Catecholaminergic neuromodulation and selective attention jointly shape perceptual decision making

Abstract Perception of sensory input is influenced by fluctuations in ongoing neural activity, most prominently driven by attention and neuromodulator systems. It is currently unknown if neuromodulator activity and attention differentially modulate neural activity and perception or whether neuromodulatory systems in fact control attentional processes. We pharmacologically enhanced cholinergic (through donepezil) and catecholaminergic (through atomoxetine) levels in humans performing a visual attention task to investigate the effects of neuromodulatory drive and spatial attention on neural activity and behavior. Attention and catecholaminergic enhancement both improved perceptual sensitivity by increasing the rate of evidence accumulation towards a decision threshold (cholinergic effects were negligible). Electroencephalographic recordings revealed that attention and catecholaminergic enhancement both modulated pre-stimulus cortical excitability, evoked sensory processes and parietal evidence accumulation. Crucially however, the spatial profile and timing of these effects were remarkably different. This suggests that selective attention and neuromodulatory systems shape perception largely independently and in qualitatively different ways.