Summary: Researchers have long studied hemispatial neglect—a disorder in which people who suffered a stroke stop acknowledging events on the left side of space despite having intact basic vision. New intracerebral recordings reveal how attention and conscious perception interact in the brain, offering fresh insights into both cognitive disorders and the mechanisms of human awareness.
To clarify how attention influences conscious perception, neurologists mapped patterns of neural activity in frontoparietal networks while participants performed a visual detection task. Their results identify distinct brain activity clusters linked to attention maintenance and reorientation, and they challenge theories that treat attention and conscious experience as entirely separate processes.
Key Facts:
- Hemispatial neglect causes unawareness of part of the environment not because of impaired vision, but because attention fails to be allocated to that side.
- Intracerebral recordings uncovered five clusters of electrical activity in frontoparietal networks that support the maintenance and redirection of attention.
- These findings provide neural evidence that attention and conscious perception interact, contradicting models that consider them fully independent functions.
Source: Paris Brain Institute
Nearly half of people who suffer a stroke in the right hemisphere later develop hemispatial neglect: they fail to perceive the left side of space.
Patients with this disorder may eat only from the right side of their plate, ignore people who approach from their left, and experience severe difficulty navigating their surroundings. Crucially, these deficits are not caused by a loss of visual acuity or basic eyesight; instead, they reflect an attentional failure: the brain receives visual information but does not bring it into awareness.
“These patients can see fine; the deficit is one of attention,” explains Paolo Bartolomeo, neurologist and researcher at the Paris Brain Institute. “Rehabilitation often focuses on retraining attentional orienting and maintenance.”
Understanding how attention and conscious perception relate is central both to treating disorders like hemispatial neglect and to broader questions about the nature of consciousness. Competing theories have long debated whether attention is necessary for conscious perception and, if so, how the two processes are connected at the neural level.
To test these ideas directly, Bartolomeo and doctoral student Jianghao Liu examined the neural dynamics of exogenous attention—attention drawn by external stimuli—using intracerebral electrophysiology, which provides far finer temporal and spatial detail than noninvasive methods such as fMRI or scalp EEG.
Gabor to starboard
The team recorded neural activity from 13 patients with drug-resistant epilepsy who had been implanted with depth electrodes for clinical reasons. Participants performed a visual task that required detecting a near-threshold Gabor patch (a striped pattern whose visibility was adjusted by contrast). The target would appear to the left or right of the screen and was preceded by a small visual cue that could be valid (indicating the correct side), invalid (misleading), or neutral; in some trials the target was absent.
By manipulating attention with the cues, the researchers measured how cueing affected whether subjects consciously reported seeing the Gabor patch. Attention could greatly increase or decrease the likelihood of conscious report depending on cue validity and target visibility. Simultaneously, intracerebral recordings revealed distinct networks engaged during these attention–perception interactions.
Supporting neural evidence
Analysis of the recorded signals revealed five clusters of electrical activity across frontoparietal regions that correlated with attentional maintenance and reorienting. The team then compared these functional clusters with white matter tractography to confirm that the observed activity patterns aligned with known anatomical projections. Finally, they used computational modeling with recurrent neural networks to test whether the identified dynamics could generalize beyond the patient sample, strengthening the claim that these mechanisms reflect general principles of attention and awareness rather than effects specific to epilepsy.
“For the first time, we can map how frontoparietal networks cooperate to shape conscious report via attention gain and reorienting,” says the research team. “Some existing hypotheses propose that attention and conscious perception rely on separate networks; our data indicate substantial interaction between them.”
These attentional interactions likely influence everyday perception: our awareness of the world is continually shaped by what our attention highlights or neglects. The researchers now plan to investigate whether internally driven attention—attention to thoughts, bodily sensations, or internal states—similarly modulates conscious experience.
“Understanding how attention to inner events shapes consciousness is the next frontier,” concludes Paolo Bartolomeo. “Our capacity to attend to ourselves is as important to study as our capacity to perceive the external world.”
About this consciousness and perception research news
Author: Marie Simon
Source: Paris Brain Institute
Contact: Marie Simon – Paris Brain Institute
Image: The image is credited to Neuroscience News
Original Research: Open access. “Fronto-parietal networks shape human conscious report through attention gain and reorienting” by Paolo Bartolomeo et al., Communications Biology
Abstract
Fronto-parietal networks shape human conscious report through attention gain and reorienting
How do attention and consciousness interact in the human brain? Competing theories disagree about the role of fronto-parietal attentional networks in conscious perception. To address this, the authors recorded neural activity from 727 intracerebral contacts in 13 patients while they detected near-threshold targets that were preceded by attentional cues.
Clustering of neural responses revealed three principal patterns. First, attention-enhanced conscious report was associated with sustained right-hemisphere fronto-temporal activity connected by the superior longitudinal fasciculus (SLF) II–III, together with late activity accumulation (>300 ms post-target) in bilateral dorso-prefrontal and right orbitofrontal regions (SLF I–III). Second, attentional reorienting influenced conscious report via early sustained activity in a right-hemisphere network (SLF III). Third, conscious report also correlated with left-hemisphere dorsolateral-prefrontal activity. Task modeling with recurrent neural networks reproduced multiple clusters matching the brain data and clarified causal relationships between clusters in shaping awareness of near-threshold stimuli.
In summary, distinct, hemisphere-asymmetric fronto-parietal networks support attentional gain and reorienting processes that shape human conscious experience.