neurobiology and behaviour Flashcards
3 main regions of the brain
forebrain, midbrain, hindbrain
what is the brain surrounded by
three membranes (the meninges)
what happens if the meninges are inflames
meningitis
purpose of the membranes
for protection
what do ventricles provide
protection
what are ventricles
spaces filled with cerebrospinal fluid that supply the neurones with oxygen and glucose (for respiration) also remove toxines (waste products- CO2)
purpose of skull
protection
what structures are in the forebrain
cerebrum, (cerebral cortex)
thalamus, hypothalamus, hippocampus
(limbic system)
structures in the midbrain
nerve fibres connecting hind and forebrain
hindbrain
containing medulla oblongata and cerebellum
function: medulla oblongata
controls HR, ventilation and blood pressure, contains important centres of the autonomic nervous system
what does autonomic mean
don’t have to think about it
function of cerebellum
maintenance of posture and co-ordination of voluntary muscular activity e.g. writing
function of cerebrum
responsible for voluntary behaviour, learning, reasoning, personality and memory
function of hypothalamus
regulation of body temperature, blood solute concentration, thirst, hunger and sleep. it is the main controlling region of the ANS and links the brain and endocrine system via the pituitary gland
function of the thalamus
a relay centre sending information to and from the cerebral cortex
function of the hippocampus
interacts with other areas of the cortex, involved with learning, reasoning, personality and consolidating memories into a permanent store
what does ANS stand for
autonomic nervous system
what does the ANS control
automatic processes (e.g. heart rate)
explain the relationship between the two branches of the ANS
the two branches of the ANS work antagonistically to maintain appropriate levels of activity, e.g. heart rate speeds up or slows down depending on the level of activity undertaken
what forms the limbic system
the hypothalamus and thalamus connect with other areas of the brain, including the hippocampus. the limbic system is involved in emotion, learning and memory
two brances of the nervous system
sympathetic and parasympathetic
explain the sympathetic system
is ‘fight or flight’, has an excitatory affect (increasing HR)
it uses noradrenaline as a neurotransmitter
difference between sympathetic and parasympathetic (simply put)
S: noradrenaline- speeds things up
P: acetylcholine- slows things down
explain parasympathetic system
‘rest and digest’ and has an inhibitory effect on the body. it uses acetylcholine as a neurotransmitter
parasympathetic/sympathetic system
what they do in the body
P: constrict pupils/ S: dilates pupils
P:stimulates salivation/S: inhibits salivation
P: slows heart rate/S: increases hear rate
P: stimulates digestion/S: inhibits digestion
how is HR increased
when you excerice the concentration of CO2 in the blood increase. the increase causes a decrease in pH of the blood. the drop in pH causes the cardiovascular centre of the medulla oblongate to send signals to the Sino Atrial node along the sympathetic nerves. Noradrenaline binds to receptors causes HR to increase
why does a higher concentration of CO2 in the blood cause a decrease in pH
(CO2 dissolves to form cabonic acid)
how is HR decreased
when you rest, the concentration of CO2 in the blood decreases. this causes an increase of pH in the blood. the rise in pH causes the cardiovascular centre of the medulla oblongata to send signals to the sinoatrial node along the parasympathetic nerves (vagus nerve) acetylcholine binds to the receptor causing HR to decrease
what is the outer area of the cerebrum
grey matter
inner area of the cerebrum
white matter
what is the white matter
contains myelinated axons of neurons
what does the cerebrum consist of
2 hemispheres linked by the corpus callosum (semetrical)
what is the cerebral cortex (adaptations)
outer layer of the cerebrum and is highly folded to increase the SA for processing.
composed of millions of neurones and is grey matter with many cell bodies
what is the cerebral cortex responsible for
most conscious thoughts and actions. the inner part of the cerebrum is myelianted white matter
what can each hemisphere be split into
4 lobes
frontal, temporal, occipital, parietal
functions of frontal lobe
reasoning, planning, motor, speech and movement, emotions and problem solving
(broca’s area)
functions of parietal lobe
sensory functions and taste (temperature detection)
functions of temporal lobe
language learning and memory
(interpretation, Wenickes area)
functions of occipital lobe
vision
where is the somatosensory cortex found
parietal lobe
where is the somatomotor cortex found
frontal lobe
3 areas of the cerebral cortex
somatosensory cortex
somatomotor cortex
association areas
what is the function of the somatosensory cortex
receives nerve impules from receptors (in the body via the thalamus)
function of the somatomotor cortex
send nerve impulses to the effectors (via motor neurone)
function of Association areas
form most of the cerebral cortex. they receive impulses from sensory areas and associate it with previously stored information from memory so it can be interpreted and given meaning to initiate appropriate responses (within the motor area)
how are things communicated between the two sides of the brain
nerve fibres from the motor area cross in the medulla oblongata so the left hemisphere controls the right side of the brain and vice versa
what area of the brain is responsible for speech and language
left cerebral hemisphere
Wernicke and Broca’s area
what are Broca and Wernickes area conncected by
a bundle of nerve fibres known as the arcuate fassiculus
what are the acruate fassiculus
a bundle of nerve fibres that connect Broca and Wernickes area
where is the Broca area located
in the frontal lobe just above the temporal lobe in the let hemisphere only
explain Broca’s area in terms of speech and language
motor neurones from here innervate the muscles involved with producing speech (larynx, mouth and intercostals)
what happens if Broca’s area is damaged
speech can still be understood but speaking is in short sentences, lacking fluency
where is Wernicke’s area found
it spans the upper part of the temporal lobe and the lowere part of the parietal in the left hemisphere
fucntion of Wernicke’s area
responsible for interpreting written and spoken language.
what happens in Wernicke’s area is damaged
speech cannot be understood but fluency is unaffected
what is a stroke
an interruption of blood flow in the brain. neurones in the affected region do not receive enough oxygen so they die
what is aphasia
Aphasia is an impairment of language, affecting the production or comprehension of speech and the ability to read or write. Aphasia is always due to injury to the brain-most commonly from a stroke, particularly in older individuals.
2 types of homunculi
sensory and motor
what do homuculi show
the relative proportions of the sensory and motor areas of the body, sensitive areas with many sensory neurones are large like tongue, lips and fingertips.
what can areas with many motor neurones do
performs intricate movements, like hands and face
explain sensory homunculi
Regions which contain fewer sensory receptors take up less space in the homunculus.
As a result, a small proportion of the sensory areas/cortex of the brain are involved with receiving impulses from these parts of the body.
what are the methods of brain imaging
EEG
CT
MRI
fMRI
PET
method: EEG
Scalp electrodes detect voltage fluctuations and record electrical activity
what does EEG stand for
electroencephalography
advanatges/disadvantages of EEG
A: Silent, non-invasive, no ionising radiation, no claustrophobia, no radioactivity or magnetic fields
D: only detects activity in the cerebral cortex. not looking at synaptic transmission
some uses of EEG
diagnosis of epilepsy
what does CT stand for
computerised tomography
method of CT
x-rays from different angles
show internal structure in slices
Advantages/disadvantages of CT
A: high resolution of bone, soft tissues and blood vessels at the same time. fast results for the whole body. can look from different angles
D: uses x-rays, images not as clear as MRI, only shows structural features
what does MRI stand for
magnetic resonance imaging
method of MRI
strong magnetic fields and a radio wave pulse. protons in water give coloured 3D map of cortex
Advantages/disadvantages of mri
A: detailed anatomical image without using ionising radiation. more sensitive than CT
D: claustrophobic and noisy, patients need to be totally still. not for people with pacemakers or cochlear implants
method of fmri
strong magnetic fields and radio waves to measure oxygen demand
advantantage/disadvantage of fMRI
A: show flow of oxygenated blood. shows what regions of the brain are most active, therefore functioning. can produce detailed images over time, can show differences. (structure and functioning)
D: difficult for people with claustrophobia
what does fMRI stand for
functional magnetic resonance imaging
what does PET stand for
position emission tomography
method of PET
shows radioactive glucose use injection of radioactive isotope
advantages/disadvantages of PET
A:detects biochemical changes in brain, shows functioning areas of the brain
D: uses gamma radiation
uses of PET scans
imaging tumours
uses of fmri scans
study brain functions in real time
uses of mri scans
identifying structures e.g. brain tumours, demyelinating nerve fibres, aneurysm
uses of CT scans
detection of brain injuries and skull fractures
what is neuroplasticity
describes the brains ability to form new connections between neurons in response to new information, sensory stimulation, development or damage. it allows the brain to change and adapt throughout life
what is developmental plasticity
young brains rapidly form branches and connections between neurons. during this critical period, sensory input is required for proper development
what does neuroplasticity happen as a result of
Input of sensory information
Normal brain development
Brain damage (e.g. stroke).
what is required for proper development
sensory input
what is synaptic pruning
as development continues, unused connections are lost
when does most pruning take place
in adolescence
what does too much synaptic pruning lead to
schizophrenia
what does not enough synaptic pruning lead to
ASD, epilepsy
what is essential for producing and decoding speech sounds during childhood
hearing and practising language
what happens to language acquisition after a critical period
may be permanently impaired.
what do feral children lack
lack stimulus in the critical period, only develop basic communication skills
what do congenitally deaf children show
deficits in vocalisations and may fail to develop language unless taught alternative means of communication, like sign language
what happens to the number of connections maintained after a critical period
large drop in the number. the ones that remain are the ones that have been strengthened
what can gene expression affect
brain development and this may impact on an individuals behaviour
what can altered gene expression in childhood lead to
could predispose adults to an increased risk of mental illness
explain cortisol levels and mental illness
the average level of cortisol is higher in individuals that were subjected to childhood abuse. it is though that high levels of cortisol predispose adults to mental illness as they have higher background stress levels.
what is cortisol released controlled by
negative feedback- the release of cortisol into the bloodstream results in the decline of cortisol production;stops us from being constantly overstressed
where is cortisol released from
from the adrenal glands (above the kidney)
what do chemical reactions do as an organism grows and develops
they activate and deactivate parts of the genome at strategic times and in specific locations.
what is epigenetics
describes the influence of chemicals like methyl and acetyl on gene expressions
what are epigenetic changes linked to
involved in brain conditions such as mental illness and addiction
what is an aces
adverse childhood experience
what are abused children more likely to do
at least 50% more likely than the general population to suffer from serious depression as adults. also harder for them to recover from this illness
what are adults who were subjected to childhood abuse and neglect at a higher risk of
schizophrenia, eating disorders, personality disorders, bipolar disease and anxiety. also more likely to abuse drugs or alcohol
what is one hypothesis for traumatic experiences in childhood
that those with these experiences change physical aspects of the brain at key development periods- this may have epigenetic component that causes alteration in gene expression, predisposing adults to an increased risk of mental illness
what can stress cause
(cortisol release)
the hippocampus to send nerve impulses to the hypothalamus
what does the hypothalamus do
(cortisol release)
releases corticotrophin-releasing hormone (CRH) which stimulates the anterior pituitary gland to release adrenocorticotrophic hormone (ACTH)
what does ACTH do
circulates in the bloodstream and links to receptors on the cortex of the adrenal gland (effector) which releases cortisol as a response
what does increased cortisol in the blood do
(cortisol release)
increased cortisol in the blood inhibits the hippocampus, preventing an individual from being continually stressed
what do adults subjected to abuse have
(cortisol release)
higher levels of CRH and therefore cortisol. the feedback loop is faulty and they are continuallu over-stressed
how do the hippocampus/hypothalamus respond to higher levels of cortisol
they do not respond appropriately
what does innate mean
behaviours are inherited and instinctive (born with)
3 types of innate behaviour
taxes
kineses
reflex
what is a reflex
a rapid automatic response to a stimulus with a protective function that enhances survival
example of a reflex
withdrawing your hand from heat
what is kineses
non-directional, random movements of a whole organism. in unfavourable conditions the whole organism moves quickly with few turns. in favourable conditions slowly with more turns
example of kineses
woodlice move more when the air is drier. increasing their chance of encountering humid air so they don’t become dehydrated
what is taxes
are directional responses by the whole organism moving towards (positive) or away from (negative) a stimulus
example of a taxes
earthworms are negatively phototaxic, moving away from the light increases their chance of survival
explain Kohlers research
put bananas out of a chimp’s reach- the only way to get them was to join two sticks together. once the chimp had worked it out it did it evvery time
what is Kohler’s research an example of
insight learning
how are innate behaviours studies
are studied using choice chambers- different conditions are supplied in each section and movement of animals tracked
what are learned behaviours
are behaviours based on past experiences and can be modified
what are the different learned behaviours
imitation
habituation
insight learning
latent
operant conditioning
classical conditioning
imprinting
what is imitation
where animals learn by observing others e.g. the spread of tool used in chimpanzees (usually the same species)
what is habituation
learning to ignore a stimulus as it brings neither reward or punishment (prevents wasting energy)
what is insight learning
where a solution to a problem is found by accident but is immediately applied in the future
what is latent learning
is exploratory learning. animals explore new surroundings and learn- this enhances survival. no reward straight away eventually (survival)
what is operant conditioning
is the association of particular behaviours with reward or punishment
example of operant conditioning
skinner studies rats, they were rewarded for pressing a lever with a food pellet
what is classical conditioning
in an artificial stimulus associated with a natural stimulus provoking the same response. association of 2 events that occur at the same time (in natural conditions)
example of classical conditioning
pavlov trained dogs to associate a bell with food, so they responded to the sound of the bell with salivation
what is imprinting
happens early in young animals, where they became attached to the first larger moving object they detect. this is reinforced by gaining food/warmth (mainly birds and animals)
example of imprinting
Konrad Lorenz worked on imprinting and famously inprinted young geese, he became their ‘mother’ and taught them to fly
what does social behaviour describe
interactions between members of the same behaviour
advantages of living in social groups
protection from predators, food sharing and mate availability.
disadvantages of living in social groups
increased competition for mates and food, increased spread of diseases and higher visibility for predators
what are interactions within a social group usually
fixed action patter (FAP).
what does a sign stimulus lead to
a fixed response
what did Tindbergen
investigated FAP in herring gulls. the sign stimulus is the red spot on the parent beak. the response is to peck at the spot until the adult regurgitates food. gull chicks will peck an artificial beak-fixed action to the sign
what does a response depend on
motivation e.g. a cheetah will only display stalking behaviour if it is hungry
example of dominance hierarchy
only vertebrates
what is dominance hierarchy
where the members of a group are ranked from high to low; higher ranked animals dominate over lower ranked ones in a linear fashion; no two animals are at the same rank
advantages of dominance hierarchy
reduction in aggression and sharing food and fighting ensures the ‘fittest survive’
how does a dominance hierarchy work
once established, dominance hierarchies are stable and fighting for position is a last result. fighting follows a fixed action pattern in response to sign stimuli with the winner taking the higher rank
what social groups do bees work
have a caste structure that gives roles specialisation.
what do a single queen in a colony produce
sterile female working bees and fertile male drones
how do queens communicate with the colonies
using pheromones and touch.
how do bees communicate about a food dance
a waggle dance. the angle of the dance relates to the angle of the sun and the length of the waggle relates to the distance, a round dance is used when the food source is close by- gives not info about distance
role of the workers (one caste)
find food, care for young and defend the colony.
what do the few members of the other cast do (+ queen)
involved with reproduction
what does courtship behaviour ensure
species and gender recognition, receptiveness to mating and maintains pair bonds for care of the young, enhancing their survival
what type of behaviours are courtship behaviours
innate and often follow a fixed action pattern
what is sexual dimorphism
where genders have different appearances (same species)
what is intra-sexual selection
involves male-to-male combat e.g. male elephant seals fight for mating rights, larger, more aggressive males are selected
what is inter-sexual selection
where the female chooses the ‘fittest’ male
what does sexual selection do to males
makes them more conspicuous (and vulnerable to predators)
what does natural selection favour
camouflage
makes characteristics less conspicuous
what is teritory
an area consistently defended against members of the same species. it allows efficient exploitation of resources.
what does territory do
enhances reproductive success
advantages of living in a colony
increased efficiency within the colony, they work together for food reproduction etc. no fighting, division of labour
what sexual selection occurs between two members of the same species
intrasexual selection, males are much bigger than female seals, they fight for sexual access to females.
consequences of intrasexual selection
only the stronger males will be selected that only stronger males will be selected for, decreasing variation. weaker males die off
