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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    • "Using LORETA, we first localized the origin of the P1 potential (collapsed across the three emotions) to the extrastriate cortex for HSF images [cuneus/BA 18, MNI coordinates: peak x, y, 100 z ¼ À24, À102, À6] and to the postcentral gyrus in the parietal lobe for LSF images (peak x, y, z ¼ 18, À53, 71; Supplementary Figure S1). In support of our ERP extraction and source localization , these source results concurred with the asymmetry of the ventral vs dorsal visual stream that HSF vs LSF information pref- 105 erentially activates, respectively (De Valois et al., 1982; Livingstone and Hubel, 1988; Merigan and Maunsell, 1993; Laycock et al., 2007). "
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    ABSTRACT: Differential processing of threat can consummate as early as 100 ms post-stimulus. Moreover, early perception not only differentiates threat from non-threat stimuli but also distinguishes among discrete threat subtypes (e.g., fear, disgust, and anger). Combining spatial-frequency-filtered images of fear, disgust and neutral scenes with high-density event-related potentials and intracranial source estimation, we investigated the neural underpinnings of general and specific threat processing in early stages of perception. Conveyed in low spatial frequencies, fear and disgust images evoked convergent visual responses with similarly enhanced N1 potentials and dorsal visual (middle temporal gyrus) cortical activity (relative to neutral cues; peaking at 156 ms). Nevertheless, conveyed in high spatial frequencies, fear and disgust elicited divergent visual responses, with fear enhancing and disgust suppressing P1 potentials and ventral visual (occipital fusiform) cortical activity (peaking at 121 ms). Therefore, general and specific threat processing operates in parallel in early perception, with the ventral visual pathway engaged in specific processing of discrete threats and the dorsal visual pathway in general threat processing. Furthermore, selectively tuned to distinctive spatial-frequency channels and visual pathways, these parallel processes underpin dimensional and categorical threat characterization, promoting efficient threat response. These findings thus lend support to hybrid models of emotion.
    Social Cognitive and Affective Neuroscience 09/2015; DOI:10.1093/scan/nsv123 · 7.37 Impact Factor
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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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    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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    Autism Research 02/2014; DOI:10.1002/aur.1336 · 4.33 Impact Factor
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