biopsychology

nervous system

highly specialised set of cells in the human body and is our primary internal communication system.

divisions of the nervous system

central nervous system and peripheral nervous system

central nervous system

consists of the brain and spinal cord

brain

involved in all psychological processes and its main job is to ensure life is maintained.

functions of the brain

collect, process and respond to information in the environment

coordinate and direct the working of different organs and cells within the body.

spinal cord

carries messages using neurons to and from the brain to the peripheral nervous system

arc reflex

automatic involuntary and rapid response to a stimulus which minimises any damage to the body from potentially harmful conditions, such as touching something hot

steps involved in arc reflex

stimulus

receptor

sensory neuron

motor neuron

effector

response

peripheral nervous system

all of the nerves in our body outside the brain and the spinal cord and its main focus is to relay nerve impulses from the CNS to the rest of the body and from the body back to the CNS.

2 main parts of the PNS

somatic nervous system and autonomic nervous system

somatic nervous system

A subdivision of the peripheral nervous system. Enables voluntary actions to be undertaken due to its control of skeletal muscles

control centre of the somatic nervous system

motor and somatosensory cortex

motor cortex

an area at the rear of the frontal lobes that controls voluntary movements

somatosensory cortex

registers and processes body touch and movement sensations

2 main components of somatic nervous system

sensory pathways and motor pathways

sensory pathways

transmit and receive information from the senses such as visual information from the eyes and auditory information from the ears to the brain (sensory neurons)

motor pathways

direct voluntary movement of skeletal muscles and orchestrate all of our movements from the brain (motor neurons)

autonomic nervous system

responsible for functions that keep the body in a stable state, many of its functions are automatic require

2 branches of the autonomic system

sympathetic and parasympathetic

sympathetic

when exposed to threats it activates and prepares the body for rapid action

parasympathetic

tries to store and conserve resources once emergency has passed

the nervous system

the network of nerve cells and fibers that transmits nerve impulses between parts of the body.

neurons

these are cells that must relay information around the brain and nervous system by using chemical impulses and neurotransmitters

neurotransmitters

electrical impulses travel from one end of a neuron to the other and release a chemical

action potential

an electrical impulse that forms when a message travels down a neuron

dendrite

branch like structures protruding from the cell body that receive nerve impulses from neighbouring neurons and then send the action potential to the cell body

nucleus

contains the genetic material of the cell

axon

carries action potential away from the body, down the length of the neuron and towards the terminal buttons

myelin sheath

a fatty layer that protects the axon from damage whilst insulating it speeding use electrical transmission of the action potential

nodes of ranvier

gaps in the myelin sheath which speed up the transmission of the action potential by forcing it to jump across the gaps along the axon

terminal button

the end of the neuron that has synaptic connections with over neighbouring neurons

types of neurons

sensory, relay and motor

sensory neurons

carry messages from the PNS to the CNS

relay neurons

allow sensory and motor neurons to communicate and connect with each other; they carry nerve impulses between neurons

motor neurons

these connect the CNS to effectors such muscles and glands

synaptic transmission

process by which neurons communicate with each other by sending chemical messages across a synapse

what happens when an electrical impulse reaches the axon terminal?

it triggers the release of neurotransmitters from vesicles in the pre-synaptic neuron.

what is the synaptic cleft?

the tiny gap between the pre-synaptic and post-synaptic neurons.

what happens to neurotransmitters after release?

they diffuse across the synaptic cleft and bind to receptor sites on the postsynaptic neuron.

what happens when neurotransmitters bind to receptors?

the chemical message is converted back into an electrical impulse in the postsynaptic neuron.

reuptake

any leftover neurotransmitter in the synaptic cleft is reabsorbed into the pre-synaptic neuron for reuse.

excitatory neurotransmitters

create a positive charge and make the neuron more likely to fire and this rise in action potential will increase activity

inhibitory neurotransmitters

create a negative charge that makes the neuron less likely to fire and this fall in action potential will decrease activity

summation

the excitatory and inhibitory influences are summed

examples of neurotransmitters

dopamine, serotonin

why is synaptic transmission unidirectional

because neurotransmitters are only released from the pre- synaptic and receptors are only on the post synaptic neuron

process of synaptic transmission

when an electrical impulse (action potential) reaches the axon terminal of the presynaptic neuron, it triggers the release of neurotransmitters from synaptic vesicles. These neurotransmitters cross the synaptic cleft and bind to specific receptor sites on the postsynaptic neuron. This binding either excites or inhibits a new action potential in the postsynaptic neuron. Any remaining neurotransmitters in the synaptic gap are reabsorbed by the presynaptic neuron in a process called reuptake. This ensures the signal is regulated and that synaptic transmission is unidirectional.

the endocrine system

secrete hormones in the bloodstream to regulate bodily functions

hormones

chemicals that are released from glands that circulate the bloodstream and are carried to target structures around the body

pituitary gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

examples of glands and hormones

adrenal gland, noradrenaline, pineal gland

adrenal gland

located on top of the kidneys that secrete hormones like adrenaline which is crucial for the fight or flight response

noradrenaline

neurotransmitter of the brain that plays an essential role in the regulation of arousal, attention, cognitive function and stress reactions

pineal gland

small gland near the center of the brain that secretes melatonin

SAM

sympathomedullary pathway - it's the body's response to acute (short-term) stress involving the sympathetic nervous system and adrenal medulla.

what is the first step in the SAM pathway when a stressor is perceived?

the hypothalamus detects the stressor and activates the sympathetic branch of the autonomic nervous system.

after the sympathetic nervous system is activated, what happens next in the SAM pathway?

the sympathetic nerves stimulate the adrenal medulla (inner part of adrenal gland).

what hormones does the adrenal medulla release during the acute stress response?

adrenaline and noradrenaline - they prepare the body for 'fight or flight'.

what are the physiological effects of adrenaline and noradrenaline in the body?

🔹 Increased heart rate🔹 Increased breathing rate🔹 Pupil dilation🔹 Blood diverted to muscles🔹 Digestion slows down

what happens after the stressor is dealt with in the SAM pathway?

the parasympathetic nervous system is activated to return the body to normal ('rest and digest') state.

homeostatisis

the process of keeping the internal environment stable/constant/balanced

how adrenaline increases respiration

adrenaline makes the heart beat faster and the lungs breathe more efficiently and during breathing, the intercostal muscles normally tighten

ways of studying the brain

fMRI, EEG, ERP, post-mortem

post mortem examinations

when a persons brain is examined after they have died to see where damage has occurred and how that might explain behaviour exhibited by the person prior to death

strengths of post mortem examinations

-more detailed examination of anatomical and neurochemical aspects of the brain

-harrison (2000), schizophrenic and during post mortem, researchers discovered structured abnormalities in neurotransmitters which are associated with the disorder, allows for understanding why schizophrenia is formed and development of successful treatment

weakness of post mortem examinations

- can lead to inaccurate data and findings because as soon as oxygen is cut off from the brain, it shrinks so findings may lack accuracy

- approach is retrospective as the individual is already dead and damaged brain area observed might be the consequence of a lifetime of disease (e.g., schizophrenia or dementia), rather than the original cause.

functional magnetic resonance imaging (fMRI)

uses strong magnetic and radio waves to monitor blood flow in the brain, takes repeated scans to create an image of the concentration of oxygen in the blood at any given time

strengths of fMRI

- provide a moving picture of brain activity rather than just bland physiology of the brain and see which parts are being utilised in certain tasks giving researchers insight in the function of different brain areas.

- non-invasive; doesn't involve insertion or any instruments into the body nor does it expose the brain to any kind of harmful radiation; ethical

weaknness of fMRI

- interpreting fMRI is complex and problematic as sample sizes are often small and unrepresentative. money is also spent for up keep and training researchers on how to effectively use the machine

- only focus on localised activity of the brain, so doesn't identify important ways in which communication between different region affects mental functioning, this reduces its usefulness

electroencephalogram (EEG)

recording of brain activity, small sensors are attached to the scalp to pick up the electrical signals produced when brain cells send messages to each other.

strengths of EEGs

- useful when trying to make a clinical diagnosis, eg epileptic seizures are caused by disturbed brain activity which means seizures are caused by disturbed brain changes, so can be used to help diagnose seizures

- cheaper than other methods of studying the brain so are frequently used in research like sleep studies

weakness of EEGs

- can only detect activity in superficial regions of the brain, cannot reveal what is going on in deeper regions of the brain like the hypothalamus or hippocampus

- not useful for pinpointing the exact source of brain activity, eg, electrical activity in the brain can be picked up by several neighbouring electrodes meaning researchers cant distinguish between activities originating in different but closely adjacent locations of the brain

event related potentials (ERPs)

use recording electrodes that measure electrical activity in response to a specific stimulus. a recording is taken from numerous presentations and then an average out of the response to obtain an even-related potential

strengths of ERPs

- useful to measure the reliability of self reported techniques, eg in drug miuse, can give an indication of lying so the researchers can determine whose results may not as valid

- directly measures neuronal activity and give the earliest indication of conscious cognitive processing, can detect the slightest changes to due to an environmental manipulation of stimulus

weakness ERPs

- the signal is not useful for pinpointing the exact source of brain activity, eg, electrical activity in the brain can be picked up by several neighbouring electrodes

- output can only be interpreted by a trained professional and training can cost a lot

similarities between fMRI and EEGs

both are non invasive

differences between fMRI and EEGs

fMRI measures blood oxygenation; EEG records electrical activity via scalp electrodes.

fMRI has high spatial resolution (good for where activity happens); EEG has high temporal resolution (good for when it happens).

fMRI is more expensive and less portable; EEG is cheaper and more widely available.

similarities between fMRI and ERP

non invasive

differences between fMRI and ERP

ERP has better temporal resolution; fMRI has better spatial resolution.

ERP is more affordable and can be used in more settings than fMRI.

similarities between EEG and ERP

Both record electrical brain activity using electrodes on the scalp.

Both are non-invasive

Both have excellent temporal resolution (detect rapid brain activity).

Differences between EEG and ERP

EEG shows general patterns of brainwave activity; ERP isolates specific responses to stimuli.

ERP is derived from EEG data but removes background noise for event-related analysis.

EEG is used for broader monitoring (e.g. sleep studies); ERP is more focused and specific.

similarities between post-mortem examinations and scanning techniques

Both aim to understand the structure and function of the brain.

Both can be used to correlate brain abnormalities with behaviour.

differences between post-mortem examinations and scanning techniques

post-mortem is carried out after death; scanning techniques are used on living brains.

Post-mortem provides static anatomical information; scanning shows real-time brain activity (e.g., fMRI, EEG, ERP).

Post-mortem can detect microscopic/chemical abnormalities (e.g., plaques in Alzheimer's); scans usually cannot.

Scanning techniques (esp. fMRI, EEG) offer temporal/spatial resolution; post-mortem doesn't.

temporal resolution

refers to how quickly the scans can detect changes in brain activity

spatial resolution

refers to the smallest measurement that a scanner can detect

localisation

the theory that specific areas of the brain are associated with particular physical and psychological functions

cerebral cortex

the outer layer of the brain made up of the left and right hemispheres connected by a bundle of fibres called the corpus callosum which enables messages to enter the right hemisphere to be conveyed to the left hemisphere and vice versa

divisions of the hemispheres

- frontal lobe

- parietal lobe

- occipital lobe

- temporal lobe

lateralisation

theory that the two halves of the brain are functionally specialized, with certain mental processes being dominant in one hemisphere rather than the othef

hemispheric lateralisation

the dominance of one hemisphere of the brain for particular physical and psychological functions

contralateral

the right hemisphere of the brain controls the left side of the body and vice versa

somatotopically

this is the point for point correspondence if an area of the body to a specific point of the central nervous system

motor cortex

located in the frontal lobes, it is responsible for the generation of voluntary motor movements, it sends neural messages to muscles via the CNS, it is both contralateral and somatotopically organised

somatosensory cortex

located in the parietal lobe, it detects sensory events arising from receptors in the different areas of the body and produces sensations of touch, pressure, pain and temperature, which is localises to specific body region, is both contralateral and somatotopically organised.

visual cortex

located within the occipital lobe, it begins in the retina at the back of the eye where light enters and strikes the photo receptors, is also contralateral

auditory cortex

located in the temporal lobes of both hemispheres of the brain, ir is used for hearing; cochlea in the inner ear-sound waves are converted o nerve impulses which travel to the brain stem to be decoded, and contralateral

strength in localisation of function in the brain

- research evidence; Miller with the case of hm; his hippocampus in the temporal lobe had been removed to stop severe epilepsy but now could form new LTM, adds validity

- more research; phineas gage; pole went through his head, taking most of the prefrontal lobe matter with it but he still survived, had a change in behaviour as the frontal lobe regulates mood

weakness in localisation of function in the brain

- research evidence; lashley trained rats to run a maze to find food and removed parts of their cortex (10-50%) but results show maze was only affected by the amount of the cortex not the localisation; brain plasticity

- case study is biased; individual experiences so cannot be generalised to general population, so cannot be used to full support and understand localisation

left hemisphere

controls the right side of the body; analytical, language, math

right hemisphere

controls the left side of the body; creative, recognition of emotion, spatial (finding your way)