The Neuroscientist Who Found Consciousness in the Feedback Loops of the Brain

When you look at a face, what happens in your brain? The answer turns out to be surprisingly complex. First, visual information streams forward from your eyes through your visual cortex, each region extracting features: edges, colors, shapes, the statistical patterns that identify this particular configuration of features as belonging to the category “face.” This feedforward sweep happens quickly, within about 100 to 150 milliseconds, and it happens without awareness. You do not yet consciously see the face.

Then something else begins. Signals start flowing backward, from higher regions down to lower ones. Different parts of the visual system begin talking to each other, comparing notes, reconciling their interpretations. The face stops being a collection of separately detected features and becomes a unified perception, an integrated whole with depth, context, meaning. This is recurrent processing, and according to Victor Lamme, this is where consciousness lives.

Lamme is Professor of Cognitive Neuroscience at the University of Amsterdam, and his Recurrent Processing Theory has emerged as one of the most empirically grounded approaches to understanding how brain activity gives rise to conscious experience. His work matters for anyone trying to understand the mind and its disorders, because it offers a specific, testable account of what distinguishes conscious from unconscious processing in the brain.

The Two Modes of Vision

The central insight of Recurrent Processing Theory emerged from decades of research on visual processing, much of it conducted using careful measurements of neural activity in monkeys and humans.

When a visual stimulus appears, the brain responds in stages. The initial response, the feedforward sweep, carries information from the retina through the thalamus and up through the hierarchy of visual areas. This happens fast. Within about 50 milliseconds, activity has reached even the highest levels of the visual system, areas in the temporal lobe that respond to complex categories like faces, houses, and animals.

The feedforward sweep is remarkably capable. It can extract features at all levels of complexity. Low-level areas detect edges and colors. Higher areas detect shapes and textures. The highest areas can categorize stimuli, distinguishing faces from non-faces, recognizing particular objects, even triggering emotional responses via connections to the amygdala. All of this happens before you consciously see anything.

What the feedforward sweep cannot do, according to Lamme’s research, is integrate. The different features detected by different areas remain separate, processed in parallel but not bound together into a unified perception. The face is detected as a category, but you do not yet experience seeing it.

Then recurrent processing begins. Higher visual areas send signals back to lower ones. Neighboring areas begin exchanging information horizontally. The flow of processing is no longer one-way but bidirectional, looping, iterative. Different regions compare their interpretations and resolve conflicts. Features that were processed separately become integrated into a coherent whole.

This is when consciousness emerges. According to Lamme, recurrent processing is both necessary and sufficient for visual consciousness. When recurrent loops are active, you see. When they are blocked, even by events that leave the feedforward sweep intact, awareness vanishes.

Evidence from Masking and Blindsight

The evidence for this two-stage model comes from multiple sources. One is the phenomenon of visual masking. If a briefly presented target stimulus is followed quickly by a second masking stimulus, the target becomes invisible. You literally cannot see it, even though your brain processed it.

What happens neurally? The feedforward sweep for the target proceeds normally. You can measure neural responses to the target in early visual areas, and these responses look the same whether the target is masked or not. What masking disrupts is the recurrent processing that would normally follow. The feedback signals from higher areas are overwhelmed by the new feedforward sweep triggered by the mask.

This shows that feedforward processing is not sufficient for consciousness. The brain can extract features, categorize stimuli, and even prepare motor responses, all without the stimulus ever entering conscious awareness. What consciousness requires is the recurrent exchange of information between brain regions.

Similar evidence comes from patients with blindsight. These patients have damage to their primary visual cortex (V1) that leaves them clinically blind in part of their visual field. They report seeing nothing in that region. Yet when forced to guess about stimuli presented there, they perform better than chance. They can point to targets, avoid obstacles, even discriminate emotional expressions, all without any conscious visual experience.

Blindsight shows that the feedforward pathway can remain functional even when conscious vision is lost. Information reaches higher visual areas via alternative routes that bypass V1. But without V1, the recurrent loops that normally establish consciousness cannot form. The patient processes visual information unconsciously but does not see.

Four Stages of Visual Processing

Lamme’s framework distinguishes four stages of visual processing, each corresponding to a different level of accessibility to consciousness and behavior.

The first stage is complete invisibility. The stimulus is so brief, so weak, or so well-masked that it produces no detectable neural response beyond the earliest stages. There is neither conscious experience nor behavioral influence.

The second stage is what Lamme calls “subjective invisibility” but objective influence. The feedforward sweep proceeds normally, and the stimulus influences behavior through priming, response preparation, or other unconscious effects. But recurrent processing does not occur, so there is no conscious experience. The person reports seeing nothing but behaves as if they had seen something.

The third stage is what Lamme considers “phenomenal consciousness” without access. Recurrent processing occurs within the visual system, creating a conscious visual experience. But this experience is not yet connected to the broader cognitive systems that enable reporting, introspection, and deliberate action. You see, but you do not yet know that you see.

The fourth stage is full access consciousness. Recurrent processing spreads beyond the visual system to involve frontal and parietal areas. The visual experience becomes available for verbal report, for integration with memory, for guidance of flexible behavior. You not only see but know that you see.

This four-stage model creates an important distinction between phenomenal consciousness, the raw experience of seeing, and access consciousness, the ability to report and use that experience. According to Lamme, these are separate, with phenomenal consciousness emerging earlier and depending only on local recurrent processing within the visual system.

The Function of Recurrence

Why would recurrent processing generate consciousness while feedforward processing does not? Lamme suggests the answer lies in what recurrence enables functionally.

The feedforward sweep extracts features in parallel across many processing streams. Different areas detect different aspects of the stimulus, but these detections remain separate. There is no mechanism for binding them together into a unified representation.

Recurrent processing solves this binding problem. When higher areas send signals back to lower areas, they create the conditions for different features to be integrated. The feedback conveys information about the global context, allowing local processing to be influenced by the larger pattern. Edge detectors are informed about which edges belong to the same object. Color-processing areas learn which colors correspond to which shapes.

This integration is what makes visual perception organized rather than fragmented. You do not experience a jumble of separately detected features. You experience unified objects in coherent scenes, with figure separated from ground, occluded surfaces completed behind occluders, ambiguous stimuli resolved into stable interpretations.

Lamme argues that this integrative function is the key to understanding consciousness. Consciousness is not merely processing information. It is integrating information across multiple processing streams into a unified representation. Feedforward processing can detect and categorize, but only recurrent processing can integrate.

Implications for Theories of Consciousness

Recurrent Processing Theory takes a distinctive position in the landscape of consciousness science. Unlike Global Workspace Theory, which emphasizes the broadcasting of information to widespread brain regions, Lamme’s theory locates consciousness in relatively local processing within sensory areas. What matters is not global access but local integration through recurrent loops.

This has important implications. If consciousness can occur locally within sensory systems, then it might exist even when that processing is not accessible for verbal report or flexible behavior. There could be conscious experiences that are phenomenally rich but cognitively isolated, never entering the global workspace that enables introspection and control.

Lamme takes this implication seriously. He argues that the right hemisphere of split-brain patients may be conscious even though it cannot generate verbal reports. He suggests that dream states, anesthesia, and various pathological conditions might involve dissociations between phenomenal and access consciousness. And he is open to the possibility that simpler creatures with recurrent processing in their sensory systems might have conscious experiences, even without the cognitive sophistication of human minds.

Recurrent Processing Theory also has implications for how we think about unconscious processing. The theory predicts that even sophisticated cognitive operations can occur unconsciously, as long as they depend only on feedforward processing. And indeed, research has shown that unconscious stimuli can activate frontal cortex, trigger response preparation, influence decision-making, and even activate semantic associations. The prefrontal cortex, long thought to be the seat of consciousness, turns out to be heavily involved in unconscious processing.

Clinical and Therapeutic Implications

For clinicians working with trauma and dissociation, Recurrent Processing Theory offers a framework for understanding how conscious experience can become fragmented.

Consider what happens in dissociative states. The normal integration that makes experience unified breaks down. Perceptions may feel unreal, the body may feel disconnected from the self, memories may be split off from their emotional significance. From the perspective of Recurrent Processing Theory, these symptoms might reflect disruptions in the recurrent loops that normally integrate different aspects of experience.

Traumatic experiences often overwhelm the brain’s integrative capacity. Information that should be bound together, the sensory details of the event, the emotional response, the narrative context, remains fragmented. Traumatic memories are often experienced as intrusive sensory fragments rather than coherent narratives, suggesting that the recurrent processing needed for integration was disrupted during encoding.

Effective trauma therapies may work in part by restoring integrative processing. EMDR involves bilateral stimulation while holding traumatic material in awareness, potentially facilitating the recurrent processing needed to integrate fragmented memories. Brainspotting uses eye position to access subcortical activation while maintaining reflective awareness, creating conditions for integration across brain systems. Somatic approaches help clients reconnect with bodily experience that has been split off from conscious awareness.

The emphasis on integration in these therapies resonates with what Recurrent Processing Theory says about consciousness. Healing from trauma may require restoring the recurrent loops that bind fragmented experience into coherent wholes.

Attention and Consciousness

One important contribution of Lamme’s work is clarifying the relationship between attention and consciousness. Common sense suggests they are closely related, that we are conscious of what we attend to and unconscious of what we ignore. But the actual relationship turns out to be more complex.

Lamme distinguishes between feedforward attention, which selects stimuli for enhanced processing, and the recurrent processing that generates conscious experience. Attention can operate unconsciously, enhancing the feedforward sweep without producing consciousness. And consciousness can occur without attention, when recurrent processing is strong enough to proceed even without top-down attentional enhancement.

This distinction matters for understanding phenomena like inattentional blindness, where people fail to notice obvious stimuli because attention is directed elsewhere. The unattended stimuli may still be processed, even recurrently, but without sufficient strength to reach the threshold for reportable awareness. They are phenomenally present but cognitively unaccessed.

For therapy, this suggests that expanding conscious awareness may require more than just directing attention. It may require strengthening the recurrent processing that integrates attended content into unified experience. Mindfulness practices, which train sustained attention to present-moment experience, may work in part by enhancing recurrent processing in sensory and somatic systems.

Continuing Research and Debates

Lamme continues to refine and defend Recurrent Processing Theory. In recent papers, he has addressed challenges from other theories, clarified the distinction between phenomenal and access consciousness, and explored the implications of his view for questions about animal consciousness and artificial intelligence.

One ongoing debate concerns whether phenomenal consciousness can really occur without access. Critics argue that if an experience is truly conscious, it should by definition be reportable. But Lamme points to cases like the right hemisphere in split-brain patients, which cannot generate verbal reports but may still have conscious experiences. He also notes that we often have experiences that are phenomenally rich but quickly forgotten, suggesting that access and phenomenality can come apart.

Another debate concerns the sufficiency of recurrent processing. Is it really enough for consciousness, or are additional ingredients needed? Lamme has argued that recurrence is sufficient when it produces certain functional properties, particularly the integration of features into organized perceptual wholes. But the exact conditions that determine when recurrence produces consciousness remain to be fully specified.

Recurrent Processing Theory has been tested in the COGITATE adversarial collaboration, a major research project that pitted different theories of consciousness against each other using preregistered predictions. The results, published in 2024, provided mixed support for various theories, with no single theory emerging as clearly superior. The field continues to debate how to interpret these findings.

Selected Publications

Lamme, V. A. F. (2006). Towards a true neural stance on consciousness. Trends in Cognitive Sciences, 10(11), 494-501.

Lamme, V. A. F. (2010). How neuroscience will change our view on consciousness. Cognitive Neuroscience, 1(3), 204-220.

Lamme, V. A. F. (2018). Challenges for theories of consciousness: Seeing or knowing, the missing ingredient and how to deal with panpsychism. Philosophical Transactions of the Royal Society B, 373(1755), 20170344. Available at: https://pubmed.ncbi.nlm.nih.gov/30061458/

Lamme, V. A. F. (2020). Visual functions generating conscious seeing. Frontiers in Psychology, 11, 83. Available at: https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2020.00083/full

Lamme, V. A. F., & Roelfsema, P. R. (2000). The distinct modes of vision offered by feedforward and recurrent processing. Trends in Neurosciences, 23(11), 571-579.

van Gaal, S., & Lamme, V. A. F. (2012). Unconscious high-level information processing: Implication for neurobiological theories of consciousness. The Neuroscientist, 18(3), 287-301. Available at: https://pubmed.ncbi.nlm.nih.gov/21628675/

Bibliography

Academic Resources

Victor Lamme Google Scholar Profile: https://scholar.google.com/citations?user=QU5-DJEAAAAJ

University of Amsterdam ResearchGate Profile: https://www.researchgate.net/profile/Victor-Lamme

Open MIND Contributor Page: https://open-mind.net/om-contributors/Victor_A_Lamme

Key Papers on Recurrent Processing Theory

Lamme, V. A. F. (2006). Towards a true neural stance on consciousness. Trends in Cognitive Sciences. Available via PubMed.

Lamme, V. A. F. (2020). Visual functions generating conscious seeing. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC7034432/

Related Resources

Stanford Encyclopedia of Philosophy entry on consciousness: https://plato.stanford.edu/entries/consciousness/

Internet Encyclopedia of Philosophy on neural correlates of consciousness: https://iep.utm.edu/consciousness-neural-correlates/

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