Data from: Feedforward attentional selection in sensory cortex

Salient objects grab attention because they stand out from their
surroundings. Whether this phenomenon is accomplished by bottom-up sensory
processing or requires top-down guidance is debated. We tested these
alternative hypotheses by measuring how early and in which cortical
layer(s) neural spiking distinguished a target from a distractor. We
measured synaptic and spiking activity across cortical columns in
mid-level area V4 of male macaque monkeys performing visual search for a
color singleton. A neural signature of attentional capture was observed in
the earliest response in the input layer 4. The magnitude of this response
predicted response time and accuracy. Errant behavior followed errant
selection. Because this response preceded top-down influences and arose in
the cortical layer not targeted by top-down connections, these findings
demonstrate that feedforward activation of sensory cortex can underlie
attentional priority.