Biological Basis of Behavior

Corpus Callosum

attaches the two hemispheres of cerebral cortex

• When removed (usually because of severe seizures) you have a split-brain patient

• part of limbic system

Reticular Activation System (RAS)

Network of neurons in brainstem that regulates Consciousness/Sleep/Arousal

Amygdala

Part of limbic system that processes emotions/fear

Hippocampus

Part of limbic system in charge of processing and consolidating explicit memories

Thalamus

pair of structures at the top of the brain stem that directs sensory information

Hypothalamus

part of limbic system that regulates homeostasis

• regulates endocrine system

Cerebellum

controls coordinated movement and balance - controls muscles 

• Control of involuntary movement 

• Athletes working to train implicit memory of cerebellum 

Frontal Lobe

Decision Making/Personality

• deals with planning, maintaining emotional control and abstract thought 

• contains Broca’s Area and Motor Cortex

• Humans have one of the largest 

Parietal Lobe

Navigation/Association areas

• spatial sense and navigation, sense of touch 

• Located on the top of our head 

• Contains the somatosensory cortex - sense of touch

Motor Cortex

voluntary movement (located in frontal lobe)

Sensory Cortex

Touch/Feeling/Pain (broad term for all places handling sensory input)

Occipital Lobe

vision (part of cerebral cortex)

Temporal Lobe

controls hearing (contains wernicke’s area)

• Processes sound sense by ears

• Not Lateralized - specific to one side of the brain

Broca's Area

Language Production

• If damaged -> wouldn’t be able to produce language - speak and write (Broca’s aphasia)

Wernicke's area

• language comprehension

  • Wernicke’s aphasia: you can’t comprehend language

Medulla

part of brainstem in charge of heart rate/breathing

• involuntary survival functions

Pituitary Gland

Releases hormones of growth

Glutamate

exciting (major exictatory)

• + headaches & anxiety

• - insomnia & exhaustion

Serotonin

mood (inhibitory)

• +hallucinations

• -depression

Endorphins

euphoria (inhibitory)

• + slowed/stopped breathing (overdose)

• - depression

GABA

calming (major inhibitory)

• + sedation/sluggish

• - anxiety/insomnia

Norepinephrine

fight or flight (excitatory)

• + anxiety

• - ADHD

Dopamine

pleasure and reward (inhibitory)

• +schizophrenia

• -parkinsons

• +/- addiction

Acetylcholine

learning and movement (excitatory)

• + convulsions

• - paralysis/Alzheimers/Myasthenia Gravis (muscles weak/tired b/c immune system attacks connection between nerves and muscles)

Substance P

pain and body repair (excitatory)

• + pain/inflammation

• - poor immune system response

neuron

cell that receives, processes, and transmits information through electrical and chemical signals (a single neuron does nothing)

sensory neuron (afferent)

allow you to feel - transmits incoming sensory info

motor neuron (efferent) 

transmit signals from the brain and spinal cord to muscles and glands

interneurons

connect sensory and motor neurons (in spinal cord) 

reflex arc

motor overrides sensory (e.g. matters more to run away than feel pain)

dendrites

the branched extensions of a neuron that receive signals (information) from other neurons and transmit them toward the neuron's cell body

axon

long, slender projection of a neuron that conducts electrical impulses away from the neuron's cell body to other neurons, muscles, or glands

soma (cell body)

containing the nucleus and serving as the metabolic center of the cell

myelin sheath

fatty, insulating layer that surrounds the axon of a neuron, significantly increasing the speed at which electrical impulses (action potentials) travel down the nerve fiber

terminal buttons

the small bulges at the very end of an axon that store and release neurotransmitters into the synapse

synapse

tiny gap between two neurons where they communicate, allowing a signal to pass from one cell to the next

threshold

minimum amount of energy needed for an action potential

all-or-nothing principle

neuron will either completely fire or won’t

resting potential 

when neuron is ‘charged’ but waiting for next action potential (+ ions outside, - ions inside)

action potential

firing of a neuron

depolarization

when a neuron fires and the negative goes out and the positive ions come in

refractory period

time it takes for neuron to ‘recharge’ after the previous action potential 

reuptake

neurotransmitter is released back (recycling)

long term potentiation (LTP)

persistent strengthening of synapses based on recent and consistent patterns of activity

ventromedial hypothalamus (VHM)

part of hypothalamus that tells you when you’re full (limbic system)

lateral hypothalamus (LH)

part of hypothalamus that tells you when you’re hungry (limbic system)

• LLL = lesion lateral less -> if you lesion the lateral hypothalamus you eat less

pons

structure in the brainstem that acts as a "bridge," connecting the cerebrum and cerebellum and relaying signals between them and the spinal cord

cerebral cortex

controls motion, vision, hearing (will live if it is damaged)

homunculus

distorted, map-like representations of the human body in the brain, showing how much sensory or motor cortex is dedicated to each part | proportion of motor/sensory neurons

EEG

amplified recording of electrical waves sweeping across the brain’s surface (result just looks like brain waves) 

MRI

uses magnetic fields and radio waves to produce computer generated images that distinguish among different brain tissue

PET Scan

a visual display of brain activity; detects gamma rays emitted by radioactive form of glucose while the brain performs a given task 

fMRI

shows structure and activity of brain by detecting changes associated with blood flow

CT

produces much more detailed images than x-ray of bone and soft tissue; images from different angles assembled in 3D image

lobotomy

severs connections in the brain's prefrontal cortex to treat severe mental illness, reducing agitation but often causing severe personality changes, passivity, and cognitive impairment

central nervous system

brain + spinal cord

peripheral nervous system

all nerves outside of brain and spinal cord

somatic nervous system

controls voluntary movements of skeletal muscles

autonomic nervous system

controls self-regulated action of internal organs and glands

sympathetic nervous system

arousing

parasympathetic nervous system 

calming

Leptin (VHM)

hormone in the pancreas and makes you feel full

ghrelin (LH)

hormone in pancreas that makes your stomach GRR when you’re hungry 

adrenaline

hormone from adrenal gland that helps with fight or flight

melatonin

hormone that regulates sleep-wake cycle

oxytocin

love hormone

estrogen

a sex hormone, primarily secreted by females, that contributes to female sex characteristics and influences behavior, including learning, memory, and mood

testosterone

a sex hormone primarily produced in the testes, which is crucial for male sexual development and function

agonist

mimics/exites

antagonists 

prevents release/inhibits

reuptake inhibitor

blocks reuptake keeping neurotransmitters in the synaptic cleft

substance use disorder

pattern of substance use leading to significant impairment or distress

addiction

brain disorder and a neuropsychological disorder characterized by a persistent, compulsive urge to engage in a behavior or use a substance, even when it causes significant harm

tolerance

body adapts to a substance, resulting in a diminished effect after repeated use

withdrawal

physical and psychological symptoms that occur when an individual discontinues or reduces the use of a psychoactive substance (like drugs or alcohol) that their body has become dependent on. 

depressants

slows down body processes and CNS; raise inhibitor neurotransmitter GABA; decrease glutamate; endorphin agonist

stimulants

speed up body processes; acts on reward system of dopamine; excites sympathetic NS; Activates CNS

hallucinogens

Causes changes in perceptions of reality

opiates

have depressive and hallucinogenic qualities; very addictive and very dangerous side effects; endorphin agonist

circadian rhythm

biological clock that regulates bodily rhythms; 25 hours long

NREM Sleep

Alpha waves; NREM 2 = Theta waves; NREM 3 = Delta Waves

beta waves

when you have full consciousnes

alpha waves

when you are feeling sleepy and when you first fall asleep

theta waves

NREM 2 and daydreaming

delta waves

slowest brain waves; allows body to heal

REM sleep

whole cycle = 90 mins, body is paralyzed in REM, only time you can dream

REM rebound

after a period of sleep deprivation, a person experiences an increase in the frequency, depth, and duration of REM (Rapid Eye Movement) sleep

hypnagogic sensations

when you feel like you’re falling (mild hallucination)

activation synthesis theory

suggests that the brain engages in a lot of random neural activity; dreams make sense of this activity

neuroplasticity 

brain's ability to change and reorganize its structure, functions, and connections throughout life in response to learning, experience, or injury; growth and remodeling of dendrites

epigenetics

study of how environmental factors can affect gene expression without changing the DNA

primary sex characteristics

body structures that are directly involved in reproduction, such as the ovaries, testes, and external genitalia

secondary sex characteristics

Physical traits that develop during puberty that are not directly involved in reproduction, such as breast development, facial hair, and voice changes

glial cell

non-neuronal cells that provide support and protection for neurons

white matter

the brain's deeper nerve fibers (axons) coated in myelin, an insulating sheath that gives it a whitish color and speeds up electrical signal transmission between neurons and brain regions

3 major brain systems

 brain stem < limbic system < cerebral cortex

Brain Stem

controls all automatic functions

• Die or coma if damaged

• All vertebrates have brain stems

Limbic System

memory, eating, sleep, hippocampus

• Will live if damaged

• How you maintain homeostasis

Cerebral Cortex

motion, vision, hearing  

• Will live if damaged 

Multiple Sclerosis (MS)

chronic, autoimmune disease of the central nervous system where the immune system destroys the myelin sheath which slows and blocks neural signals