Biopsychology key definitions

central nervous system (CNS)

brain and the spinal chord

peripheral nervous system (PNS)

somatic nervous system and autonomic nervous system

the spinal chord

acts as a relay between the brain and the body, it monitors and regulates processes such as breathing and digestion and contains relay neurons for quick reactions

the 4 main areas of the brain

cerebrum, cerebellum, diencephalon, brain stem

cerebrum

is in two halves and split into 4 main areas; frontal lobe for thought, occipital lobe for vision, ,motor cortex for movement, auditory cortex for speech

cerebellum

motor skills and balance

diencephalon

comprised of the thalamus - relay station sending nerve impulses for senses to the correct brain area, and the hypothalamus - responsible for memory, hunger and thought

brain stem

regulates automatic functions e.g. breathing

autonomic nervous system

involuntary actions, comprised of the sympathetic division - excitatory; involved in fight or flight primarily and the parasympathetic division - inhibitory; relaxes the body

somatic nervous system

made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves, sensory nerves relay messages to CNS and motor neurons from CNS to the body

sensory neurons

are found in receptors such as eyes and skin, and carry nerve impulses to the spinal chord and brain. when the nerve impulses reach the brain they are translated into 'sensations' such as vision and touch. however some stop at the spinal chord for quick reflex actions - long dendrites and short axons

motor neurons

found in the CNS and control muscle movements, when they are stimulated they release neurotransmitters that bind to receptors on muscles to trigger a response, which lead to movement - short dendrites and long actions

relay neurons

found between sensory input and motor output/response, are in the brain and spinal chord and allow sensory and motor neurons to communicate - short dendrites and short axons

sensory neuron diagram

relay neuron diagram

motor neuron

dendrites

receives messages from other cells

cell body

the cells life support centre

axon

passes messages away from the cell body to other neurons, muscles and glands

nerve impulses

electrical signal traveling down the axon (action potential)

myelin sheath

covers the axon of some neurons and helps speed neural impulses, also insulates

terminal branches of axon

forms junctions with other cells

synaptic transmission

the process by which neighbouring neuron communicate by sending chemical messages across the synapse

first stage of synaptic transmission

an action potential (electrical charge) travels down the pre-synaptic neurons axon

second stage of synaptic transmission

when the action potential reaches the terminal at the end of the neuron, vesicles release the neurotransmitters they control

third stage of synaptic transmission

neurotransmitters (chemical messages) travel out of the neuron, across the synapse gap into receptors on the dendrites of the receiving post-synaptic neuron

fourth stage of synaptic transmission

the chemical messages are converted back into an electrical impulse and the process of transmission begins again

reuptake of neurotransmitters

after the messages have been sent, any leftover neurotransmitters are recycled. process in the brain of the neuron to retrieve chemicals that were not retrieved by the next neuron

neurotransmitters in the synaptic gap

have a greater effect, the effect is lessened when the message has been received by the post-synaptic neuron and during reuptake when it is taken back into the vesicles of the pre-synaptic neuron

SSRI drugs and reuptake

work by inhibiting reuptake of serotonin by the pre-synaptic neuron. serotonin neurotransmitters stay in the synaptic gap for longer, having a greater effect. the persons mood would remain stable and regulated for longer

neurotransmitters

have either an excitatory or inhibitory effect on the neighbouring neuron

excitatory

increases positive charge inpost synaptic neuron (EPSP) that it sends the message to, this increases the chances of another action potential to fire and messages to continue to be transmitted e.g. adrenaline

inhibitory

increases negative charge in post-synaptic neuron (IPSP) that it sends the message to, this decreases the chances of another action potential occurring and messages slow down or stop being transmitted e.g. serotonin

the endocrine system

collection of glands that produces hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep and mood

hypothalamus

a collection of specialised cells that is located in the lower central part of the brain, it is the main link between the endocrine and nervous systems

the pituitary gland

the 'master gland', controls the release of hormones from all the other endocrine glands in the body

hormone negative feedback loop

hormones are secreted into the bloodstream and affect any cell in the body that has a receptor for that particular hormone, the hormones are detected and the hypothalamus responds by shutting down secretion from the pituitary gland

hormone

a chemical that circulate the bloodstream and carry messages to target cites throughout the body

fight or flight response

evolutionary survival mechanism

sympathetic stress response symptoms

increased heart rate, increased blood pressure, dilates pupils, slows digestion - acute

parasympathetic return to normal after stress symptoms

decrease heart rate, decreases blood pressure, consrticts pupils, returns to normal - rest and digest

acute stress

sympathomedullary pathway (SAM)

chronic stress

HPA

SAM pathway

hypothamus - autonomic nervous system - sympathetic branch - adrenal medulla - releases adrenaline and noradrenaline - activates fight or flight response

evaluate fight or flight response

Taylor et al (2000) says that females have a tend or befriend response to help protect themselves and young explained by high levels of oxytocin, not evolved to modern day stressors, Gray (1988) says there is a freeze response first

Frontal lobe

parietal lobe

occipital lobe

temporal lobe

cerebellum location

brain stem location

localisation

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

Broca's area

responsible for speech production in the left frontal hemisphere, based off case study of Tan, able to comprehend language but not to speak it

Wernicke's area

responsible for language comprehension in the left temporal lobe, can speak but unable to comprehend language

motor cortex

responsible for voluntary motor movements in the frontal lobe

somatosensory cortex

detects sensory events and produces sensations of touch, pressure, pain and temperature in the parietal lobe

visual centres

receives and processes visual information in the occipital lobe

auditory centres

receives acoustic information in the temporal lobes

evaluation of localisation

equipotentiality Lashley 1930 only motor and sensory functions localised, case studies support these areas when studying brain damage, gender (beta) bias

lateralisation

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

hemispheric lateralisaion

each hemisphere has a specific function, left hemisphere is dominant in language and speech, right hemisphere excels in visual and motor tasks

corpus callosum

bundle of nerve fibres that connect the two hemispheres of the brain, this allows information received from one hemisphere to be sent to the other hemisphere - treatment for severe epilepsy involves cutting the corpus callosum creating split-brain patients

Sperry and Gazzaniga (1967)

quasi-experiment that studied split brain patients who had gone under hemispheric lateralisation for severe epilepsy

Sperry and Gazzaniga (1967) procedure

11 split brain patients, compared with control group, blindfolding one of pps eyes and asking them to fixate on a point, stimulus was projected on either the left or right side of the fixation for less than 1/10 of a second

Sperry and Gazzaniga (1967) findings

patients can verbalise an image shown to their right visual field, patients cannot verbalise an image shown to their left visual field but can draw it with their left hand, if a patient is shown two different images in their full visual field they will say they've seen the one in their right visual field but draw the image they've seen in the left

evaluation of lateralisation

increases neural processing capacity as only one hemisphere is needed for specific tasks leaving the other free, lateralisation of function doesn't stay the same throughout a lifetime

evaluation of split brain research

Gazzaniga (1998), early discoveries from split brain research have been disconformied by more recent discoveries, split brain procedure is rarely carried out so it is hard to find large samples for research

plasticity

the brains ability to change and adapt as a result of experience, plays an important role in brain development and behaviour

functional plasticity

the brains ability to move functions from a damaged area to other undamaged areas

structural plasticity

the brains ability to change its psychical structure as a result of learning

Boyke et al (2008)

found evidence of brain plasticity in 60 year olds, taught them a new skill of juggling and found an increase in grey matter in the visual cortex and when practice stopped these changes reversed

Maguire et al (2000)

studies london taxi drivers to discover whether changes to the brain could be detected as a result of their extensive navigational experience. MRI scanners showed that there was more grey matter in the brains of taxi drivers in the posterior hippocampus compared to a control group - functional plasticity

evaluation of Maguire et al (2000)

scientific, objective measurement (MRI), control group which shows significant difference, real world application, drivers weren't tested prior to becoming tai drivers so there could be an existing difference

neural unmasking Wall (1977)

'dormant synapses' exist but their function is blocked as neural input is too low. increased rate to these synapses as a result of a damage to the surrounding area can 'unmask' them

stem cells

stem cells transplanted directly into the brain could replace dead or dying cells. stem cells could secrete growth factors to rescue dying cells. stem cells could link an uninjured brain site with the damaged region

research support from animal studies

Tajiri et al (2013) assigned rats with brain damage to two groups, one group recieved stem cells and the other didnt. the stem cell group showed development of neuron-like cells in the area of injury

age differences in functional recovery

functional plasticity reduces with age however studies have suggested that adults can modify some abilities with retraining

post-mortem exams

after death the brain can be opened to look for abnormalities. can be used to establish a link between psychiatric disorders and underlying brain abnormalities

post-mortem exam evaluation

helped understand the cause of some disorders, very detailed of structure and neurochemistry. cant establish causal relationships

fMRI (functional magnetic rensonace imaging)

measues changes in brain activity while a person performs a task. measures changes in blood flow to particular areas of the brain

fMRI evaluation

spacital validity (between 1-2mm), non-invasive. low temporal validity (up to 4 sec delay), no direct measure of neural activity

EEG (electroencephalogram)

measures electrical activity in the brain resulting from the activity of brain cells. can be used to help diagnose brain disorders (e.g. epilepsy and alzheimers). 4 types of wave

alpha waves

when a person is awake but relaxed, rhymical

beta waves

when a person is physiologically aroused, low amplitude but fast, also found in REM sleep

theta and delta waves

occur during sleep. as a person moves fom light to deep sleep the occurance of alpha waves decreases and are replaced by lower frequency theta waves and then by delta waves

EEG evaluation

can be used as a diagnostic tool, high temporal resolution (1-10 ms). low spatial resolution

ERP (event-related potentials)

small voltage changes in the brain triggered by specific events or stimuli. waves occurring within the first 100 ms after stimulus presentation are 'sensory'. after the first 100 ms they are termed 'cognitive'

ERP evaluation

good temporal resolution (1-10 ms), non-invasive. low spatial resolution, enables determination of processing

circadian rhythms

any cycle which lasts around 24 hours such as the sleep-wake cycle

suprachiasmatic nuclei

the master circadian pacemaker found in the hypothalamus. neurons within the SCN spontaneously synchronise with each other so that their target neurons in sites elsewhere in the body receive correctly time-coordinated signals

the sleep-wake cycle

our strongest sleep drive usually occurs in two dips, 2-4am and 1-3pm. driven by exogenous zeitgebers such as light and social cues which controls the release of melatonin.

core body temperature

at its lowest at about 4:30am (36 degrees) and at its highest about 6pm (38 degrees). sleep occurs when the core temperature begins to drop and the body temperature begins to rise during the last hours of sleep, promoting a feeling of wakefulness in the morning.

hormone production

the production and release of melatonin from the pineal gland follows a circadian rhythm. by activating chemical receptors in the brain, melatonin encourages feelings of sleep, when its dark more melatonin is produced

Michel Siffre

spent long periods of time living underground with no access to zeitgebers to guide his rhythms. after 61 days underground in 1962 he resurfaced on the 17th of september believing it was august 20th. 6 months in a cave settled his circadian rhythm to just over 24 hours.

evaluation of circadian rhythms

individual differences - (Czeisler et al 1999) found that cycle length can vary from 13-65 hours,
research methodology - in most studies people are isolated from variables which may affect their cycles but are still exposed to artificial light, which research suggests can vary circadian rhythms
biological determinism

endogenous pacemakers

anything whose origins are within the organism, most probably the product of inherited genetic mechanisms

the pineal gland

the SCN sends signals to the pineal gland, directing it to increase the production and secretion of the hormone melatonin at night and to decrease it as light levels increase - endogenous pacemaker

melatonin

induces sleep by inhibiting the brain mechanisms which promote wakefulness

exogenous zeitgebers

anything whose origins are outside the organism. environmental events that are responsible for entraining the biological clock of an organism

light

receptors in the SCN are sensitive to changes in light levels during the day and use this info to synchronise the activity of the body's organisms and glands. light resets the internal biological clock each day, keeping it on a 24 hour cycle.