Biopsychology Flashcards
What makes up the nervous system?
CNS - brain and spinal chord, PNS - somatic nervous system (motor neurones), autonomic nervous system (regulates glands, blood, etc) - sympathetic (fight or flight), parasympathetic (rest state)
Cerebrum
4 lobes - behaviours
Cerebellum
Motor skills, muscle coordination
Diencephalon
Made up of thalamus and hypothalamus
Brain stem
Automatic function
Somatic
Connects CNS and senses- 12 cranial nerves - involved in reflex action.
Autonomic
Automatic actions - regulate organs
Sympathetic
Deal with emergencies - fight or flight - increase heart rate/ blood pressure
Parasympathetic
Relaxes body after emergency passed- rest state.
Sensory neurones
Carry nerve impulses from sensory receptors to spinal cord toward brain
Relay neurones
Allow communication between motor and sensory neurones
Motor neurones
Control muscle movements
Structure of a sensory neurone
Receptor cell > myelin sheath > axon > cell body/ nucleus > axon terminal
Structure of a motor neurone
Dendrites > cell body / nucleus > Axon > Myelin sheath > Axon terminal
Structure of a relay neurone
Dendrite > Cell body / nucleus > axon > axon terminal
What is the process of synaptic transmission?
As the message is converted to an electrical impulse and is rapidly fired down the axon as an action potential, it reaches the axon terminal where it makes contact with the synaptic vesicales that burst releasing neurotransmitters. These diffuse across the synapse and make contact with receptors on the dendrites. Once the impulse has been transferred and summation has occurred, it is sent back to be reabsorbed.
Excitatory Neurotransmitters
Cause the excitation of the post synaptic neurone - positive charge.
Inhibitory Neurotransmitters
Calming body and mind - negatively charged.
Summation
Likelihood of impulse firing calculated by adding up excitatory and inhibitory neurotransmitters - more excitatory = fire, more inhibitory = not fire.
Glands
Secrete hormones into the blood stream to regulate the body.
Pituitary
Master gland - regulates endocrine system
Adrenal Glands
Fight or flight - adrenaline
Testes
Testosterone in males.
Ovaries
Oestrogen and progesterone in females
What do the adrenal glands release?
- Outer part (cortex) - cortisol - anti-inflammatory and cardiovascular
- Inner part (medulla) - adrenaline and noradrenaline
How are hormones released?
The hypothalamus sends a signal to the pituitary gland to release a stimulating hormone to the target gland. This will then release its hormone. When too much has been released the hypothalamus will shut down the release of the stimulating hormone from the pituitary, inhibiting the hormone from the target gland.
What can too high/ too low levels of hormones do?
Cause symptoms like high blood pressure, fatigue, weight gain or loss, heart attacks, Cushing’s syndrome (too high cortisol)
What does the pituitary gland release?
Anterior - ACTH (stress hormone), LH, FSH
Posterior - oxytocin (contraction of uterus)
Fight or Flight
Response survival mechanism when the body detects a threat.
Process of Fight or Flight
Amygdala detects a threat from senses and sends a signal to the hypothalamus. This triggers either the acute stressors response, or the chronic stressors response.
Acute Stressors Response
Adrenaline released by the sympathetic nervous system > causes physiological changes > parasympathetic nervous system calms the body after the even has passed.
Chronic Stressors Response
HPA Axis - hypothalamus releases CRH, causing the production of ACTH in the pituitary. This stimulates the adrenal cortex to produce cortisol. Once levels are back to normal, CRH and ACTH production is stopped.
Gray 1988 - fight or flight or run away
First phase of reaction to a threat is not to fight or flee but avoid confrontation. Most animals display ‘freeze’ response, where they ‘stop, look and listen’- able to take in new information to decide on response.
Von Dawans et al 2012 - gender differences in fight or flight
Men ‘fight or flight’ and women ‘tend and befriend’. Found that acute stress often leads to more cooperative/ friendly behaviour in anyone- can explain human connection in times of crisis like 9/11.
Lee and Harley (2012)- gender in fight or flight
Found evidence of genetic basis for gender differences in fight or flight response. The SRY gene found in male Y chromosomes promotes aggression. May cause fight or flight more in males with the release of adrenaline. Lack of gene in females causes release of oestrogen and oxytocin, preventing fight or flight response.
Localisation
Specific functions located in specific areas of the brain.
Motor cortex
Responsible for voluntary motor movements - frontal lobe alone the pre central gyrus.
Somatosensory cortex
Detects sensory information - parietal lobe
Visual Cortex
Visual processing - occipital lobe
Auditory cortex
Audio processing - temporal lobe
Broca’s Area
Left frontal lobe - language production. Research into ‘Tan’ (could only say that syllable) found that damage to this area resulted in an ability to speak.
Wernicke’s Area
Posterior left temporal lobe - language comphrension
Lashley 1930 - Equipotentiality
Basic functions are localised but more complex ones are not. Intact areas can take over function of damaged ones.
Joseph Dejerine (1892)- localisation and reading
Loss of ability to read resulted in damage to connection between Wernicke’s area and visual cortex- complex processes built up gradually.
Bavelier et al (1997)- activation individual differences
Large variability in patterns of activation across different individuals. Activity on right temporal lobe as well as left frontal, temporal and occipital lobes.
Harasty et al (1997)- gender localisation
Women have larger Broca’s and Wernicke’s areas than men- greater use of language.
Dronkers et al (2007)- re-examination
Re-examined brains of Tan and another Broca patient using MRI technology- other defective areas may have contributed to speech problems. Lesions to Broca’s area usually don’t cause severe speech issues.
Localisation evaluation
- Communication may be more important
- Aphasia studies
- Individual differences - pattern of activation
- May not be due to damage in one area.
Lateralisation
Hemispheres have their own functional specialisations.
Sperry and Gazzaniga - Split Brain Research
Used participants who had already had split brain surgery to treat epilepsy. Displayed different images to their left and right visual field - left could draw with left hand, right could only be spoken.
Lateralisation evaluation
+ Increased neural processing compatibility
- Changes with age
Split Brain evaluation
- New research shown that functions aren’t always entirely lateralised.
- Limited sample
- Ungeneralisable
Brain Plasticity
Brains ability to change and adapt as a result of new experience.
Life experience
Natural decline in cognitive functions with age, but we always have some grey matter.
Kuhn et al 2014 - Plasticity/ Video games
Video games increase grey matter in cortex, hippocampus and cerebellum. Compared a control group with a group who trained on Super Mario for at least 30 minutes a day.
Boyke et al 2008 - Juggling
Taught 60 year olds a new skill of juggling, increased grey matter in visual cortex that reduced again when they stopped practicing.
Davidson et al 2004 - Monks
Compared 8 Tibetan monks with 10 students who had never meditated before. Fitted with electrical sensors- meditation increased gamma wave activity, monks had generally higher gamma wave activity.
Functional recovery
Brain rewires so function of a damaged area can be recovered.
Neural unmasking
‘Dormant synapses’ can be unblocked to open regions of the brain not normally activated.
Stem cell treatments
Stem cells can be implanted to replace dead cells, rescue damaged ones or transfer function to undamaged areas.
Kempermann et al 1998 - Rats/ Plasticity
Rats housed in complex enriching cages had an increased number of new neurones.
Maguire et al 2000 - taxi drivers
Studied the brains of London Taxi Drivers with MRI scanning- found that the posterior hippocampus was larger than a control group, and its volume correlated with the amount of time spent driving.
Tajiri et al 2013- rat stem cells
Randomly assigned rats with brain injuries to 2 groups - 1 was infused with stem cells the other nothing - stem cell group had new neurones developing after 3 months.
Huttenlocher 2000 - age
Functional recovery reduces with age
Schneider et al 2014 - education/ functional recovery
Carried out a retrospective study based on data from the US Traumatic Brain Injury Systems Database- 769 patients, 214 disability free after recovery- 39.2% with 16+ years of education, 30.8% had 12-15 years, 9.7% had less than 12 years of education.
Turk et al (2002)- lateralisation opposition
J.W. sustained damage to the left hemisphere but developed the capacity to speak out of the right.
Rogers et al (2004)- increased brain efficiency
In the domestic chicken, brain lateralisation is associated with an enhanced ability to perform two tasks simultaneously- finding food and being vigilant for predators- enhanced efficiency.
Szaflarski et al (2006)- language lateralisation changes
Language became more lateralised to the left with age, but after 25 lateralisation decreased.
Post-mortem
Analysis of the brain after death
fMRI
Measure changes in blood flow/ activity in brain while performing a task
EEG
Electrical changes measured with a graph
ERP
Voltage changes in response to a stimulus
Post-mortem evaluation
+ Developed early knowledge
+ Useful for research
+ Detailed
- Damage may be linked to other trauma
- Ethics
- Confounding variables
fMRI evaluation
+ No radiation
+ High spatial resolution
- Expensive
- Requires stillness
- Poor temporal resolution - 5 seconds
EEG evaluation
+ Helpful for epilepsy diagnosis
+ Useful to track stages of sleep
+ Cheaper
+ High temporal resolution
- Generalised nature - 1000s of neurones
- Cannot pinpoint source
ERP evaluation
+ More specific/ targeted
+ High temporal resolution
+ See role of ERPs in cognitive functions
- Lack of standardisation
- Eliminate extraneous variables
Circadian Rhythms
Cycles that last ~24 hrs.
SCN
Master circadian pacemaker in hypothalamus
Photoentrainment
Light resets/ coordinates circadian system/ body clock.
Melatonin
Melatonin released when dark from pineal gland to encourage sleep.
Light Cycle
Light > Retina > Optic Nerve > SCN > Pineal Gland > Inhibit/ secrete melatonin
Free Running
Maintains 24-25 hour cycle.
Core Body Temperature
Lowest (36 degrees C) at 4:30am, highest (38 degrees C) at 6pm.
Michel Siffre
French cave explorer- lived in cave for periods of time. Circadian rhythm settled to 24 hours with dramatic variations (free running). Slowed with age (up to 48 hours).
Aschoff and Wever 1976- CR
Participants left in a WW2 bunker- most CRs settled at 24-25 hours, but some up to 29 hours.
Folkard 1985- cave
12 people lived in a cave with only a clock. They agreed to go to sleep at around 11pm each night. The clock gradually sped up and only one person followed its change.
Hughes- Antarctic
4 participants in British Antarctic Station. Cortisol highest as they awoke and lowest when going to bed. Changed over time to be highest at noon.
Czeisler et al 1999- individual differences with CR
Cycles may vary from 13-65 hours.
Czeisler et al 1999- artificial lighting
Altered rhythms with lighting between 22 and 28 hours.
Duffy et al 2001- morning people
Morning people rise early and go to bed early, where evening people wake later and sleep later.
Evans and Marain (1996)- chronotherapeutics
How timing affects drug treatments. Meds taken at 10pm won’t release until vulnerable period of 6am-noon.
Buhr et al (2010)- temperature
Temperature controls our body clock instead of light. Fluctuations in temperature set the timing of cells in the body and cause tissues/ organs to become more or less active.
Ultradian rhythms
Cycles spanning less than a day
Infradian rhythms
Cycles spanning more than a day
Sleep Cycle Rhythm
Alternates between 4 stages of REM and non-REM every 90 mins. Stage 1 and 2 are light sleep, slowing our body down to prepare for deeper sleep- high prevalence of alpha and theta waves. Stage 3 and 4 are deep sleep with slow high amplitude delta waves. Stage 5 is REM, which is where we commonly dream.
Kleitman (1969)- BRAC
Referred to the 90 minute cycle found during sleep as the BRAC. Suggested that the 90 minute ultradian rhythm continues during the day when we are away. Rather than moving through sleep, we move progressively from a state of alertness to a state of physiological fatigue every 90 minutes.
Refinetti (2006)- menstrual cycle variation
Women’s menstrual cycles vary between 23 days and 36 days.
Magnusson (2000)- SAD
Seasonal variation in mood in humans, especially women. Some people are severely depressed during winter months.
Trudeau (1997)- deaths
Most deaths occur in January.
Ultradian/ Infradian evalutation
- Individual differences have biological aspects to them.
+ Research support - violinists - Can be altered with extraneous variables- menstrual cycle study
Tucker et al (2007)- rhythm biological
Individual differences are biologically determined. Studied participants over 11 days and nights in a controlled lab environment- assessed sleep duration, time to fall asleep and the amount of time in each sleep stage. Found individual differences in each characteristic- for deep sleep stages, the individual differences were very significant- must be somewhat biologically determined.
Ericsson et al (2006)- violinists
Studied a group of elite violinists and found that among the group practice sessions were no more than 90 minutes in length. Those who frequently napped were the best violinists.
Russell et al (1980)- sweat
Collected daily samples of sweat from one group of women and rubbed it on the upper lip of another group of women- menstrual cycles became synchronised with their ‘odour donor.’
Penton-Voak et al (1999)- preferences of men
Human mate choice varies across the menstrual cycle, with different preferences at different stages of the cycle. Women picked ‘slightly feminised’ male faces when picking for a long term relationship, but during the ovulatory phase, showed a preference for more masculine faces- represent a preference for kindness and cooperation in parental care in long term mates.
Arliss et al (2005)- full moon
Many midwives believe more babies are born on a full moon- stats show this is purely subjective association.
Vance (1995)- moon
Workers in mental health professions have shown a persistent belief that the full moon alters behaviour.
Foster and Roenneberg (2008)- moon support
Occasional studies have found correlations between the phase of the moon and various aspects of human behaviour, but there is no evidence.
Endogenous pacemakers
Pacemakers within our body that keep time - e.g. SCN/ pineal gland
Pineal gland
Secretes melatonin for inducing sleep
Exogenous zeitgebers
External events that entrain biological clock.
Light Proteins
Light receptors on the retina have protein cells called melanopsin that send signals to SCN to set daily cycle.
Social Cues
Cues like meal times/ activities are zeitgebers.
Endogenous pacemakers evalutation
+ Research support
- Case study to support zeitgebers
Exogenous zeitgebers evalutation
+ Blind people can still have an entrained CR
+ Light exposure to avoid jet lag study
+ Artificial light study
Ascoff et al (1971)- absense of light
Individuals are able to compensate for the absence of zeitgebers like light by responding to social zeitgebers instead.
Klein and Wegmann (1974)- jet lag
Being more active outside at the destination reduces jet lag.
Morgan (1995)- hamsters
Bred a strain of hamsters with abnormal circadian rhythms of 20 hours. SCN neurones of these hamsters were transplanted into the brains of normal hamsters. They then displayed the symptoms of the abnormal circadian rhythm.
Folkard (1996)- Kate Aldcroft
Volunteered to spend 25 days in a controlled laboratory environment. She had no access to daylight or other zeitgebers, but her core temperature rhythm stayed at 24 hours. Her sleep wake cycle had extended to 30 hours with sleep often reaching as long as 16 hours.
Skene and Arendt (2007)- blind people
The vast majority of blind people who have some light perception remaining have normally entrained circadian rhythms.
Burgess et al (2003)- light on flight
Exposure to bright light prior to an east west flight decreased the time needed to readjust. Participants were either exposed to continuous bright light, intermittent bright light, or dim light, which shifted their sleep-wake cycle back by an hour a day over 3 days. Those exposed to continuous bright light shifted their circadian rhythm by 2.1 hours over the study, those exposed to intermittent bright light shifted by 1.5 hours, and those exposed to dim light shifted theres by 0.6 hours.
Veter et al 2001- light colour
Investigated the importance of light in regulation of sleep-wake and activity-rest patterns of 2 groups of volunteers over 5 weeks. One group stayed in ‘warm’ artificial light while the other stayed in ‘blue enriched’ light. They kept a sleep log and wore devices to measure their movement over a 24 hour period. Those working under warm light synchronised with the natural light of dawn. As sunrise advanced by 42 minutes they conformed, the others did not.
