In a fascinating article inThe Guardian titled “Acid test: scientists show how LSD opens doors of perception,” science editor Ian Sample discusses recent research on the mechanism by which LSD alters the brain and the mind. He begins by quoting Aldous Huxley (1894–1963) who noted that LSD “lowers the efficiency of the brain as an instrument for focusing the mind on the problems of life.” Remarkably, recent work in neuroscience supports Huxley’s view.

The research, conducted at Cornell University, confirms what has been called the Rebus model of psychedelics. Rebus is a rough acronym for “relaxed beliefs under psychedelics”; the model proposes that the brain is essentially a prediction engine for daily life. In this model, the brain processes information from the senses to help us understand the world efficiently. In doing so, it must take shortcuts and make predictions to enable quick perceptions and efficient responses. Psychedelic drugs suppress the ability of the brain to streamline perception and understanding. As the researchers put it, “Our findings provide support for a fundamental theory of the mechanism of action of psychedelics by showing that LSD flattens the brain’s energy landscape, allowing for more facile and frequent state transitions and more temporally diverse brain activity.”

The Cornell researchers used functional magnetic resonance imaging (fMRI) to study the brains of people on LSD or on placebo (= the control group). While using LSD, the brains of volunteers showed less high-level processing and more activity related to more rudimentary sensation. One of the investigators described the effect as flattening the landscape over which the brain can roam — the drug makes it easier for the mind to transcend mundane perceptual habits and see the world in greater detail. Thus they enabled people to break out of repetitive and ruminative thought.
This work, whatever its other merits, lends credence to an understanding of the mind–brain relationship that goes back centuries. It was stated perhaps most clearly by Oxford philosopher Ferdinand Schiller in 1891 when he proposed that

… matter is not what produces consciousness but what limited and confines its intensity within certain limits… This explanation admits the connection of matter and consciousness, but contends that the course of interpretation must proceed in the contrary direction. Thus it will fit the facts with materialism rejected as supernatural and thereby attain an explanation which is ultimately tenable instead of one which is ultimately absurd. It is an explanation the possibility of which no evidence in favor materialism can possibly affect.

Quoted in Chris Carter, Science and the near-death experience: how consciousness survives death (2010) Chapter 1.

Schiller argued that brain injuries are better understood as preventing the manifestation of consciousness than as extinguishing it. He suggested that, with regard to memory, it is forgetfulness and not memory that needs to be explained by neuroscience. For example, he noted the remarkable clarity of total recall that many people have under hypnosis or experience in near-death scenarios.

Schiller saw the brain as a sort of magnifying glass focusing sunlight (i.e., the mind) on the sidewalk. This dualist view has been endorsed by other philosophers and scientists, including French philosopher Henri Bergson (1859–1941) and American psychologist and philosopher William James (1842–1910). The recent research at Cornell supports that perspective. It is evidence for a dualist and even an idealist view of the mind and the brain.

We have direct access only to our thoughts, not to material objects. Our understanding of the function of the brain is always secondhand, via perception and reasoning. But we do not perceive our thoughts or even reason about them. We experience our thoughts, which suggests the ontological priority of mind over matter. The idealist viewpoint is certainly inconsistent with the various crude materialistic theories of mind and brain. Perhaps even the more robust dualist theories have the situation backwards. The brain does not generate the mind — the mind precedes the brain and the brain constrains and focuses the mind so that we can function normally in material world.

This view of the mind–brain relationship dovetails nicely with extensive research on near-death experiences which suggests that dysfunction of the brain expands the mind rather than extinguishing it. That should not be a surprise. The idea that in order to experience spiritual reality more profoundly one must suppress mundane activities of the mind and the brain has been a core characteristic of the spiritual practices of mystics and contemplatives thousands of years.

It is refreshing to see that some modern neuroscientists, such as these investigators at Cornell, are considering the implications of their science objectively and are coming to acknowledge, at least implicitly, that the materialist understanding of the brain is not only incoherent philosophy but junk neuroscience.

You may also wish to read these articles by Dr. Egnor:

Yes, split brains are weird, but not the way you think. Scientists who dismiss consciousness and free will ignore the fact that the higher faculties of the mind cannot be split even by splitting the brain in half.

Some people think and speak with only half a brain. A new study sheds light on how they do it.
Boy born with 2% of brain does maths, loves science. Noah Wall’s story raises intriguing questions about the relationship between the brain and the mind

and

Four researchers whose work sheds light on the reality of the mind The brain can be cut in half, but the intellect and will cannot, says Michael Egnor. The intellect and will are metaphysically simple.