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8.7c. Visual Pathways (Visual Pathways on PhilPapers)

See also:
Baylis, Gordon C.; Gore, Christopher L.; Rodriguez, P. Dennis & Shisler, Rebecca J. (2001). Visual extinction and awareness: The importance of binding dorsal and ventral pathways. Visual Cognition. Special Issue 8 (3):359-379.   (Cited by 12 | Google | More links)
Bridgeman, Bruce & Huemer, V. (1998). A spatially oriented decision does not induce consciousness in a motor task. Consciousness and Cognition 7 (3):454-464.   (Cited by 86 | Google | More links)
Abstract: Visual information follows at least two branches in the human nervous system, following a common input stage: a cognitive ''what'' branch governs perception and experience, while a sensorimotor ''how'' branch handles visually guided behavior though its outputs are unconscious. The sensorimotor system is probed with an isomorphic task, requiring a 1:1 relationship between target position and motor response. The cognitive system, in contrast, is probed with a forced qualitative decision, expressed verbally, about the location of a target. Normally, the cognitive system is influenced by context-induced illusions of visual direction, while the sensorimotor system is not. Here, we inquire whether the process of making a spatially based decision is critical in forcing subjects to use the information in the cognitive system for spatial tasks. Subjects hear a tone that determines whether they jab an ''X'' or an ''O'' with the forefinger. Despite making a decision about which target to contact, the jab is not influenced by the position of a surrounding frame, indicating that choice can be handled within the context-insensitive sensorimotor system
Bridgeman, Bruce (2000). Interactions between vision for perception and vision for behavior. In Yves Rossetti & Antti Revonsuo (eds.), Beyond Dissociation: Interaction Between Dissociated Implicit and Explicit Processing. John Benjamins.   (Cited by 14 | Google)
Bridgeman, Bruce (2002). The grand illusion and Petit illusions: Interactions of perception and sensory coding. Journal of Consciousness Studies 9:29-34.   (Google)
Carey, D. P.; Dijkerman, H. Chris & Milner, A. David (1998). Perception and action in depth. Consciousness and Cognition 7 (3):438-453.   (Cited by 46 | Google | More links)
Abstract: Little is known about distance processing in patients with posterior brain damage. Although many investigators have claimed that distance estimates are normal or abnormal in some of these patients, many of these observations were made informally and the examiners often asked for relative, and not absolute, distance estimates. The present investigation served two purposes. First, we wanted to contrast the use of distance information in peripersonal space for perceptual report as opposed to visuomotor control in our visual form agnosic patient, DF. Second, we wanted to see to what extent her abilities to process distance cues were dependent on binocular vision, in light of Milner et al.'s (1991) observations of preserved stereopsis in DF, and Dijkerman et al.'s (1996) and Marotta et al.'s (1997) observations that her visual guidance of grasping may be particularly dependent on binocular vision of the target. We hypothesized that DF's visuomotor responses would show normal sensitivity to target distance, while her perceptual estimates would not. In the first experiment, we required DF and two age- and sex-matched control subjects to reach out and grasp black cubes placed at varying distances, or to estimate the distance of the cubes from the hand starting position without making a reaching movement. In the second experiment, we required DF and two age-matched control subjects to point as rapidly and accurately as possible to small LED targets which differed in spatial location, under binocular and monocular conditions. The results showed that, relative to the control subjects, DF's grasping movements produced normal peak velocity-distance scaling-when she reached for blocks which varied in depth or pointed to LED targets which were presented at different distances in depth. In contrast, in the cube experiment, her verbal estimates of object distance were poorly scaled, although they improved slightly under the binocular conditions. The results are discussed in terms of current theories of processing streams in extrastriate visual cortex and the distinction between categorical and coordinate spatial processing
de Schotten, Michel T.; Urbanski, Marika; Duffau, Hugues; Volle, Emmanuelle; Lévy, Richard; Dubois, Bruno & Bartolomeo, Paolo (2005). Direct evidence for a parietal-frontal pathway subserving spatial awareness in humans. Science 309 (5744):2226-2228.   (Cited by 31 | Google | More links)
Dijkerman, H. Chris; Milner, A. David & Carey, D. P. (1998). Grasping spatial relationships: Failure to demonstrate allocentric visual coding in a patient with visual form agnosia. Consciousness and Cognition 7 (3):424-437.   (Cited by 43 | Google | More links)
Abstract: The cortical visual mechanisms involved in processing spatial relationships remain subject to debate. According to one current view, the ''dorsal stream'' of visual areas, emanating from primary visual cortex and culminating in the posterior parietal cortex, mediates this aspect of visual processing. More recently, others have argued that while the dorsal stream provides egocentric coding of visual location for motor control, the separate ''ventral'' stream is needed for allocentric spatial coding. We have assessed the visual form agnosic patient DF, whose lesion mainly affects the ventral stream, on a prehension task requiring allocentric spatial coding. She was presented with transparent circular disks. Each disk had circular holes cut in it. DF was asked to reach out and grasp the disk by placing her fingers through the holes. The disks either had three holes (for forefinger, middle finger, and thumb) or two holes (for forefinger and thumb). The distance between the forefinger and thumb holes, and the orientation of the line formed by them, were independently varied. DF was quite unable to adjust her grip aperture or her hand orientation in the three-hole task. Although she was able to orient her hand appropriately for the two-hole disks, she still remained unable to adjust her grip aperture to the distance between the holes. These findings are consistent with the idea that allocentric processing of spatial information requires a functioning ventral stream, even when the information is being used to guide a motor response
Fecteau, Jillian H.; Chua, Romeo; Franks, Ian & Enns, James T. (2001). Visual awareness and the on-line modification of action. Canadian Journal of Experimental Psychology 55 (2):104-110.   (Cited by 9 | Google | More links)
Giaschi, Deborah; Jan, James E.; Bjornson, Bruce; Young, Simon Au; Tata, Matthew; Lyons, Christopher J.; Good, William V. & Wong, Peter K. H. (2003). Conscious visual abilities in a patient with early bilateral occipital damage. Developmental Medicine and Child Neurology 45 (11):772-781.   (Cited by 3 | Google | More links)
Goodale, Melvyn A. (2007). Duplex vision: Separate cortical pathways for conscious perception and the control of action. In Max Velmans & Susan Schneider (eds.), The Blackwell Companion to Consciousness. Blackwell.   (Google)
Goodale, Melvyn A.; Cant, Jonathan S. & Króliczak, Grzegorz (2006). Grasping the past and present: When does visuomotor priming occur? In Ögmen, Haluk; Breitmeyer, Bruno G. (2006). The First Half Second: The Microgenesis and Temporal Dynamics of Unconscious and Conscious Visual Processes. (Pp. 51-71). Cambridge, MA, US: MIT Press. Xi, 410 Pp.   (Cited by 1 | Google)
Goodale, Melvyn A. (2004). Perceiving the world and grasping it: Dissociations between conscious and unconscious visual processing. In Michael S. Gazzaniga (ed.), The Cognitive Neurosciences. MIT Press.   (Cited by 4 | Google)
Goodale, Melvyn A. & Murphy, K. (2000). Space in the brain: Different neural substrates for allocentric and egocentric frames of reference. In Thomas Metzinger (ed.), Neural Correlates of Consciousness. MIT Press.   (Cited by 1 | Google)
Goodale, Melvyn A. & Milner, A. David (2004). Sight Unseen: An Exploration of Conscious and Unconscious Vision. Oxford University Press.   (Cited by 53 | Google | More links)
Abstract: Vision, more than any other sense, dominates our mental life. Our visual experience is just so rich, so detailed, that we can hardly distinguish that experience from the world itself. Even when we just think about the world and don't look at it directly, we can't help but 'imagine' what it looks like. We think of 'seeing' as being a conscious activity--we direct our eyes, we choose what we look at, we register what we are seeing. The series of events described in this book radically altered this attitude towards vision. This book describes one of the most extraordinary neurological cases of recent years--one that profoundly changed scientific views on consciousness. It is the story of Dee Fletcher--a woman recently blinded--who became the subject of a series of scientific studies. As events unfolded, Milner and Goodale found that Dee wasn't in fact blind--she just didn't know that she could see. Taking us on a journey into the unconscious brain, the two scientists who made this incredible discovery tell the amazing story of their work, and the surprising conclusion they were forced to reach. Written to be accessible to students and popular science readers, this book is a fascinating illustration of the power of the 'unconscious' mind
Goodale, Melvyn A. & Milner, A. David (1992). Separate visual pathways for perception and action. Trends in Neurosciences 15:20-25.   (Cited by 1299 | Google | More links)
Humphreys, Glyn W.; Troscianko, Tom; Riddoch, M. J. & Boucart, M. (1992). Covert processing in different visual recognition systems. In A. David Milner & M. D. Rugg (eds.), The Neuropsychology of Consciousness. Academic Press.   (Cited by 6 | Google)
Humphrey, G. K. & Goodale, Melvyn A. (1998). Probing unconscious visual processing with the Mccollough effect. Consciousness and Cognition 7 (3):494-519.   (Cited by 36 | Google | More links)
Abstract: The McCollough effect, an orientation-contingent color aftereffect, has been known for over 30 years and, like other aftereffects, has been taken as a means of probing the brain's operations psychophysically. In this paper, we review psychophysical, neuropsychological, and neuroimaging studies of the McCollough effect. Much of the evidence suggests that the McCollough effect depends on neural mechanisms that are located early in the cortical visual pathways, probably in V1. We also review evidence showing that the aftereffect can be induced without conscious perception of the induction patterns. Based on these two lines of evidence, it is argued that our conscious visual experience of the world arises in the cortical visual system beyond V1
Jiang, Huai; Stein, Barry E. & McHaffie, John G. (2003). Opposing basal ganglia processes shape midbrain visuomotor activity bilaterally. Nature 423:982-986.   (Cited by 24 | Google | More links)
Milner, A. David & Dijkerman, H. Chris (2001). Direct and indirect visuals routes to action. In Beatrice De Gelder, Edward H. F. De Haan & Charles A. Heywood (eds.), Out of Mind: Varieties of Unconscious Processes. Oxford University Press.   (Google)
Milner, A. David (1998). Streams and consciousness: Visual awareness and the brain. Trends in Cognitive Sciences 2:25-30.   (Cited by 33 | Google)
Milner, A. David & Goodale, Melvyn A. (1995). The Visual Brain in Action. Oxford University Press.   (Cited by 10 | Google | More links)
Abstract: Although the mechanics of how the eye works are well understood, debate still exists as to how the complex machinery of the brain interprets neural impulses...
Milner, David & Goodale, Melvyn A. (1998). The visual brain in action (precis). Psyche 4 (12).   (Google)
Overgaard, Morten; Nielsen, Jorgen Feldbaek & Fuglsang-Frederiksen, Anders (2004). A TMS study of the ventral projections from v1 with implications for the finding of neural correlates of consciousness. Brain and Cognition 54 (1):58-64.   (Cited by 1 | Google)
Poppel, Ernst; Held, R. & Frost, D. (1973). Residual function after brain wounds involving the central visual pathways in man. Nature 243:295-96.   (Google)
Silveira, Luiz Carlos L. (2004). Parallel visual pathways from the retina to the visual cortex – how do they fit? Behavioral and Brain Sciences 27 (1):50-51.   (Google)
Abstract: Which roles are played by subcortical pathways in models of cortical streams for visual processing? Through their thalamic relays, magnocellular (M) and parvocellular (P) projecting ganglion cells send complementary signals to V1, where their outputs are combined in several different ways. The synergic role of M and P cells in vision can be understood by estimating cell response entropy in all domains of interest
Thier, Peter; Haarmeier, Thomas; Chakraborty, Subhojit; Lindner, Axel & Tikhonov, Alexander (2002). Cortical substrates of visuospatial awareness outside the classical dorsal stream of visual processing. In Hans-Otto Karnath, David Milner & Giuseppe Vallar (eds.), The Cognitive and Neural Bases of Spatial Neglect. Oxford University Press.   (Google)
Thomas, Nigel J. T. (online). New support for the perceptual activity theory of mental imagery.   (Cited by 1 | Google)
Abstract: Since the publication of my "Are Theories of Imagery Theories of Imagination? An _Active Perception_ Approach to Conscious Mental Content," (Thomas, 1999 - henceforth abbreviated as ATOITOI on this page), a good deal of published material has appeared or has come to my attention that either provides additional support for the Perceptual Activity Theory PA theory) of mental imagery presented in ATOITOI, or that throws further doubt on the rival (picture and description) theories that are criticized there. Other relevant evidence was not mentioned in ATOITOI because I lacked the space for a proper explanation of its relevance. I hope eventually to write and publish a new account of
PA
theory, that will make use of much of this material. In the meantime this page provides citations (and, where possible, links) to the "new" support, and discussion sections that briefly explain the relevance of the cited material. Quite apart from presenting new lines of supporting evidence and argument, I hope this page will help to clarify many aspects of