PYSC531 Exam 2

Pre-synaptic

Terminal end of the neuron that sends signal, releases neurotransmitters.

Post-synaptic

Membrane that receives signal after crossing synaptic cleft, converts chemical signal into electrical.

Excitatory Post-synaptic potential

Change in membrane voltage that makes a neuron more likely to fire an action potential by depolarizing the membrane.

Inhibitory Post-synaptic potential

Hyperpolarizes the membrane, making it less likely for the neuron to fire an action potential.

Spatial summation

Multiple stimuli applied close together at the same time.

Temporal summation

Multiple stimuli applied across time.

Vesicle

Small membranous sac that can hold contents and move substances.

Ionotropic receptor

(Ligand gated ion channels) protein that allows ions to pass through membrane.

Metabotropic receptor

Proteins that control channels and what passes through, regulate transmission and excitability.

Hebbian synapse

Synapse that strengthens when pre and post neurons fire together over and over.

Sensitization

Learning response to stimuli.

Cross-tolerance

Tolerance of one drug gives tolerance to another drug because of similar effects (usually on the same cell).

Disinhibition theory

Loss of control on thoughts, emotions and behavior.

Behavioral myopia

Bias when someone focuses a lot on short term consequences and not on long term.

Incentive sensitization theory

Wanting increases over time as liking decreases, explains how repeated drug use leads to addiction.

Substance abuse

Overindulgence/dependence on an addictive substance.

Substance dependence

Individual's functionality is dependent on substance and can have withdrawals if not taken.

Diablo

Protein that promotes apoptosis by blocking other proteins.

Apoptosis

Programmed cell death (pruning).

Dopamine

Neurotransmitter that aids in memory, movement, motivation, mood and attention.

Norepinephrine

Neurotransmitter and hormone that plays vital role in response to stress and danger.

Serotonin

Chemical that carries messages between nerves and brain, aids in mood, sleep, appetite, learning, memory, heart and gut function.

Sodium potassium pump

Keeps higher concentration of K+ inside cell and higher concentration of Na+, Cl- and Ca2+ outside cell.

Voltage gated calcium channels

Open during action potential causing neurotransmitters to be released from synaptic vesicles.

Ligand gated ion channels

Opened by neurotransmitters binding to the receptor on the ion channel, usually located in dendrites/cell body.

Voltage gated ion channels

Open in response to membrane potential changes (voltage), located along axon.

Post-synaptic potentials

Graded potentials that decrease over time, caused by neurotransmitter binding to receptors on post synaptic membrane.

Action potentials

All or nothing signals that stay constant and travel along axon, initiated when membrane reaches certain threshold.

Membrane reabsorb neurotransmitters

Mechanism by which neurotransmitters are taken back into the presynaptic neuron.

Degradation

Enzymes break down neurotransmitters.

Diffusion

Neurotransmitters diffuse away from the synapse.

Four classes of neurotransmitters

Amines, amino acids, peptides, gases.

Cholinergic pathways

Origin at the base of the forebrain; terminate in hippocampus, cortex, and amygdala.

Noradrenergic pathways

Origin in the brainstem; terminate in cortex, hippocampus, and spinal cord.

Serotonergic pathways

Origin in the brainstem; terminate in brainstem and cortex.

Dopaminergic pathways

Origin in midbrain (substantia nigra and ventral tegmental area); terminate in striatum (forebrain) and prefrontal cortex.

Mesolimbic pathway

Inaccurate to call it the reward pathway as it also involves motivation and reinforcement learning.

Blood-brain barrier (BBB)

A highly selective semipermeable membrane that separates blood in the brain's circulatory system from the extracellular fluid of the brain.

Compromised blood-brain barrier

Less effective in the hypothalamus and area postrema.

Oral drug administration

Easy but slow absorption.

Inhalation drug administration

Quick absorption but can irritate airway and lungs.

Intravenous drug administration

Fastest method but carries risk of overdose and infection.

Transdermal drug administration

Slow release over time and less effective.

Drug elimination

Occurs through metabolism and excretion.

Types of tolerance

Metabolic, functional, and behavioral.

Metabolic tolerance

Body reduces drug effect by increasing metabolism.

Functional tolerance

Neural adjustments reduce drug effects at the receptor level.

Behavioral tolerance

Learning and adapting to compensate for drug effects.

Major classes of drugs

Depressants, stimulants, opiates, hallucinogens.

Effects of barbiturates

Depress CNS activity, leading to sedation and potentially respiratory depression.

Effects of benzodiazepines

Anxiety-reducing and sedative effects by enhancing GABA activity.

Effects of anti-psychotics

Block dopamine receptors, treating schizophrenia.

Effects of dissociative anesthetics

NMDA receptor antagonists lead to altered perception and pain relief.

Effects of opioid analgesics

Bind to opioid receptors to block pain transmission.

Effects of stimulants

Increase dopamine, norepinephrine, and serotonin, leading to enhanced alertness and euphoria.

Effects of anti-depressants

Often increase serotonin and/or norepinephrine activity.

Effects of hallucinogenics

Alter serotonin signaling and lead to altered perceptions.

Dopaminergic pathways in addiction

Involved in the mesolimbic pathway; abusive drugs can increase dopamine release, reinforcing behavior.

Sex differences in addiction

Females are more sensitive to addiction, but more males are addicted.

Vulnerability to addiction

Influenced by genetic and environmental factors, early life experiences, and neurobiological differences.

Evidence of drug abuse leading to brain damage

Alterations in mesolimbic pathway, memory, and decision-making areas.

Mullerian ducts

pair of embryonic ducts that develop into female reproductive structures

Wolffian ducts

pair of embryonic ducts that develop into male reproductive structures

Diabetes Mellitus

metabolic disorders by high blood pressure over long period, can lead to complications

Alpha feto-protein

protein produced by liver of fetus; high levels suggest neural tube defects and low levels suggest down syndrome

Neuropsychology

study of relationship between brain and behavior

Corti Block Tapping Task

neuropsychological test to assess function and motor skills using blocks

Mirror Drawing

test where individual draws shape looking in mirror to assess motor skills and visual coordination

Morris Water Maze

behavioral test to assess spatial awareness and memory in rodents

Behavioral Neuroscience

studies biological basis of behavior and how brain and NS influence actions and processes

Magnetic Resonance Imaging

MRI, uses magnetic fields and radio waves to create detailed images of body structures

Computed Topography

CT, uses x rays to create images of detailed views of tissues and structures

Histology

study of tissues

Ethology

study of animal behavior in natural environments

Compensation

brains ability to adapt and recognize its functions after injury

Stereotaxic Frame

device to position brain or tissues during procedures

Optogenetics

technique to control activity of specific neurons using light

Chemogenetics

uses receptors or ion channels to manipulate neuron activity in response to drugs/chemicals

Microdialysis

technique to measure chemical composition or extracellular fluid in brain to monitor neurotransmitter levels

Decussation

crossing over of nerve fibers from one side of CNS to other such as in spinal cord

Aromatization hypothesis

During early development testosterone is converted into estrogen in brain to differentiate between sexes

Androgen insensitivity syndrome

condition where individuals with XY chromosomes (male) resist male hormones and develop female characteristics

Turner's syndrome

condition where females have only one X chromosome leading to infertility

Negative feedback loop

Regulation of blood glucose levels by insulin and glucagon, where increased blood sugar triggers insulin release, which lowers blood sugar, and then the process reverses when blood sugar drops too low, triggering glucagon release

Sexual differentiation during fetal development

Y chromosome determines male or female to produce testosterone to masculinize and anti-Mullerian hormone to prevent development of female structures

Differences between male and female brains

Male- larger, hypothalamus can differ in size and function; Female- corpus callosum is larger

Fast-acting response pathway

involves sympathetic NS to release adrenaline for fight or flight response

Slow-acting response pathway

releases cortisol to manage stress over long periods

Chronic stress effects on brain

brain damage, anxiety, depression and cognitive impairment

Mesolimbic dopamine pathway

activation of this pathway leads to increased motivation and reward seeking behavior

Transmagnetic stimulation

non invasive method to stimulate specific brain regions using magnetic fields, studies brain function and to treat conditions

Limitations of transmagnetic stimulation

limited depth of stimulation and potential discomfort

Kyoto/SHR rat

Model to study hypertension (high blood pressure), cardiovascular diseases and behavioral disorders, used to understand effects of hypertension on brain function and behavior