Cannabis Use Linked to Altered Functional Connectivity of the Visual Attentional Connectivity in Patients With Psychosis and Controls

Sami, Musa; McCutcheon, Robert; Williams, Steve; Lythgoe, Dave; McGuire, Philip; Bhattacharyya, Sagnik

doi:10.1093/schizbullopen/sgaa018

Cited by 10 publications

(5 citation statements)

References 53 publications

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“…This broad pattern of hyperconnectivity was also paralleled by moderate reductions of functional connectivity between remaining network edges. The prime finding of hyperconnectivity across the whole brain connectome of chronic cannabis users adds to findings of previous imaging studies showing increased functional connectivity in subcortical and frontal regions 33 , 37 , 68 or between those regions 34 – 36 . The present study, however, suggests that functional hyperconnectivity in chronic cannabis users is not restricted to local brain circuits but can be observed across the entire whole brain connectome.…”

Section: Discussionsupporting

confidence: 75%

Functional brain connectomes reflect acute and chronic cannabis use

Ramaekers

Mason

Toennes

et al. 2022

Sci Rep

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Resting state fMRI has been employed to identify alterations in functional connectivity within or between brain regions following acute and chronic exposure to Δ9-tetrahydrocannabinol (THC), the psychoactive component in cannabis. Most studies focused a priori on a limited number of local brain areas or circuits, without considering the impact of cannabis on whole-brain network organization. The present study attempted to identify changes in the whole-brain human functional connectome as assessed with ultra-high field (7T) resting state scans of cannabis users (N = 26) during placebo and following vaporization of cannabis. Two distinct data-driven methodologies, i.e. network-based statistics (NBS) and connICA, were used to identify changes in functional connectomes associated with acute cannabis intoxication and history of cannabis use. Both methodologies revealed a broad state of hyperconnectivity within the entire range of major brain networks in chronic cannabis users compared to occasional cannabis users, which might be reflective of an adaptive network reorganization following prolonged cannabis exposure. The connICA methodology also extracted a distinct spatial connectivity pattern of hypoconnectivity involving the dorsal attention, limbic, subcortical and cerebellum networks and of hyperconnectivity between the default mode and ventral attention network, that was associated with the feeling of subjective high during THC intoxication. Whole-brain network approaches identified spatial patterns in functional brain connectomes that distinguished acute from chronic cannabis use, and offer an important utility for probing the interplay between short and long-term alterations in functional brain dynamics when progressing from occasional to chronic use of cannabis.

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Section: Discussionsupporting

confidence: 75%

Functional brain connectomes reflect acute and chronic cannabis use

Ramaekers

Mason

Toennes

et al. 2022

Sci Rep

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“…Results revealed increased connectivity in the dorsal attention network ( P = 0.019) and visual dorsal attention internetwork ( P = 0.036) in cannabis consuming patients compared to nonusing controls. Interestingly, however, there was no significant difference between patients with cannabis usage and patients without cannabis usage in terms of connectivity [ 34 ]. Given that the current state of literature on the effect of cannabis consumption on connectivity in SCZ patients points toward mixed results, further research is warranted.…”

Section: Environmental Factors Implicated In Synaptic Pruningmentioning

confidence: 99%

Abnormal synaptic pruning during adolescence underlying the development of psychotic disorders

Germann

Brederoo²,

Sommer

2021

Current Opinion in Psychiatry

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Purpose of review Excessive synaptic pruning has first been suggested by Irwin Feinberg (1982) as an important pillar in the pathophysiology in schizophrenia (SCZ). This article reviews recent developments highlighting factors implicated in aberrant synaptic pruning and its contribution to disease onset and emergence of cognitive symptoms in SCZ. Unraveling these factors provides new insights for potential prevention and treatment strategies for psychotic disorders. Recent findings Increased pruning in SCZ was recently confirmed by a positron emission tomography-study employing the novel tracer [11C]UCB-J, demonstrating the consequential loss of synaptic density. Recent evidence supports the contributing role of astrocytes and increased complement-mediated microglial pruning in disease onset and cognitive symptoms in SCZ. Increased microglial pruning is mediated specifically by C4. Furthermore, environmental factors (e.g., infections and stress) can lead to dysbiosis which was recently linked to microglial activation and pruning in SCZ. Summary Recent findings render the pruning machinery a potential target for early treatment and prevention in individuals at high risk for SCZ. Minocycline can improve cognition in SCZ, probably by reducing excessive pruning. Probiotics might also have beneficial effects on cognition, although recent findings are not encouraging. N-acetyl-cysteine recovers functional connectivity in SCZ both in vitro and in vivo, making it an interesting candidate.

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“…Weaker long-range connectivity (i.e., fewer/weaker connections between high GE nodes) of the DAN has been associated with inattention and impulsivity in children with attention-deficiency/hyperactivity disorder (ADHD) [84]. In addition, the increased connectivity of the DAN and VN has been observed in chronic cannabis users, and DAN connectivity was found to be positively correlated with the severity of cannabis use in adults [85]. To date, we did not find any literature connecting DAN topology and alcohol use in the context of rs-fMRI analyses; however, the study by Sami and colleagues implicated aberrant DAN connectivity with cannabis misuse, thus identifying the DAN as a target for future substance and alcohol abuse studies.…”

Section: Discussionmentioning

confidence: 99%

Differences in Brain Network Topology Based on Alcohol Use History in Adolescents

Kirse,

Bahrami,

Lyday

et al. 2023

Brain Sciences

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Approximately 6 million youth aged 12 to 20 consume alcohol monthly in the United States. The effect of alcohol consumption in adolescence on behavior and cognition is heavily researched; however, little is known about how alcohol consumption in adolescence may alter brain function, leading to long-term developmental detriments. In order to investigate differences in brain connectivity associated with alcohol use in adolescents, brain networks were constructed using resting-state functional magnetic resonance imaging data collected by the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA) from 698 youth (12–21 years; 117 hazardous drinkers and 581 no/low drinkers). Analyses assessed differences in brain network topology based on alcohol consumption in eight predefined brain networks, as well as in whole-brain connectivity. Within the central executive network (CEN), basal ganglia network (BGN), and sensorimotor network (SMN), no/low drinkers demonstrated stronger and more frequent connections between highly globally efficient nodes, with fewer and weaker connections between highly clustered nodes. Inverse results were observed within the dorsal attention network (DAN), visual network (VN), and frontotemporal network (FTN), with no/low drinkers demonstrating weaker connections between nodes with high efficiency and increased frequency of clustered nodes compared to hazardous drinkers. Cross-sectional results from this study show clear organizational differences between adolescents with no/low or hazardous alcohol use, suggesting that aberrant connectivity in these brain networks is associated with risky drinking behaviors.

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Cannabis Use Linked to Altered Functional Connectivity of the Visual Attentional Connectivity in Patients With Psychosis and Controls

Cited by 10 publications

References 53 publications

Functional brain connectomes reflect acute and chronic cannabis use

Functional brain connectomes reflect acute and chronic cannabis use

Abnormal synaptic pruning during adolescence underlying the development of psychotic disorders

Differences in Brain Network Topology Based on Alcohol Use History in Adolescents

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