Conscious perception in patients with prefrontal damage.

Damage to the right dorsolateral prefrontal cortex and reduced integrity of the ventral branch of the right superior longitudinal fasciculus (SLF III) are causally linked to conscious perception of near-threshold stimuli. Patients with right prefrontal damage required greater perceptual contrast to detect near-threshold targets compared to matched healthy controls, supporting a causal role of the prefrontal lobe in conscious processing.

Study at a glance

Abstract

We are conscious and verbally report some of the information reaching our senses, although a big amount of information is processed unconsciously. There is no agreement about the neural correlates of consciousness, with low-level theories proposing that neural processing on primary sensory brain regions is the most important neural correlate of consciousness, while high-level theories propose that activity within the fronto-parietal network is the key component of conscious processing (Block, 2009). Contrary to the proposal of high-level theories, patients with prefrontal lobe damage do not present clinical symptoms associated to consciousness deficits. In the present study, we explored the conscious perception of near-threshold stimuli in a group of patients with right prefrontal damage and a group of matched healthy controls. Results demonstrated that perceptual contrast to perceive the near-threshold targets was related to damage to the right dorsolateral prefrontal cortex, and with reduced integrity of the ventral branch of the right superior longitudinal fascicule (SLF III). These results suggest a causal role of the prefrontal lobe in conscious processing.