Monkey area MT response latencies are shaped by attention and correlate with reaction time F O Galashan, H C Saßen, A K Kreiter, D Wegener |
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Theoretical Neurobiology, Institute for Brain Research, University of Bremen, Germany
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| Adaptive behavior in dynamic environments relies on the ability to reliably encode relevant visual information and to quickly transform this into appropriate motor actions. Attention is known to modulate stimulus representations in early visual cortex and to improve behavioral performance, but the neuronal mechanisms by which attention-dependent modulations in visual cortex are linked to behavior are not well understood. One frequently discussed hypothesis is a relation between behavioral reaction times and neuronal response latencies, although previous single-cell studies failed to provide experimental evidence. We used a speed-change detection paradigm and single-unit recordings in monkey motion-sensitive area MT and we introduced some presumably important methodological and analytical adaptations to investigate this issue in detail. Our data provide support for a marked influence of attention on neuronal latencies in response to the stimulus event to which the animals were required to respond. Furthermore, relating neuronal response patterns to the animals' perceptual performance revealed a strong correlation between latencies and behavioral reaction times. Various control conditions and analyses verified these results. The data also show that neuronal firing rates, even though being modulated by attention, do not relate to behavioral performance, whereas neuronal response variability prior to the behaviorally relevant event does. |
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