Unit 2: Biological Bases of Behavior

Dendrites

Receive signals from other neurons.

Soma (Cell Body)

Contains the nucleus and maintains the cell's health.

Axon

Transmits electrical impulses away from the soma.

Terminal Buttons (Axon Terminals)

Release neurotransmitters to communicate with other neurons.

Myelin sheath

A fatty layer that surrounds the axon of some neurons.

Insulation

It helps speed up the transmission of electrical signals along the axon.

Protection

It protects the axon from damage and interference.

Resting state/resting potential

The electrical charge of a neuron when it is not actively firing an action potential.

Firing threshold

IF the neuron receives enough input, it 'fires' into an all or more/nothing manner.

All - or - nothing principle

The neuron will either fire or not fire, nothing in between.

Refractory period

A brief period in which the neuron cannot fire while it reloads its charge.

Reuptake

Recollecting/regarding excess molecules of the neurotransmitters left out in the synapse.

Action potential

The electrical charge that skips down the axon if a neuron.

Depolarization

Similar to firing threshold, either an all or nothing mechanism.

Glial cells

Make the myelin sheath that wraps around the axon of a neuron.

Motor neuron

Carry messages out from the CNS to the muscles and glands.

Sensory neurons

Carry messages into the CNS (known as afferent neurons).

Neurotransmitters

Chemical messages that cross the synapse between neurons & bind to receptors on sight.

Glutamate

Stimulates brain activity by making synaptic connections more sensitive.

GABA

Helps to slow brain activity.

Substance P

Sends pain messages, helpful feedback from the body to urge us to move or avoid harm.

Endorphins

Natural pain killers.

Norepinephrine

Active when our sympathetic nervous system is around; increases heart rate, BP, muscle strength, and sugar metabolism.

Acetylcholine

Necessary for voluntary muscle movement; active in hippocampus -> formation of memory.

Serotonin

Regulates mood, sleep & arousal, appetite hunger/satisfy.

Dopamine

Regulates feelings of pleasure; important for learning and memory.

Multiple sclerosis

Autoimmune disease where the myelin sheath is attacked and destroyed -> loss of strength, muscle control, & coordination.

Myasthenia gravis

Autoimmune neuromuscular disorder that leads to weakness and rapid fatigue of voluntary muscles.

Agonists

Chemicals that mimic the action of a neurotransmitter by binding to its receptor and activating it.

Antagonists

Chemicals that block or inhibit the action of a neurotransmitter by binding to its receptor but not activating it.

Excitatory

Stimulates activity, makes firing an action potential.

Inhibitory

Decrease neural firing, making firing on action potentials less likely.

Reflex arc

A neural pathway that controls a reflex action.

Key analogy

Lock represents the receptor on the post-synaptic neuron; key represents the specific neurotransmitter.

LTP (Long Term Potentiation)

A lasting enhancement in signal transmission between two neurons that results from their repeated stimulation

The central nervous system

The brain and spinal cord, responsible for processing and transmitting information.

The cerebral cortex

The outer layer of the brain, characterized by its wrinkled and folded structure, allowing for greater surface area.

Frontal lobes

Located just behind the forehead, involved in speaking, muscle movement, thinking, planning, and making judgments.

Motor cortex

Located at the rear of the frontal lobe, consists of all movement.

Prefrontal cortex

Responsible for higher order thinking, executive functioning, and impulse control.

Parietal lobes

Located at the top of the head behind the frontal lobe, helps process and organize information, including understanding language and performing mathematical calculations.

Somatosensory cortex

Recreates all of the information related to the sense of touch, located right behind the motor cortex.

Occipital lobes

Located at the back of the head, receives information from the visual fields.

Visual cortex

Determines colors, interprets objects and depth perception, and assists with visual short term memory.

Temporal lobes

Located between the ears, receives auditory information, interprets language, and processes smell and taste.

Broca's area

Controls expressive language and is one of the last parts of the brain to finish developing.

Wernicke's area

Controls language reception and comprehension.

Association areas

Parts of the cerebral cortex involved in integrating and processing information.

Brain stem

Maintains homeostasis by controlling autonomic functions such as breathing, heart rate, and blood pressure.

Medulla

Responsible for regulating essential autonomic functions including heart rate and blood pressure.

Pons

Receives auditory information from the ears, regulates sleep, and communicates with other parts of the brain to help regulate breathing.

Reticular activating system

Regulates wakefulness and attention by filtering sensory information.

The limbic system

Involved with emotions, memory, and motivation.

Thalamus

Relays information between the cortex and brain stem, involved in perception, attention, timing, and movements.

Hypothalamus

Regulates hunger, thirst, body temperature, sexual activity, circadian rhythm, and controls automatic functions.

Amygdala

Processes emotions, fear learning, and emotional learning and memory.

Hippocampus

Involved in memory formation, early storage of long-term memories, and spatial navigation.

Split brain research

Used to treat patients with severe epilepsy by cutting the connection (corpus callosum) between the two hemispheres of the brain.

Corpus callosum

A large bundle of nerve fibers that connects the left and right hemispheres of the brain.

Brain lateralizations

The division of the brain into two sections, left and right.

Hemispheric specialization

The division of labor between the left and right hemispheres of the brain.

Left hemisphere

Controls and receives sensory input from the right half of the body - specialized for verbal processing.

Right hemisphere

Controls and receives sensory input from the left half of the body - few exceptions are vision and hearing.

Contralateral hemisphere organization

The right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body.

Aphasia

Disorder that can affect an individual's ability to communicate, impacting speaking, understanding, reading, and writing.

Broca's Aphasia

Difficulty in speech production.

Wernicke's Aphasia

Fluent speech that lacks meaning.

EEG

Understands brain waves.

MRI

Provides structural image of brain.

fMRI

Provides both brain waves and structural images.

Pituitary glands

Produces hormones, maintains hormonal balance, influences growth, metabolism, and stress response.

Hormones

Chemical messengers.

Oxytocin

Involved in social bonding, sexual reproduction, and childbirth.

Melatonin

Produced by the pineal gland that regulates sleep-wake cycles (circadian rhythm).

Adrenaline

Produced by the adrenal glands that prepares the body for a 'fight or flight' response.

Leptin

Produced by fat cells that helps regulate energy balance by inhibiting hunger.

Ghrelin

Produced in the stomach and stimulates appetite.

Circadian rhythm

About a day - cira diem - our biological clock, the regular bodily rhythms that occur in a 24 hour cycle.

REM Sleep

Paradoxical sleep; brainwaves similar to waking beta waves, occurs ~25% of sleep.

NREM 1

Similar to waking alpha waves; brief, 5-10 minutes; includes hallucinations and hypnagogic sensations.

NREM 2

Characterized by theta waves and sleep spindles; most common stage, 50% of a night's sleep.

NREM 3

Characterized by slow delta waves; hardest to waken; when most sleep abnormalities occur.

Insomnia

Recurring problem falling asleep or staying asleep; can be short term (days-weeks) or long term (>3 months).

Sleep Apnea

Frequent stoppages of breathing during sleep; often leads to exhaustion even after a full night's sleep.

Somnambulism

Sleep walking; most common in children, often grows out of it.

Narcolepsy

A sudden, involuntary drop into REM sleep; usually begins 10-30 min into sleep.

REM Sleep Behavior Disorder

When individuals act out what they are dreaming during REM sleep.

Activation synthesis dream theory

The theory that dreams are the way our brain interprets activity during sleep.

Consolidation dream theory

Sleep allows us to process and consolidate the information collected the previous day.