Biopsychology L5-12 Flashcards
Which hemisphere controls the left side of the body?
Right
Which hemisphere controls the right side of the body?
Left
Describe the auditory pathway. Where is the cortex located?
Located in the temporal lobe
- Cochlea (sound waves converted to electrical impulses)
- Brain stem (basic decoding takes place)
- Thalamus (further processing)
- Auditory cortex
Describe the visual pathway. Where is the cortex located?
Located in the occipital lobe
- Retina (light strikes photoreceptors)
- Thalamus (via optic nerve)
- Visual cortex
What is the motor cortex responsible for? Where is it located?
Responsible for voluntary motor movements - different parts control different body parts.
Located in frontal lobe along the precentral gyrus
What is the somatosensory cortex responsible for? Where is it located?
Responsible for detecting sensory events to produce sensations localised to certain parts of the body.
Located in parietal lobe along postcentral gyrus
What is the Broca’s Area responsible for? Where is it located?
Responsible for producing speech. Fedorenko et al (2012) found two regions - one involved in language and the other in demanding cognitive tasks.
Located in ONLY THE LEFT frontal lobe.
What is the Wernicke’s Area responsible for? Where is it located?
Responsible for receiving/understanding speech.
Located in ONLY THE LEFT temporal lobe.
What is expressive aphasia? What is the cause?
Inability to produce speech, due to lesions to the Broca’s Area
What is receptive aphasia? What is the cause?
Inability to understand and respond accordingly to speech, due to lesions to the Wernicke’s Area
State 3 negative evaluation points for localisation of function?
- Dronkers et al (2007) re-examined brains of Broca’s patients - found several areas of brain damaged, concluded lesions to Broca’s area causes temporary speech disruption
- Bavelier et al (1997) found individual differences in activated brain areas when silently reading. Activity observed in temporal lobe, left frontal lobe, and occipital lobe
- Dejerine (1892) found patient who couldn’t read due to damage to the visual cortex and Wernicke’s area - communication between brain areas may be more important than specific areas
Define localisation of function.
The principle that specific functions have specific locations within the brain.
Define lateralisation of function.
The idea that the two different hemispheres of the brain have different specialisations
What is the left hemisphere dominant at?
Language and speech
What is the right hemisphere dominant at?
Visual-motor tasks and facial recognition
What is the corpus callosum?
Bundle of nerve fibres that connects the hemispheres
State 2 positives about lateralisation of function.
- Increases neural processing capacity. Multi-tasking hemispheres (one does one task, one does the other). Rogers et al (2004) found lateralisation in chickens linked to ability to multi-task
- Architects and math experts tend to have superior right hemispheric skills to left hemispheric skills
State 2 negatives about lateralisation of function.
- Doesn’t remain the same during a lifetime. Szaflarski et al (2006) found language become more lateralised to the left until 25yrs old, then lateralisation decreased
- JW developed capacity to speak out of right hemisphere - can speak on info given to right or left hemisphere (Turk et al 2002)
What is split-brain research?
Research into patients that have had their corpus callosum cut to prevent violent epileptic seizures
Describe Sperry and Gazzaniga’s 1968 research study.
1) Patients stare at dot at centre of screen
2) Information presented to either left or right visual field
3) Patient response through left or right hand, or verbally
What was found in Sperry and Gazzaniga’s resarch study?
If information enters the left visual field (right hemisphere), the patient won’t be able to say it because only the left hemisphere has language centres. The patient can draw the item, but only with their left hand (controlled by right hemisphere)
State 3 negatives of split-brain research.
- Hard to generalise study - some only use 3 patients
- Disconnection between hemispheres is greater in some patients than others - having drug therapy for epilepsy for longer could affect brain
- Not valid to compare previously epileptic patients with control group with no epileptic history
State 2 positives of split-brain research
- Gives greater understanding of differing functions of brain sections
- Doesn’t have much effect on daily life of patient, but removes their painful epileptic seizures
Define brain plasticity.
The brain’s ability to change and adapt as a result of experience. Plays an important role in development and behaviour.
What are the three influencers of plasticity?
- Life experience
- Meditation
- Video games
How are life experiences and plasticity related?
Frequently used nerve pathways develop stronger connections, rarely used pathways die - brain adapts to change.
What evidence is there to support the relationship between life experience and plasticity?
Boyke et al (2008) taught 60yr olds to juggle - increased grey matter in visual cortex
How are video games and plasticity related?
Kuhn et al (2014) compared control group to group that played Super Mario for 30mins/day for 2 months. Found increased grey matter in visual cortex, hippocampus and cerebellum. Concluded video games increases synaptic connections in brain involved in spatial navigation, strategic planning, working memory and motor performance.
What areas of the brain are affected by video games?
Cerebellum, Hippocampus, Visual Cortex
How is meditation and plasticity related?
Davidson et al (2004) comapred 8 Tibetan monks with 10 students with no experience of meditation. Both groups meditated for short periods. Greater gamma wave activity in monks before meditating
What is the role of gamma waves in the brain?
Co-ordinate neural activity
State 2 positive points on plasticity?
- Kemperman et al (1998) found more new neurons in brains of rats in complex environments than lab cages. Increase prominent in hippocampus (issue of generalisation)
- Maguire et al (2000) measured grey matter of London taxi drivers with MRI scan - found larger hippocampus (forming memories and navigation) than control group
Define functional recovery.
When neurones are damaged the brain re-wires itself over time. Other parts of the brain take over the functioning of the damaged part(s).
What are dormant synapses?
Synaptic connections that exist, but their function’s been blocked.
What is neuronal unmasking?
The process of increasing neural input to dormant synapses to open connections to areas that aren’t usually active - occurs when areas are damaged, can lead to development of brain structures
What are stem cells?
Unspecialised cells that have the potential to differentiate into any cell type.
What are the hopes for stem cells in research?
- Implanted into brain to replace dead/dying cells
- Transported stem cells secrete growth factors to ‘rescue’ damaged cells
- Transported stem cells form neural network linking from damaged site to functioning brain site
State 2 positives of functional recovery.
- Tajiri et al (2013) studied rats with traumatic brain injuries - one group received stem cell transplants into damaged brain area, 3 months later showed development of neuron-like cells. (ethical issues - caused injury, can’t generalise)
- Studies show abilities learnt in childhood can be modified in adulthood, but takes intensive retraining
State 2 negatives of functional recovery.
- Elbert et al (2001) concluded capacity for neural reorganisation after brain injury is greater in children
- Schneider et al (2014) found patients with college education are 7x more likely to be disability-free a year after brain injury than those who didn’t finish secondary school. Concluded neural reserve could be a factor in recovery
Describe the technique of a post-mortem. What is its use?
- Person who displays interesting behaviour dies
- Brain analysed for abnormalities
It’s used to discover links between brain structures and psychiatric disorders.
State 2 strengths and 2 weaknesses of post-mortems.
Strengths:
- Allows for more detailed examination of anatomical and neurochemical aspects of the brain than scans
- Provides greater understanding of rare disorders
Weakness:
- Only observes what’s happening on the surface
- Death circumstances could affect the brain, e.g. disease, age of death, time since death
Describe the technique of Functional Magnetic Resonance Imaging (fMRI). What is its use?
- Patient placed in MRI scanner
- Blood flow of brain monitored when carrying out certain tasks
It’s used to measure brain activity in relation to a task
State 2 strengths and 2 weaknesses of fMRI scans.
Strengths:
- Non-invasive - no exposure to harmful radiation
- High resonance images taken
Weaknesses:
- Expensive
- Critics say it overlooks the networked nature of the brain - focuses on localised activity
Describe the technique of electroencephalograms (EEGs). What is its use?
- Electrodes palced on scalp of patient to detect small electrical charges in cerebral cortex
- Electrical signals graphed over time
It’s used to measure electrical activity in the brain.
State 2 strengths and 2 weaknesses of EEGs.
Strengths:
- Useful in clinical diagnosis e.g. confirm occurence of epileptic seizures
- Non-invasive
Weaknesses:
- Cannot reveal activity in deeper regions (e.g. hypothalamus, hippocampus) - only the surface
- Poor spatial resolution - detect when neurons fire, but not where
What are the four basic EEG patterns?
- Beta - Awake with mental activity
- Alpha - Awake but resting
- Theta - Sleeping
- Delta - Deep Sleep
What is the EEG pattern for epileptic patients and those with a brain injury?
Epileptic patients - spikes of activity
Brain injury - slowing activity
Describe the technique of event-related potentials. What is its use?
Same as EEG, but in response to a stimulus. The stimulus is presented many times to establish specific response
What are event-related potentials?
Very small voltages in the brain that are triggered by stimuli. Action potentials related to an event
What are sensory event-related potentials?
ERP waves generated in the first 100 miliseconds of presenting the stimulus - response to physical nature of stimulus
What are cognitive event-related potentials?
ERP waves generated after the first 100 miliseconds - reflects the evaluation of the stimulus, and information processing
State 2 strengths and 1 weakness of Event-Related Potentials.
Strengths:
- Can measure processing of stimulus in absense of behavioural response - determine truthful reactions
- Non-invasive
Weaknesses:
1. Activity deeper in the brain isn’t recorded - restricted to the neocortex
What is the neocortex?
Part of the cerebral cortex associated with sight and hearing - most recently evolved part
What are biological rhythms?
Cyclical changes in physiological systems due to environment
What are the three types of biological rhythms?
Ultradian
Circadian
Infradian
How long do ultradian rhythms last?
Less than 24 hours
How long do circadian rhythms last?
24 hours
How long do infradian rhythms last?
More than 24 hours
What drives circadian rhythms?
The suprachiasmatic nuclei (SCN) in the hypothalamus
What is the suprachiasmatic nuclei (SCN)?
A pacemaker that controls the rate of occurrence - must be constantly reset so our bodies remain in synchrony with the outside world
What is photoentrainment?
Natural light provides input that sets body clock to the correct time. Light-sensitive cells in eye acts as brightness detectors - send messages about environmental light to SCN
When are the strongest sleep drives?
2-4am and 1-3pm
What mechanism affects sleep and wakefulness?
Homeostatic control. When awake for long, homeostasis indicates the need for sleep is increasing - this increases continually until the night
How do circadian rhythms operate in the absence of light?
Maintains a cycle of 24-25hrs regardless - homeostatic system makes us tired regardless of light
When is the core body temperature at its lowest?
4:30am (36c)
When is the core body temperature at its highest?
6:00pm (38c)
What hormone induces sleep? How does it work?
Melatonin
Inhibits neural mechanisms that promote wakefulness, during darkness
Where is melatonin released from?
Pineal gland
What are chronotherapeutics? How are they related to circadian rhythms? (Advantage)
They’re a practical application of circadian rhythms.
Drugs that are released in the target area of the body at a certain time.
Give an example of chronotherapeutics.
Medication for preventing heart attacks are designed to release around 6:00am - heart attack most likely in the early morning
What was found on the relationship between artificial light and circadian rhythms? (Disadvantage)
Artificial light alone can alter circadian rhythms - Cziesler et al (1999) altered pps rhythms to 22-28 hours
State two disadvantages of Circadian rhythms.
- Individual differences - cycles vary from 13-165 hours
2. Individual differences - people have different peaks - ‘morning people’
How does temperature affect circadian rhythms?
The SCN transforms light into neural messages that set the body’s temp. The fluctuations in temp (due to light) set the timing of the cells
State a real-life application of circadian rhythms.
- Research (BBC) shows our cardiovascular system has the best output in the afternoon - record athletic times done in the afternoon
- Research shows women are likely to go into labour at night
What are the five sleep stages?
- Light sleep (NREM)
- Sleep (NREM)
- Deep Sleep (NREM)
- Very Deep Sleep (NREM)
- Dreaming (R.E.M.)
Describe stage 1 of the sleep cycle.
Muscle activity slows, occasional muscle twitching.
‘Theta’ EEG pattern
Describe stage 2 of the sleep cycle.
Breathing and heart rate slow, slight decrease in body temp.
‘Theta’ EEG pattern
Describe stage 3 in the sleep cycle.
Brain begins to generate slow delta waves.
‘Delta’ EEG pattern
Describe stage 4 in the sleep cycle.
Rhythmic breathing, limited muscle activity.
‘Delta’ EEG pattern
Describe stage 5 of the sleep cycle.
Muscles relax and heart rate increases. Breathing is rapid and shallow.
Faster brainwaves on EEG pattern
How often does the cycle repeat itself?
Every 90 minutes
What is the sleep cycle called?
Basic Rest Activity Cycle (BRAC)
How does the Basic Rest Activity Cycle (BRAC) affect us when awake?
Human mind can focus for about 90 minutes - body runs out of resources (fatigue, hunger) towards the end of the 90 minutes.
State an example of an infradian rhythm.
Menstrual cycle
State a practical example of BRAC being utilised (advantage)
Ericsson et al (2006) studied group of elite violinists that had practice sessions of 90mins, same found with athletics, chess players and writers
How do infradian rhythms affect behaviour? (Advantage)
Penton-Voak (1999) found women more attracted to masculine faces during ovulation, and feminine faces for long-term relationship
How do individual differences affect sleep patterns? (Disadvantage)
Tucker et al (2007) studied pps over 11 days and nights in lab - assessed sleep duration, time to fall asleep, amount of time in each sleep stage. Found differences in all variables
What factor affects the menstrual cycle other than ultradian rhythms?
Pheromones
What study showed the affect of pheromones on the menstrual cycle?
Samples of sweat collected from one group of women and rubbed onto upper lip of another group of women - menstrual cycles synchronized
What two things reset our biological rhythms every day?
- Endogenous pacemakers
2. Exogenous zeitgebers
What is the most important endogenous pacemaker?
Suprachiasmatic nuclei (SCN) - links all brain regions that control sleep and arousal, has control over biological clocks throughout the body
How does the SCN operate?
Neurons within the SCN synchronise with each other and co-ordinate signals with target neurons elsewhere in the body. It has a built-in circadian rhythm that is only reset when external light levels change (receives info through optic nerve)
How does the SCN regulate melatonin levels?
It sends a signal to the pineal gland via the interconnecting neural pathway - increases production of melatonin when dark and decreases when light
State two advantages of research into endogenous pacemakers.
- SCN is vital. Morgan (1995) bred hamsters with 20 hour circadian rhythm, SCN from these hamsters transferred to normal hamsters - displayed 20 hour rhythm
- Student spent 25 days in a lab without daylight or external factors that could reset SCN - core temp rhythm was still 24 hours
State a disadvantage of research into endogenous pacemakers
The university student studied for 25 days developed a sleep-wake cycle of 30 hours with 16 hour sleep periods. External factors are needed to maintain rhythm
What are exogenous zeitgebers?
Environmental events that are responsible for maintaining the biological clock of an organism
What’s the most important exogenous zeitgeber?
Light
How does light influence our biological clock?
Receptors in SCN sensitive to light changes use this to synchronise bodily activity - resets each day to keep cycle.
Melanopsin (protein) is critical in this - sensitive to natural light
What are the effects of jet lag and working in alternating shifts?
Endogenous pacemaker out of sync with exogenous zeitgebers - disrupted sleep pattern, decreased alertness, increased anxiety
State three advantages of exogenous zeitgebers.
- Majority of blind people with light perception have normal circadian rhythms, those w/out have abnormal rhythms
- Exposure to bright light before a flight (east to west) decreased time needed to adjust to local time
- When sleep-wake and activity-rest patterns of two groups are compared over 5 weeks: one group in warm artificial light, other in blue artificial light - pps kept sleep log. Warm light group sychronised rhythms to natural light, blue light group synchronised rhythms to office hours
How is a threatening stimulus initially perceived in the brain?
Amygdala detects threat and signals the hypothalamus
Describe the acute response to stress
- Hypothalamus sends signal to sympathetic nervous system
- Sympathetic nervous system uses neuronal pathways to activate smooth muscle and glands, and stimulates adrenal medulla to release noradrenaline and adrenaline
- Parasympathetic returns body to resting state once threat is gone
Describe the chronic response to stress
- Hypothalamus releases CRH into bloodstream
- CRH stimulates pituitary gland to release ACTH
- ACTH stimulates adrenal cortex to release cortisol (inhibits immune system and cognitive functioning)
- Hypothalamus and pituitary gland have receptors that monitor cortisol levels - reduce CRH and ACTH if too high
Give two advantages of research into the fight or flight response
- Has a survival benefit - helps to unconsciously respond to threatening situations
- Research shows adrenaline is essential in preparing the body for stress - those with damaged adrenal glands don’t illustrate the fight/flight response
Give two disadvantages of research into the fight or flight response
- Gray (1998) suggests that the first response to a threatening situation isn’t to fight or flight, but to freeze instead to be hyper vigilant to danger
- Taylor (2000) found there to be another response - tend and befriend. Women are more likely to tend and befriend (biological disposition to be nurturing and protect offspring). However, men are found to tend and befriend too. Fight/flight too simplistic?
