Theories of Tobacco Addiction
Rajmohan Panda, Manu Raj Mathur in Tobacco Cessation, 2019
Our brains are wired to ensure that we will repeat life-sustaining activities by associating those activities with pleasure or reward. Whenever this reward circuit is activated, the brain notes that something important is happening that needs to be remembered, and teaches us to do it again and again. The “rewarding” effect of nicotine is attributed to its ability to activate the dopaminergic pathways projecting from the ventral tegmental area of the midbrain to the cerebral cortex and the limbic system.1,5,6 The increase in dopamine in the nucleus accumbens is mediated by receptors in cell bodies in the ventral tegmental area (VTA). Food, for example, stimulates reward via the VTA which leads to dopamine overflow in the nucleus accumbens, which leads to pleasure. The “amount” of pleasure depends on how enjoyable the food is, and the degree of hunger. In comparison, nicotine acts directly on the cell bodies in the VTA resulting in a sustained response. When tobacco is used, it can release 2–10 times the amount of dopamine that natural rewards, such as eating and sex, do. In some individuals, this occurs almost immediately (as when nicotine is smoked), and the effects can last much longer than those produced by natural rewards. The resulting effects on the brain's pleasure circuit dwarf those produced by naturally rewarding behaviors. The effect of such a powerful reward strongly motivates people to smoke again and again.4–6
The Deep Brain Connectome
Yu Chen, Babak Kateb in Neurophotonics and Brain Mapping, 2017
The basal ganglia are a set of subcortical nuclei with strong recurrent connections between the cerebral cortex, the thalamus, and the brainstem. Abnormalities in basal ganglia circuitry have been implicated in a diverse set of neurological and psychiatric disorders. These include movement disorders, such as Parkinson’s disease, Huntington’s disease, dystonia, and essential tremor; behavioral disorders, such as Tourette’s syndrome and obsessive–compulsive disorders; and psychiatric disorders such as schizophrenia, depression, and addiction (Ring and Serra-Mestres 2002). Many of these disorders have been treated by surgically targeting the basal ganglia using deep brain stimulation (DBS), pallidotomies, or thalamotomies. Consequently, a thorough understanding of the basal ganglia can provide insight not only into the functioning of the brain but also into the treatment of a number of neurological and psychiatric disorders. Recent advances in human brain mapping techniques offer to advance our understanding significantly by generating detailed connectivity maps of the entire brain—the connectome. The deep brain connectome, the wiring diagram of the basal ganglia, its projections, and adjacent white matter tracts, will provide a number of insights into the diagnosis and surgical treatment of basal ganglia disorders. This chapter will review the reasons for studying the deep brain connectome, the current approaches for analyzing the connectome, and the potential of the deep brain connectome for advancing the surgical treatment of basal ganglia disorders.
Mesolimbic Interactions with Mesopontine Modulation of Locomotion
Peter W. Kalivas, Charles D. Barnes in Limbic Motor Circuits and Neuropsychiatry, 2019
Two regions where interaction seems most evident are the medial striatum at the telencephalic level, indicated by the stippled region between the striatum and the NAc where dopaminergic (DAergic) terminals from the VTA and SNc overlap, and the PPN in the rostral brain stem which receives afferents from both systems. Also included are the zona incerta (ZI) and the substantia nigra pars reticulata (SNr) which appear to parallel the projections from the SubP and pallidal regions to the PPN, respectively. Similar to the cerebral cortex, which has input to the motor system at several sites down to the level of the MED and spinal cord, limbic system structures also influence the motivation system at every level down to the PPN (Figure 2).
Stretching beyond our perceived boundaries: The role of speech-language pathology in realising autonomy through supported decision-making
Published in International Journal of Speech-Language Pathology, 2023
This article has explored how the concepts of autonomy and decision-making capacity can be reconceptualised for people with PIMD by drawing on emerging developments in neuroscience, consciousness, and relational autonomy. The cerebral cortex has historically assumed to be the seat of conscious action, while the brain stem has been seen to be responsible for performing automatic/unconscious functions. As it is the cortex that is typically damaged for people with PIMD, based on these assumptions there is a long-held hypothesis that these people lack the ability to engage in conscious action, thought, and expressions of feelings and preferences. However, emerging developments in neuroscience that provide evidence that emotional consciousness and therefore a person’s emotional reactions to an experience are in the brainstem rather than the cerebral cortex refute this hypothesis, suggesting that people with PIMD can emotionally respond to experiences and therefore express preference. Where a person with PIMD needs support is in the cortical functions of making sense of these feelings and expressions of preference, by acknowledging them, interpreting, and then acting upon them. This is where the crucial role of the decision-making supporter comes to the fore.
Differences in the Level of Functional Fitness and Precise Hand Movements of People with and without Cognitive Disorders
Published in Experimental Aging Research, 2022
Rohan Anna, Fugiel Jarosław, Winkel Izabela, Lindner Karolina, Kołodziej Małgorzata, Sobieszczańska Malgorzata
People with cognitive impairment achieve worse results in hand coordination tests. The differences are significant in complex motor tests in which the motor activities require both speed and accuracy of hand movements.People with cognitive impairment do not differ significantly from people without impairment in terms of condition-based functional fitness: lower extremity strength, aerobic capacity and agility. The lack of differences applies to both gender groups.In the group of people with cognitive disorders, the differences in functional and fine motor skills compared to people without disorders are due to the involvement of different parts of the nervous system. Functional – more habitual activities are coordinated by areas at lower levels of the central nervous system, while the latter depend mainly on the function of the cerebral cortex.
Influence of smartphone addiction and poor sleep quality on attention-deficit hyperactivity disorder symptoms in university students: a cross-sectional study
Published in Journal of American College Health, 2022
Soo Jin Kwon, Yoonjung Kim, Yeunhee Kwak
Lastly, academic achievement, smartphone addiction, sleep disturbance, and daytime dysfunction were identified as factors significantly affecting the ADHD symptoms of university students. Students with low academic achievement may show high levels of ADHD symptoms, as attention, self-control, and decision-making may be problematic, causing various cognitive and learning difficulties.47 A review of a series of studies analyzing the effects of addiction to computers, smartphones, and games on brain functioning showed that this addiction induces functional deficits in the prefrontal area in the cerebral cortex.48 The prefrontal area is responsible for executive functioning, which is an essential cognitive function. Deficits in executive functioning cause problems with attention, self-control, and decision-making, resulting in various cognitive and learning difficulties, and ADHD is a representative disorder caused by executive functioning deficits.47 Individuals with smartphone addiction fail to focus on or sustain attention to a stimulus, showing symptoms similar to ADHD.14,19
Related Knowledge Centers
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