Neurobiology of Substance Abuse Flashcards
3 Structures of the Nervous System
- brain
- spinal cord
- peripheral nerves
3 Stages of Brain Stimulus and Response
- sensory reception
- interconnection
- motor response
CNS
Central Nervous System, brain + spinal cord
Peripheral Nervous System
Nerves that branch out from the CNS and connect the system to other body parts, including hands and feet
Somatic system
Cranial and spinal nerves, which connect the CNS to the skin and skeletal muscles
Autonomic System
Nerves that connect the CNS to organs like heart, stomach, intestines, glands, etc.
Sympathetic Division of Autonomic System
Prepares body for activities that expend energy
Parasympathetic Division of the Autonomic System
Aids body in returning to normal after period of expending energy.
Neuron
Basic unit of the nervous system. Capable of receiving stimuli and transmitting electrical messages.
Dendrites
Fibers that send nerve impulses toward the cell body.
Axon
Carry impulses away from the cell body
Synapses
Delivers neurotransmitters from neuron to neuron
Synaptic cleft
Gap filled with fat that acts as an insulator between cells.
Depressants: thicken medium and slow down transmission.
Stimulants: thin the medium, causing more rapid transmission of chemicals.
Blood-brain barrier
Microvascular endothelial cells protect the brain by forming a blood-brain barrier. These cells are tightly wound and prevent many substances from leaving the blood and reaching the brain.
-Small or fat soluble substances, like drugs, pass through.
Metabolism
The process through which a substance is eliminated from the body.
Acetylcholine
Memory, attention, and mood
Norepinephrine
Movement and pleasure
Serotonin
Sensory perception, sleep, sex, and body temperature
Gamma Aminobutyric (GABA)
Inhibitory NT, blocks transfer of a nerve impulse to adjoining neuron, slows neuronal activity
Glycine
Inhibitory NT found in spinal cord
Enkephalins and Endorphins
Regulates pain, pain-killing properties more powerful than morphine
Dopamine
Movement, memory, concentration, pleasure
Epinephrine
Fight or flight
Glutamate
Memory, learning, cognition
What does prevent reuptake mean?
When a NT is blocked from being absorbed by an appropriate synapse, thereby increasing NT’s concentration in brain.
Agonist
When a substance causes receptors to react or activate
Antagonist
Substances that block receptors from activating
Amygdala
Responsible for emotion, motivation, and memory formation - particularly related to stress response.
-Go system. Keeps you alive from immediate threats.
ARAS (Reticular Activating System)
Sleeping, walking, behavioral alerting. Depressants block activity, amphetamines increase activity. Responsible for individual’s state of arousal.
Medulla Oblongata
Controls vital centers of the brain - breathing, blood pressure, heart rate.
Pons
Relays impulses among cerebrum, cerebellum, and spinal cord.
Midbrain
Center which controls auditory reflect as well as head movement. Psychedelics create hallucinations.
Cerebellum
Reflex center (skeletal muscle movements.)
-When depressed by psychoactive drugs there is a loss of muscle coordination and balance.
Thalamus
Central relay station (incoming sensory impulses are channeled to cerebrum.) Are sensations pleasurable or painful?
Hypothalamus
Homeostasis, controls heart rate, blood pressure, water, hunger, sexual behavior, regulates emotions
-Stress response
Limbic System
Regulation of emotions.
-Tranquilizing drugs depress the limbic system, resulting in a calming effect.
Cerebrum
Coordinates and interprets internal and external stimuli
Frontal Lobes
In cerebrum, controls internal processes like concentration, planning, and problem solving
Parietal Lobes
In cerebrum, sensory areas responsible for temp, touch, pressure, and skin pain
Temporal lobes
Responsible for hearing
Occipital lobes
Responsible for vision
Basal ganglia
Motivation, movement, habits
-Controls psychoactive substance use’s pleasurable and rewarding effects
-Woohoo! System
Reinforces pleasurable experiences
Prefrontal Cortex
Thinking, planning, problem solving, impulse control.
-STOP system.
Basal ganglia = woohoo system, amygdala = go system
prefrontal cortex = stop system
Brain’s Communication Pathways
- Neurons (uses synapses to send and receive messages)
- Synapses (deliver NT to neurons)
- Dendrites (receive synaptic input)
- Axon (determines whether neuron will fire signal to release NT)
- soma (cell body)
Myelination
During adolescence, synaptic refinement that affects biopsychosocial development, which reduces gray matter and makes brain more efficient.
What is the primary NT implicated in the development of SUD?
Dopamine
Synaptic pruning
Reducing gray matter and making the brain more efficient during adolescence, occurs in the temporal cortex and subcortical structures.
