24(23): 2822-2826.
- Kentridge, R.W., Thomson, R. & Heywood, C.A. (2012). Glossiness perception can be mediated independently of cortical processing of colour or texture. Cortex 48(9): 1244-1246.
- Kuhn, C, Heywood, CA & Kerkhoff G (2010). Oblique spatial shifts of subjective visual straight ahead orientation in quadrantic visual field defects. Neuropsychologia 48(11): 3205-3210.
- Cavina-Pratesi, C. , Kentridge, R.W. , Heywood, C.A. & Milner, A.D. (2010). Separate channels for processing form, texture, and color: Evidence from fMRI adaptation and visual object agnosia. Cerebral Cortex 20(10): 2319-2332.
- Schuett, S., Kentridge, R.W., Zihl, J. & Heywood, C.A. (2009). Are hemianopic reading and visual exploration impairments visually elicited? New insights from eye movements in simulated hemianopia. Neuropsychologia, 47(3): 733-746.
- Schuett, S, Kentridge RW, Zihl J & Heywood CA (2009). Is the origin of the hemianopic line bisection error purely visual? Evidence from eye movements in simulated hemianopia. Vision Research 49(13): 1668-1680.
- Mullin, CR, Démonet, JF, Kentridge, RW, Heywood, CA & Goodale, MA (2009). Preserved striate cortex is not sufficient to support the McCollough effect: Evidence from two patients with cerebral achromatopsia. Perception 38(12): 1741-1748.
- Schuett, S., Heywood, C. A., Kentridge, R.W. & Zihl, J. (2009). Rehabilitation of hemianopic dyslexia: Are words necessary for re-learning oculomotor control?. Brain 131(12): 3156-3168.
- Cole, G.G. , Kuhn, G. , Heywood, C.A. & Kentridge, R.W. (2009). The prioritization of feature singletons in the change detection paradigm. Experimental Psychology 56(2): 134-146.
- Kentridge, R.W., Nijboer, T.C.W. & Heywood, C.A. (2008). Attended but unseen: Visual attention is not sufficient for visual awareness. Neuropsychologia 46(3): 864-869.
- Cowey, A., Alexander, I., Heywood, C. & Kentridge, R. (2008). Pupillary responses to coloured and contourless displays in total cerebral achromatopsia. Brain 131(8): 2153-2160.
- Arnott, S.R., Heywood C.A., Kentridge, R.W. & Goodale M. (2008). Voice recognition and the posterior cingulate: An fMRI study of prosopagnosia. Journal of Neuropsychology 2(1): 269-286.
- Kentridge, R.W., de-Wit, L.H. & Heywood, C.A. (2008). What is attended in spatial attention? Journal of Consciousness Studies 15: 105-111.
- Kentridge, R.W., Heywood, C.A. & Weiskrantz, L. (2007). Color contrast processing in human striate cortex. Proceedings of the National Academy of Sciences 104: 15129-15131.
- Cole, G.G., Kentridge, R.W. & Heywood, C.A (2005). Object onset and parvocellular guidance of attentional allocation. Psychological Science 16(4): 270-274.
- Kentridge R.W., Heywood, C.A. & Cowey, A (2004). Chromatic edges, surfaces and constancies in cerebral achromatopsia. Neuropsychologia 42: 821-830.
- Kentridge, R.W., Heywood, C.A. & Milner, A.D. (2004). Covert processing of visual form in the absence of area LO. Neuropsychologia 42(11): 1488-1495.
- Kentridge, R.W., Heywood, C.A. & Weiskrantz, L (2004). Spatial attention speeds discrimination without awareness in blindsight. Neuropsychologia 42: 831-835.
- Cole, G.G., Kentridge, R.W. & Heywood, C.A. (2004). Visual salience in the change detection paradigm: The special role of object onset. Journal of Experimental Psychology: Human Perception and Performance 30(3): 464-477.
- Heywood, C.A. & Kentridge R.W. (2003). Achromatopsia, color vision and cortex. Neurologic Clinics 21(2): 483-500.
- Cole, G.G., Heywood, C.A., Kentridge, R.W., Fairholm, I. & Cowey, A (2003). Attentional capture by colour and motion in cerebral achromatopsia. Neuropsychologia 41(13): 1837-1846.
- Cole, G.G., Kentridge, R.W., Gellatly, A.R.H. & Heywood, C. (2003). Detectability of onsets versus offsets in the change detection paradigm. Journal of Vision 3(1): 22-31.
- Kentridge, R.W., Cole, G.G. & Heywood, C.A. (2003). The primacy of chromatic edge processing in normal and cerebrally achromatopsic subjects. Progress in Brain Research 144(3): 161-167.
- Gilchrist, I.D., Heywood, C.A. & Findlay, J.M. (2003). Visual sensitivity in search tasks depends on the response requirement. Spatial Vision 16: 277-293.
- Cowey, A., Heywood, C.A. & Irving-Bell, L. (2001). The regional cortical basis of achromatopsia: a study on macaque monkeys and an achromatopsic patient. European Journal of Neuroscience 14(9): 1555-1566.
- Heywood, C.A. & Kentridge, R.W. (2000). Affective blindsight?. Trends in Cognitive Sciences 4: 125-126.
- Kentridge, R.W. & Heywood, C.A. (2000). Metacognition and awareness. Consciousness and Cognition 9: 308-312.
- Kentridge, R.W., Heywood, C.A. & Weiskrantz, L. (1999). Attention without awareness in blindsight. Proceedings of the Royal Society of London (Series B) 266: 1805-1811.
- Kentridge, R.W., Heywood, C.A. & Weiskrantz, L. (1999). Effects of temporal cueing on residual visual discrimination in blindsight. Neuropsychologia 37: 479-483.
- Gilchrist, I.D., Heywood, C.A. & Findlay, J.M. (1999). Saccade selection in visual search: evidence for spatial frequency specific between-item interactions. Vision Research 39: 1373-1383.
- Gilchrist, I.D., Findlay, J.M. & Heywood, C.A. (1999). Surface and edge information for spatial integration: a saccadic-selection task. Visual Cognition 6: 363-384.
- Gulyas, B. Cowey, A., Heywood, C.A., Popplewell, D.A. & P.E. Roland, P.E. (1998). Visual form discrimination from texture cues: A PET study. Human Brain Mapping 62(2): 115-127.
- Heywood, C.A., Kentridge, R.W. & Cowey, A. (1998). Cortical color blindness is not 'blindsight for color'. Consciousness and Cognition 7: 410-423.
- Hurlbert, A.C., Bramwell, D.I., Heywood, C.A. & Cowey, A. (1998). Discrimination of cone contrast changes as evidence for colour constancy in cerebral achromatopsia. Experimental Brain Research. 123:136-144. Experimental Brain Research (123): 136-144.
- Heywood CA, Kentridge, R.W. & Cowey, A. (1998). Form and motion from colour in cerebral achromatopsia. Experimental Brain Research 123: 145-153.
- Heywood CA, Nicholas, J.J., Le Mare, C.M. & Cowey, A. (1998). The effect of lesions to cortical areas V4 or AIT on pupillary responses to chromatic and achromatic stimuli in monkeys. Experimental Brain Research 122: 475-480.
- Cowey, A. & Heywood, C.A. (1997). Cerebral achromatopsia: colour blindness despite wavelength processing. Trends in Cognitive Science 1(4): 133-139.
- Kentridge, R.W., Heywood, C.A. & Weiskranttz, L. (1997). Residual vision in multiple retinal locations within a scotoma: Implications for blindsight. Journal of Cognitive Neuroscience 9: 191-202.
- Heywood, C.A., Nicholas, J.J. & Cowey, A. (1996). Behavioural and electrophysiological chromatic and achromatic contrast sensitivity in an achromatopsic patient. Journal of Neurology, Neurosurgery and Psychiatry 61: 638-643.
- Heywood, C.A. & Cowey, A. (1996). Colour Vision: Now you see it, now you don't. Current Biology 6(9): 1064-1066.
- Heywood, C.A., Gaffan, D. & Cowey, A. (1995). Cerebral achromatopsia in monkeys. European Journal of Neuroscience 7: 1064-1073.
- Eacott, M.J. & Heywood, C.A. (1995). Perception and memory: Action and interaction. Critical Reviews in Neurobiology 9: 311-320.
- Eacott, M.J., Heywood, C.A., Cowey, A. & Gross, C. (1993). Visual discrimination impariments following lesions to the superior temporal sulcus in monkeys are not specific for facial stimuli. Neuropsychologia 31: 609-619.
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- Vision / eye movement: vision
- Vision / eye movement: visual disorders after brain damage
- Memory and brain function: research development, Stockton Campus