A groundbreaking study by Lund University in Sweden has found that psychoactive drugs like LSD and ketamine can induce psychedelic neural hypersynchrony or simultaneous high-frequency electrical waves in multiple brain regions.
The study, published in Communication Biology, gives an unprecedented glimpse at the brain’s ‘symphony’ of neural activity during psychedelic experiences, potentially paving the way for a better understanding of human consciousness or new avenues for treating mental health disorders.
Humans have been captivated by altered states of consciousness for centuries, often induced by psychedelic substances. Despite their historical notoriety, only in the last decade or so have scientists been able to peek under the hood to understand what’s going on in the brain during a mind-altering experience.
Led by cognitive neuroscientist Dr. Pär Halje at Lund University, the study used nine Sprague-Dawley rats to explore how substances like LSD, ketamine, and DOI (2,5-dimethoxy-4-iodoamphetamine) affect electrical brain activity.
Laboratory rats are frequently used in medical research because virtually all disease-linked human genes can be found in rats, and their brain structure closely resembles the human brain.
“I think that psychedelics is a great tool to study the neural basis of consciousness in laboratory animals since we share most of the same neural ‘hardware’ with other mammals,” Dr. Halje told PsyPost.
Researchers developed a state-of-the-art microelectrode array that simultaneously monitored the electrical activity in 128 regions of the rat’s brain. The novel array allowed researchers to monitor local field potentials (LFPs)—signals generated by thousands of neurons—and single unit activities, which are the firing patterns of individual neurons.
The lab rats were then administered different psychedelic substances, including LSD, DOI, ketamine, and PCP (phencyclidine). An amphetamine was also included as a non-psychedelic psychoactive control.
“For several of these areas, it is the first time anyone has successfully shown how individual neurons are affected by LSD in awake animals,” Dr. Halje said in a press release. “When we gave the rats the psychedelic substances LSD and ketamine, the waves were clearly registered.”
Examining the results, Dr. Halje and his team found that despite interacting with different types of neural receptors, both 5-HT2AR psychedelics like LSD and NMDAR psychedelics like ketamine-induced remarkably similar repetitive patterns of high-frequency electrical activity in the brain.
Researchers noted that differing brain regions fired almost perfectly in sync, with minuscule delays often less than 1 millisecond. This suggests the psychedelic neural hypersynchrony of brain activity was not a result of communication through chemical synapses, which are relatively slow.
These unique psychedelic neural hypersynchrony oscillations were also independent of individual neuronal firing rates, challenging prevalent models that link psychedelic states directly to changes in individual neuron activities.
“Activity in the individual neurons caused by ketamine and LSD looks quite different, and as such cannot be directly linked to the psychedelic experience,” Dr. Halje explained. “Instead, it seems to be this distinctive wave phenomenon – how the neurons behave collectively – that is most strongly linked to the psychedelic experience.”
According to a 2020 study published in the Annual Review of Medicine, rapid and synchronous oscillations of neural activity are associated with improved cognition, highlighting the potential implications in the discovery of psychedelic neural hypersynchrony for understanding not just altered but also normal states of consciousness.
The unique synchrony in brain wave activity seen in psychedelic states also offers a potential avenue for modeling specific aspects of psychotic disorders. According to a 2017 study in the Journal of Psychopharmacology, understanding how psychedelic substances affect neural activity could help science identify a “unified theory” of brain serotonin function.
“Given how drastically a psychosis manifests itself, there ought to be a common pattern that we can measure. So far, we have not had that, but we now see a very specific oscillation pattern in rats that we are able to measure,” added Dr. Halje.
Researchers say the true “dream” is that the discovery of psychedelic neural hypersynchrony will mark a pivotal step in unraveling the human mind’s complexities and understanding the neural foundation of human consciousness.
“In light of the development of AI, it is becoming increasingly important to clarify what we mean by intelligence and what we mean by consciousness. Can self-awareness occur spontaneously, or is it something that needs to be built in? We do not know this today, because we do not know what the required ingredients for consciousness in our brains are,” said Dr. Halje.
“This is where it is exciting, the synchronized pattern we see, and whether this can help us to track down the neural foundations of consciousness.”
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com