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Article

Joan N. Vickers and A. Mark Williams

Considerable debate has arisen about whether brain activity in elite athletes is characterized by an overall quieting, or neural efficiency in brain processes, or whether elite performance is characterized by activation of two simultaneous networks. One network exercises cognitive control using increased theta activation of premotor and cingulate gyrus, whereas the second reduces alpha activation in an inhibitory network that prevents the intrusion of debilitating thoughts emanating from the temporal lobe and other areas. Also, there is controversy about how a long-duration “quiet eye” (QE) can fit within a single efficient neural system, or whether a dual system where both increased cognitive control and reduced inhibitory processes has advantages. The literature on neural efficiency, the QE, and theta cognitive control, suggest that a long-duration QE promotes both an increase in theta band activation of the medial prefrontal cortex and anterior cingulate and reduced activation and inhibition of the temporal regions during high-pressure situations when a high level of focused, cognitive control is essential.

Article

Holly Bridge

The sensation of vision arises from the detection of photons of light at the eye, but in order to produce the percept of the world, extensive regions of the brain are required to process the visual information. The majority of information entering the brain via the optic nerve from the eye projects via the lateral geniculate nucleus (LGN) of the thalamus to the primary visual cortex, the largest visual area, having been reorganized such that one side of the brain represents one side of the world. Damage to the primary visual cortex in one hemisphere therefore leads to a loss of conscious vision on the opposite side of the world, known as hemianopia. Despite this cortical blindness, many patients are still able to detect visual stimuli that are presented in the blind region if forced to guess whether a stimulus is present or absent. This is known as “blindsight.” For patients to gain any information (conscious or unconscious) about the visual world, the input from the eye must be processed by the brain. Indeed, there is considerable evidence from functional brain imaging that several visual areas continue to respond to visual stimuli presented within the blind region, even when the patient is unaware of the stimulus. Furthermore, the use of diffusion imaging allows the microstructure of white matter pathways within the visual system to be examined to see whether they are damaged or intact. By comparing patients who have hemianopia with and without blindsight it is possible to determine the pathways that are linked to blindsight function. Through understanding the brain areas and pathways that underlie blindsight in humans and non-human primates, the aim is to use modern neuroscience to guide rehabilitation programs for use after stroke.