Biopsychology Flashcards
The nervous system
A specialised network of cells in the human body, a primary internal communication system. It collects, processes and responds to information in the environment and also co ordinates the working of different organs and cells in the body.
The nervous system
Divided into two sub systems:
Central nervous system (CNS)
Peripheral nervous system (PNS)
The central nervous system
Made up of the brain and spinal cord.
The brain is the centre of all conscious awareness.
The spinal cord is an extension of the brain. It is responsible for reflex actions such as pulling your hand away from a hot plate.
The peripheral nervous system
The PNS transmits messages, via millions of neurons to and from the central nervous system. The peripheral nervous system splits into: the autonomic nervous system (ANS) and the somatic nervous system (SNS).
Somatic nervous system
Transmits information from receptor cells in the sense organs to the CNS. It also receives information from the CNS that directs muscles.
Autonomic nervous system (ANS)
Transmits information to and from the internal bodily organs (breathing, heart rate, digestion). It is automatic. It has two main divisions, the sympathetic and parasympathetic nervous systems.
The endocrine system
The body’s major information system that instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target organs in the body. Works alongside the nervous system.
Glands and hormones (endocrine system)
Various glands in the body, eg. Thyroid/ pituitary gland, produce hormones. The pituitary gland is in the brain and it controls the release of hormones from all the other endocrine glands in the body. (Adrenals, ovaries, testes).
Gland
An organ in the body that synthesises substances such as hormones.
Hormones
Chemical substances that circulate in the bloodstream and only affect target organs. They are produced in large quantities but disappear quickly. Their effects are very powerful.
Fight or flight
The way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an aggressor or in some cases, run.
Endocrine and ANS working together fight of flight
When a stressor is perceived, the hypothalamus triggers activity in the sympathetic branch of the ANS. The stress hormone adrenaline is released from the adrenal gland into the blood. This increases heart rate and other physiological changes needed for fight or flight.
Sympathetic state
Increases heart rate Increases breathing rate Dilates pupils Inhibits digestion Inhibits saliva Contracts rectum
Parasympathetic state
Decreases heart rate Decreases breathing rate Constricts pupils Stimulates digestion Stimulates saliva production Relaxes rectum
Neuron
The basic building blocks of the nervous system. They are nerve cells that process and transmit messages through electrical and chemical signals.
Sensory neurons
Carry messages from the PNS to the CNS. Long dendrites and short axons.
Relay neurons
Connect the sensory neurons to the motor or the other relay neurons. Short dendrites and short axons.
Motor neurons
Connect CNS to effectors such as muscles and glands. Short dendrites and long axons.
Structure of a neuron
Cell body includes a nucleus.
Axon carries the impulses away from the cell body.
Dendrites carry nerve impulses from neighbouring neurons towards the cell body.
Axon is covered by a myelin sheath, a fatty layer that protects it.
Nodes of ranvier leave gaps in the myelin sheath to speed it up as it jumps across.
Electric transmission
At resting state the inside of the cell is negatively charged compared to the outside. When its activated by a stimulus it becomes positively charged causing an action potential to occur. This creates an electrical impulse.
Synaptic transmission
When neighbouring neurons communicate with each other by sending chemical messages across the synaptic gap that separated them.
Neurotransmitter
Brain chemicals released from the synaptic vesicles that relay signals across the gap. Can be divided into excitatory and inhibitory function.
Excitation
When a neurotransmitter increases the positive charge of the post synaptic neuron. Neuron will fire and pass on the electrical impulse.
Inhibiton
When a neurotransmitter makes the charge of the postsynaptic neuron more negative. Decreases the likelihood that the neuron will fire and pass on the electrical impulse.
Chemical transmissions - synapses
Each neuron is separated from the next by a synapse. Signals within neurons are transmitted electrically, however signals between neurons are transmitted chemically by synaptic transmission.
When the electrical impulse reaches the end of the neuron, it triggers the release of neurotransmitter from tiny sacs, synaptic vesicles.
Excitation and inhibition
The neurotransmitter serotonin causes inhibition.
The neurotransmitter adrenaline causes excitation.
Localisation of function
Theory that different areas of the brain are responsible for different behaviours, processes or activities.
Brain - motor area
In frontal lobe regulating movement.
Brain - somatosensory area
In the parietal lobe that processes sensory information such as touch.
Brain - visual area
Part of the occipital lobe that receives and processes visual information.
Brain - auditory area
In the temperal lobe and concerned with the analysis of speech based information.
Brain - broca’s area
In frontal lobe in the left hemisphere responsible for speech production.
Brain - wernicke’s area
In the temporal lobe in the left hemisphere responsible for language comprehension.
Localisation vs holistic theory
Broca and wernicke discovered that specific areas of the brain are associated with particular physical and psychological functions. If a certain area of the brain becomes damaged, that function of the area will also be affected.
Hemispheres in the brain and cerebral cortex
Theres two symmetrical hemispheres. Left side of body is controlled by the right hemisphere and right side of the body is controlled by the left hemisphere. The cerebral cortex is the outer layer like a tea cosy. It’s grey.
Lateralisation
Physical and psychological functions are controlled by a particular hemisphere of the brain.
Different lobes
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Broca’s aphasia
Damage to broca’s area causes broca’s aphasia. This makes speech slow and lacking in fluency.
Wernicke’s aphasia
If wernicke’s area is damaged, patients often produce nonsense words as part of the content of their speech.
Evaluation of localisation
Brain scan evidence of localisation, loads of scientific evidence of localisation.
Neurosurgical evidence, surgically removing or destroying areas to help eg. OCD. Successful, mental health are localised.
Case study evidence, Phineas Gage.
Phineas Gage
Pole through his left frontal lobe, survived but changed personality dramatically. Calm to rude.
Plasticity
This describes the brains tendency to change and adapt as a result of experience and new learning. Rarely used connections are deleted and frequently used connections are strengthened. (Synaptic pruning).
Research into plasticity, Eleanor Maguire.
Studied brains of London taxi drivers, found more grey matter in the posterior hippocampus than in a matched control. This part is associated with navigational skills. The longer they had been on the job, the more structural difference.
Functional recovery of the brain after trauma
The unaffected areas of the brain are often able to adapt and compensate for the areas that are damaged.
Functional recovery
A form of plasticity. Following damage through trauma, the brain’s ability to redistribute or transfer functions usually performed by a damaged area.
The brain during recovery
Axonal sprouting, the growth of new nerve ending which connect with other undamaged nerve cells to form new neuronal pathways.
Reformation of blood vessels.
Recruitment of homologous areas on the opposite side of the brain.
Plasticity evaluation
Practical application- neurorehabilitation, therapy, shows the brain may have capacity to fix itself to a point, this process requires further intervention to be completely successful.
Negative plasticity, phantom limb syndrome.
Age and plasticity, reduces with age. Ladina bezzola, 40 hours of golf for ages 40-60, does continue throughout lifespan.
Split brain research- hemispheric lateralisation
The idea that two halves of the brain are functionally different and certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other, eg language is localised and lateralised.
Split brain research
It involved epileptic patients who had experienced surgical separation of the hemispheres. This allowed researchers to investigate the extent to which brain function is lateralised.
Sperry’s study, split brain
Included patients having the corpus callosum to be cut meaning the hemispheres separated.
Sperry’s procedure/findings
Describing what they see, in the right field (left hemisphere) they could easily describe, in the left field (right hemisphere) they couldn’t describe the item or said it wasn’t there.
Composite words, if two words were presented, eg key on the left field and ring on the right field, they would write with their left hand the word key and say the word ring.
Split brain research evaluation
Demonstrated lateralised brain function, research suggests the left hemisphere is the analyser and right is the synthesiser.
Standardised procedures, very useful and well controlled procedure.
Issues with generalisation, epileptic seizures.
Ways of investigating the brain, scanning and other techniques
Functional magnetic resonance imaging (fMRI)
Electroencephalogram (EEG)
Event related potentials (ERPs)
Post mortem examinations
Functional magnetic resonance imaging (fMRI)
Detects changes in blood oxygenation and flow that occur with activity in specific parts of the brain. Parts rich in oxygen are active.
Electroencephalogram (EEG)
Measures electrical impulses in the brain with electrodes. Measures wave patterns and can help diagnose certain conditions of the brain.
Event related potentials (ERPs)
The brain’s electrophysiological response to a specific sensory, cognitive or motor event can be isolated through statistical analysis of EEG data.
Post mortem examinations
Brain is analysed after death to determine whether certain observed behaviours during the patients lifetime can be linked to abnormalities in the brain.
Strengths and weaknesses of fMRI
+ no radiation, high resolution so provide clear pictures
- expensive, only clear if person is still.
Strengths and weaknesses of EEG
+ high temporal resolution, in a millisecond, contributed to stages involved in sleep.
- generalised information can’t pin point
Strengths and weaknesses of ERPs
+ excellent temporal resolution
- lack of standardisation, to get pure results must get rid of background noise and extraneous material.
Strengths and weaknesses of post mortems
+ improve medical knowledge and help generate hypotheses for further study
- ethical issues, consent.
Biological rhythms
Distinct patterns of changes in body activity that confirm to cyclical time periods. They are influenced by internal body clocks (endogenous pacemakers) as well as external changes to the environment (exogenous zeitgebers)
Endogenous pacemakers
Internal body clocks
Exogenous zeitgebers
External changes to the environment.
Circadian rhythm
A type of biological rhythm, 24 hour cycle, such as sleep/wake cycle.
Ultradian rhythms
Occur many times during the day
Infradian rhythm
Take longer than a day to complete
The sleep/wake cycle
We feel tired at night and alert in the day, the could be to do with the effect of daylight.
Siffre’s cave study
A caveman who spent several extended periods underground to study the effects of his own circadian rhythms. He continued to sleep and wake up on a regular schedule.
Circadian rhythms evaluation
Practical application to shift work, shift workers 3 times more likely to develop heart disease, could be due to stress of different sleep/wake cycles.
Practical application to drug treatments, certain times of the day when drugs are more likely to be more effective.
May not be generalisable, small samples. Siffre’s age changed internal body clock.
Infradian rhythm
A biological rhythm with a frequency of less than 1 cycle in 24 hours, eg Menstruation.
The menstrual cycle
Cycle is typically 28 days. During each cycle, rising levels of oestrogen cause the egg to release. The hormone progesterone helps the womb lining to grow thicker. If pregnancy doesn’t occur, the egg is absorbed and the womb lining leaves the body. A period.
Kathleen stern and Martha mcclintock
Demonstrated how menstrual cycles may synchronise due to other females pheromones.
29 women, 9 women wore pads under armpits for 8 hours and then rubbed on the upper lip of another participant every day (day 1 through 28)
68% experienced changes to match closer to their odour donor.
Ultradian rhythms
A biological rhythm with a frequency of more than one cycle in 24 hours, eg stages of sleep.
Stages of sleep
5 stages altogether last 90 mins, can be measured by EEG.
Stage 1 and 2 of the sleep cycle
Light sleep, easily woken.
Brainwave patterns become slower and more rhythmic (alpha waves).
As sleep becomes deeper, brainwaves are even slower. (Theta waves)
Stages 3 and 4 of sleep cycle
Involve delta waves which are slower still and have greater amplitude. This is deep sleep.
Stage 5 (REM) of sleep cycle
Body is paralysed but brain activity speeds up. Fast jerky eyes under eyelids. Dreams occur here.
Infradian and ultradian rhythms evaluation
Validity has been questioned, make competition between other females, therefore naturally selected.
There are many factors that effect change in a menstrual cycle, eg stress, meaning confounding variables, so change would be due to chance in the studies.
Supporting evidence, rem sleep is important and there are distinct stages.
The suprachiasmatic nucleus (SCN)
A tiny bundle of nerve cells in the hypothalamus in each hemisphere of the brain. A primary endogenous pacemaker and maintains circadian rhythms. It receives information about light directly, even when we have our eyes closed.
Animal studies and the SCN
Patricia decoursey destroyed the SCN in 30 chipmunks and observed for 80 days. Their sleep/wake cycle disappeared and a proportion had been killed by predators.
The pineal gland and melatonin
The SCN passes the information on day length and light to the pineal gland. During the night it produces melatonin and in the day it’s inhibited.
Exogenous zeitgebers and the sleep/wake cycle
Light- could be skin too, light was shone on patients knees and they woke up
Social cues- adapting to local times for eating and sleeping, eg skipping jetlag.
Endogenous pacemakers and exogenous zeitgebers evaluation
Ethics in animal studies, exposed to harm and hard to generalise.
Occasions when exogenous zeitgebers may have little bearing on our internal rhythm, bling man and artic regions where the sun doesn’t set in summer.