Regret is a powerful feeling. Disappointment and penitence about events that have already taken place can really wear an individual down, so much so that for some people, it is as if they cannot escape the past. It is like their mind perpetually relives unpleasant past experiences and the negative feelings associated with them. Fortunately, there is very promising research being conducted that is improving our understanding of this "mental time travel" phenomenon. In fact, a recently conducted study has found that lysergic acid diethylamide (LSD) actually seems to possess properties that temporarily inhibit the connectivity of regions in the brain that are responsible for keeping the past in focus.
In this study, which was published in the Journal of Psychopharmacology, the researchers stated that “mental time travel refers to the ability of humans to mentally project themselves backwards and forwards in time, to recollect aspects of past autobiographical episodes or imagine future experiences.” Several scholars believe that our ability to access and involuntarily replay past events plays a significant role in a person's sense of self and identity, most commonly referred to as the "ego."
Several studies have identified a particular brain network called the default-mode network (DMN) that has been found to be the key component in the occurrence of this mental time travel. Research shows that individuals who have higher rates of connectivity in the DMN tend to dwell on the past more, engage in more ruminative thought, and regularly suffer from depression and general low mood. What is interesting, however, is that functional magnetic resonance imaging (fMRI) scans performed on people under the effects of a variety of psychedelic substances have shown that such substances have the ability to decrease activity of DMN. Researchers believe that it is this effect that serves as the key component for "ego dissolution," an event in which an individual experiences a subjective decomposition of their sense of self.
For this study, a research team, led by Jana Speth of the University of Dundee, devised an experiment to evaluate LSD's ability to decrease activity of the DMN in particular. For the experiment, the team administered either LSD or a placebo intravenously to a group of volunteers and immediately conducted fMRI scans for any rapid change in brain activity. Then, the team conducted a series of interviews with the volunteers, the transcripts of which were used to look for any "theta roles," linguistic constructs that signify mentalizations of particular temporal domains, indicating mental time travel to either the past or the future, or a presently focused mind.
Results of the experiments show that the individuals who received the LSD referred to the past far less often than those that were given the placebo, representing a decrease of mental time travel and a heightened focus on the present. This effect was a direct result of the dampening of the DMN, which means that LSD does in fact inhibit the regions of the brain that cause involuntary mental time traveling.
It is yet to be scientifically determined how this trait persists after the acute effects of the LSD have subsided, however, LSD's ability to influence this self destructive neural circuit may lead to ground breaking discoveries by those searching for new and improved methods for fighting depression. Currently, a number of mindfulness-based treatments for depression encourage depressed individuals to adopt an improved present-focused mode of thinking, and this inhibition of the DMN may very well be the key.
More research is to be done before we can know, with certainty, the long-term depression alleviation effects of LSD, although the results of previous and ongoing experiments are extremely promising. It is becoming clear that the positive impact of some psychedelic substances on mood disorders, if enduring, could be exactly what psychiatric therapy has been waiting for.
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