Biopsychology Flashcards
Nervous system
a specialised network of cells in the human body - our primary communication system
two main functions of nervous system
- collect, process and respond to information in the environment
- co-ordinate the working of different organs and cells in the body
two main subsystems
- central nervous system (CNS)
- peripheral nervous system (PNS)
centeral nervous system (CNS)
- considts of brain and spinal chord
- its the origin of all complex commands and decisions
the brain: centre of conscious awareness, contains the cerebral cortex - the reason we have higher mental functions compared yo other animals
the spinal chord: an extension of the brain responsible for out reflexes (short cuts) passes messages to and from the brain. connects nerves to PNS
- may causes paralysis, responsible;e for reflexes
Peripheral nervous system
the rest of the body
- uses millions of nerve cells (neurons) to send messages from the outside world to the brain (CNS) through the use of sensory neurons
- it also sends messages from the brain (CNS) to muscles and glands
it has two subdivisions : - autonomic nervous system (ANS)
- somatic nervous system (SNS)
somatic nervous system
- recives information for senses ( sensory receptors) to the CNS (brain)
- controls muscle movement (brain signals motor movment)
e.g. sensory reseptors on hand (flame on hands)
->
CNS (brain or spinal chord)
->
muscles (move hands)
autonotmic nervous systems (ANS)
AKA automatic - system operates involuntarily DONT SAY AUTOMATICALLY
- governs vital functions in the body, involuntary bodily processes NOT MOVMENT
- transmits info to and from organs
has 2 subdivisions:
-systematic
- parasympathetic
Parasympathetic and sympathetic nervous systems
- their actions are mostly antagnositic - they usually work in opposition to each other
- sympathetic - prepares the body to expand energy (fight or flight)
- parasympathetic - conserves energy and activity of bodily functions (homeostasis )
both are very important for the stress response
The endocrine system
a bodily system that works alongside the nervous system to control bodily functions
- the main difference is it works much slower than the NS
- it instructs glands to release hormones directly into the bloodstream
- the hormones are then carried towards organs in the body
glands
organs in the body that secrete substances
hormones
powerful chemicals that travel through the blood to affect target organs
distinction between nervous and endocrine systems
communicati0on via neurotransmitters in neurons (very fast)
communicates via hormones in blood (very slow)
endocrine system
pituitary gland : known as the ‘master gland’ controls the release of hormones in all other endocrine glands in the body
adrenal gland: secretes the hormones of adrenaline
pineal gland: secretes melatonin (hormones for sleep)
the most important are in the centre, protected
what makes up the endocrine system
pituitary gland
adrenal gland
pineal gland
the role of adrenaline
a hormone produced by the adrenal glands
- part of the body’s immediate stress response response system AKA fight or flight
adrenaline is needed to activate the sympathetic nervous system - which then prepares the organs for an appropriate response (increased heart rate, dialted pupils)
Heart
SNS - heart rate increases
PNS - heart rate decreases
salivary glands
SNS - low salivation
PNS - high salivation
lungs
SNS - increase oxygen uptake
PNS - decreased oxygen uptake
Brain
An organ that serves as the centre of the nervous system in all vertebrates and most invertibrate animals
Autonomic nervous system
Connects the central nervous system to internal organs
Parasympathetic nervous system
Works to counteract the body’s response to stress
Somatic nervous system
Connects the central nervous system to muscles and sensory receptors
Sympathetic nervous system
Controls body’s response to emergency
Centeral nervous system
Contains the brain and spinal chord and is the origin of all complex commands
Peripheral nervous system
The nerves leading to and from the brain and spinal chord
Spinal chord
The main pathway for information connecting the brain and peripheral nervous system (involved in reflex actions)
The nervous system
A network of all the neurons in the body
Neurons
Nerve cell
The basic building blocks of the nervous system
They are the nerve cells that process and transmitt messages through electrical and chemical signals
- there are 100 billion neurons in the human nervous system, 80% of which are located in the brain
- they provide the NS with its primary means of communication (almost like mini messages)
- there are three types of neurons (motor, sensory, relay)
Dendrites
-the receiving end of the neuron
- dendtrites are branch-like structures that protrude from the cell body
There are many branches so that electrical impulses (messages) can be received from many other neurons at once
-the most important / used neurons tend to have the most dendrites
Nucleus
As with any cell, the nucleus contains the genetic material of the cell
Cell body
The nucleus lives inside the cell body (the soma) usually the largest part of the neuron
Axon
-the longest part of the neuron e.g. 1m
- axon carries the impulses away from the cell body down the length of the neuron
- axons have adapted in two ways to help speed up the transmission of the impulses
Myelin sheath
-this is a fatty layer that covers the axon to protect its structure
It also speeds up the transmission of the impulse
-however if myelin sheath was continuous across the axon, it would have the reverse effects (slow down)
-therefore the axon has adapted to form gaps between the layers of myelin sheath
Gaps between the myelinth sheath
Nodes of ranvier
Terminal button
This is at the end of the neuron (hence terminal)
Once all electrical impulses reach the next terminal button; it is communicated to the next neuron
-this is done across a mall gap between neurons
-known as synapses
Terminal button
This is at the end of the neuron (hence terminal)
Once all electrical impulses reach the next terminal button; it is communicated to the next neuron
-this is done across a mall gap between neurons
-known as synapses
Gaps between neurons
Synapses
How do neurons communicate
-terminal buttons from one neuron, connect to the dendrites of the next neuron
- a neuron will “fire” when positively charged,
the resting state of the cell is negatively charged however when activated by a stimulus, the inside of the cell becomes positively charged (for a split second)
This causes an action potential to occur- this then creates an electrical impulse that travels down the axon to stimulate the next neuron
This is known as an electrical transmission
Which type of neuron has longer axons
Motor neurons
Types of neurons
Relay
Motor
Sensory
Relay
These connect the neurons together
Sensory
These carry messages from the PNS to the CNS
Cell body is on the outside
dendrites/ axons
motor
dendrites- short
axon - long
dendrites/ axons
sensory
dendtrites: long
axons: short
dendrites/ axons
relay
dendrites: short
axons: short
synaptic transmission
the transmission (of messages) across the synapse
the process by which neighboring neurons communicate with each other by sending chemical messages across the gap (synapse) that separates them
- signals within neurons are transmitted electrically
- however sgnals between neurons are transmitted chemically across the synapse
- neuron communicate in groups known as neural networks
how does the process change
- the transmittion process changes from electrical to chemical
- the transmission process changes from electrical to chemical
- the electrcal impulses (triggered by a posiive charge) travels from the dendrites -> axon -> terminal button
- once the impulse reaches from terminal button it triggers the release of neurotransmitters
neurotransmitters
brain chemicals that relay signals across the synapse from one neuron to another
neurotransmitters travel across
the synapse to the next neuron (chemical transmission)
- this then creates a charge in the next neuron (positive/negative)
- if this charge is positive it will cause electrical transmission to tak place in the next neuron
The process at the synapse
- neurotransmitters live tiny sacs called synaptic vesicles fround at the terminal buttons of the pre-synaptic neuron
- once an action potential (electrical potential) reaches the terminal button, it triggers the release of neurotransmittes
- the neurotransmitters diffuse across the synapse and bind to the receptor sites on the dendrites f the post synaptic neuron
once this happens the message is converted back into an electrical impulse and then the process starts again
re-uptake (synapse)
- when neurotransmitters are released across to the post synaptic neuron
- once the post-synaptic neuron is full, its receptor sites will close
- remaining neurotransmitters recycled back into the original pe-synaptic neuron, where they can be used again - this is called re-uptake
A note on neurotransmitters
- different neurotransitters can be found in differen neurons (as they have different fuctions)
- each neurotransmitter has its own specific molecular structure
- this is to ensure that neurotransitters fit perfectly ino the receptor sites on the post synaptic neuron
- this also helps make sure that the wrong chemicals don’t enter the wrong neurons
therefore synaptic transmission uses a ‘lock and key diagram’
excitation and inhibition
multiple neurons fire at the same time, sometimes at the same neuron
excitation
when a neurotransmitter increases the positive change of the postsynapic neuron. this increases the likelehood that the neuron will fire and pass on the electrical impulse
inhibition
when a neurotransiter increases the negative charge of the postsynaptic neuron
This decreases the like
what does this mean
all neurotransmitters can be classified as eitherexcitatiobary or inhibitiontory
this means that they either have excitatory post-synaptic potentical (EPSP) or inhibitory post-synaptic potential (IPSP)
(they can either positevely or negatavely charge the cell)
if a post synaptic neuron has enough positive change, it will fire its own action potential (to another neuron)
- if a post-synaptic neuron doesn’t enough positive charge (negitavely charge) it will not fire
localisation of function
the notion that specific functions have specific locations in the brain
the lobes
frontal
occipital
parietal
temporal
frontal lobe
cognitive skills (memory, problem solving)
occipital lobe
processes visual information
parietal lobe
process sensory info and spatial navigation
temporal lobe
processes auditory information
areas and centres of the brain
motor and somatosensory areas
visual and auditory centres
language centres
motor and somatosensory areas
- motor cortex
- somatosensory cortext
visual and auditory centres
- visual centre
- auditory centre
langages centres
- wernickes area
- brocas area
the motor corext
-located in the forntal lobe (precenteral gyrus)
- found in both hemispheres of the brain but controls the opposite side of the body
- each region is
biological rhythms: circadian rhythms
distrinct patters of changes in the body activity that confrom to cyclical time period
- all living organisms are subject to biological rhythums - they have a very important influence on how body systems behave
- (they have evolved due to changes in the enviroment day/night, summer/winter)
e.g. sleeping,eating, menstural cycle
circa
about
dian
day
what are circadian rhymthms influenced by?
endogenous pacemakers (internal body clocks)
exogenous zeitgebers ( changs in the enviroment) e.g. light
three types of biological rhythms
- circdian rhthyms - 24 hours
- infadian rhythms - less than one cycle in 24 hors
- ultradian rythms - more than one cycle in 24 hours
circadian rythm
A type of biological rhythm, subject to a 24-hour cycle, which regulates a number of body processes such as the sleep/wake cycle and changes in core body temperature
Sleep/wake cycle
The sleep/wake cycle is largely affected by daylight – an
important exogenous zeitgeber
Daylight helps set the body clock to the correct time – so
we are awake in the day and asleep at night
The cycle is regulated by the suprachiasmatic nuclei
(SCN) – known as the master circadian pacemaker,
located in the hypothalamus
Light-sensitive cells in our eyes detect brightness and send
this info to the SCN – this then resets to make sure our
bodies are synchronised with the outside world
the amount of daylight and darkness detected by the SCN
tells the body when to fall asleep and when to wake up
The circadian rhythm will keep us awake as long as there
is daylight, so sleep is prompted once it’s dark
The circadian rhythm is ‘free-running’ as it will run even
without external cues
but major alterations in sleep/wake schedules can cause
our biological clock to lose its synchrony
circadian rythum research
Researchers wanted to investigate what would happen if the body clock was left to its own devices (without daylight)
Siffre’s cave study (1960s)
- Siffre was a self-styled caveman who spent several extended periods of time underground to study the effects of his own biological rhythms
- He had food and drink, but was deprived of natural light and sound
- On his first venture, he went underground for two months – believing it was mid August when he returned, when it was actually mid September (lost a month of time)
- A decade later he went underground for 6 months in a (Texan cave)
- He found that his circadian rhythm only extended to around 25 hours, as he continued fall asleep and wake up on a regular
schedule - However during his last underground stay in 1999 (at 60 yrs old) his circadian rhythm extended to nearly 48 hours at
times
Aschoff and Wever (1976)
- Convinced a group of ppts to spend 4 weeks in a WWII
bunker deprived of natural light. - They found that all but one ppt kept a circadian rhythm of
24-25 hours (one developed a rhythm of 29 hours)
Core body temperature
varies by around 2 degrees centigrade during the course of a day
At its lowest at 36⁰C in the morning and peaks around 38 ⁰C in the evening
During the normal circadian rhythm, sleep occurs when the core temp drops, and the temp starts to rise in the last hours of sleep – preparing our body for alertness in the morning – body temp also drops around 2-4pm
Infradian rhythms
A type of biological rhythm with a frequency of less than one cycle in 24 hours
These cycles take longer than 24 hours to complete – longer than circadian rhythms
These can last days, weeks or months
- The two examples we will be looking at are
The menstrual cycle
Seasonal affective disorder (SAD)
examples
infradian rhythms
menstural cycle
seasonal affective disorder (SAD)
The menstrual cycle
Governed by monthly changes in hormone levels which regulate ovulation
The typical cycle refers to time between day 1 of the cycle (shedding of womb lining) to the day before the next cycle
The cycle lasts approximately 28 days (24-35 also normal)
The cycle is regulated by hormones which either promote ovulation or fertilisation
The sex hormone cycle
- Oestrogen levels peak arond halfway through the cycle to promote ovulation
-Progesterone then rises towards the end of the cycle, preparing the body for fertilisation in the uterus
the menstral cycle
Research
Although the menstrual cycle is an endogenous system, research has shown that it may be influenced by exogenous factors – pheromones
stern and mcclintock
- Studied 29 women with a history of irregular periods
- 9 of the women were given cotton wool pads to place under their arms to collect their pheromone levels at different stages of their cycles
- Pads were then treated with alcohol and frozen – then placed onto the upper lips of the other ppts…
- Pads from day 1 of the menstrual cycles were placed on all 20 of the other ppts on day 1 – this continued each day in the same pattern
- They found that 68% of women experienced changes to their cycle – being closer in line with their ‘odour donor’
seasonal affective disorder
SAD is a depressive disorder which has a seasonal pattern of onset
- it described and diagnosed to general depression (persistent low mood, lack of interest in life)
- but is often referred to as ‘winter blues’ as symptoms are only triggers during the winter moths of the year
- SAD is a circannual rhythm - subjected to a yearly cycle
melatonin
Less daylight 🡪 more melatonin 🡪 less serotonin 🡪 less balanced mood
Psychologists have hypothesised that the hormone melatonin is the cause of SAD
During the night, the pineal gland secretes melatonin until morning (regulated by the SCN)
Lack of light in the winter means that that melatonin is secreted for longer
This has a knock-on effect on the production of serotonin – linked to depression
the menstural cycle
Practical implications
Evolutionary basis of the menstrual cycle?
For our ancestors it may have been advantageous for females to menstruate together – this means women are more likely to fall pregnant at the same time
New-borns could be cared for together, increasing chances of survival
This suggests menstrual synchronisation has a purpose
However, Schank (2004) argued that too many females cycling together within a social group would produce competition…(competing for the best quality sperm)
From this perspective, avoiding synchrony is the most adaptive evolutionary strategy
Implications for breeding in zoos?
animals may get agressive due to compettitivness
Effects of the menstrual cycle
enton-Voak et al. (1999) – mate choice preferences
Found that at different stages of the menstrual cycle, women’s mate preferences varied
Women generally preferred a slightly ‘feminised’ face when choosing long-term partner
However, when during the ovulatory phase of their cycle, they preferred more ‘masculinised’ faces
Why might this be?
Feminised faces are likely to represent kindness, cooperation and parental care
Masculinised faces are likely to represent “good genes” that can be passed down to offspring
SAD: practical application
SAD can be treated by phototherapy – this is a lightbox that simulates very strong (blue) light in the morning and evening
It is thought to reset melatonin levels in people with SAD
Eastman (1998) found that this technique relieves symptoms in 60% of sufferers
What is the strength here?
However, the same study also found a placebo effect
30% of pts reported a relief of symptoms when using a sham generator – why is this a problem?
ultradian rhythms
- a type of biological rhythm with a freqency of more thn one cycle in 24 hours
- this means that there are numerous cycles that will occour within a 24 hour period
- e.g. sleep stages
the sleep stages
Psychologists have identified 5 distinct stages of sleep
that altogether span across a 90 minute period
This cycle continues throughout the course of the night
EEGs have been used to detect brainwave activity which
has shown different waves at different stages of sleep
Sleep stages include
REM sleep and
NREM sleep (stages
1-4)
most dreams take place in REM sleep
levels of sleep cycle
vunlerable, evolution for alertness
research
the basic rest activity cycle
- kleitman - named on spec as BRAC
- he proposed that the sleep cycle continues yhrought the day as well as night
- progress through stages of alertness which decline and progress into stages of psychological fatigue every 90 mins at a time
- the human body runs on resources, resulting in poor concentration, hunger and fatigue
- e.g. 10 am cofees/ afternoon naps allow or time to be organised into 90 min phases
endogenous pacemaker def
internal body clock that regulates many of our biological rhythms
exogenous zeitgebers def
external cues that may affect our biological rhythms
examples of endogenous pacemakers
pineal gland
example of exogenous zeitgebers
social cues, daylight
endogenous pacemakers
the suprachiasmatic nuclei SCN AO1
- a tiny bundle of nerve cells in the hypothalamus
- nerve fibres connected to the eye cross in the optic chiasm on their way to the visual area
- the SCN is directly above the optic chiasm (‘supra’ means above)m
- info is sent directly to the SCN using the route-this happens even when the eyes are closer
- this enables the biological clock to adjust to changing patterns of daylight whilst we sleep
hemispheric lateralisation
there are two ways in which we divide amd investigate the brain
- localisation of function
- lateralisation of hemispheres
the idea that two halves of the brain (hemispheres) are functionally different and certain processes and behaviours are mainly controlled by one hemisphere rather than the other
hemispheric lateralistaion
langauge
wernicke’s and broca’s language areas have only been identified within the left hemisphere of the brain
- this suggests processing and understanding language is controlled by the left side of the brain
left hemisphere
- sensory stimulus from right side of the body
- motor control of right side of the body
- speech, language and comprehension
- recognition of words/ numbers
right hemisphere
- sensory stimulus from left side of the body
- motor control of left side of the body
- creativity
- spacial ability
- context/ perception
- recognition of places/ faces
how do hemispheres communicate
- if one hemisphere is more dominant for controlling certain functions, how does the other hemisphere know whats goign on?
- communicate via the CORPUS CALLOSUM
- network of fibres that allow info from one hemisphere to be passes over to the other hemisphere
how is lateralisation investigated?
split brain research - sperry et al
epileptic patients who had experienced a surgical separation of hemispheres in brain
allowed researchers to investiagte the extent to which the brain is lateralsised
epilepsy patients
- sperry studied a unique group of epileptic patients that had undergone surgery called commissurotomy
- this involves removing the corpus callosum
- this meant that these patients no longer had communication between hemispheres
- this allowed sperry to investiagte which hemisphere was most dominant to compelete specific fucntions
sperry’s procedure
- he asked patients to fixate on a dot in the centre of a screen and projected an image in the patients left or right field
- they would be asked to make a response with either their left or right hand
- pr would be aksed to respond verbally without bieng able to see what thier hands were doing
sperry key investiagtions
describing what they saw
shown an image of an object in either their left or right visual field and had to descibe what they saw
couldnt descibe what they saw in the left visual field, because the image is being processed in the right hemisphere but langauge is processed in the left hemisphere
could describe what they saw in the right visual field, as its processed in the left hemisphere and this is where langage is processed
sperry key investiagtions
recognition by touch
- shown an image of an object in either their left or right visual field and had to recognise it via touch
- could recognise what they saw in the left/ right visual field, because recognition by touvh (sesnory processing info) is not lateralsised, the somatory cortex is found in both hemispheres
sperry key investiagtions
composite words
shown two different words in either their left/ right visual field and had to write/ say what they saw
sperry’s key investigateions
matching faces
pick ot a face they saw with a series of other facespick ot a face they saw with a series of other faces
right hem showed to be dominant for recognising faces
- patients tended to continously choose the face in the left visual field and ignore the image on the right
four methods of investigating the brain
fMRI
EEG
ERP
Post-mortem examinations
Functional magnetic resonance imaging fMRI
- a method used to examine brain activity
- while performing a task
- uses technology that detects radio waves from changes in magnetic fields
- this enables researchers to detect the regions in the brain that are rich in oxygen (active)
fMRI
blood oxygenation
- fMRI detects changes of oxygen in blood
- when a specific area of the brain is more activeit consumes more oxygen
- this also increases the blood flow to that specific area
- the fMRI produces a 3-D image of the brain highlight the levels of blood oxygen
EEG
- a record of a tiny electrical impulse produced by the brain’s activity
- the EEGs measure electrical activity via electrodes that are fixed onto the scalp using a skull cap
- brainwave patterns are recorded - generated from the action of millions of nerons representing overall of the neurons - representing overall brain activity
- by measuring characteristic wave patterns diagnoses can be made for certain conditions
ERPs (event-related potentials)
- th brain’s e’ectrophysiological response to a specific sensory cognitive or motor event
- more formally it is any steryotyped electrophsyiological response to stimulus
- this is the opposite to EEG - rather than measuring overall brain activity, we can tease out specific neurons and isolate the responses
- this allows us to measure responses to specific processes such as cognitive processes (attention)
e.g. detecting a stimulus, a motor response such as pressing a button
post mortem examinations
- the brain is analysed after death to determine whether certain observed behaviours during the patient’s lifetime can be linked to abnormalitoesin the brain
- usually used on those who may have had a rare disorder or deficits in mental processes/ behaviour
- areas with damage are examined and can help establish the causes of any affliction sufferef - usually compared to a neruotypical brain
evaluation
fMRI
+high spatial resolution - produces images depicting detail by the millimetre, clear indictation for localisation
+non-invasive - doesnt rely on radiation or injecting other substances e.g. PET scans, more credible, practical, ethical
- low temporal resolution - can only capture an image if individual stays perfectly still
- has a 5 second lag time behind image on the screen
- only measures blood flow, doesnt tell us abot the type of brain activity
evaluation
EEG
+strong application - has diagnosed conditions such as epil[sy and has hel[ed pur understanding of sleep stages, good use beyond explanatory power
+ high temporal resolution - can accurately detect brain activity at a single milliesecond
- unable to pinpoint the exact source of neural activity only averall activity - unable to distinguish between activity in different but adjacent locations
ERPs
+ high specificity - can pinpoint exact neural brain activity
+ high temporal resolution - ERPs are derived from EEGs - can also picked up activity by the millisecond
+ application - different types of ERP have been used to describe cognitive fucntions e.g. P300 component a specific neuron, is found to be involved in working memory
- lack of standerdisation across different research
- difficult to remove background noise
evaluation
post-mortem
+application - has provided a foundation for understanding key processes in the brain (Broca and wernicke both relied on this method to investigate links to language)
+ improves medical knowledge - allows new hyoptheses to be generated for further study
- causation - unable to confirm whether a deficit/ abnormality in the brain caused issues during lifetime (maybe the differences we see in the brain are consequences of something, not a cause)
- difficult to gather informed consent (you need personal/ family to do this)
brain plasticity
the brain’s tendancy to change and adapt (functionally and physically) as a result of experience and new learning
during infancy, breain has a huge growth of synaptic connections in brain (150,000 at age 2-3)
this is nearly as twoce as many as the adult brain - we lose the connections that we rarely use and more frequently used connections are strengthened - synaptic pruning
synaptic pruning
we lose the connections that we rarely use and more frequently used connections are strengthened
functional recovery
a form of brain plasticity
followeing damage throgh trauma the brain’s ability to transfer fucntions usally performed by the damaged area to other undamaged areas
following physical ingry or other forms of trauma (stroke) unaffected areas of the brain can adapt and compensate for those areas that are damaged
- neuroscientists way this process can happen quickly after trauma (spontaneous recovery) and then slow down after weeks/ months
- they may then require rehabilative therapy to further their recovery
mechanisms for recovery
the brain can change structally and functionally in two ways
Neuronal unmasking - wall
- identified dormant synapses in the brain - synapses that exist automatically but their functions are blocked- these synapses are ineffective because the areas around them are too inactive
- if an area becomes damaged the surronding areas increase in activity, opening dormant synapses
- these synapses can then acticate new areas of the brain, leading to a development of new structures
stem cells
unspecialised cells - have the potential to adapt different cell types and carry out different functions e.g. nerve cells
they can be used for treatment for brain damage
- stem cells can be implanted into the brain - they shoulld replace dead/ dying cells
- stem cells once implanted secrete growth that rescue the injured cells
suprachiasmatic nuclei
regulates sleep wake cycle
known as the master circadian pacemaker,
located in the hypothalamus
Light-sensitive cells in our eyes detect brightness and send
this info to the SCN – this then resets to make sure our
bodies are synchronised with the outside world
