The basal ganglia plays a pivotal role in the brain’s reward circuit, which is responsible for feelings of pleasure and motivation. When drugs are used, the basal ganglia is overactivated, resulting in the euphoria commonly experienced during drug use. This heightened activation can reinforce drug-seeking behavior and contribute to addiction. The acute and chronic effects of ethanol on microcircuits can help reveal changes in local control of synapses that alter the output of key brain regions. As the majority of synapses in microcircuits are GABAergic, this research has focused mostly on changes in the effects of GABA. Some of the ethanol-induced changes in interneuron function and synaptic transmission were mentioned earlier in this review, and we will now focus on recent data from striatum and cerebellum.
What Are the Emotional and Behavioral Impacts of Addiction?
With repeated heavy drinking, however, tolerance develops and the ability of alcohol to produce pleasure and relieve discomfort decreases. Widely distributed in the brain, its general role is to activate the firing of neurons; it’s called an excitatory neurotransmitter. Glutamate helps mediate the rewarding effects of drugs of abuse and speeds the hard-wiring of substance response into the brain.
Genetic and Molecular Factors
- Ethanol generally potentiates cys-loop ligand-gated ion channels (LGICs) (e.g., GABAA and glycine receptors GlyRs) but inhibits ionotropic glutamate receptors (reviewed in Lovinger and Roberto, 2013; Söderpalm et al., 2017).
- Fentanyl is a synthetic opioid medication that is used for severe pain management and is considerably more potent than heroin.
- Thus, a top-down analysis indicated that ethanol’s effect on GABAA-mediated fast synaptic transmission was likely to be a fruitful area of study to better understand intoxication and high-dose ethanol actions.
• dopamine neurons, which are concentrated in the nucleus accumbent and form pathways of connection to other parts of the brain when activated by positive experiences. At first glance, the fact that addiction shifts the way the brain works lends credibility to the drug addiction treatment idea of a disease. However, the brain alterations reflect the normal capacity of the brain to change in response to experience.
In Summary: The Binge/Intoxication Stage and the Basal Ganglia
The process by which removal of a stimulus such as negative feelings or emotions increases the probability of a response like drug taking. Dr. Wakim is a board-certified psychiatrist with a passion for and expertise in addiction, mood disorders, trauma-related disorders and the subspecialty of interventional psychiatry. He obtained his medical degree from West Virginia University where he also completed his residency training, finishing as chief resident. Dr. Wakim co-founded and served as the CEO of Transformations leading to a successful merger with Shore Capital in May https://ecosoberhouse.com/ 2021. He is purpose driven towards improving the standard of and removing stigma related to behavioral healthcare.
This disruption leads to the euphoric effects of drug use, reinforcing the desire to use drugs again. The human body naturally produces its own opiate-like substances and uses them as neurotransmitters. These substances include endorphins, enkephalins, and dynorphins, often collectively known as endogenous opioids. Endogenous opioids are produced within the body and modulate our reactions to painful stimuli.
Figure 2.11
Many scientists think that this process contributes to the steady reduction in gray matter volume seen during adolescence (depicted as the yellow to blue transition in the figure). As environmental forces help determine which connections will wither and which will thrive, the brain circuits that emerge become more efficient. However, this is a process that can cut both ways because not all tasks are desirable. This interference with neurotransmitter function can result in overactivation or disruption of the brain’s reward system, which is responsible for feelings of pleasure and motivation.
What factors can impact brain health?
High amounts of alcohol use are causal risk factors in the development of disease in the heart, liver, pancreas, and brain (including the brains of children in utero). When it comes to adults, excessive alcohol use can cause multiple well-defined brain issues ranging from short-term confusion to dementia. As anyone who’s consumed alcohol knows, ethanol can directly influence brain function. Ethanol is classified as a “depressant” because it has a generally slowing effect on brain activity through activation of γ-aminobutyric acid (GABA) pathways.
- To understand how addictive substances affect the brain, it is important to first understand the basic biology of healthy brain function.
- Other studies also show that when an addicted person is given a stimulant, it causes a smaller release of dopamine than when the same dose is given to a person who is not addicted.
- Ethanol enhances GIRK channel function (Bodhinathan and Slesinger, 2013; Glaaser and Slesinger, 2017), and genetic studies have identified a 43-amino-acid C-terminal region that is crucial for this action of ethanol (Lewohl et al., 1999).
- On the other hand, the brain of a person not addicted to any substance has greater control over impulses and decision-making processes.
- Pleasure or euphoria—the high from drugs—is still poorly understood, but probably involves surges of chemical signaling compounds including the body’s natural opioids (endorphins) and other neurotransmitters in parts of the basal ganglia (the reward circuit).
Cognitive-behavioral therapy (CBT) and practices like mindfulness have been shown to aid in the rewiring of the brain, improving emotional regulation, decision-making, and impulse control. Detoxification helps manage the initial phase of stopping drug use by easing withdrawal symptoms. Medications like buprenorphine and methadone mimic the effects of opioids without producing the same high, allowing the brain to gradually adjust to the absence of the abused substance.
Why Do Individuals with Addiction Experience Cravings and Relapses?
In the following sections, we will consider the neurophysiological and behavioral effects of ethanol. The emphasis will be on the effects of ethanol in particular brain circuits and their ramifications for ethanol-related behaviors. Neuroplasticity is the brain’s natural ability to change its wiring patterns in response to life experience. When stimulated, nerve cells generate new tendrils of connection to other nerve cells, called synapses. All learning hinges on the brain’s capacity to form new nerve cell connections, and mental and behavioral flexibility is the hallmark of that capacity. • the hippocampus, seat of memory; under the influence of dopamine, the memory of an expected reward results in overactivation of the reward and motivation circuits and decreased activity in the cognitive control centers of the prefrontal cortex.
- Unfortunately, the belief that people with addictions are simply making bad choices pervades.
- For example, some networks are involved with thinking, learning, emotions, and memory.
- Ethanol also inhibits MSN-MSN synapses via a mechanism that is not as well characterized (Patton et al., 2016).
- A growing body of substance use research conducted with humans is complementing the work in animals.
- This knowledge has opened the door to new ways of thinking about prevention and treatment of substance use disorders.
- The chronic and withdrawal effects of ethanol on dopamine neuron firing are mixed, with decreases observed in anesthetized rats (Diana et al., 1996) but no change (Okamoto et al., 2006; Perra et al., 2011) or increases (Didone et al., 2016) detected in slices.
The chapter explains how these substances produce changes in brain structure and function that promote and sustain addiction and contribute to relapse. The chapter also addresses similarities and differences in how the various classes of addictive substances affect the brain and behavior and provides a brief overview of key factors that influence risk for substance use disorders. Individuals with addiction experience cravings and relapses due to the profound changes difference between drugs and alcohol addiction causes in the brain’s reward system.