biopsychology

central nervous system

the brain and the spinal cord, the brain stem connects the spine and brain and controls involuntary processes

occipital lobe

visual info

temporal lobe

auditory info

pariental lobe

spatial navigation

frontal lobe

high order functioning e.g., planning

The brain stem

Connects the brain and spine, controls involuntary processes, controls reflex actions

The peripheral nervous system

Relay messages from the CNS to the rest of body

Adrenal gland

The adrenal medulla - releasing adrenaline and noradrenaline

Adrenal cortex - glucose to provide energy while suppressing the immune system

Hypothalamus

Responsible for controlling hormone release from pituitary goand. Regulates endocrine system

Ovaries

Makes oestrogen and progesterone, develops breasts and menstrual cycle

Parathyroid gland

Controls calcium and phosphorus

Pineal gland

Melatonin is responsible for biological rhythms

Pituitary gland

Control and stimulate the release of other hormones from other glands

Testes

Makes testosterone which helps grow facial and body hair

Thymus

Makes t-lymphocytes that fight infection and help immune system develop

Pancreas

Makes digestive enzyme, makes insulin and glucagon to control blood sugar

Thyroid

Released thyroxine which regulates metabolism

Strength of endocrine system

Weakness of endocrine system

F&F response to acute stressors

Sympathetic nervous system - triggers fight or flight providing phsiologivak changes

Adrenaline - activated sympathetic nervous system by sending signals to adrenal glands. Respond by pumping adrenaline into bloodstream

Parasympathetic nervous system - rest and digest respond

Response to chronic stress

Hypothalamus - releases CRH into the bloodstream

Pituitary - responds to CRH and releases ACTH

Adrenal gland - stimulated by ACTH to release adrenaline and cortisol

Feedback - the hypothalamus and pituitary gland regulate when cortisol goes too high

Strength of fight or flight (Taylor et al)

The tend and befriend system may be a better explanation for females, who create safety in numbers. Oxytocin in caregivers decreases anxiety, there are genetic differences in sexes

Strength of fight or flight

Supporting evidence, animals and humans do initially freeze, this allows them to assess the situation and choose the response

Types of neurons

Sensory

Relay

Motor

Sensory neuron

Carry nerve impulses from spinal cord and brain. Translates impulses to sensations

Relay neurons

Found between sensory input and motor output, allowing communication

motor neurons

Carry impulses from the brain and spinal cord to muscles and glands, responsible for movement and action.

dendrites

receive signals from other neuron’s and sensory receptors and transmit them to the cell body.

axon

carries nerve impulses in the form of electrical impulses to the axon terminal

myelin sheath

insulates the axon so electrical impulses can travel faster

axon terminal

connects the neuron to other neuron’s through synaptic transmission

reflex actions

way for the body to automatically and rapidly respond to stimulus to minimise further damage. does not involve the brain

reflex process

1. stimulus

2. receptor

3. sensory neurons

4. relay neurons

5. motor neurons

6. effector

7. response

pre-synaptic transmission

when one neuron communicates with another, info passed down axon terminal as electrical impulses. when reaches the end of the axon, needs to be transferred to another neutron, where there are synaptic vesicles which contain neurotransmitters. electrical impulses bind to vesicles which release contents to neurotransmitters, which carry electrical signals across synaptic gap.

synaptic transmission

1. action potential arrives in the form of an electrical signal

2. vesicles fuse/bind with the membrane of the presynaptic neuron

3. neurotransmitters are released where they can diffuse across the synaptic gap

4. neurotransmitters bind with their specific receptors found on the post synaptic membrane

5. if neurotransmitter is excitatory and bind with their receptors an action potential will be fired. if it is inhibitor, and enough bind with receptors then an action potential will be prevented from firing.

6. neurotransmitters are recycled by re-enetering the presynaptic membrane via reuptake ports so the process can restart

neurotransmitters

chemical releasers that carry signals between neurons and other cells in the body

exitatory neurotransmitter example

acetylcholine and noradrenaline

inhibitory neurotransmitter example

seretonin and GABA

localisation of function

specific areas associated with particular psychological and physiological functions. different parts perform different tasks and are associated with different parts of the body

language areas

language restricted to left side of the brain.

broca’s area

small area in the left temporal/frontal lobe, language production. damage causes speech to be slow, laborious and influent.

wernickes area

language understanding in the left temporal lobe. damage can make speech meaningless, nonsense words.

frontal lobe

manages core cognitive functions e.g., thinking, attention, emotions

pariental lobe

processes sensory information from the body e.g., touch, spatial awareness

occipital lobe

processes visual information e.g., visual memory, face recognition

cerebellum

controls gross and fine motor skills e.g., hand eye coordination

Brian stem

regulates body functions e.g., temp control

somatosensory area

sense of touch in specific areas of body

broca’s area

speech production

wernickes area

understanding language

motor area

movement in specific body parts

primary-visual

converts impulses from retina into sight

strength of localisation

there is support from aphasia studies, such as Broca and wernickes findings, of damage to their areas

weakness of localisation

communication may be more important than localisation, damage to the connection between wernickes area and the visual cortex results in loss of reading

eqiopotentiality = basic motor and sensory functions are localised but higher order functions are not. damage is determined by extent not location

weakness of brocas area

remained brains of brocas patients, identifying in more detailed MRIs the extent of lesions. other areas could have contributed and it is more complicated, with networks of the brain,

lateralisation

each hemisphere is responsible for different functions, left = language, right = spatial awareness and visual motor.

corpus callosum

connects the left and right side of the brain, facilitating interhemespheric communication

sperry and gazziniga aim (split brain)

examine the extent the 2 hemispheres are specialised for certain functions

sperry and gazziniga patients (split brain)

surgery to treat seizures caused by interhemespheric electrical storm, their corpus callosum is cut.

sperry and gazziniga procedure (split brain)

image projected into right or left visual field for less than a second, as it cannot be transferred to the other hemisphere.

1. describe what you see

2. tactile test

3. drawing task

sperry and gazzaniga

left = speech and language

right = visual-motor tasks

strength of lateralisation

it is assumed to increase neural processing capacity, showing an evolutionary advantage, as they can engage in 2 different tasks. this can be seen with elderly people using both hemispheres to compensate for cognitive decline

weakness of lateralisation

patients are rare, and it is not often performed these days. health conditions such as seizures could have caused brain damage, decreasing validity and replicability

plasticity as weakness of lateralisation

proves people can develop new abilities after traumatic injuries, as the brain takes over functions of damaged areas. evidence for a changing and adapting brain. must accept lateralisation is not fixed.

plasticity

functions can change as a result of experience or injury. the brain is malleable

developmental plasticity

natural part of growth that slows as we age

synaptic pruning

at birth = 2500 synapses

by 3 = 15000 synapses

adult has half the synapses of a 3 year old due to our experiences strengthening some connections and limiting others. neurons that don’t recieve or transmit information die, to allow the brain to adapt to a changing environment.

age’s effect on plasticity

it is more prominent when we are younger as our brains are more sensitive and responsive to experiences. it never stops changing

injury induced plasticity

in instances of damage, healthy parts of the brain take over damaged functions and restore abilities. as they recover, the brain shows evidence of functional recovery.

weakness of plasticity

the brain is not infinitely malleable, damage to key areas that are largely responsible for certain functions can result in deficits.

strength of plasticity

people are not limited to the abilities we are born with, our brains continue to adapt to new experiences and learn new information

Tajari et al (stem cell treatment)

rats given injections into area or damaged brain, sowed evidence of neural recovery

Elbert et al (stem cell treatment)

we must consider individual differences, adults find change more demanding, and capacity for neural reorganisation is greater in children.

neuronal unmasking

dormant synapses open connections to compensate for a nearby damaged area. this allows new connections to be activated

hubert and wiesel

worked with kittens to investigate plasticity, found an innate period of early development and later critical period

plata

patients over 40 had less function, showing the abity for functional recovery deteriorates with age

schneider

higher levels of education predicts later recover, those attending college = 7x more likely to be disability free a year after recovery

Maguire et al (strength of plasticity)

found an increase in grey matter in the rear hippocampus of right handed taxi drivers who had been driving 1.5+ years. there was a correlation between the amount of time spent driving and the volume. extensive practice with spatial navigation affects the hippocampus.

weakness of maguires study

amount of grey matter could predispose someone to a profession dependent on navigation skills.

boyke (strength of plasticity)

60-year olds taught to juggle, showed growth in brain matter of the visual cortex, when the practice ended the growth receded.

rosenweig et al (strength of plasticity)

the group of rats raised in an enriching environment showed increased synapse numbers than the control group

Kuhn et al (strength of plasticity)

trained 30 minute a day on Mario for 3 months, showed new synaptic connection structures associated with spatial navigation and planning

real life application (strength of plasticity)

has lead to neurorehabilitation which uses motor therapy and electrical stimulation to counter deficits in motor and cognitive functions. this shows the positive application in research to improve cognitive functions.

functional magnetic resonance imaging

measures blood flow when a person performs a task. neurons that are most active use the most energy, which used deoxygenated haemoglobin. this has a different magnetic quality which is detected, creating a 3d map of the brain, highlighting areas involved in different activities

strength of functional magnetic resonance imaging

they are non-invasive and can study living brains without causing any harm

weakness of fictional magnetic resonance imaging

overlooks the networked nature of the brain that is more important than localised functions

electroencephalogram (EEG)

measure electrical activity trough electrodes. electrical changes are graphed indicating levels of brain activity, in amplitude and frequency. they produce synchronised or desynchronised patterns

strength of EEG

strong real-life application as it is used clinically for the diagnoses of conditions such as epilepsy

weakness of EEG

cannot detect activity in deeper regions of the brain

event-related potentials

stimulus is presented to a participant who is connected to electrodes to look for activity related to the stimulus which is presented hundred of times to get an average

strength of event-related potentials

continuous measure of the brains response to stimulus and pinpoints it to a localised area.

weakness of event-related potentials

multiple repetitions required to gain meaningful data, taking more time and cost

post mortem examination

study of a brain of someone who displayed a patricular behaviour, that possibly suggested brain damage

post mortem strength

due to its in depth investigation, without time constraints, it has lead to our understanding of many disorders

post mortem weakness

confounding variable in substances which can effect brain tissue, meaning it is difficult to establish cause and effect

circadian rhythms

24 hour rhythm is reset by levels of light which provides an external cue.

examples of circadian rhythms

sleep wake cycle - also determined by homeostasis and body temp. homeostatic drive for sleep increases throughout the day and when body temp starts to drop sleep occurs.

siffre (circadian rhythms)

case study of a man with no natural light for 6 months, only artificial light. his sleep wake cycle was distorted to 25-30 hours

duffy et al (circadian rhythms)

there are differences in people such as being a morning or evening person, research should focus on this.

buhr et al

temperature may be more important than light, as fluctuations in temperature set the timing of cells in the body.