A role for the “magnocellular advantage” in visual impairments in neurodevelopmental and psychiatric disorders

School of Psychological Science, La Trobe University, Bunndoora, Vic. 3086, Australia.
Neuroscience & Biobehavioral Reviews (Impact Factor: 8.8). 02/2007; 31(3):363-76. DOI: 10.1016/j.neubiorev.2006.10.003
Source: PubMed


Evidence exists implicating abnormal visual information processing and visually driven attention in a number of neurodevelopmental and psychiatric disorders, suggesting that research into such disorders may benefit from a better understanding of more recent advances in visual system processing. A new integrated model of visual processing based on primate single cell and human electrophysiology may provide a framework, to understand how the visual system is involved, by implicating the magnocellular pathway's role in driving attentional mechanisms in higher-order cortical regions, what we term the 'magnocellular advantage'. Evidence is also presented demonstrating visual processing occurs considerably faster than previously assumed, and emphasising the importance of top-down feedback signals into primary visual cortex, as well as considering the possibility of lateral connections from dorsal to ventral visual areas. Such organisation is argued to be important for future research highlighting visual aspects of impairment in disorders as diverse as schizophrenia and autism.

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    • "Interaction of these two streams is done at few levels in mammalian brains [19, 20] whereas many neurobiological, physiological, and psychological evidences show that the information coupling occur in many places for instance in STS level [21] and in different ways, that is, recurrent feedback loops [14]. Mutual links have suggested recurrent processing loops that permit interaction of top-down and bottom-up processing [14, 15, 22]. However, current neuroscience and psychophysics research specifies more extensive form signals influences on motion processing than previously assumed [15]. "
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    ABSTRACT: Research on psychophysics, neurophysiology, and functional imaging shows particular representation of biological movements which contains two pathways. The visual perception of biological movements formed through the visual system called dorsal and ventral processing streams. Ventral processing stream is associated with the form information extraction; on the other hand, dorsal processing stream provides motion information. Active basic model (ABM) as hierarchical representation of the human object had revealed novelty in form pathway due to applying Gabor based supervised object recognition method. It creates more biological plausibility along with similarity with original model. Fuzzy inference system is used for motion pattern information in motion pathway creating more robustness in recognition process. Besides, interaction of these paths is intriguing and many studies in various fields considered it. Here, the interaction of the pathways to get more appropriated results has been investigated. Extreme learning machine (ELM) has been implied for classification unit of this model, due to having the main properties of artificial neural networks, but crosses from the difficulty of training time substantially diminished in it. Here, there will be a comparison between two different configurations, interactions using synergetic neural network and ELM, in terms of accuracy and compatibility.
    09/2014; 2014:723213. DOI:10.1155/2014/723213
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    • "INSAR the ventral stream [Kveraga, Boshyan, & Bar, 2007; Laycock, Crewther, & Crewther, 2007]. Thus, the inconsistent findings regarding impairment in dorsal and ventral visual streams may better be understood , as Tsermentseli, O'Brien, and Spencer [2008] have argued, as an abnormality in the interaction between dorsal and ventral visual streams in ASD. "
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    ABSTRACT: Autism is usually defined by impairments in the social domain but has also been linked to deficient dorsal visual stream processing. However, inconsistent findings make the nature of this relationship unclear and thus, we examined the role of stimulus-driven transient attention, presumably activated by the dorsal stream in autistic tendency. Contrast thresholds for object discrimination were compared between groups with high and low self-rated autistic tendency utilizing the socially based Autism Spectrum Quotient (AQ). Visual stimuli were presented with either abrupt or with ramped contrast onsets/offsets in order to manipulate the demands of transient attention. Larger impairments in performance of abrupt compared with ramped object presentation were established in the high AQ group. Furthermore, self-reported social skills predicted abrupt task performance, suggesting an important visual perception deficiency in autism-related traits. Autism spectrum disorder may be associated with reduced utilization of the dorsal stream to rapidly activate attention prior to ventral stream processing when stimuli are transient. Autism Res 2013, ●●: ●●-●●. © 2013 International Society for Autism Research, Wiley Periodicals, Inc.
    Autism Research 02/2014; DOI:10.1002/aur.1336 · 4.33 Impact Factor
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    • "The ability to rapidly detect a threat at the periphery, detection of fast moving objects and use of larger receptive fields and thus less neural resources, are all advantages of LSF processing. A magnocellular advantage is essential for the initiation of attention mechanisms in the parietal cortex, facilitating rapid and automatic initial global analysis of the stimulus (Schroeder, 1995; Vidyasagar, 1999, 2004, 2005; Laycock et al., 2007). Evidence presented here suggests that early processing of specific SF information facilitates rapid detection and may encode global stimulus categorization. "
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    ABSTRACT: Research exploring the role of spatial frequencies in rapid stimulus detection and categorization report flexible reliance on specific spatial frequency (SF) bands. Here, through a set of behavioral and magnetoencephalography (MEG) experiments, we investigated the role of low spatial frequency (LSF) (<8 cycles/face) and high spatial frequency (HSF) (>25 cycles/face) information during the categorization of faces and places. Reaction time measures revealed significantly faster categorization of faces driven by LSF information, while rapid categorization of places was facilitated by HSF information. The MEG study showed significantly earlier latency of the M170 component for LSF faces compared to HSF faces. Moreover, the M170 amplitude was larger for LSF faces than for LSF places, whereas the reverse pattern was evident for HSF faces and places. These results suggest that SF modulates the processing of category specific information for faces and places.
    Frontiers in Human Neuroscience 03/2013; 7. DOI:10.3389/fnhum.2013.00091 · 2.99 Impact Factor
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