Chapter 3 The Biological Bases of Behaviour Flashcards
Neurons
specialized cells that make up the nervous system
cell body (soma)
structures that keep the cell alive (nucleus)
dendrites
“branches” from cell body, recieve signals
axon
conducts electrical impulses away from soma and towards axon terminals
- axon terminals
sends signals to other cells
Glial cells
hold neurons in place
- make and move nutrients
- from the Myeline Sheath
- Remove toxins
blood-brain barrier
a bunch of glial cells that form a wall between the blood and neurons because blood kills neurons
- allows nutrients to be taken out of the blood for the neurons
2 functions of neurons
- generate electricity
- create nerve impulses
- goes down the cell never the other way!
- Release chemicals
- communicate with other cells
Neural Impulses
ctivation occurs in the three steps:
cell is at rest with electrical resting potential
. -70mV on average
2. means inside of cell is more negative than outside of the cell
3. this is due to ions.
Na+
(positives ion. Lots in outside of cell)
. K+
(potassium is also positive and inside the cell, less potassium than sodium, therefore outside is more positive than inside which is more negative. Difference is 70 mV)
. resting potential
neither one of channel is open.
cell is stimulated and electrical charged (ions) flows across cell membrane
- reverse charge of resting potential
2. produces action potential, or neural impulses
when the sodium channels open
all the positive ions flood into the inside of the cell and makes the inside of the cell positive. Ex/ -70mV to +40 mV
depolarization
when we go more positive. sodium enters (more positive, less negative)
Restore distribution of ions, cell at rest again.
potassium opens now, but sodium is closed. potassium stars flooding outside of the cell. Turns inside of the cell negative again.
2. as one part of the axon repolarizes the next one depolarizes.
repolarization
potassium leaves (less positive, more negative)
hyperpolarization
: extra negative
The all-or-none law:
action potentials occur at a uniform and maximal intensity, or they do not occur at all
- stronger signals DO NOT cause stronger action potential
- it just means it will cause action potential
- you can increase number of action potential in a period of time, and it send a signal of more important message
Absolute refractory period:
cell cannot fire again
- impossible to have a second action potential
- limits how often nerve impulses can occur
- ensures that impulses only travel in a single direction
- cell has to reset
- always a small gap in which nothing can happen
The myelin sheath:
created by glial cells
- a fatty, whitish insulation layer derived from glial cells during development
- i.e., support (help protect from damage) and surround neurons
- insulated neurons (quick signals)
- in-between each myelin sheath is the nodes of ranvier
- only around the axon
- not all neurons myelinated
Node of Ranvier
places here the myelin is either extremally thin or absent
- allows conduction to “skip ahead”
- foster signals
Synapses
where axon terminals meet dendrites
- neurons do not make physical contact
- communicate across gaps called synaptic cleft
Synaptic gap
functional (not physical) connections between neurons and their target (contracts muscles). They are not toucing, but very close to its other
Neurotransmitters
chemcial substance shat carry messages across the synapse toeither excite otehr nerons, or inhibit their firing
- five stages fo chemcial communcation:
- five stages fo chemcial communcation:
- five stages fo chemcial communcation:
- synthesis - make them oin the neuron
- stoarge - held in synaptic vessels
- release - into synaptic space
- binding - attach to receptor sites
- deactivation - stop the neurotransmitter signal
excitation vs inhibition
- inhibitory neurotransmitter:
decreases resting postential of post-synaptic neuron; hypopoloarization
- chill eurons out
hypopoloarizes neruon’s membrane -> DECREASES likelihood of action potential
- exitary neurotrasnmitter:
increases resting potentail of post-synaptic neuron; may even fire
- it rev neurons up
depolarizes neruon’s membrane -> INCREASES likelihood of action potential
Specific neurotransmitters: glutamate (glutamic acid)
exitaory
- expressed in whoel brain
- control fo behaviours
- especially learning and memor
- GABA (gamma-aminobutyric acid)
inhibitory
- expressed in whole brain
- control of behaviours
- especailly anxietyt and motor control
- huntington’s deisease
Acetylcholine (ACh)
exitaroy
- function at synapses invovled in muscle movement and memory
- memory in loss in Alzhemier’s disesase
Norepinephrine
exitaory and inhibitoary
- functions at various sites
- invovled in learning, memory, wakefyllnes, eating
- depression and panic disorders
Seretonin
- Inhibitory (mostly)
- functions at various sites
- mood, eating, sleep, arousal
- I.e., depression, sleeping, and eating disorders
Dopamine
excitaroy and inhibitory
- functions at various sites
- voluntary movement, learning, motivatiion, pleasreu
- depression, parkinson’s deisaese, schizophrenia
-
Endorphin
inhibitory
- isnenstive to pain (oversupply)
- hypersenstiivitty to pain, immune proboems (undersupply)
Types of neruons:
sesnory, mototr and interneurons
- sensory neruons
- carry inpit messages fom the sense organs to the spinal cord and brain
- Motor neruons
- transmist output impulses fro the brain and the spinal cord to mnuscles and organs
- internerouns
- perform connective or associative functions within the nervous system
2. by far most cominternerounsmon type
forebrain (cerebrum)
highly developed, numerous functions
frontal lobe
main fxn: personality
parietal lobe
sensations (feelings, sensory sensations)
occipital lobe
vision
temporal lobe
hearing
cerebral cortex
outer layer of the cerebral hemispheres
6. involved in thinking and mental processes
basal ganglia
collections of neurons crucial to motor function
hippocampus (hippo goes to school to learn)
memory
amygdala
amygdala
nucleus accumbens
reward centre
thalamus
relays incoming sensory information through groups of neurons that project to the appropriate region in the cortex
hypothalamus
regulates basic biological drives
reticular formation
involved in regulation of consciousness
1. conscious awareness and control
2. regulates sleep, wakefulness, and attention
3. extends into hindbrain and lower forebrain
superior colliculi
involved in vision (especially visual reflexes)
2. ex/ dilating pupils or focusing far vs near
3. *eyes are above my ears, so vision is superior to hearing
inferior colliculi (in exams)
involved in hearing
midbrain
reflex actions and voluntary movements
5. right in the middle, cannot see unless you cut the brain
hindbrain: brainstem
vital functions and coordinating movements
medulla
- controls heart activity and largely controls breathing, swallowing, and digestion
2. all sensory and motor nerve tracts ascend from the spinal cord and descent from the brain
3. damaging means death or life support
4. keeps us alive
pons
- relay station for signals between higher levels of the nervous system and lower levels
2. regulates sleep and dreaming
3. controls muscles and glands in face and neck
4. controls vital functions like respiration
3. cerebellum
cerebellum
- controls bodily coordination, balance, and muscle tone
2. involved in procedural memory
1. motor skills
nerve =
nerve =
tract =
central
motor cortex
(frontal lobe)
1. controls the muscles involved in voluntary body movements
somatic sensory cortex
(right next to motor cortex, also frontal lobe)
. receives input: sensations of heat, touch, cold, and our senses of balance and body
2. from skin to internal organs
primary auditory cortex
- temporal lobe of both hemispheres
- receives auditory sensations first
. primary visual cortex
(occipital lobe. extreme back
Wernicke’s area
(temporal lobe, right next to occipital lobe)
1. involved in speech comprehension
2. involved in even reading
Association cortex;
found within all lobes of cerebral cortex
- invovled in high-level functions
- e.g., percetion, thought, langauge, etc
- appear ‘silent’ because electrical stimulation does not give rise to sensory or motor responses
Hemispheric Lateralization: right hemisohere:
- feelings, intution, humour
- aesthetic, colour
- relationships, rhtym, phsycal sesne,s motor skills
- note: connects to the left side of the body
Left hemisphere:
- anayltical thinknig, rules, logic
- structure, mathmeatics, planning
- speech, langyage, time
- note: connects to the right side of the body
visual lateralization
- left visual field - processed in right hemispoehre of brian
- right visual fieled - proceiisses in left hemisphere of brain
corpus callostomy
when the corpus callosum is severed
- resuls in “split-brain” patreints
hemispheres often communciate across corpus callosum
trasnfer of uinformaiton from one hemisohere to the other
Methods of study:
postmortem studies
- stiyding live non-human animals
- studying live humans
- surgical techniques
- brain imaging
CT - computer tomography
builds a pciture of the brain based on the diffrential abosrption of x-rays
- reveals gross features of the brain
PET - psotiron emission tomography
PET - psotiron emission tomography
Strucutral MRI - magnetci ersonance imaging
bulds a pcture of the brain using strong magentic field athat interac with tissues
- reveals gross features and strcurre of the rbrain
- used in conjucntion with fMRI to measrue strucutral integrity
fMRI - funcitinal magnetic resonacne imaging
detects changes in blood oxygenation and flow
- tied to neural activity
- high acitivyt = high oxygen use and high blood flow
DTI - functinal magnetic resonance imaging
builds a pcture of water ovement in the brain usign an MRI scanner
- observe bloood flow along specific neural tracts
- high spatial resolution and directinality
NIRS - Near infared spectorscopy
Measrues cahnges in blood oxygenation
- shines near IR light through the skull
- detects attenuation of reemrging light
- indirect measrue of brain activity
EEG - elctroencephalography
measrues electrical actiivty via electrodes
- can be inter- or intra-cranial
- ectrodes either on or in the skull
- very good time resolution (milliseconds)
TMS - transcranial magnetic stimulation
induces electrical acitivty via magnetic field
- can temporarily disrrupt (or activate) cortical nerual tissue
- task = letter dection
- worse performance when TMS pulse to visual cortect just after stimulus presentation
radical behaviorism
akcowedlge genetics exist, normal behaviorsim
third varaible problem:
is ther arealtion between two vairables x and y. is it correlated?
removing the infleunce of z, the third vairbale to accurately see the realtionship between x and y
infranteial statystics:
look at our stats and decide is it good sceince, gives us info that makes it easy to compare between studies
sympathetic anaylsys:
fight or flight.
ex/ youre sitting in class and ur pupils dialte and heart statrts to race what nervous system is being activated?
