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The role of feedback in visual masking and visual processing.

Macknik SL, Martinez-Conde S - Adv Cogn Psychol (2008)

Bottom Line: We propose a feedforward model of visual masking, and provide a hypothesis to explain the role of feedback in visual masking and visual processing in general.We review the anato-my and physiology of feedback mechanisms, and propose that the massive ratio of feedback versus feedforward connections in the visual system may be explained solely by the critical need for top-down attentional modulation.Finally, we propose a new set of neurophysiological standards needed to establish whether any given neuron or brain circuit may be the neural substrate of awareness.

View Article: PubMed Central - PubMed

Affiliation: Barrow Neurological Institute, Phoenix, USA.

ABSTRACT
This paper reviews the potential role of feedback in visual masking, for and against. Our analysis reveals constraints for feedback mecha- nisms that limit their potential role in visual masking, and in all other general brain functions. We propose a feedforward model of visual masking, and provide a hypothesis to explain the role of feedback in visual masking and visual processing in general. We review the anato-my and physiology of feedback mechanisms, and propose that the massive ratio of feedback versus feedforward connections in the visual system may be explained solely by the critical need for top-down attentional modulation. We discuss the merits of visual masking as a tool to discover the neural correlates of consciousness, especially as compared to other popular illusions, such as binocular rivalry. Finally, we propose a new set of neurophysiological standards needed to establish whether any given neuron or brain circuit may be the neural substrate of awareness.

No MeSH data available.


Related in: MedlinePlus

Layout of retinotopic areas that potentially maintain awareness of simple							targets. An individual brain model from all perspectives, including both							hemispheres flat-mapped, overlaid with the functional activation from							one typical subject. The yellow shaded areas are those portions of the							brain that did not show significant dichoptic masking (as in Figure 11B & 11C), and thus are ruled out for							maintaining visual awareness of simple targets. The pink colored voxels							represent the cortical areas that exhibited significant dichoptic							masking, and thus are potential candidates for maintaining awareness of							simple targets. Reprinted from Tse, et al. (2005).
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Figure 13: Layout of retinotopic areas that potentially maintain awareness of simple targets. An individual brain model from all perspectives, including both hemispheres flat-mapped, overlaid with the functional activation from one typical subject. The yellow shaded areas are those portions of the brain that did not show significant dichoptic masking (as in Figure 11B & 11C), and thus are ruled out for maintaining visual awareness of simple targets. The pink colored voxels represent the cortical areas that exhibited significant dichoptic masking, and thus are potential candidates for maintaining awareness of simple targets. Reprinted from Tse, et al. (2005).

Mentions: These combined results suggested that visual areas beyond V2, within the occipital lobe, are responsible for maintaining our awareness of simple unattended targets (Figure 13). Awareness of complex targets is expected to lie outside the occipital lobe, where higher visual processes take place.


The role of feedback in visual masking and visual processing.

Macknik SL, Martinez-Conde S - Adv Cogn Psychol (2008)

Layout of retinotopic areas that potentially maintain awareness of simple							targets. An individual brain model from all perspectives, including both							hemispheres flat-mapped, overlaid with the functional activation from							one typical subject. The yellow shaded areas are those portions of the							brain that did not show significant dichoptic masking (as in Figure 11B & 11C), and thus are ruled out for							maintaining visual awareness of simple targets. The pink colored voxels							represent the cortical areas that exhibited significant dichoptic							masking, and thus are potential candidates for maintaining awareness of							simple targets. Reprinted from Tse, et al. (2005).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864985&req=5

Figure 13: Layout of retinotopic areas that potentially maintain awareness of simple targets. An individual brain model from all perspectives, including both hemispheres flat-mapped, overlaid with the functional activation from one typical subject. The yellow shaded areas are those portions of the brain that did not show significant dichoptic masking (as in Figure 11B & 11C), and thus are ruled out for maintaining visual awareness of simple targets. The pink colored voxels represent the cortical areas that exhibited significant dichoptic masking, and thus are potential candidates for maintaining awareness of simple targets. Reprinted from Tse, et al. (2005).
Mentions: These combined results suggested that visual areas beyond V2, within the occipital lobe, are responsible for maintaining our awareness of simple unattended targets (Figure 13). Awareness of complex targets is expected to lie outside the occipital lobe, where higher visual processes take place.

Bottom Line: We propose a feedforward model of visual masking, and provide a hypothesis to explain the role of feedback in visual masking and visual processing in general.We review the anato-my and physiology of feedback mechanisms, and propose that the massive ratio of feedback versus feedforward connections in the visual system may be explained solely by the critical need for top-down attentional modulation.Finally, we propose a new set of neurophysiological standards needed to establish whether any given neuron or brain circuit may be the neural substrate of awareness.

View Article: PubMed Central - PubMed

Affiliation: Barrow Neurological Institute, Phoenix, USA.

ABSTRACT
This paper reviews the potential role of feedback in visual masking, for and against. Our analysis reveals constraints for feedback mecha- nisms that limit their potential role in visual masking, and in all other general brain functions. We propose a feedforward model of visual masking, and provide a hypothesis to explain the role of feedback in visual masking and visual processing in general. We review the anato-my and physiology of feedback mechanisms, and propose that the massive ratio of feedback versus feedforward connections in the visual system may be explained solely by the critical need for top-down attentional modulation. We discuss the merits of visual masking as a tool to discover the neural correlates of consciousness, especially as compared to other popular illusions, such as binocular rivalry. Finally, we propose a new set of neurophysiological standards needed to establish whether any given neuron or brain circuit may be the neural substrate of awareness.

No MeSH data available.


Related in: MedlinePlus