FIGURE 8.6. Attentional response enhancement, suppression, and increases in baseline activity in the LGN and in visual cortex.

FIGURE 8.6

Attentional response enhancement, suppression, and increases in baseline activity in the LGN and in visual cortex. Time series of fMRI signals in the LGN and visual cortex were combined across left and right hemispheres. Activity in visual cortex was pooled across areas V1, V2, V3/VP, V4, TEO, V3A, and MT/ MST. (a, d) Attentional enhancement. During directed attention to the stimuli (gray curves), responses to both the high-contrast stimulus (100%, solid curves) and low-contrast stimulus (5%, dashed curves) were enhanced relative to an unattended condition (black curves). (b, e) Attentional suppression. During an attentionally demanding “hard” fixation task (black curves), responses evoked by both the high-contrast stimulus (100%, solid curves) and low-contrast stimulus (10%, dashed curves) were attenuated relative to an easy attention task at fixation (gray curves). (c, f) Baseline increases. Baseline activity was elevated during directed attention to the periphery of the visual hemifield in expectation of the stimulus onset; the beginning of the expectation period is indicated by the dashed vertical line. Gray vertical lines indicate the beginning of checkerboard presentation periods. (Reprinted by permission from Macmillan Publishers Ltd. [Nature Neuroscience] O’Connor, D.H., Fukui, M.M., Pinsk, M.A., Kastner, S., 5, 1203, copyright 2002.)

From: Chapter 8, Sight

Cover of Neurobiology of Sensation and Reward
Neurobiology of Sensation and Reward.
Gottfried JA, editor.
Boca Raton (FL): CRC Press/Taylor & Francis; 2011.
Copyright © 2011 by Taylor and Francis Group, LLC.

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