Members

Professor Charles Heywood

(email at c.a.heywood@durham.ac.uk)

Biography

Some 25% of cortex in man is devoted to visual processing. In the macaque monkey it is well established that such cortex is composed of a patchwork of visual areas. However, the role of each of these areas in vision has remained elusive. The early view that each map subserves the processing of a single attribute (colour, motion, disparity etc.) proved to be a false dawn. It is now known that cortical areas do not markedly differ in the relative proportions of single neurons that respond to different attributes and the ablation of a single map rarely leads to a single deficit. Nevertheless, the existence of patients with selective visual disorders after brain damage (e.g. cortical colour blindness) suggests otherwise. To elucidate the role of multiple visual areas, 3 approaches have been taken,

(1) single-case studies of patients with selective visual disorders.

(2) Positron emission tomography of normal observers, using tasks derived from clinical testing.

(3) Testing of non-human primates with cortical ablation on identical tasks to those used above.

Indicators of Esteem

• Member of the Board of Associate Editors of Journal of Neuropsychology:

Research Groups

Department of Psychology

• Cognition and Cognitive Neuroscience

Research Interests

• Cortical processes in colour vision
• Neuroimaging
• Visual disorders after brain damage

Selected Publications

Edited works: contributions

• 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.

Journal papers: academic

• 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, RW, Heywood, CA & Milner, AD (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). (2008) Attended but unseen: Visual attention is not sufficient for visual awareness. Neuropsychologia, 46 : 864-869.
• Cowey, A., Alexander, I., Heywood, C. & Kentridge R. (2008). Pupillary responses to coloured and contourless displays in total cerebral achromatopsia. Brain, 131: 2153-2160. Brain, 131: 2153-2160.
• Schuett, S., Heywood, C.A., Kentridge, R.W. & Zihl,J. (2008). The significance of visual information processing in reading: Insights from hemianopic dyslexia. Neuropsychologia, 46: 2441-2458.
• Arnott, S.R., Goodale M.A., Kentridge R.W. & Heywood, C.A. (2008). Voice recognition and the posterior cingulate: an fMRI study of prosopagnosia. Journal of Neuropsychology 2: 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. Proc. Nat. Acad. Sci 104: 15129-15131.
• Kentridge RW, Heywood CA & Milner AD (2005). Covert processing of visual form in the absence of area LO. Neuropsychologia 42(11): 1488-1495.
• 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. & 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 Science 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. & Weizkrantz, 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 122 475-480 122: 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 CA, 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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Media Contacts

Available for media contact about:

• Health & welfare services: vision
• Health & welfare services: visual disorders after brain damage
• Health & welfare services: research development, Stockton Campus
• Vision / eye movement: vision
• Vision / eye movement: visual disorders after brain damage
• Memory and brain function: research development, Stockton Campus

Supervises

• Mr Liam Norman