A Working Hypothesis for the Role of the Cerebellum in Impulsivity and Compulsivity

Abstract

Growing evidence associates cerebellar abnormalities with several neuropsychiatric disorders in which compulsive symptomatology and impulsivity are part of the disease pattern. Symptomatology of autism, addiction, obsessive-compulsive (OCD), and attention deficit/hyperactivity (ADHD) disorders transcends the sphere of motor dysfunction and essentially entails integrative processes under control of prefrontal-thalamic-cerebellar loops. Patients with brain lesions affecting the cortico-striatum thalamic circuitry and the cerebellum indeed exhibit compulsive symptoms. Specifically, lesions of the posterior cerebellar vermis cause affective dysregulation and deficits in executive function. These deficits may be due to impairment of one of the main functions of the cerebellum, implementation of forward internal models of the environment. Actions that are independent of internal models may not be guided by predictive relationships or a mental representation of the goal. In this review article, we explain how this deficit might affect executive functions. Additionally, regionalized cerebellar lesions have been demonstrated to impair other brain functions such as the emergence of habits and behavioral inhibition, which are also altered in compulsive disorders. Similar to the infralimbic cortex, clinical studies and research in animal models suggest that the cerebellum is not required for learning goal-directed behaviors, but it is critical for habit formation. Despite this accumulating data, the role of the cerebellum in compulsive symptomatology and impulsivity is still a matter of discussion. Overall, findings point to a modulatory function of the cerebellum in terminating or initiating actions through regulation of the prefrontal cortices. Specifically, the cerebellum may be crucial for restraining ongoing actions when environmental conditions change by adjusting prefrontal activity in response to the new external and internal stimuli, thereby promoting flexible behavioral control. We elaborate on this explanatory framework and propose a working hypothesis for the involvement of the cerebellum in compulsive and impulsive endophenotypes.

The Modulation of Reward and Habit Systems by Acupuncture in Adolescents with Internet Addiction

“…The cerebellum, involved in rapid and automatic behavioral responses, was suggested as a key node in the process underlying habit formation [60]. As a result, cerebellar lesions might lead to failure of developing habits or new skills in both humans and rodents [61,62].…”

“…As a result, cerebellar lesions might lead to failure of developing habits or new skills in both humans and rodents [61,62]. As to addiction, over responsiveness of the cerebellum was found in a variety of substance dependence, associated with the habitual and compulsive use of drug [60]. Additionally, reciprocal projections between the cerebellum and PMC were revealed by virus transneuronal tracers [41].…”

Orbitrap mass spectrometry for monitoring the ganglioside pattern in human cerebellum development and aging

“…Human cerebellum represents a highly specialized brain region, divided into three anatomically distinctive lobes and located at the base of the skull, behind the brainstem. Cerebellum is responsible for motor learning and coordination, in particular for controlling voluntary movements, including the eye movement that supports vision, the body posture, and the gait . Damages at the cerebellar level result, among other impairments, in loss of muscle control and movement coordination, difficulties in swallowing, speaking, walking, maintaining the balance, and the normal stance of the body …”

The Cerebellum on Cocaine

“…Direct and indirect reciprocal connectivity between the cerebellum and other brain regions as the amygdala, basal ganglia, and mPFC can explain cerebellar roles in fear memory, cognitive flexibility, behavioral control, and goal-directed behavior (Sacchetti et al, 2002;Bostan et al, 2013;Wagner et al, 2017;Xiao et al, 2018;Schmahmann, 2019). Likewise, it can also explain why cerebellar dysfunction is associated with neuropsychiatric disorders in which impairment of behavioral and cognitive inhibitory control is a central part of the disease pattern as to happen in autism, obsessive-compulsive (OCD), attention deficit/hyperactivity (ADHD) and addiction (Miquel et al, 2019; Figure 2). Accordingly, in 2009 and then in 2016, we raised the question to why we should consider the cerebellum when thinking about drug addiction and drew attention to the cerebellum's roles in several of the brain functions affected in drug addicts.…”