Furlan M, Schwarzbach J, 2009, "Attention increases input gain when processing motion coherence" Perception 38 ECVP Abstract Supplement, page 19
Attention increases input gain when processing motion coherence
M Furlan, J Schwarzbach
Several alternative models try to explain how attention affects sensory processing. Attention is thought to enhance the representation of attended stimuli by increasing the stimulus strength (input gain model) or by multiplying the neuronal response (output gain model) or by stimulus-unspecific activity increase (baseline shift model). We used high-field functional magnetic resonance imaging (fMRI) at 4T in seven participants to test how attention affects the blood-oxygen-level dependent (BOLD) signal in middle temporal (MT) and medial superior temporal areas (MST) to attended or ignored low-contrast moving dots in the periphery. In an event-related design participants either judged the predominant direction of the dots or they were engaged in a central task. In both tasks moving dots were present and coherence was parametrically varied. Behavioural results produced clear coherence-response functions. BOLD responses showed that only intermediate motion coherence levels (25% and 50%) profited from attention, while the lowest (12.5%) and the highest (100%) levels did not. This suggests that attention increases behavioural performance in motion processing by increasing the input strength of motion signals.
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