Mapping brain function associated with cue-reactivity and changes pre-to-post a mindfulness-based intervention in cannabis use disorder

Globally, cannabis is used by ~210 million people and 10-to-30% endorse symptoms consistent with a cannabis use disorder (CUD), which constitutes a substantial social burden including health and treatment services. CUD is characterised by a loss of control over cannabis consumption despite significant adverse outcomes including strong cravings when exposed to cannabis cues. Such outcomes have been (partly) ascribed to altered brain function in addiction related pathways. Preliminary functional magnetic resonance imaging (fMRI) evidence in cannabis users, show different brain activity when exposed to cannabis (vs neutral) cues, in prefrontal, striatal and parietal regions. However, no study has examined cannabis users with a DSM-5 diagnosis of CUD, or tested if psychological interventions targeting cravings (e.g., mindfulness-based interventions [MBI]) reduce neural cue-reactivity in CUD. This thesis comprises three studies aimed to examine brain activity during cannabis cue-reactivity in cannabis users and CUD, and whether such activity can be reduced with a MBI. Study 1 was a systematic review of the fMRI literature on brain function during cue-reactivity in cannabis users. It synthesised findings on brain function during fMRI cue-reactivity tasks (cannabis vs neutral stimuli) in regular cannabis users, and their association with behavioural variables (e.g., craving). Eighteen studies showed that cannabis users had greater activity in prefrontal, striatal, and parietal regions, some of which (orbitofrontal cortex [OFC]) correlated with and greater subjective craving. The literature was limited by the lack of assessment of CUD using the DSM-5 and the inclusion of a non-using control group. Study 2 aimed to examine differences in brain activity during a cue-reactivity task (cannabis vs neutral images), i) between 49 adults with moderate-to-severe CUD and 30 controls; and ii) their association with craving, cannabis exposure and mental health. CUD vs controls had greater activity in the lingual gyrus (FWE-corrected p 10), and in the MFG, medial OFC, and cerebellum (uncorrected, p 10). Greater MFG activity correlated with more past month cannabis grams. Overall, the findings from this thesis provide novel information on the current understanding of the neural correlates of cannabis cue-reactivity in CUD. The results of the first two studies suggest that CUD has a (partly) overlapping neurobiology with that of other SUDs as per prominent neuroscientific theories of addiction. Different brain function during cannabis cue-reactivity may reflect alterations in reward processing, including salience evaluation and attention pathways resulting from regular exposure to cannabis/related cues; or predating CUD. As such, interventions that target these regions may be effective at reducing cue-reactivity/craving in CUD. Study 3 was a double-blind fMRI experiment. It aimed to investigate for the first time if a brief MBI compared to both an active relaxation and passive no intervention placebo controls, reduces neural cue-reactivity in the regions of interest (ROIs) functionally different in Study 2 (i.e., MFG, OFC, lingual gyrus and cerebellum), in the same sample with CUD (N = 40). It also explored if changes in brain activity pre-to-post MBI were associated with changes in behaviour. It was hypothesised that the greater activity in the ROIs would significantly decrease pre-to-post the MBI only. A significant decrease in the activity of the OFC was observed pre-to-post all three interventions, as well as in subjective craving and arousal rating of cannabis images. No correlations emerged. Overall, the findings from the research in this thesis demonstrates that cannabis cue-reactivity in CUD is associated with different activity in selected brain pathway implicated in salience and reward processing; and the activity of some of these regions (e.g. OFC) can be reduced during a brief engagement with monitoring of daily cannabis use, cravings and mood. More research in larger samples is required to identify with precision the neurobiology of cannabis cue-reactivity in CUD and to reduce these with novel interventions. Such new knowledge is necessary to alleviate the harmful impacts of the increasing prevalence of CUD to both the individual and to society, particularly when cannabis products and related cues are increasingly accessible and visible to vulnerable members of the community

Show me your face and I will tell you your height, weight and body mass index

International audienceBody height, weight, as well as the associated and composite body mass index (BMI) are human attributes of pertinence due to their use in a number of applications including surveillance, re-identification, image retrieval systems, as well as healthcare. Previous work on automated estimation of height, weight and BMI has predominantly focused on 2D and 3D full-body images and videos. Little attention has been given to the use of face for estimating such traits. Motivated by the above, we here explore the possibility of estimating height, weight and BMI from single-shot facial images by proposing a regression method based on the 50-layers ResNet-architecture. In addition, we present a novel dataset consisting of 1026 subjects and show results, which suggest that facial images contain discriminatory information pertaining to height, weight and BMI, comparable to that of body-images and videos. Finally, we perform a gender-based analysis of the prediction of height, weight and BMI

Interaction between Dysfunctional Connectivity at Rest and Heroin Cues-Induced Brain Responses in Male Abstinent Heroin-Dependent Individuals

BACKGROUND: The majority of previous heroin cue-reactivity functional magnetic resonance imaging (fMRI) studies focused on local function impairments, such as inhibitory control, decision-making and stress regulation. Our previous studies have demonstrated that these brain circuits also presented dysfunctional connectivity during the resting state. Yet few studies considered the relevance of resting state dysfunctional connectivity to task-related neural activity in the same chronic heroin user (CHU). METHODOLOGY/PRINCIPAL FINDINGS: We employed the method of graph theory analysis, which detected the abnormality of brain regions and dysregulation of brain connections at rest between 16 male abstinent chronic heroin users (CHUs) and 16 non-drug users (NDUs). Using a cue-reactivity task, we assessed the relationship between drug-related cue-induced craving activity and the abnormal topological properties of the CHUs' resting networks. Comparing NDUs' brain activity to that of CHUs, the intensity of functional connectivity of the medial frontal gyrus (meFG) in patients' resting state networks was prominently greater and positively correlated with the same region's neural activity in the heroin-related task; decreased functional connectivity intensity of the anterior cingulate cortex (ACC) in CHUs at rest was associated with more drug-related cue-induced craving activities. CONCLUSIONS: These results may indicate that there exist two brain systems interacting simultaneously in the heroin-addicted brain with regards to a cue-reactivity task. The current study may shed further light on the neural architecture that supports craving responses in heroin dependence

Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 314)

This bibliography lists 139 reports, articles, and other documents introduced into the NASA scientific and technical information system in August, 1988

Multi-neuroimaging model of identifying neuroplasticity under motor cognitive learning condition: MRI based study.

Motor learning is a fundamental ability and one of the most robust models to study neural plasticity. The majority of human motor learning imaging studies focused on either short-term or long-term learning using one single imaging modality. These studies were thus not able to systematically investigate the dynamic process of motor learning from a multimodal perspective. The current project combined both short-term and long-term motor learning to comprehensively characterize neural plasticity at multiple phenotypic levels of the brain: functional activation, functional connectivity, grey matter volume, and glutamate concentration. To this end, this project involved a cross-sectional and a longitudinal study with multimodal brain imaging techniques (task fMRI, resting-state fMRI, gray matter structural fMRI, pharmacological fMRI, and MRS). Short-term motor learning was significantly correlated with brain network features related to network efficiency. It was also associated with a highly reliable cerebellum-centered network which was significantly modulated by the NMDA antagonist ketamine. Long-term motor learning was associated with increased activation in premotor / SMA and parietal regions and with increased gray matter volume of the SMA and the hippocampus. In addition, long-term motor learning was accompanied by a decrease in the functional connectivity of a network centered on the sensorimotor cortex which was related to handknob glutamate concentration levels and which involved regions that were highlighted by our activation and structural analyses. Taken together, this thesis contributes important evidence to the neurofunctional and neurostructural underpinnings of motor learning and points to the critical roles of the cerebellum, the hippocampus and the relevance of glutamate for motor learning in humans