Biopsychology Flashcards
Briefly outline the types of neuron
Motor- carries messages from CNS to muscles and glands
Sensory- carries messages from the PNS to the CNS
Relay- carries messages from sensory to motor neurons or other relay neurons
Describe the structure of a neuron
Contains a cell body
Dendrites which carry nerve impulses towards the cell body
Axon covered in myelin sheath to speed up message
Terminal buttons that communicate with the next neuron in the chain
Describe a sensory neuron
Found in receptors
Carry nerve impulses from the PNS to the CNS
Translated into sensations when they reach the brain
Some stop at the spinal cord for reflex actions
Long dendrites and short axons
Describe a relay neuron
Most common
Only found in the CNS
Connect sensory neurons to motor or other relay neurons
Short dendrites and short axons
Describe a motor neuron
Carry messages from CNS and control motor movements
When stimulated, release neurotransmitters that bind to receptors on muscle and trigger a reaction
Muscle relaxation = inhibition
Short dendrites and long axons
Describe synaptic transmission
Nerve impulse travels down the axon of a pre-synaptic neuron
End of axon, neurotransmitters are released from vesicles within the pre-synaptic neuron
These diffuse across the synapse
Neurotransmitters bind to receptors on the post-synaptic neuron
Stimulates post-synaptic neuron to transmit a nerve impulse down its axon, to the next neuron
Neurotransmitters deactivate by being reabsorbed back or being broken down by enzymes
Describe excitation and inhibition
Inhibitory neurotransmitters result in the neuron becoming negatively charged and less likely to fire- inhibitory synapse
Excitatory neurotransmitters ie dopamine, causes neuron to increase its positive charge and making it more likely to fire.
Describe summation
After receiving inhibitory and excitatory at the same time,
Combined and added up
Describe the peripheral nervous system
Transmits messages via millions of neurons to and from the CNS.
Relay nerve impulses from the CNS to the rest of the body and from body back to CNS.
Divided into
Somatic nervous system-
Voluntary actions,
Senses- carry motor and sensory info to and from CNS
Automatic nervous system-
Vital functions
Carries only motor info to and from the CNS
Describe the somatic nervous system
Controls voluntary actions
Carries sensory and motor information from the senses to the CNS and back
Part of the peripheral nervous system
Describe the sympathetic nervous system
Involved in responses that help us deal with emergencies
Fight or flight
Neurons preparing the body for rapid action,
Release stored energy
Pupils to dilate
Slows down digestion and urination
Describe the automatic nervous system
Involuntary/ vital actions
Eg, breathing, increasing heart rate
Carries only motor information from senses to and from the CNS
Divided into;
Sympathetic nervous system
Parasympathetic nervous system
Describe the parasympathetic nervous system
Returning the body to a rest state once the emergency has passes
Rest and digest
Slow heartbeat
Bodily processes inhibited by sympathetic are returned to normal
Describe the fight or flight response
After acute stressor,
Hypothalamus directs the sympathetic branch of ANS to send neurotransmitters to the adrenal medulla
Releases adrenaline into the bloodstream
And noradrenaline
Triggers physiological reactions
What is meant by localisation of function
Specific functions have specific locations within the brain
If a certain area is damaged, the associated function will also be affected
State 7 parts of the brain and where they are
Auditory cortex,
Temporal lobe either side of the brain
Motor cortex,
Back of the frontal lobe
Somatosensory cortex,
Next to the motor cortex, at the front of the parietal lobe
Visual cortex,
In the occipital lobe at the back of the brain
Broca’s area,
Left frontal lobe
Wernicke’s area,
Small area in left temporal lobe
Describe support for localisation of function
Supported by case study evidence,
Man who could only say Tan. Broca performed an autopsy, found a lesion in a region of his brain,
Concluded that his aphasia was caused by damage to the area that controlled speech.
Increases validity,
H Lacks external validity, based on one individual
Phineas gage
Brain scan research
Peterson et al demonstrated how W’s area was active during listening tasks and Broca’s was active during a reading task.
Tulving et al
Episodic and semantic memories recalled from different sides of the prefrontal cortex whilst procedural in the cerebellum
Demonstrates how specific brain regions are active
Define hemispheric lateralisation
The idea that these two hemispheres of the brain are functionally different,
Certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other
What connects the two hemispheres
Corpus callosum
Bundle of fibres
Communication pathway do that they can exchange information
Loosely describe the left hemisphere
Language processing
Strokes often lead to speech impediments in broca or wernicke area
Loosely describe the right hemisphere
Facial recognition
Spatial relationships
Evaluate hemispherical lateralisation
Supporting evidence
Fink
PET scans to identify active areas during a visual processing task
Ps asked to attend to elements of an image, right hem active
Finer detail, left hem active
Tasks such as visual processing are feature of connected brain
Plasticity
When damaged, brain can adapt to reorganize itself to recover the function
Turk et al,
Brain damage to left hemisphere developed capacity to speak in right hem
Undermines lateralisation, can be distributed
Animal research
Lashley
Removed 10-50% of cortex in rats and got them to learn a maze
Found that there were no important areas
Suggests higher cognitive processes like learning are distributed holistically
Reduces validity of theory, challenges
Lateralisation may be further complicated by age
Szflarski
Language became more lateralised to the left hem as children developed,
After 25, lateralisation decreased with each decade
Suggests lateralisation is a more complex process, unanswered questions
Challenges how stable it is throughout our lives.
Describe research into split-brain studies
Sperry
11 split brain patients
Procedure:
Verbal recognition-
A visual image presented to LVF with a tachistoscope.
Ps asked to describe what they had seen.
Repeated on RVF
Touch recognition-
Ps hands screened
Asked to pick up object with right hand and asked to describe.
Repeated with left
Findings:
Verbal recognition-
When picture shown in RVF, patients would easily describe.
If on left, reported there was nothing there
Bc
Lacked language ability to describe it
Touch recognition-
Able to select matching object from a bag with left hand.
In each case patient couldn’t verbally describe but could understand what the object was using right hem and select corresponding object accordingly
Evaluate research into split-brain studies
Supports lateralisation
Image flashed quickly to make sure info couldn’t pass to other hem
Ensures research measured what it intended to
Methodology is high,y standardised, reliable, internally valid
Flawed
Only 11 patients used who had history of epileptic seizures and had drug therapy- unique sample
Problematic
Undermines validity, confounding variables, weaken reliability
State 4 methods of studying the brain
fMRI
EEG
ERP
Post mortem
Describe functional magnetic resonance imaging
Detects changes in blood oxygenation and flow in the brain.
When area of the brain active, consumes more oxygen as the haemodynamic response)
Produces 3D images showing which part of the brain is involved in particular mental processes
Shows activity 1-4 seconds after an event occurs
Accurate within 1-2mm
Evaluate fMRI
Less invasive,
Don’t use radiation or require insertion into the brain,
Risk free
Good spatial resolution
1-2mm
Allows R to investigate brain regions with greater accuracy
Expensive
Require trained operators
More difficult to organize, less attainable
Low temporal resolution
1-4 seconds , worse than others
Unable to predict with a high degree of accuracy the onset of brain activity
Describe electroencephalogram
Places electrodes on Ps scalp to measure electrical activity in the brain
Records brainwave patterns generated from millions of neurons
Provides real time recording
Describe Event-Rekated potentials
Uses a stimulus with the EEG to filter recordings leaving only event related potentials
Evaluate EEG and ERP
Less invasive than other techniques like PET scans,
Don’t use radiation or inserted instruments
Cheaper methods in comparison to fMRI, more widely available.
Help to gather data leading to a greater understanding of sleeping and memory disorders
High temporal resolution
Takes readings every millisecond providing real time data.
Accurate measurements
Poor spatial resolution
Only detect activity in superficial regions of the brain
Unable to provide info on what is happening in deeper regions of the brain,
Limited technique in comparison to fMRI
Evaluate post mortem
Provide a detailed examination of the structure of the brain that aren’t possible with scanning techniques
Access regions otherwise struggled
Useful for further research
Ethical issues
Consent and nether they provide it before death.
Many carried out on severe psychological deficits like HM who would be unable to provide fully informed consent
Causation
Deficits may not be liked to those found in the brain. Could’ve been result of other illness.
Other confounding variables,
Medication , length of time between death and exam, age of person at death
Describe brain plasticity
Brains capacity to change or adapt because of experience and new learning
As we age, synaptic pruning occurs, rarely used synaptic connections are deleted, frequently used are strengthened
Describe four methods of forming new synaptic connections
Axon sprouting-
Growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
Denervation supersensitivity-
Axons that do similar job become aroused to a higher level to compensate. This can make the area over sensitive to pain
Recruitment of homologous areas-
Similar areas on opposite side of the brain carry out function
Neuronal unmasking-
Dormant neurons open connections to regions that are not normally activated,
Gives way to the development of new structures
Evaluate plasticity
Evidence to support
Maguire et al
Used mri to scan London taxi drivers.
Had greater posterior hippocampus, correlated with the time they had been a taxi driver
Supports that the brain can adapt
Demonstrates structural changes
Evidence to support in animal studies
Huber and Wiesel
Kittens had eyes sewn up
Brains cortical responses analysed
Area with visual cortex not idle. It continued to process info from open info
Supports that brain can adapt as result of experience
Brain can reorganise neural connections
Doesn’t completely stop as we age
Describe functional recovery
Unaffected areas are often able to adapt and compensate for those areas that are damaged.
Type of neural plasticity
The process can occur quickly after trauma and then slow down after several weeks or months.
Then rehabilitation can be used to extend recovery.
Axon sprouting- Roth of new nerve endings which connect with other undamaged nnerve cells to form new neuronal pathways
Denervation supersensitivity-
Occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost. - can make area over sensitive to pain
Recruitment of homogulous areas- opposite side of the brain to perform specific tasks. E.g Broca’s area damaged, right side would carry out function
Neuronal unmasking- side of brain’s neurons are dormant. Then unmasked to open connections in regions of the brain that are not normally activated.
Evaluate functional recovery
practical applications
Contributed to neurorehabilitation
Physical therapy helps when recovery slows down.
E.g. constraint-induced movement therapy is used with stroke patients. Repeatedly practice using affected part of their body while unaffected is restrained.
Shows research is useful by helping professionals know when interventions need to be made.
Demonstrates understanding of brain plasticity inform effective interventions. Improves outcomes for patients
Cognitive reserve
Affected by individual differences .
Schneider et al- the more time people with brain injury had spent in education, greater chances of a disability-free recovery.
40% of DFR had more than 16 years education compared to 10% less than 12.
Implies people with Britain damage who have insufficient DFR are less likely to achieve full recovery.
Highlights role of cognitive reserve in functional recovery after brain injury.
Indicates higher education have greater ability to recover.
Factors affecting -
Age
Gender
Existing disabilities
Education
Describe circadian
the sleep-wake cycle
Happens every 24 hours
Others - core body temperature follows a daily rhythm. Highest around 4pm and lowest at 4 am
Hormone production-
Hormones follow a circadian rhythm.
E.g. production and release of melatonin from pineal gland peaks during hours of darkness,
Activates chemical receptors in the brain, melatonin encourages feelings of sleep.
Dark = more melatonin then drops when wake.
Sleep wake cycle-
Light and darkness are external signals that determine when we feel the need to sleep.
Dips and rises ar different times of the day.
Strongest sleep drive 2-4 am and 1-3 pm
Describe research into circadian rhythms
Sniffer
Live underground ina cave in Texas for 6 months with no external cues, e.g. daylight.
Sleep-wake cycle settled into a ‘free-running’ rhythm of around 25 hours.
Suggests endogenous pacemakers, scn , are important in controlling sleep-wake cycle. Despite absence of exogenous xeitgebers, suffer was able to maintain a relatively normal cycle.
Folkard-
Studied a university student, Kate aldcroft, volunteered to spend 25 days in the controlled environment of a laboratory.
During her time, no access to daylight or other zeitgebers. Sleep wake cycle was extended to 30 hours.
Describe infradian rhythms
Last more than 24 hours.
E.g. menstruation, breeding, hibernation and seasonal affective disorder.
Menstrual cycle-
Governed by monthly changes in hormones that regulate ovulation.
Typical cycle lasts 28 days.
Rising levels of oestrogen cause ovary to release an egg.
After ovulation, progesterone helps womb lining to grow thicker, readying the womb for pregnancy.
If not pregnant, egg is absorbed into the body.
Describe research into infradian rhythms
McClintock-
29 women with irregular periods.
Samples of pheromones gathered from 9 women at different stages by cotton pads in armpits.
Pads rubbed on upper lip of other participants.
68% of women experienced changes to their cycle bringing them closer to the ‘odour donor;
Evaluate research into infradian rhythsms
supported by theory of evolution.
It would have been advantageous for women to menstruate and become pregnant at similar times.
Allows babies who had lost their mothers during childbirth to have access to breast milk, improving chance of survival.
Suggests that the synchronisation of menstrual cycle is an adaptive strategy.
Many factors that may cause mentrual cycle change, e.g. stress, dieting and exercising.
Describe ultradian rhythms
Last less than 24 hours.
E.g. eye blinking, heartbeats, sleep patterns, breathing, pulse, appetite and digestion
Stages of sleep:
5 stages lasting 90 minutes.
1- light sleep, easily woken.
Alpha brain waves (high frequency, low aptitude)
2- light sleep continues. Sleep spindles(short bursts of activity)
3 and 4- deep sleep or slow wave sleep
Delta waves (lower frequency, high amplitude) difficult to wake.
5- REM sleep. Body is paralysed yet brain activity closely resembles a woke brain.
Theta waves. Eyes move around.
Evaluate ultradian rhythms
has Improved understanding of age-related changes in sleep
E.g. SWS reduces with age, leading to alertness in the elderly.
Suggests knowledge has practical value
Ignores individual differences
Tucker- large differences in the duration of each sleep stage in many participants.
Makes it difficult to describe ‘normal sleep’
What is meant by an endogenous pacemaker
internal body clocks that regulate many of our biological rhythms
Describe the SCN
Suprachiasmatic nucleus
Tiny bundle of nerve cells located in the hypothalamus.
Maintains circadian rhythms e.g. sleep wake cycle.
If it’s damaged or destroyed, sleep becomes erratic.
Lies above the optic chaism.
Receives information about light directly from this structure.
Continues even with yes closed, enabling biological clock to adjust to changing patterns of daylight whilst we are asleep.
If biological clock is running slow, morning light automatically adjusts the clock, putting its rhythm in step with the world outside.
This synchronisation is called entrainment
What is meant by entrainment
The synchronisation of the SCN by changes in light
Describe the pineal gland and melatonin as endogenous pacemakers
SCN passes information on day length and light to the pineal gland. During the night, increases production of melatonin - induces sleep and is inhibited during wakefulness.
Linked to seasonal affective disorder.
Evaluate endogenous pacemakers
supporting evidence
Morgan-
Hamsters
If their SCN was removed, SW cycle disappeared .
Transplanting scn cells from foetal hamsters into these hamsters helped to re-establish sleep wake cycle.
If it was given a transplanted scn from a mutant strain with a shorter SWC of 20 hours, adopts same activity.
Supports view that SCN is vital in maintaining the SWC.
Provides strong evidence. Demonstrates importance in regulating circadian rhythms.
However should be careful applying to humans. Social cues might influence human cycles. Difficult to generalise.
Siffre- supports SCN.
Lived underground in a cave in Texas for 6 months with no external cues. SWC settled into a ‘free-running’ rhythm of around 25 hours.
Suggests endogenous pacemakers are important in controlling sleep wake cycle because he maintained a regular cycle.
However only based on one individual case. His ma be different to general population, reducing external validity. Also used artificial lighting which may have acted as an extraneous variable, reducing internal validity
Practical apps
Circadian rhyths affect when drugs are most effective.
TF when prescribed drugs it is now advised that they are taken at different times of the day to maximise effects.
Suggests we have an internal body clock that controls SWC as medication is advised to be taken a round it.
Highlights importance for understanding endogenous pacemakers in everyday healthcare practices, optimising treatment outcomes by aligning drug administration with body’s natural rhythms
Contradictory evidence-
Folkard-
Kate aldcroft-
Spent 25 days in controlled environment. No access to any light or other zeitgebers that might have reset SCN.
At the end, SWC had extended to 30 hours.
Reduces validity of role of endogenous pacemakers bc exogenous xeitgebers are needed.
Suggests external cues are crucial in synchronising.
Descirbe exogenous zeitgebers
light
Helps to maintain SWC by resetting the SCN.
Receptors in SCN are sensitive to changes in light levels and use this to synchronise the activity of the bosy’s organs and glands.
Light resets the internal biological clock each day, keeping it on a 24 hour cycle.
Describe social cues
mealtimes, bedtimes and social events.
Research suggests that adapting to local times for eating and sleeping is an effective way of entraining circadian rhyth,s and beating jet lag when travelling long distances.
Evaluate exogenous zeitgebers
Supporting evidence
Campbell and Murphy-
Shining light on the ack of p’s knees shifted the circadian rhythm.
Implies natural light plays a role in entraining our biological clocks to keep SWC synchronise with outside world.
Demonstrates how external cues can influence timing of biological processes.
Practical applications
Treatments for jet lag-
Burgess-
Exposure to bright light prior to an east-west flight reduced jet lag.
Ps who were exposed to bright light felt sleepier 2 hours earlier in the evening and woke up 2 hours earlier.
Benefits economy as preventing jet lag improves productivity.
E.g. people more likely to return to work after a flight.
Shows how interventions can mitigate effects of jet lag .
Contradictory evidence-
Miles-
Studied a young man who was blind from birth. Despite exposure to social cues, his SWC remained abnormal (24.9 hours)
Suggests social cues alone aren’t effective in resetting biological rhythm.
Suggests other factors e.g. light play a more crucial role
