56Fe/V1-V4-LFPs-and-Visual-Attention: Data and code for: Directed information exchange between cortical layers in V1 and V4 and its modulation by selective attention. Data contain simultaneous ephys recording of LFPs in V1 and V4 during covert, visual attention behavior. Code runs characterization of spectral power, coherence, and custom designed Conditional Granger Causality (cGC) based on Mutual Information extraction for layer-wise and contact-wise interplay between and within cortical areas.