Viewing the personality traits through a cerebellar lens. A focus on the constructs of novelty seeking, harm avoidance, and alexithymia

The variance in the range of personality trait expression appears to be linked to structural variance in specific brain regions. In evidencing associations between personality factors and neurobiological measures, it seems evident that the cerebellum has not been up to now thought as having a key role in personality. This paper will review the most recent structural and functional neuroimaging literature that engages the cerebellum in personality traits, as novelty seeking and harm avoidance, and it will discuss the findings in the context of contemporary theories of affective and cognitive cerebellar function. By using region of interest (ROI)- and voxel-based approaches, we recently evidenced that the cerebellar volumes correlate positively with novelty seeking scores and negatively with harm avoidance scores. Subjects who search for new situations as a novelty seeker does (and a harm avoiding does not do) show a different engagement of their cerebellar circuitries in order to rapidly adapt to changing environments. The emerging model of cerebellar functionality may explain how the cerebellar abilities in planning, controlling, and putting into action the behavior are associated to normal or abnormal personality constructs. In this framework, it is worth reporting that increased cerebellar volumes are even associated with high scores in alexithymia, construct of personality characterized by impairment in cognitive, emotional, and affective processing. On such a basis, it seems necessary to go over the traditional cortico-centric view of personality constructs and to address the function of the cerebellar system in sustaining aspects of motivational network that characterizes the different temperamental trait

Neural and cognitive biomarkers of binge and heavy drinking

BACKGROUND: Theories suggest two motivations that drive people to consume alcohol at pathological levels: (1) seeking of short-term pleasurable effects and (2) alleviation of unpleasant states. The former is associated with binge drinking (BD; i.e. high intake during fewer occasions) and the latter with heavy drinking (HD; substantial intake during more occasions). Although direct comparisons have not been made, BD has been associated with impairments in top-down executive control (related to frontal-parietal regions) and HD has been linked to bottom-up changes in internal mentation (related to the default mode network anatomical structure and function). This dissertation compares the two drinking patterns with the goal of testing for differential neurocognitive and neuroanatomical characteristics that would be indicative of two disorder subtypes. METHODS: The sample consisted of adult participants with a history of adolescent onset: BD (N = 16), HD (N = 15), and Healthy Controls (HC; N = 21). All groups were equated on age, education, amount of lifetime alcohol consumed (BD and HD groups), as well as other factors. The study compared group performance on an affective go/no go task and group differences in brain volume and cortical thickness based on structural MRI. RESULTS: Behavioral results showed a higher number of errors for the HD group, in comparison to other groups. Volumetric results indicated a smaller bilateral ventral diencephalon in both BD and HD, in comparison to the HC, and smaller bilateral globus pallidus in BD only. Cortical thickness analyses revealed a thinner left superior parietal region (overlapping with the dorsal attention and fronto-parietal networks) in BD, whereas a left medial occipito-parietal region was thicker in HD (overlapping mainly with the visual network). CONCLUSION: These data, interpreted in the context of prior studies, suggest that BD findings might be indicative of an executive control dysregulation that could contribute to continued BD. HD findings might be indicative of tissue damage due to frequent drinking. Prior research has found the occipital region to have the highest concentration γ-Aminobutyric acid receptors that are affected by alcohol, which might explain the thicker occipital region findings in the HD group

Translating Preclinical Models of Alcohol Seeking and Consumption into the Human Laboratory using Intravenous Alcohol Self-Administration Paradigms

Preclinical models of Alcohol Use Disorder (AUD) have advanced theoretical, mechanistic, and pharmacological study of the human condition. “Liking” and “wanting” behaviors reflect core processes underlying several models of AUD. However, the development and application of translational models of these preclinical approaches are at an incipient stage. The goal of this study was to examine how intravenous free-access and progressive-ratio, operant-response human alcohol self-administration paradigms can be used as translational human model parallel of preclinical “liking” and “wanting”. Participants were 40 adults (Mean age=23.7, SD=2.0; 45% Female) of European descent who reported 12.6 drinking days (SD=5.2) out of the previous 30 (average= 4.1 drinks/drinking day (SD=1.7)). Individuals diverged in their alcohol self-administration behavior, such that free-access and progressive-ratio paradigm outcomes were not significantly correlated (p=.44). Free-access alcohol seeking was related to enjoying alcohol (p.70) to preferred level of breath alcohol concentration (BrAC) in the free-access session, a measure of liking alcohol. Family history of alcoholism, disinhibition traits, and recent drinking history were significantly related (p’s<.05) to alcohol seeking in the progressive-ratio paradigm, a measure of wanting alcohol. We conclude that intravenous alcohol self-administration paradigms show promise in modeling behaviors that characterize and parallel alcohol “liking” and “wanting” in preclinical models. These paradigms provide a translational link between preclinical methods and clinical trials