British neuroscientist Peter Coppola contends that human consciousness takes its roots in the brain’s oldest regions. In doing so, he opposes the prevailing view that assigns consciousness to the neocortex. His work is a literature review published in Neuroscience & Biobehavioral Reviews, which gathers clues without providing definitive proof.
There is no scientific consensus on this point.
The Cortex, Presumed Seat of Consciousness
Traditionally, neuroscience views the cerebral cortex—the folded outer layer of the brain—as the “seat of consciousness.” The scientific theories also adopt a materialist stance. They posit that consciousness emerges from the matter of which we are made, in contrast to dualists, for whom the body and mind are two realities of different natures. Most of these models assign a central role to the cortex.
Physicalist theories have been grouped into four families: higher-order theories, global workspace theories, integrated information theory, and theories of re-entry and predictive processing. Two of them dominate the debate. Global workspace theory links consciousness to the widespread and sustained propagation of cortical activity, with an “ignition” that disseminates information between brain regions. Integrated information theory characterizes the conscious state in quantitative terms.
These two models suffered a setback in 2025. An adversarial study of human brain activity did not confirm key predictions of either major cortico-centric theory, leaving open the question of where and how the brain generates subjective experience.
The stage was thus set for challengers.
Coppola’s Method: Searching for Atypical Brains
His work divides the brain into three regions—the cortex, the subcortex, and the cerebellum—to identify cases in which one or more of them are altered, and then examine the effects on consciousness. The review covers more than a century of neuroscience research. It yields a set of data that, in his view, tests the most widespread theories of consciousness.
Clinical cases are telling. Coppola notes that people born without a cerebellum, or without the front part of their cortex, can appear conscious and lead fairly normal lives.
Two readings are possible, and he lays them out himself. Either the neocortex, a relatively recent development in evolutionary terms, is not necessary for basic consciousness, or the other two regions learn to compensate for a cortex that is deficient from birth. His conclusion leans toward the former. After surveying decades of work, he deems the view that the origin of consciousness lies in the neocortex outdated. These subcortical areas are typically regarded as “primitive” and, in theory, incapable of hosting the seat of human consciousness.
The cerebellum, often cited in such debates, is also among the structures whose absence does not preclude apparent consciousness.
An Hypothesis Not Isolated, and Still Debated
Coppola is not the only one looking beneath the cortex. In The Neuroscientist, 2026, two authors, Devor and Baron, have proposed a similar hypothesis. In their model, the brainstem provides the foundational experience of being conscious, while the cortex processes the information that fills this experience. Their main support comes from pain, the only sense that, they argue, does not require the cortex. Yet stimulating the cortex almost never produces a pain sensation.
These works are not all on the same footing. An earlier study mapped wakefulness pathways rather than testing a theory of subjective experience, while placing brainstem circuits at the base of human consciousness. Much of the evidence on the brainstem remains compatible with the classical views, which already admit it is necessary to keep the cortex awake.
The definitional question also weighs on the discussion. Consciousness denotes wakefulness, self-awareness, and perception of the environment, along with thoughts, emotions, and sensations. The disagreement is therefore less about what it is than about what in the brain gives rise to it. The subjectivity of conscious experience challenges the objectivity of a scientific explanation, making verification delicate.
Even researchers critical of the cortex acknowledge its limits as a challenger. They concede that higher-order consciousness involves the cortex and complex exchanges between brain regions. The cortex enables us to interpret our environment, draw on memories, imagine possibilities, and reflect on our own thoughts.
Thus, the debate concerns the origin of raw experience, not elaborated thought.
There remains one consequence that the authors themselves emphasize. If consciousness arises in the brainstem, its origins may not be as specifically human as commonly thought. The question would then extend to animals, patients in altered states of consciousness, and, ultimately, the criteria we would apply to a machine.
Sources: ncbi.nlm.nih.gov | nature.com | pmc.ncbi.nlm.nih.gov
