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Life Enrichment through Sensation
Published in Lisa D. Hinz, Beyond Self-Care for Helping Professionals, 2018
There are many benefits of using art in ways that emphasize its sensual aspects. Using art, people can be immersed in tactile or visual sensation as a way to feel centered and calm. The rhythmic stroking of clay, for example, can slow down the thoughts that seem to continuously crowd people’s minds, allowing for a time of focused calm. Research in the neuroscience of human experience demonstrates that several large-scale brain networks dominate brain functioning; the two most applicable here are the Default Mode Net work (DMN) and the Direct Experience Network (DEN). Functional magnetic resonance imaging (fMRI) studies show that when people are not active, meaning they are daydreaming, the medial prefrontal cortex (involved in the valuation of stimuli) and the hippocampus (involved with memory) work in conjunction to produce self-referential thought. The DMN has been called the “narrative network” (Bressler & Menon, 2010) because it provides the stream of self-referential internal dialogue that characterizes thoughts when people are not occupied. These thoughts tend to be self-focused and often self-critical.
Pharmacological Therapy for Neurobehavioural Disability
Published in Tom M. McMillan, Rodger Ll. Wood, Neurobehavioural Disability and Social Handicap following Traumatic Brain Injury, 2017
Richard Greenwood, Simon Fleminger
Over the last 25 years pre-clinical studies have demonstrated that TBI results in catecholamine (epinephrine, norepinephrine and dopamine) and cholinergic depletion, and disordered serotoninergic, GABAergic or glutamatergic transmission, and have begun to define the structure and function of the large scale brain networks and the neurotransmitters that underpin arousal, speed of processing, rewardability, apathy and motivation, mood, working memory and attentional skills, executive function, self-regulation, and learning and plasticity (Sharp et al., 2014; Yan et al., 2015; Shin & Dixon, 2015). Specific drug treatments, and latterly invasive and non-invasive brain stimulation, have at times been shown to result in improvement of both impairment and function (Kim et al., 2012; Fridman & Schiff, 2014).
Resting-State and Structural Brain Connectivity in Individuals with Stimulant Addiction
Published in Hanna Pickard, Serge H. Ahmed, The Routledge Handbook of Philosophy and Science of Addiction, 2019
Anna Zilverstand, Rafael O’Halloran, Rita Z. Goldstein
Addiction is a complex disease process, encompassing a relapsing cycle of intoxication, bingeing, withdrawal and craving. While neuroimaging studies describing brain functioning at the level of single brain regions have decisively shaped our understanding of each of these stages, the importance of moving beyond this approach and investigating how brain regions assemble into brain networks, which support complex psychological processes such as reward seeking or inhibitory self-control, has long been recognized (Goldstein and Volkow 2002; Koob and Volkow 2010; Goldstein and Volkow 2011). In recent years, numerous studies have therefore started to explore the role of disrupted brain networks in addiction by investigating structural and functional connectivity between and within these large-scale brain networks. Neuroimaging can be used to evaluate structural brain connectivity through ‘diffusion-weighted imaging’, which can assess the integrity of the white matter tracts (comprised of nerve cell projections) connecting brain regions to one another. Second, functional neuroimaging can be employed to compute the strength of ‘functional connectivity’, which uses co-activation of brain regions as an indicator of shared neuronal activity between them (Shmuel and Leopold 2008). The latter is usually acquired during resting-state, a baseline state in which the brain is not actively involved in a task and drugs have not been administered. Resting-state functional connectivity therefore captures a default brain state independent of external input/challenges, providing insight into the intrinsic ‘functional architecture’ of the brain that underlies functioning during task demands (Fox and Raichle 2007). Both structural and resting-state neuroimaging are therefore useful tools for understanding the fundamental makeup of the brain and assessing how this is changed in addiction.
Social dysfunction is transdiagnostically associated with default mode network dysconnectivity in schizophrenia and Alzheimer’s disease
Published in The World Journal of Biological Psychiatry, 2022
Ilja M. J. Saris, Moji Aghajani, Lianne M. Reus, Pieter-Jelle Visser, Yolande Pijnenburg, Nic J. A. van der Wee, Amy C. Bilderbeck, Andreea Raslescu, Asad Malik, Maarten Mennes, Sanne Koops, Celso Arrango, Jose Luis Ayuso-Mateos, Gerard R. Dawson, Hugh Marston, Martien J. Kas, Brenda W. J. H. Penninx
Our post hoc analyses did not find any significant links between social dysfunction and SN or CEN connectivity (P’s>0.05, Bonferroni corrected), which was performed to probe the specificity of DMN disintegrity to social dysfunction. This is somewhat in contrast to current literature on large-scale networks and human behaviour or neuropsychiatry (Menon 2011). The triple network model of psychopathology, for instance, postulates that an imbalance within or between large-scale brain networks could derail key cognitive and emotional processes. Specifically, the SN mainly seems to serve as a crucial switch from the internal oriented DMN with the more externally oriented CEN (Menon 2011; Uddin 2015; Seeley 2019). Whereas the DMN is directly linked to self-related and social processes, the SN seems to differentiate between internal and extra personal stimuli in order to guide (social) behaviour. While the roles of the SN and CEN are notable in adaptive behavioural processes, findings from current and prior research indicate that the DMN is highly specific for social dysfunction. This is most convincingly illustrated in the massive UK Biobank study (N∼38000) where there was a link between impaired social behaviour and the DMN, but no other brain network (Spreng et al. 2020).
What have we learned from past failures of investigational drugs for Alzheimer’s disease?
Published in Expert Opinion on Investigational Drugs, 2021
Bruno P. Imbimbo, Mark Watling
Functional magnetic resonance imaging (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. Functional connectivity is defined as the temporal dependency of neuronal activation patterns in anatomically separated brain regions. Cognitive tasks are performed not by individual brain regions working in isolation but by networks consisting of different brain regions that are functionally connected [64]. Large-scale brain networks are collections of widespread brain regions showing functional connectivity [65]. fMRI studies in subjects with mild cognitive impairment (MCI) and in AD patients have revealed abnormalities in large-scale memory and cognitive brain networks. A number of fMRI studies have focused on the medial temporal lobe (MTL), a site of very early pathology in AD [66]. Other fMRI studies have identified abnormalities early in AD in the frontal, temporal, and parietal cortices. Functional hypoactivation has been documented in brain regions with marked pathology and atrophy. However, there are also areas of hyperactivation in brain memory and cognitive circuits, possibly representing compensatory responses. Resting state functional connectivity has been shown to be impaired in cognitively normal subjects with preclinical ADAD [67] and may be of value in the near future to monitor ‘global’ effects of therapeutic candidates in both early and late stages of AD.
Transcranial magnetic stimulation and neuroimaging for cocaine use disorder: Review and future directions
Published in The American Journal of Drug and Alcohol Abuse, 2021
Yong Shen, Heather Burrell Ward
There is a large body of literature describing the brain regions responsible for substance use disorders, including the mesolimbic pathway (7,8), prefrontal cortex (9,10), and insula (11–13). Brain regions are organized into functional networks that interact to perform tasks (14,15). These large-scale brain networks can be identified by measuring changes in blood-oxygen-level-dependent (BOLD) signal using functional MRI (fMRI). The intrinsic connectivity of these networks can be measured when the brain is at rest without any interference from the external environment (16). Functional connectivity refers to the temporal coherence of the BOLD signal within or between networks at rest and is the degree to which the brain regions in networks function synchronously. The salience network has been extensively implicated in substance use disorders and other psychiatric disorders (17). This network comprises the dorsal anterior cingulate cortex (dACC), bilateral anterior insula, dorsolateral prefrontal cortex (DLPFC), inferior parietal lobule, head of the caudate nucleus, mediodorsal nucleus of the thalamus, and dopaminergic brainstem nuclei (18).