Biological Bases: The Brain and Nervous System

physiological psychology

study of behavior as influenced biology

imaging techniques

map the structure and/or activity of the brain

EEG stands for

electroencephalogram

EEG function

measures subtle changes in brain electrical activity through electrodes placed on the head

CAT scan stands for

computerized axial tomography scans

CAT scan function

generate cross-sectional images of the brain using a series of x-ray pictures taken from different angles

MRI stands for

magnetic resonance imaging

MRI function

uses extremely powerful electromagnets and radio waves to get 3-D structural information from the brain, capture “snapshots” of the brain

fMRI stands for

functional MRI

fMRI function

allows viewing of the brain as it is working by rapid sequencing of MRI images

PET scans stands for

positron emission tomography scans

PET scans function

allows viewing of the brain as it is working by providing images via diffusion of radioactive glucose in the brain

nervous system divided into two subsystems

central nervous system and peripheral nervous system

central nervous system (CNS)

comprises the brain and the spinal cord

peripheral nervous system (PNS)

comprises all nerves in the body besides brain and spinal cord

neurons

nerve cells

cerebrospinal fluid

protective liquid around the brain and spinal cord

sensory or afferent neurons

nerves sending information to the brain

motor or efferent neurons

nerves sending information from the brain

reflexes

quick and involuntary responses from afferent to efferent cells without the brain’s control

PNS divided into two systems

somatic nervous system and the autonomic nervous system

somatic nervous system

responsible for voluntary movement of large skeletal muscles

autonomic nervous system

controls the nonskeletal or smooth muscles, typically not under voluntary control (heart, digestive tract)

autonomic nervous system divided into two systems

sympathetic and parasympathetic nervous systems

sympathetic nervous system

processes that burn energy, helps you deal with a problem, fight or flight

parasympathetic nervous system

processes that conserve energy, helps you come down from a problem, returns body to homeostasis

brain divided into three regions

hindbrain, midbrain, forebrain

hindbrain

oldest part of brain to develop, regulates basic bodily functions and coordinates movement and balance

hindbrain composed of

cerebellum, medulla oblongata, reticular activating system (RAS), and pons

cerebellum

controls muscle tone and balance

medulla oblongata

controls involuntary basic life actions, such as breathing, digestion, heart rate, and swallowing

RAS stands for

reticular activating system

reticular activating system (RAS) also known as

reticular formation

reticular activating system (RAS) / reticular formation

controls arousal (wakefulness and alertness)

pons

“bridge,” passes information, REM sleep

midbrain

connects forebrain and hindbrain, motor function and sensory information

midbrain composed of

tectum and tegmentum

tectum

processes visual and auditory information, roof of brain

tegmentum

sensory and motor control, floor of brain

forebrain

variety of functions

forebrain divided into two

limbic system and cerebellum

limbic system

emotional center of the brain

limbic system composed of

thalamus, hippocampus, amygdala, hypothalamus

thalamus

relays sensory information, receives and directs sensory information from visual and auditory systems

hippocampus

processes and integrates memories, forms new memories

neocortex

stores memories

anterograde amnesia

condition of inability to form new memories

amygdala

controls anger, frustration, and fear

hypothalamus

1. controls the temperature and water balance of the body
2. controls hunger and sex drives
3. orchestrates activation of the sympathetic nervous system and the endocrine system

hypothalamus divided into two

lateral and ventromedial hypothalamuses

lateral hypothalamus

“on switch” for eating, promotes hunger

ventromedial hypothalamus

“off switch” for eating, promotes fullness

cerebrum

covered by cerebral cortex

cerebrum composed of

left and right cerebral hemispheres, corpus callous

left hemisphere

specialized for language processing, Paul Broca, Carl Wernicke

Paul Broca

Broca’s area, expressive aphasia

Broca’s area

located in left frontal lobe, controls speech production, damage causes expressive aphasia

expressive aphasia

inability to speak

Carl Wernicke

Wernicke’s area, receptive aphasia

Wernicke’s area

located in left temporal lobe, controls language comprehension, damage causes receptive aphasia

receptive aphasia

inability to comprehend speech

right hemisphere

processes visual and spatial information

Roger Sperry

demonstrated two hemispheres can operate independently, split-brain patients, contralateral processing

corpus callosum

band of connective nerve fibers joining the hemispheres

split-brain patients

corpus callosum severed to control epileptic seizures

contralateral processing

the ability of the brain to use both hemispheres and integrate information between them

cerebral cortex

wrinkled outer layer of the brain, higher cognitive functions such as thinking, planning, language use, and fine motor control

cerebral cortex divided into lobes

frontal, parietal, temporal, occipital lobes

frontal lobe

higher-level thought and reasoning: accessing working memory, paying attention, solving problems, making plans, forming judgments, and performing movements

parietal lobe

handles somatosensory information, home of primary somatosensory cortex

somatosensory cortex

processes information about temperature, pressure, texture, and pain

temporal lobe

handles auditory input, critical for processing speech and appreciating music

occipital lobe

processes visual input, connected to optic chiasm

optic chiasm

transmits visual information from eyes to occipital lobe

neurons composed of

nucleus, soma, dendrites, axon, myelin sheath, nodes of Ranvier, terminal buttons, synapse, neurotransmitters

soma

clearly defined, nucleated cell body

dendrites

branch out from the soma, receive input from other neurons through receptors on their surface

axon

long, tubelike structure that responds to input from the dendrites and soma, transmits neural messages through it

myelin sheath

surrounds axon, works as insulation and speeds up transmission rate

nodes of Ranvier

small gaps between myelin, speeds up neural transmission

terminal buttons

knobs on the branched end of the axon, very close to soma and dendrites of other neurons but don’t touch

synapse

gap between terminal button and dendrites of two neurons

neurotransmitters

chemical messengers released by terminal buttons across the synapse where they bind with receptors on subsequent dendrites

resting membrane potential

\-70 mV, interior is negatively charged in respect to exterior

depolarization

firing of neuron

repolarization

returns neuron membrane potential to normal after depolarization

action potential / nerve impulse

disturbance in membrane potential, wave of depolarization

absolute refractory phase

period of time after neuron fires where it can’t fire again

relative refractory

period of time after absolute refractory phase where the neuron needs a lot more stimulation to fire

excitatory neurotransmitter

excite the cell or cause the neuron to fire

inhibitory neurotransmitter

stop cell firing

neurotransmitters after finishing their purpose

either broken down by enzymes or go through reuptake

reuptake

absorption of a neurotransmitter back into the cell that released it

acetylcholine

memory function and muscle contraction in heart

serotonin

arousal, sleep, pain sensitivity, mood and hunger regulation

dopamine

movement, attention, reward and “happiness,” Parkinson’s disease, schizophrenia

GABA stands for

gamma-Aminobutyric acid

gamma-Aminobutyric acid

inhibitory neurotransmitter, opposite of glutamate

glutamate

excitatory neurotransmitter, opposite of GABA

norepinephrine

levels of alertness, depression