Lesions of prefrontal cortex reduce attentional modulation of neuronal responses and synchrony in V4

Abstract

It is widely held that the frontal eye field (FEF) in prefrontal cortex (PFC) modulates processing in visual cortex with attention, although the evidence for a necessary role is equivocal. To help identify critical sources of attentional feedback to area V4, we surgically removed the entire lateral PFC, including the FEF, in one hemisphere and transected the corpus callosum and anterior commisure in two macaques. This deprived V4 of PFC input in one hemisphere while keeping the other hemisphere intact. In the absence of PFC, attentional effects on neuronal responses and synchrony in V4 were significantly reduced and the remaining effects of attention were delayed in time indicating a critical role of PFC. Conversely, distracters captured attention and influenced V4 responses. However, because the effects of attention in V4 were not eliminated by PFC lesions, other sources of top-down attentional control signals to visual cortex must exist outside of PFC.

Causal evidence for frontal cortex organization for perceptual decision making

“…The decrease in the RT advantage for attended stimuli following FEF TMS could be reproduced by decreasing the difference in drift rate between attended and unattended stimuli. Thus, one possibility is that the caudal frontal cortex biases the processing of visual information such that one stimulus is favored over another through a process akin to gain amplification (16,29). This possibility is further corroborated by the known connectivity of FEF to early visual areas that respond to the visual stimulus (30).…”

On the neural basis of sensory weighting: Alpha, beta and gamma modulations during complex movements

“…Taken together, our findings are therefore in line with the existence of a general sensory gain control mechanism driven by the adaptive state of the sensorimotor system in a given sensory context. The control exerted over the visual and somatosensory inputs may originate from different neural substrates, such as the thalamus (Purushothaman et al, 2012;Womelsdorf et al, 2014), the prefrontal cortex (Barcelo et al, 2000;Gregoriou et al, 2014;Haggard and Whitford, 2004) and the cerebellum (Cebolla et al, 2017;Knight et al, 1999).…”

Visual attention: Linking prefrontal sources to neuronal and behavioral correlates

“…Consistent with these 280 findings, gamma-band LFP power in response to distractor stimuli 281 is elevated on trials in which the animal incorrectly responds to the 282 distractor (Taylor et al, 2005). Gamma-band power and synchro-283 nization increase at the attended location; in contrast, V4 alpha-284 band LFP activity decreases at the attended location, and the 285 magnitude of this drop in alpha power was larger on correct trials 286 (Gregoriou et al, 2014). 287 However, not every observed signature of attentional deploy-288 ment is correlated with correct performance or reaction time.…”