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Drug use from adolescence to later years: Persistence or progress?
Published in Ilana B. Crome, Richard Williams, Roger Bloor, Xenofon Sgouros, Substance Misuse and Young People, 2019
Roy Robertson, Saket Priyadarshi, James Robertson
Young brains are still changing as ‘synaptic pruning’ continues into early adulthood. This makes the possibility for long-term negative effects of substance involvement even more likely and goes some way to explaining why risk-taking is prevalent during these years (Brown and Tapert, 2004; Wetherill and Tapert, 2013). Whether or not drug-taking initiated in adolescence causes permanent structural brain damage remains unclear, but some evidence indicates that this might be true for cannabis users (Meier et al., 2012). Similar findings from brain imaging of people with schizophrenia suggest the possibility of permanent, progressive changes (Watson et al., 2012; Prestia et al., 2015).
Development and Developmental Disorders
Published in Andrei I. Holodny, Functional Neuroimaging, 2019
The subsequent process of synaptic pruning, a systematic reduction in the number of synapses, increases the functional maturity of specific brain regions. The more effective and important connections are maintained, while superfluous connections are eliminated. This process takes place rapidly in certain cortical regions (i.e., visual cortex), but is much more prolonged in others (i.e., prefrontal cortex, where logical processing and key elements of personality develop), extending into adolescence (14).
Adolescence and young adult mental health
Published in Mary Steen, Michael Thomas, Mental Health Across the Lifespan, 2015
The development of the brain and connections between brain regions during adolescence can be defined as being one of immense change (Dahl and Spear, 2004; Fair et al., 2009; Kelly et al., 2009; Lenroot and Giedd, 2010; Paus, 2010; Steinberg, 2008; Supekar et al., 2009). By way of synaptic pruning, the brain facilitates the neural structure to develop more efficient, focused and specialised systems (Fair et al., 2008, 2009; Luna et al., 2010). Pruning refers to the overall reduction of the neuronal and synaptic connections within the brain. This process is important in facilitating ‘top-down’ executive thinking over ‘bottom-up’ reactive thinking (Casey et al., 2008; Ernst et al., 2005; Hwang et al., 2010). It is thought to be critical in the processes of learning and can be influenced by factors in the environment (Craik and Bialystock, 2006).
Datumetine exposure alters hippocampal neurotransmitters system in C57BL/6 mice
Published in Drug and Chemical Toxicology, 2022
Azeez Olakunle Ishola, Aminu Imam, Moyosore Salihu Ajao
Increased excitatory transmission leads to synaptic pruning (Henson et al.2017, Inquimbert et al.2018) to regulate brain activities. The neural connection was assessed using expansion microscopy techniques stained for neurofilament. Datumetine induces loss of neural connections in all regions of the hippocampus. This may be due to the increased excitatory transmission (Sattler et al.1999, Dong et al.2009, Zhou et al.2013) induced by datumetine. Glia cells also play a major role in synaptic pruning (Paolicelli et al.2011, Li et al.2012b), as stated earlier datumetine exposure increased the activities of glia. This together showed that prolong exposure of datumetine increased NMDAR activities leading to hyperexcitation in the hippocampus.
A preliminary study of atypical cortical change ability of dynamic whole-brain functional connectivity in autism spectrum disorder
Published in International Journal of Neuroscience, 2022
The GMV, CT and surface area (SA)are important morphological methods of cortical anatomy. Generally, the GMV is the product of SA and CT. Indeed, cortical anatomy reflects the density, size, and arrangement of neuroglia, neurons, and nerve fibers. Evidence from developmental diseases suggests that abnormal synaptic pruning and neuronal loss at microcosmic level, further, awry neural circuit wiring (excitatory/inhibitory balance) at mesoscopic level will give rise to full-down anomaly of cortical structure at macroscopic perspective [40]. Further, as the radial unit of functional column hypothesis [41], the CT mirrors the number of the neurons within a column, the SA mirrors the number of columns however [42, 43]. The structures shape patterns of spontaneous functional activity. Meanwhile, disease-specific neuroanatomical changes will lead to specially disordered activity signals. The fMRI data are endowed with the general characteristics of multiple dimensions, short-time, and synchronous-like fluctuations. The signal activity indices, such as fALFF, ReHo, entropy and frequency spectrum, are focused on time and frequency domains of time series [19].
Levels of lymphocyte-associated regulators of complement system CD55 and CD59 are changed in schizophrenia patients
Published in International Journal of Psychiatry in Clinical Practice, 2021
Alper Togay, Bilge Togay, Deniz Ozbay Gediz, Sadıka Halide Akbaş, Sadi Köksoy
Genome-wide association studies on schizophrenia detected a strong association with loci in the MHC region (Ripke et al. 2014), which was confirmed by later studies with larger sample sizes (Li et al. 2017; Pardiñas et al. 2018). Further studies demonstrated that this association may be explained by the involvement of the complement system and specifically by the complement factor 4A (C4A) (Sekar et al. 2016). The classical complement cascade is important for the synaptic refinement and pruning in the developing central nervous system, and inhibition of C4 results in reduced synaptic pruning in mice (Sekar et al. 2016). Since synaptic pruning is also altered in schizophrenia (Wang et al. 2019), many studies were conducted to reveal the role of immune system genes in the disease (Li et al. 2017; Sanders et al. 2017; Pardiñas et al. 2018). In a recent study, Sager et al. (2020) reported that CD46 and CD55 were increased in the human prefrontal cortex in the first 5 years of life, suggesting that dysregulation of complement system may predispose the brain to neurodevelopmental disorders such as schizophrenia. However, the involvement of immune system in the disease aetiology and pathology is still not well understood.