Biopsychology Flashcards
Outline the fight or flight response
The amygdala in the limbic system sends a stress signal to the hypothalamus which activates the SAM pathway. The sympathetic system can the stimulate the adrenal medulla to release adrenaline and noradrenaline.
Adrenaline kick starts the fight or flight response, temporarily stopping bodily functions which aren’t essential for survival so more energy can be given to those that are. Breathing rate, heart rate and blood pressure all increase.
When perceived or real danger/threat is removed the parasympathetic system can begin restoring the body to its previous rested state.
Outline the nervous systems
The central nervous system consists of the brain and the spinal cord. It acts as the body’s control centre, processing sensory information and directing responses.
The PNS (peripheral nervous system) relays messages (nerve impulses) from the CNS to the rest of the body.
The PNS can be further subdivided into the somatic and autonomic nervous system.
Somatic - The somatic nervous system facilitates communication between the CNS and the outside world via voluntary movements and processes.
Autonomic - controls involuntary, vital
functions of the body, such as maintaining heart rates and breathing rates.
The autonomic nervous system can be divided further into the sympathetic and parasympathetic nervous system.
SNS - “fight or flight”
PNS - “rest and digest”
Outline the role of the endocrine system
The endocrine system is the main chemical messenger system of the body, where hormones are secreted into the bloodstream from glands, and then are transported towards target cells in the blood, with complementary receptors.
Outline the role of neurons
Primary means of communication within the nervous system via electrical and chemical transmission.
Sensory - found in sensory receptors and carry messages (nerve impulses) from the PNS to CNS,
Relay - found in the brain and spinal cord and allow sensory and motor neurons to communicate.
Motor - connect the CNS to effectors, bringing about a response from the impulse.
Outline the process of synaptic transmission
When a nerve impulse is sent out from a cell body, the sodium channels in the cell membrane open and the positive sodium ions enter the cell.
Once the cell reaches a certain threshold and is said to be depolarised, an action potential will fire and travel along the axon of the presynaptic neuron.
This causes the presynaptic neuron to release chemical messengers in the form of neurotransmitters across the synaptic cleft.
These neurotransmitters bind to specific receptor sites of the neighbouring post-synaptic neuron.
The chemical messengers are converted back into electric impulses.
Outline the role of inhibitory and excitatory neurotransmitters
Excitatory neurotransmitters (e.g. dopamine) increase the potential difference across the
postsynaptic membrane, increasing the likelihood of an action potential being generated.
Inhibitory neurotransmitters decrease the likelihood of a neuron firing as they decrease the potential difference across the postsynaptic membrane.
Outline brain plasticity
The brain’s ability to change its structure and function. This can happen in response to internal and external stimuli, such as injuries, learning experiences, and environmental inputs.
Synaptic pruning: neural connections which are frequently used are strengthened whereas connections which aren’t used often become weaker.
Outline functional recovery
Functional recovery is a form of plasticity that describes when healthy regions of the brain compensate for damaged areas of the brain typically after the brain has undergone some form of trauma or damage.
This can involve several things
Axonal sprouting: when new neural pathways are formed via the growth of new nerve endings.
Reformation of blood vessels.
Recruitment of homologous areas to the opposite side of the brain to perform specific functions.
Spontaneous recovery- functional recovery happens quickly after trauma and then slows down after several weeks. Then rehabilitative therapy may be required.
Evaluate the strengths of functional recovery and brain plasticity.
There is lots of research to support the concept of functional recovery and brain plasticity making it more reliable and credible.
Maguire et al:
Used fMRI scanners to compare the posteriori hippocampi of London taxi drivers to a control group. The size of the hippocampus was significantly larger in those of taxi drivers than the control group. Moreover, the volume of their hippocampus was directly proportional to the length of time the individual had worked as a taxi driver. The hippocampus has a crucial role is forming and storing memories as well as spatial navigation. Its increase in size suggests it adapted to the taxi drivers’ jobs requiring good navigational skills.
Research used reliable, objective methodologies, providing credible evidence that the brain adapts to help carry out certain functions.
However, correlation does not prove causation.
Kuhn et al:
The amount of grey matter was compared between the brains of participants in a control group and participants who were told to play 30 mins of Mario kart a day.
They found a significant increase in grey matter in the experimental group, including regions of the brain associated with spatial navigation and motor performance. As this difference was not seen in the control group, these findings support the idea of brain plasticity and how it was able to adapt its structure when demands cause it to do so, such as how playing a motor sports video game demands more navigational skills.
These findings demonstrated the plasticity of the brain and how it can adapt its structure when demands cause it to do so, such as how playing a motor sport video game demands more navigational skills.
Real life application:
The understanding of brain plasticity has contributed to the field of neurorehabilitation. Research into spontaneous recovery shows recovery tends to slow down after a few weeks. This shows that even though the brain has the ability to heal itself to a certain point, further intervention is also required for it to be completely successful.
This knowledge has led to treatments such as movement therapy and electrical stimulation of the brain which can help counter any deficits in cognitive and/or motor functioning that may be experienced following brain trauma.
This research has helped identify ways in which recovery can be maintained and improved and thus can enable patients following trauma a better quality of life.
Evaluate the weaknesses of brain plasticity and functional recovery.
Individual differences: despite supporting evidence for functional recovery, alternative research suggests level of recovery differs between people. Therefore, we must consider individual differences when assessing the likelihood of functional recovery in the brain after trauma.
Ebert et al concluded that the capacity for neural reorganisation is much greater in children than in adults, meaning that neural regeneration is less effective in older brains. This may explain why adults find change more demanding than do young people.
Mathias conducted a metanalysis which demonstrated IQ and educational background are positively correlated with better outcomes after traumatic brain injury, suggesting certain individuals have better cognitive reserve which helps in the process of recovery. ), stated that education level and IQ will effect how well the brain copes and changes with trauma
Outline localisation of function in the brain
Localisation of function is the idea that certain functions (e.g. language, memory, etc.) have certain locations or areas within the brain.
Motor cortex: located in the frontal lobe the motor cortex controls voluntary movement in the opposite side of the body. Damage to this area leads to loss of control over fine motor movements.
Somatosensory cortex: this region is located in the parietal lobe and Detects sensory events from different regions in the body and produces sensations such as touch and pain from receptors.
Auditory area is located in the temporal lobe and analyses and processes acoustic information.
Visual area: located at the back of the occipital lobe the visual area receives and processes visual info. With the right visual cortex processing information from the left eye and the left visual cortex processing information from the right eye.
Broca’s area: located in the left frontal lobe and known to be responsible for the motor control used in speech production.
Wernicke’s area: located in the left temporal lobe and is involved in the comprehension of written and spoken language.
Evaluate localisation of function in the brain
Supporting case studies:
Phineas Gage’s frontal lobe was impaled with a pole. The damage to his brain left a mark on his personality from a calm to quick-tempered individual. This suggested that the frontal lobe may be responsible for regulating mood.
Neuroimaging support: Peterson et al used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task, suggesting that areas of the brain have different functions.
Counter evidence:
The Holistic Theory of brain function undermines that localisation of function occurs. Lashley conducted an animal study involving rats and found that there was not specific areas involved in memory but instead memory was stored all over the brain. This undermines the idea that specific parts of the brain perform functions and is potentially invalid.
Lashley’s study:
50 rats run and re-run a course of a maze after having regions of their cortex destroyed. Lashley found that their ability to successfully re-run the route was impacted not by which regions of the cortex were destroyed but rather the amount that was damaged. This suggested that higher cognitive brain processes such as learning and memory weren’t localised but distributed across the brain.
Outline the role of exogenous zeitgebers and endogenous pacemakers.
Endogenous pacemakers are the body’s internal body clocks which help govern biological rhythms.
The suprachiasmatic nucleus is an example of an important endogenous pacemaker which has an important role in maintaining and governing the body’s sleep-wake cycle. However, its function is also dependent on external factors.
The SCN contains receptors that are sensitive to light, when low light levels are detected the SCN sends signals to the pineal gland, which leads to an increase in the production of melatonin at night, helping to induce sleep. The SCN and pineal glands work together as endogenous pacemakers; however, their activity is responsive to the external cue of light.
Exogenous zeitgebers are external, environmental factors which influence the function of the body’s internal body clocks. Examples include natural factors such as sunlight, temperature changes, and social cues such as meal times and daily routines.
Evaluate research into biological rhythms:
Research support:
Siffre - found that the absence of external cues significantly altered his circadian rhythm: When he returned from an underground stay with no clocks or light, he believed the date to be a month earlier than it was.
Menaker: bred a strain of hamsters with an abnormal sleep /wake cycle (20 hours) and transplanted SCN neurons into hamsters with a normal cycle. Their circadian rhythm changed to 20 hours, highlighting the importance of the SCN.
Lack of generalisability:
As Siffre’s case study was only conducted on one person, himself, this makes it difficult to generalise his findings to a wider demographic and to draw reliable conclusions about if other’s circadian rhythms would be influenced in the same way as a result of an absence of external light.
Humans would respond very differently to manipulations of their biological rhythms,
not only because we are different biologically, but also because of the vast differences between environmental contexts. This makes research carried out on other animals limited in their ability to explain the role of endogenous pacemakers
in the biological processes of humans.
The role of individual differences:
Duffy et al distinguished between the different sleeping patterns between “morning” and “night” people and their preferences for when they get up and go to bed. Therefore, there may be innate differences governing our circadian rhythms which should be taken into account when studying biological rhythms.
Real life applications:
Chronotheraputics - the study of how timing can effect drug timings.
Describe ways of studying the brain
EEGs - electroencephalogram
measures electrical activity within the brain by attaching electrodes to the scalp. When graphed over a period of time an EEG is produced displaying brain waves patterns. These can be used to detect various brain disorders that effect brain activity. Eg: sporadic spikes may be indicative of epilepsy whilst general slowing down of brain waves can be a sign of Alzheimer’s.
ERPs - event related potentials
ERPs measure the small voltage changes in brain activity as a result of a specific event. It is difficult to pick out these small changes amongst all other activity, therefore the stimulus is repeatedly presented in order to establish a response.
ERPs have a very short latency so can be divided into two categories. Responses/waves which occur within 100ms are known as sensory ERPs, whilst those which take longer than 100ms are known as cognitive ERPs.
fMRI - electromagnetic fields align nuclei (present in hydrogen atoms in red blood cells) using magnets. fMRI scans measure changes in blood flow to see which areas of the brain are more active. More blood flow to certain regions identifies which areas are more active, as these areas will demand more oxygen.
Post-mortem examinations:
Examination of the brain after someone has died in attempts of establishing any underlying causes for a particular behaviour displayed whilst alive. Researchers compare any abnormalities with brains of a control group. Post-mortems have given insight into the function of certain areas of the brain (eg: Broca’s area)
PET scans - Patient injected with a radioactive tracer which attaches to glucose and will be used as an energy source. A PET scan will present more active regions of the brain as red/yellow, and lower activity regions as blue/purple.
CAT scans - X rays fired through brain multiple times
