Physiology of the Pain System
Sahar Swidan, Matthew Bennett in Advanced Therapeutics in Pain Medicine, 2020
The limbic system is a set of brain structures on either side of the thalamus that directs emotion, behavior, motivation, long-term memory, and olfaction. The mesolimbic pathway is part of the reward circuit. Dopaminergic neurons in the ventral tegmental area (VTA) of the midbrain project to the forebrain nucleus accumbens (NAc). Burst firing of dopaminergic neurons into the NAc serves as a reward signal and is inhibited by tonic GABA input.15 Opioids inhibit GABAergic tone on these neurons, while pain relief directly engages dopamine circuitry.15 The mesolimbic pathway has been implicated in depression, anxiety, pain sensation, anticipation of analgesia or placebo-induced analgesia, and chronic pain.16 Different types of pain can impact different aspects of the VTA and result in either activation or inhibition. In this way, dopamine release is variable based on various pain signals.16 These dopaminergic pathways are variably altered with stress as well as opioids. Dynorphin and the kappa opioid receptor can play a role in impairing dopamine release in the Na.16
Impact of Drugs and Alcohol on the Brain Through the Life Cycle: Knowledge for Social Workers
Richard T. Spence, Diana M. DiNitto, Shulamith Lala Ashenberg Straussner in Neurobiology of Addictions, 2014
Why should stress have an impact on the brain? Research has clearly established that stress hormones, such as glucocorticoids, contribute to the maturation of selective neurons of the emotional centers in the brain, known as the Limbic System. The Limbic System is that part of the brain involved in emotional expression (e.g., mood, aggression, anger). Rats exposed prenatally to glucocorticoids have 80% larger serotonin cell bodies for producing serotonin, which form more elaborate dendritic branches (Azmitia, Liao, & Chen, 1993). The more branches a neuron has, the more connections it seeks to make. Thus, exposure to stress steroids, especially in children, can alter the balance of brain connections by producing an increased demand for new connections within the limbic system. This can influence the activity of these brain centers, by either increasing the number of inhibitory or excitatory connections. Thus, a child exposed to stress may be unusually quiet and withdrawn, or hyperactive and aggressive.
Application of the neuropsychological evaluation in vocational planning after brain injury
Robert T. Fraser, David C. Clemmons in Traumatic Brain Injury Rehabilitation, 2017
Beneath the cerebral cortex lie other brain structures that are relevant to this discussion of brain physiology in traumatic brain injury. Immediately underneath the cortex is an important structure known as the limbic system (Figure 5). This system is connected to the brain stem, which will be discussed later. There are a number of specific structures that make up the limbic system including the amygdala, hippocampus, basal ganglia, septum, fornix, cingulate gyrus, and parts of the anterior thalamus, and the hypothalamus. The limbic system is considered a deeper brain structure and may be considered a more primitive part of the brain from an evolutionary perspective. This is because the limbic system appears to be similar in all mammals. This system is essential for regulating emotion, initially storing and manipulating information, and distributing information to recent verbal and visual memory. It is also responsible for different components of body movements. It is termed a system because the structures of the limbic system work as a whole with higher level cortical structures in a highly interconnected way.
Drug treatment strategies for depression in Parkinson disease
Published in Expert Opinion on Pharmacotherapy, 2019
Melody Ryan, Courtney V. Eatmon, John T. Slevin
The classical pathophysiology of PD primarily concerns the area of the brain known as the basal ganglia. The basal ganglia (BG) is composed of the striatum, globus pallidus, ventral pallidum, substantia nigra, and subthalamic nucleus. It has extensive connections with the cerebral cortex, thalamus, and brainstem. The motor function of the BG is well documented and the amygdala and striato-pallidal circuits are likely involved in the cognitive and emotional/motivational functions of this area [36,37]. More of the emotional components of the brain such as the limbic system are likely involved in the depression and cognitive dysfunction that may accompany PD. The limbic system consists of many structures, including some areas of the cortex such as the hippocampus, some subcortical areas such as the amygdala and the nucleus accumbens, the hypothalamus with its connections to the reticular formation and the thalamus, and the anterior nuclei of the thalamus. The limbic system is involved in learning, memory, emotion, and motivation. The amygdala receives projections from the thalamus and, indirectly, from the cortex [38]. In depression associated with PD, there are changes in brain structure and function and in neurotransmitters and cytokines within the brain.
Hypertension linked to allostatic load: from psychosocial stress to inflammation and mitochondrial dysfunction
Published in Stress, 2019
Feres José Mocayar Marón, León Ferder, Fernando Daniel Saraví, Walter Manucha
Of central interest for the present review, the brain is critical as a modulator and stress adapter organ (Karatsoreos & McEwen, 2011) and becomes essential for predictive regulation of the internal milieu (Sterling, 2014). Functions such as emotional processing, memory, cognition and, therefore, recognition and reaction to stress, are executed by the limbic system. The relevant circuit is composed of the telencephalon, the medial prefrontal cortex (mPFC), the amygdala and the hippocampus. The mPFC, amygdala, and hippocampus project their fibers and form an interconnected network of emotional and cognitive regulation (Herman et al., 2003). Output of these nuclei also converges on subcortical sites, primarily within anteroventral and posteroventral subregions of the bed nucleus of the stria terminalis (BST), distinct regions of the hypothalamus (e.g. lateral hypothalamic area, medial preoptic area, and posterior hypothalamus), and the brainstem (e.g. ventrolateral medulla, raphe nuclei, subfornical organ, locus coeruleus, and nucleus of the solitary tract -NTS-) (Ulrich-Lai & Herman, 2009). The hierarchical disposition allows the transduction of emotional stimuli in physiological reactions through synapses with sympathetic and parasympathetic preganglionic neurons (Myers, 2017). The prefrontal cortex integrates several inputs arriving from neocortical and limbic structures – and feeds back to both (Sterling, 2012).
An examination of motives for tramadol and heroin use in an Egyptian sample
Published in Journal of Addictive Diseases, 2018
Momtaz Ahmed AbdelWahab, Samir Fouad Abou el Magd, Christine E. Grella, Dalia Ahmed Enaba, Reham Abdel Maqsoud
Tramadol is a centrally acting analgesic with a dual mechanism of action on opioid receptors and on pain-inhibitory pathways in the spinal cord by stimulating serotonin receptors and blocking reuptake of serotonin and norepinephrine. This precipitates release of dopamine into the limbic system and thus promotes addiction due to the reinforcing effects.3–6 Tramadol elicits antidepressant-like effects in mice and rats.7–11 In clinical practice, tramadol is often preferred for treatment of pain because it presents a lower risk for addiction and respiratory depression compared to other opioids.12 Tramadol is also used to treat psychiatric disorders such as refractory major depression,13 severe suicidal ideation and antidepressant potentiation,14 and anxiety and obsessive-compulsive disorders.15 Many experimental studies have proven the efficacy and safety of tramadol as a treatment of premature ejaculation.16 Tramadol also increases the patients’ satisfaction with sexual intercourse.17 Because of its short half-life, tramadol can be used with an on-demand dosing protocol for treatment of sexual dysfunction.18–20
Related Knowledge Centers
- Amygdala
- Emotion
- Forebrain
- Cerebrum
- Temporal Lobe
- Brain
- Thalamus
- Long-Term Memory
- Sense of Smell
- Mammillary Body