An international research team led by the Universitat Jaume I (UJI) has shown that the cerebellum, contrary to what was thought, fulfils functions that go beyond the motor sphere and can be co-responsible for the brain alterations associated with addictive consumption of drugs. The findings, which are shown in two recent reviews published in Neuroscience & Biobehavioral Reviews and Journal of Neuroscience — with an image taken at the UJI laboratories — , would represent a step forward towards the design of new therapies for the future.
These studies are based on a series of works published over the last two years by the research group Addiction and Neuroplasticity at the Universitat Jaume I, directed by the lecturer of the Area of Psychobiology at the UJI, which has had the collaboration of researchers from European, Mexican and North American universities. The most relevant, according to Miquel, is that the studies show that changes in the cerebellum “only occur in those subjects who appear to be especially vulnerable to the effect of drugs.” For a long time, “we have verified that the cerebellum responds in a very potent way to the effect of cocaine, to the point of changing the mechanisms of plasticity,” states Miquel, who is also coordinator of the master’s degree in Research in Brain and Behaviour.
Consequently, the cerebellum is a region of the brain relevant to understanding and designing future treatments for drug addiction. “There is progress in describing the neuronal circuits affected by drug addiction, a chronic brain disorder that is difficult to treat because it affects the basic processes of acquiring and storing the information whose description is still incomplete,” explains the teacher, who acknowledges that, in this way, “the path to new therapies will be accelerated.”
Addiction involves alterations in the neuronal mechanisms of plasticity that allow the brain to store information, regenerate itself and recover from possible disorders or injuries. In an addicted person, the brain’s mechanisms of learning and memory that allow you to make decisions and carry out acts of will are sick. Addictive drugs force the brain to store harmful data about where, when and how to consume the substance. In fact, the drug is the predominant information in the brains of people affected by addiction.
The Effects of Cocaine
On this occasion, the reviewed investigations address the function of the cerebellum in these storage processes involved in the addictive disorder. Specifically, “experimental work shows that these effects of cocaine on cerebellar function only occur in those individuals dominated by stimuli that predict drug availability and suggest that the cerebellum may be crucial to understanding mechanisms of vulnerability to addiction,” explains Marta Miquel.
Science has corroborated that certain regions of the brain, such as the prefrontal cortex, amygdala, hippocampus, and basal ganglia, may be relevant for addiction. However, the cerebellum had traditionally been excluded from this circuit because it was considered a structure exclusively dedicated to motor control, especially motor coordination. “Today we know that this is a very partial view on the complexity of the cerebellum, and a growing volume of data suggests its involvement in many of the brain functions affected in addicted subjects,” refers Marta Miquel. “The cerebellum comprises 80% of all neurons in the brain; it contains 60 billion neurons packaged in only 10% of the brain mass and is a fundamental structure in the consolidation and automation of learned behavioural repertoires,” concludes the lecturer.
In addition to the UJI team, scientists from the University of Kentucky (USA), University of Turin (Italy), Universidad Veracruzana (Mexico), Washington State University (USA), University of Cambridge, University of Leeds (United Kingdom), McLean Hospital Translational Neuroscience Laboratory and Mailman Research Center (USA) also participate in the research works. After presenting the papers at the last congress of the International Society for Neuroscience (San Diego, USA), the work will be discussed soon at the Albert Einstein Institute in New York.
The priority line of the research group Addiction and Neuroplasticity from the Universitat Jaume I, directed by the lecturer Marta Miquel, is the brain’s function in drug addiction.