New research demonstrates that bias toward a potentially more valuable outcome can influence how visual information is processed in the human brain. The study, published by Cell Press in the December 26th issue of the journal Neuron, provides insight into how the visual centers encode more valuable stimuli at the expense of less valuable alternatives.
Acquisition and evaluation of incoming sensory information is absolutely critical for guiding interactions with the environment. There is no doubt that prior rewards have a strong influence on decision making and that the value of a stimulus modulates the activity of neurons involved in initiating movements towards the more favorable of alternatives.
However, although recent studies have suggested that value also influences areas of the brain involved in processing sensory input, many questions remain. "Little is known about how value influences the acquisition and representation of incoming sensory information, or about the neural mechanisms that track the relative value of different objects to guide behavior," explains senior study author, Dr. John Serences from the Department of Psychology at the University of California, San Diego.
To examine how value impacts visual processing, Dr. Serences used functional magnetic resonance imaging to estimate changes in neural activity as human subjects selected one of two spatially separated targets (red or green) that varied in value across the course of the experiment. His experimental paradigm was carefully designed so as to measure value-related modulations within areas of the visual cortex and to dissociate the influence of prior rewards and subjective value.
The study revealed value-related modifications in many different areas of the human visual system. Interestingly, value influenced activation of early regions of visual cortex that are thought to play a key role in representing features of objects in the environment (s
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