Which Visual Pathways Cause Fixation-Related Inhibition?
| Autor: | Sarah Castor-Perry, Christopher Kennard, Parashkev Nachev, Heather Isenman, Petroc Sumner |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Adult
Male Supplementary eye field Superior Colliculi Adolescent genetic structures Physiology Fixation Ocular Visual system Stimulus (physiology) Humans Attention Visual Pathways Visual Cortex General Neuroscience Superior colliculus Eye movement Neural Inhibition Frontal eye fields Saccadic masking Fixation (visual) Female Psychology Neuroscience Color Perception Photic Stimulation |
| Zdroj: | Journal of Neurophysiology. 95:1527-1536 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.00781.2005 |
| Popis: | Visual stimuli can both inhibit and activate motor mechanisms. In one well-known example, the latency of saccadic eye movements is prolonged in the presence of a fixation stimulus, relative to the case in which the fixation stimulus disappears before the target appears. This automatic sensory-motor effect, known as the gap effect or fixation-offset effect, has been associated with inhibitory connections within the superior colliculus (SC). Visual information is provided to the SC and other oculomotor areas, such as the frontal eye fields (FEF), mainly by the magnocellular geniculostriate pathway, and also by the retinotectal pathway. We tested whether signals in these pathways are necessary to create fixation-related inhibition, by using stimuli invisible to them. We found that such stimuli, visible only to short-wave–sensitive cones (S cones), do produce fixation-related inhibition (including when warning effects were equated). We also demonstrate that this fixation-related inhibition cannot be explained by residual activation of luminance pathways and must be caused by a route separate from that of luminance fixation signals. Thus there are at least two routes that cause fixation-related inhibition, and direct sensory input to the SC or FEF by the magnocellular or retinotectal pathways is not required. We discuss the implications that there may be both cortical and collicular mechanisms. |
| Databáze: | OpenAIRE |
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