Biopsychy Flashcards
The central nervous system (CNS)
Made up of the brain and spinal chord. The brain controls how we think, learn, move, and feel. The spinal cord carries messages back and forth between the brain and the nerves that run throughout the body.
The peripheral nervous system (PNS)
Made up of the neurones that connect the CNS to the rest of the body. It also has systems: the ANS, SNS
The semantic nervous system
Controls conscious activities
The automatic nervous system (ANS)
Controls unconscious activities like digestion and has two divisions that have opposing effects on the body
Sympathetic nervous system
Gets the body ready for action. It’s the ‘fight or flight’ system
Parasympathetic nervous system
Calms the body down. It’s the ‘rest and digest’ system
Sensory neurones
The nerve cells that transmit electrical impulses from receptors to the CNS
Relay neurones
The nerve cells that transmit electrical impulses between sensory neurones and motor neurones
Motor neurones
The nerve cells that transmit electrical impulses from the CNS to effectors
How neurones transmit information around the body
The cell body has dendrites that receive info from other neurones. This info passes along the axon in a form of electrical impulses which end up at the synaptic knob. The myelin sheath insulates the axon to speed up transmission. Neurotransmitters are released from the synaptic knob across the synapse to pass onto new dendrites
Transmission of info to and from CNS
Stimulus → receptors → CNS → effectors → response
Reflexes
Fast, automatic responses to certain stimuli. Bypass conscious brain and are rapid to help avoid danger
Synapses
The presynaptic neurone contain synaptic vesicles filled with neurotransmitters. When an electrical impulse reaches the end of a neurone it causes the neurotransmitters to be released into the synaptic cleft (the gap between neurones). They diffuse across to the postsynaptic membrane and bind to specific receptors. This may trigger a muscle contraction or cause a hormone to be secreted. Neurotransmitters are removed from the cleft so the response doesn’t keep happening (reuptake)
Two types of neurotransmitters
Excitatory- increase the likelihood that an electrical impulse will be triggered in the postsynaptic neurone
Inhibitory- decrease the likelihood that an electrical impulse will be triggered in the postsynaptic neurone
5 main neurotransmitters
Acetylcholine, Dopamine, Noradrenaline, Serotonin, GABA
Acetylcholine
Voluntary movement, memory, learning and sleep. Too much is linked to depression and too little to dementia
Dopamine
Helps with movement, attention and learning. Too much is linked to schizophrenia, and too little to depression
Noradrenaline
Closest related to adrenaline and often associated with ‘fight or flight’ response. Too much is linked to schizophrenia and too little to depression
Serotonin
Involved in emotion, mood, sleeping and eating. Too little is linked to depression
GABA
Inhibitory neurotransmitter. Too little is linked to anxiety disorders
Glands and Hormones
A gland is a group of cells that are specialised to secrete a useful substance, such as a hormone. Hormones are ‘chemical messengers’. Many are proteins or peptides
The endocrine system
A gland is stimulated by a change in concentration of a specific substance or by electrical impulses. This secretes a hormone which diffuses directly into the blood and is taken around the body. They diffuse out of the blood all over the body, but each hormone will only bind to specific receptors found on the membrane of target cells. This triggers a response
Hypothalamus
Produces hormones that control the pituitary gland
Pituitary gland
The ‘master gland’ as it releases hormones to control other glands in the endocrine system
Pineal gland
Produces melatonin, which helps control of sleep patterns
Thyroid gland
Produces thyroxine and is responsible for controlling the body’s metabolic rate, as well as regulating growth and maturation
Parathyroid glands
Produces parathyroid hormone, helps control the levels of minerals such as calcium within the body
Thymus gland
Regulates the immune system
Adrenal glands
Produce hormones such as adrenaline. Responsible for the ‘fight or flight’. Also produces cortisol which causes us to wake up from sleep
Pancreas
Release insulin and glucagon to regulate blood sugar level
Gonads
Ovaries and testes which produce the sex hormones
Differences between endocrine and nervous system
Endocrine system is slower, longer lasting, and more wide-spread as they are sent all over the body
How the ‘fight or flight’ activates
In the initial shock response, the hypothalamus triggers activity in the sympathetic branch of the ANS. This stimulates the adrenal medulla which releases adrenaline and noradrenaline. This prepares the body to use energy to deal with the situation
The affects of adrenaline and noradrenaline
Blood pressure and heart rate increase, digestion decreases, muscles become more tense, perspiration increases, breathing rate increases, pupil size increases, salivation decreases
Localisation of Function
Certain areas of the brain are thought to be responsible for particular functions e.g. vision, language
Motor cortex
Controls voluntary movement. Frontal lobe
Broca’s area
Responsible for the production of speech
Somatosensory cortex
Processes information about touch, pain, temperature and proprioception (the position of your body). Parietal lobe
Visual cortex
Processes information from our eyes, Occipitual lobe
Auditory cortex
Processes information from our ears. Temporal lobe
Wernicke’s area
Responsible for the understanding of language
Two hemispheres
Connected by the corpus callosum. In most, Broca’s and Wernicke’s areas are only found in the left so it handles the bulk of language functions. Left is responsible for logic, analysis, problem solving. The right involves spatial comprehension, emotions and face recognition
Sperry (1968)- Effects of split brain surgery
Involves case studies and experiments. 11 pptts underwent split brain surgery. A control group was used who had no hemisphere disconnection. Pptts covered one eye and looked at a fixed point on a projection screen. Pictures were shown onto the right or left of the screen at high speeds. If the picture was shown in the right visual field, all pptts could say or write what it was but if it was the left the split brain pptts couldn’t say or write what they saw but they could select a corresponding object with their left hand. Proves that different areas of the brain have different functions. Sperry obtained both qualitative and quantitative data. Small sample size, artificial experiment
Plasticity
The brains ability to alter its structure and function in response to changes in the environment. This constant reworking and reorganisation of the brain is the basis of how we learn and adapt.
How plasticity works
Information takes a pathway through the brain, travelling from one neurone to the next. When we are represented with new information, new neural pathways begin to form. Using a neural pathway strengthens it and not using it weakens it, like learning how to drive, the more you drive the better you get
Elbert et al (1995)
Nine musicians were compared to six non-musicians. Magnetic source imaging was used to measure the area of the somatosensory cortex representing the left hand of each pptts. The area of the cortex was larger in the musicians. Show that increased amount of sensory processing required from left hands of musicians results in structural changes in the brain, providing support for plasticity. Small sample size, can be argued that musicians are genetically good/ talented
Cortical representation
Different areas in the somatosensory cortex and the motor cortex of the brain represent different parts of the body. For example one part of the somatosensory cortex processes sensory info from your lips and another part from your toes
How can plasticity help in brain damage
The brain has potential to recover some of its lost functions from brain damage because the brain begins to rewire itself through plasticity. There is evidence that healthy areas of the brain located near the damaged area begin to take over the function of the damaged area
Adv and Dis of constraint-induced movement therapy (CIMT)
Produces cortical reorganisation which results in regained or improved function. Principles can be applied to patients who suffer from aphasia. Studies have shown this therapy caused dysfunction areas near the damaged area to become functional again.
CIMT can be very frustrating for the patient. Needs to be intensive to be effective. Patients are often required to train the affected limb for several hours a day for weeks and have their unaffected limb restrained. It’s most effective for those who have suffered mild to moderate strokes and may not work with larger damage to the brain
Functional Magnetic resonance imaging (fMRI) scans
3D scans providing structural and functional information. They show changes in brain activity as they actually happen. More oxygenated blood flows to active areas of the brain to supply neurones with oxygen and glucose. Molecules in oxygenated blood respond differently to a magnetic field than those in deoxygenated blood so the more active areas can be identified
Uses of fMRI scans
Used to research the function of the brain as well as its structure. If a participant carries out a task whilst in the scanner, the part of the brain that’s involved with that function will be more active. Can be used to diagnose medical problems since they can also show damaged or diseased areas. They are also used to study abnormal activity in the brain like during hallucinations for patients with schizophrenia
Pros and Cons of fMRI
Really useful tool for bio psychologists as they provide a non-invasive way of studying the brain. However the machines are very expensive to buy and run. They also require people to lie very still in an enclosed space for a period of time, which can be a problem for claustrophobic patients. They have poor temporal resolution- don’t show changes over time accurately
EEGs
An electroencephalogram (EEG) shows the overall electrical activity of the brain. It picks up the signal of many neurones firing together, not individual neurones. Multiple electrodes are placed on the scalp and the electrical activity in the brain is recorded for a period of time. This produces a pattern of waves which represent different levels of arousal or consciousness. For example the stages of sleep each have their own typical waves patterns
Uses of EEGs
Commonly used in sleep studies, have been used in studies of depression and schizophrenia ( meta analysis showed that participants with schizophrenia had abnormal EEG wave patterns). Abnormal EEGs have all been identified in patients with eating disorders like anorexia nervosa. This means EEGs have the potential to be used as a diagnostic tool.
ERPs
Bio psychologists can also look at how an EEG wave pattern changes in response to a stimulus. This change is known as an event-related potential (ERP). If a specific stimulus is presented, it produces a specific change in the wave pattern. Different ERPs have been identified as a response to different stimuli
Uses of ERPs
Have been used a lot in memory research, as they give bio psychologists lots of clues about information processing in the brain. Research has shown differences in the ERPs of people suffering from certain psychiatric disorders compared to healthy individuals. For example, Miltner (2000) found that people with phobias had an ERP of a greater amplitude in response to images of objects they feared, compared to non-phobic individuals
Post-mortem examinations with uses
Involve dissecting the brain of a person who has died. This allows researchers to physically look at the internal structure of the brain. If a person had a medical condition when they were alive, a post-mortem could show off any structural abnormalities that could explain their condition. They have provided evidence for localisation of function in the brain- Paul Broca found that two patients with speech problems both have damage to the same areas of the brain (now Broca’s area) suggesting that it was involved in speech production
Pros and Cons of EEGs and ERPs
Both also non-invasive, and they are cheaper to carry out than fMRI scans. Although they have good temporal resolution, they have poor spatial resolution- it’s hard to work out which area of the brain the waves originate from
Pros and Cons of Post-mortem examinations
An obvious disadvantage is that the person has to have died before the examination can be carried out so they will not benefit from any findings. It doesn’t allow a cause and effect to be established (goes for fMRI, EEGs and ERPs as well).
Circadian rhythms
Have cycles that generally occur once every 24hours. For example we will usually go through sleep-wake cycle once a day
Infradian rhythms
Have cycles that occur less than once every day. For example the menstrual cycle
Ultradian cycles
Cycles that occur more than once every 24hours.
Endogenous pacemakers
Some aspects of our biological rhythms are set by genetically determined structures and mechanisms within the body. The suprachiasmatic nucleus (SCN) seems to act as an internal clock to maintain sleep cycle.
Exogenous zetigebers
These are influences outside the body that act like a prompt to trigger a biological rhythm. Light is the most important EZ. Siffre (1975) spent 6 months in a cave with no clocks or natural light and his sleep wake cycle extended from 24hrs to 25-30hrs therefore natural light is needed to fine tune our normal 24-hour cycle
Aschoff and Wever (1976)
In a group of people isolated from daylight, some maintained their regular sleep cycle while other members displayed their own very extreme sleep cycles such as 29 hours awake followed by 21 hours asleep. This also shows that EP and EZ factors must interact to control or influence biological rhythms
Consequences of biological rhythm disruption
When EP become out of line with EZ it can disrupt the sleep-wake cycle. In natural environment EZ usually changes slowly however in modern society EZ can change quickly which can have negative effects on our ability to function- slower reactions, impaired problem-solving, limiting our ability to concentrate
Czeisler et al (1982) - Shift work
Studied workers at a factory whose shift patterns appeared to cause sleep and health problems. The researcher recommended 21-day shifts, to allow more time for workers to adapt, and changing shifts forward in time. After implementing the changes, productivity and job satisfaction increased
Limitations of research on biological rhythms
Findings from animal studies cannot be generalised to humans. Studies that deprive humans of natural light still allow artificial light which may have given benefits of natural light, reducing validity. Individual differences, some people are more alert at different times in the day and the speed of adaptation varies per person. It’s difficult to say whether a person’s lifestyle is a cause or effect of their biological rhythm
Localisation of function areas in the brain
Motor cortex- Top middle
Somatosensory cortex- top right middle
Broca’s area- left middle
Auditory cortex- middle middle
Wernicke’s area- middle right
Visual cortex- bottom right
The suprachiasmatic nucleus (SCN)
It is sensitive to light and regulates the pineal gland which secretes melatonin to make us sleepy
