Where does the mind “meet” the brain? Although there is no shortage of research into the effects of psychedelics, drugs like LSD still have much to learn about how the brain works – and can shed light on the mysterious interface between consciousness and neural physiology, the research suggests.
In a new study investigating the effects of LSD on volunteers, scientists found that the psychedelic allows the brain to function in a way beyond what anatomy usually dictates, by changing the states of dynamic integration and segregation in the human brain.
“The psychedelic compound LSD induces a profoundly altered state of consciousness,” explains first author and neuroscience researcher Andrea Luppi of the University of Cambridge.
Combining pharmacological interventions with non-invasive brain imaging techniques such as functional MRI (MRI) can provide insight into normal and abnormal brain function.
The new research is part of the study of dynamic functional connectivity – the theory that brain phenomena demonstrate states of functional connectivity that change over time, in the same way that our flow of consciousness is dynamic and always flows.
As this happens, and the human brain processes information, it must integrate this information into an amalgamated form of understanding – but at the same time separate the information, keeping sensory flows distinct from each other so that they can be treated by particular neural systems.
This distinction – the dynamics of brain integration and segregation – is something that is affected by psychedelic drugs, and with the advent of brain imaging technology, we can see what happens when our normal functional connectivity is disrupted.
In the study, a group of 20 healthy volunteers underwent brain scans in two separate sessions, two weeks apart. In one session, participants took a placebo before entering the fMRI scanner, while in the other slot, they were given an active dose of LSD.
Comparing the results of the two sessions, the researchers found that LSD unleashes functional connectivity from the constraints of structural connectivity, while changing the way the brain manages the balancing act between information integration and segregation.
“Our main finding is that the effects of LSD on brain function and subjective experience are not uniform over time,” says Luppi.
“In particular, the well-known sense of ‘ego dissolution’ induced by LSD is correlated with the reorganization of brain networks during a state of high global integration.”
In fact, the altered state of consciousness of the drug could be seen as an abnormal increase in the functional complexity of the brain – the data showing times when the brain revealed predominantly segregated functional connectivity patterns.
In other words, the “dissolving ego” of a psychedelic journey could be the subjective experience of your brain, which sheds the segregation dynamic, decoupling the structure of the brain from its functioning – which means your ability to integrate and amalgamate separate flows. of information in a unified whole becomes diminished.
“Thus, LSD seems to induce particularly complex models of functional connectivity (CF) by inducing additional decoupling of CF from the underlying structural connectome, precisely at those times when structural-functional coupling is already at its lowest level,” the authors explain in their work. .
“Because of the effects of LSD, the brain is free to explore a variety of functional patterns of connectivity that go beyond those dictated by anatomy – probably resulting in unusual beliefs and experiences reported during the psychedelic state.”
The findings are reported in NeuroImage.