Brain and Neuropsychology Flashcards
Nervous system
Specialised network of cells in the human body that is our primary internal communication
Functions of the nervous system
- collect, process and respond to information in environment
- coordinate working of different organs + cells
Nervous system divisions
- central nervous system
- peripheral nervous system
Central nervous system divisions
- brain
- spinal cord
Brain
- centre of all conscious awareness
- outer layer (cerebral cortex) highly developed in humans
Spinal cord
Extension of brain responsible for reflex actions
Peripheral nervous system divisions
- somatic nervous system
- autonomic nervous system
Somatic nervous system
Responsible for carrying sensory + motor information to and from CNS
Autonomic nervous system
- controls autonomic functions
- governs vital functions in body (breathing/digestion)
Autonomic nervous system divisions
- sympathetic nervous system
- parasympathetic nervous system
Sympathetic nervous system
Sets off physiological arousal - can be mild (anxiety) or extreme (fight or flight response)
Parasympathetic nervous system
Lets body rest and digest after stress
Fight or flight response
- hypothalamus in brain detects threat
- ANS changes from resting parasympathetic state to aroused sympathetic state
- adrenaline hormone released
- adrenaline triggers fight or flight response - pupils dilate, heart rate increases, ect
- after threat - ANS returns to resting parasympathetic state - may be tired/hungry as vital energy has been used
Homeostasis
Process by which the body maintains a constant and balanced state
Emotion
Strong feeling/mood that has important motivational properties
James-Lange theory of emotion DATE
1964
James-Lange theory of emotion PARTS
- physiological arousal first
- emotion after
- no physical changes = no emotion
- example
James-Lange theory of emotion PHYSIOLOGICAL AROUSAL FIRST
- event (stressor/threat in environment) activates hypothalamus which changes ANS to sympathetic state
- adrenaline is released - creates physiological arousal that increases bodily activity (e.g- faster heart rate + blood pressure)
James-Lange theory of emotion EMOTION AFTER
Brain interprets physiological arousal, resulting in emotion (e.g- excitement, fear)
James-Lange theory of emotion EXAMPLE
- person comes across bear in forest (stressor)
- sympathetic nervous system arousal - breathe heavier + higher heart rate
- person interprets this as fear
James-Lange theory of emotion STRENGTH
- makes sense in real life
- e.g - in case of phobias, person may shake or experience heart rate increase which leads to panic, phobic patient then wants to avoid stimulus in future
- theory applicable to real life situations
James-Lange theory of emotion WEAKNESSES
- arousal doesn’t always lead to emotion
- e.g - in hot weather, body goes through changes like starting sweating, doesn’t cause us to feel emotionally different
- difficult to say physiological arousal always causes emotion
+ - reductionist with opposing theories
- Cannon-Bard theory (1927) suggests emotion + arousal are 2 separate processes which can happen at same time, why physiological changes like sweating during exercise don’t cause emotion
- suggests emotion is more complex thst James-Lange believed
Neuron
- cell that communicates messages through electrical + chemical signals
- carry electrical impulses to + from CNS
Nerve
Many neurons together
Parts of a neuron
- soma
- nucleus
- dendrites
- axon
- myelin sheath
- nodes of Ranvier
- terminal button
Soma
Cell body containing nucleus
Nucleus
Contains genetic material
Dendrites
- carry electrical signals from neighbouring neurons to cell body
- stick out from cell body
Axon
Carries electrical signals away from cell body, down length of neuron
Myelin sheath
- fatty layer
- covers + protects axon
- speeds up electrical signals
Node of Ranvier
- gaps between myelin sheathes
- make signals go even faster as they jump across gap
Terminal button
- at end of axon
- communicates with next neuron in chain across gap
Types of neuron
- sensory
- relay
- motor
Sensory neuron function
- carry messages from PNS to CNS (brain)
- one end of neuron receives info from sense organ
Sensory neuron structure
- long dendrites
- short axon
Relay neuron function
- connect sensory + motor neurons
- only work within CNS
Relay neuron structure
- short dendrites
- short axon
Motor neuron function
Carry messages from CNS to effectors
Motor neuron structure
- short dendrites
- long axon
Synaptic transmission PARTS
- synapse
- neurons
- firing
- reuptake
Synaptic transmission SYNAPSE
- synapse - area between 2 neurons where they are close enough to pass messages between each other
- synaptic cleft - tiny gap separating 2 neurons
Synaptic transmission NEURONS
- presynaptic neuron contains neurotransmitters (chemical messengers) enclosed in vessicle
- action potential (electrical impulse) comes down axon
- vessicles fuse with presynaptic neuron’s membrane, causing release of neurotransmitters into synaptic cleft
Synaptic transmission FIRING
- in synaptic cleft, neurotransmitters interact with receptors of postsynaptic neuron’s membrane - bind to receptors, causing action to happen - excitation or inhibition
- excitation - increases positive charge of next neuron, making it more likely to fire action potential
- inhibition - decreases positive charge of next neuron, making it less likely to fire action potential
Synaptic transmission REUPTAKE
Unused neurotransmitters being returned to presynaptic neuron to be reused
Hebb’s theory of learning and neuronal growth DATE
1949
Hebb’s theory of learning and neuronal growth PARTS
- the brain is plastic
- the brain adapts
- engrams
- cell assemblies
Hebb’s theory of learning and neuronal growth BRAIN IS PLASTIC
- when we learn, we create new connections between neurons in the brain
- brain can be changed/moulded, more we use synaptic connection, stronger it becomes
Hebb’s theory of learning and neuronal growth BRAIN ADAPTS
Structure + connections within brain can change as we learn at any point in life, regardless of what we are learning
Hebb’s theory of learning and neuronal growth ENGRAMS
During learning, groups of neurons fire together - leaves trace in brain called ‘engram’
Hebb’s theory of learning and neuronal growth CELL ASSEMBLIES
- group of neurons that fire together
- ‘cells that fire together wire together’
- the more that neurons fire, the stronger the synaptic curve becomes
- they change physically and will grow with rehearsal (neuronal growth)
Hebb’s theory of learning and neuronal growth STRENGTHS
- scientific basis
- explains cognitive processes in terms of brain function, objective basis for understanding behaviour, raises psychology’s status as science, led to increased focus on brain as basis for behviour
- shows it’s possible to study learning through looking at brain processes
+ - education application
- Hebb thought more cell assemblies grew in more stimulating learning environments, Hebb + daughters raised rats, ones in stimulating environments better found way through mazes as adults, Hebb right about environment + learning being related
- application to education - create more stimulating environments
Hebb’s theory of learning and neuronal growth WEAKNESS
- learning reduced to neuronal level
- right to describe brain changes when learning, but learning deeper, e.g- learning is cognitive activity (Piaget), also social activity - observe others, involves biology
- reductionist - reduces learning to brain cell activity, doesn’t include wider factors
Brain structures
- frontal lobe
- temporal lobe
- parietal lobe
- occipital lobe
- cerebellum
Localisation of function
Particular areas of the brain are responsible for particular jobs
Areas of localisation
- motor
- somatosensory
- visual
- auditory
- language
Frontal lobe
- controls thought, memory, problem solving, movements like facial expressions
- contains motor area - controls deliberate movement, uses motor neurons to send signals to muscles
Temporal lobe
- control of understanding and producing spoken language
- contains auditory area - related to hearing, receives information from the ears
- contains language area - controls speech production
Parietal lobe
- processes sensory information from body
- contains somatosensory area - processes sensations like heat + pressure
Occipital lobe
- processes visual info like colour/distance
- contains visual area - receives info from both eyes through the optic nerves
Cerebellum
Supports movement + coordination + balance
Interpretive cortex
According to Penfield - area of temporal lobe where interpretations of memories are stored, contains emotions/feelings during certain times
Penfield’s study of the interpretive cortex DATE
1959
Penfield’s study of the interpretive cortex AIM
Investigate psychological responses patients gave when different parts of brain stimulated
Penfield’s study of the interpretive cortex METHOD
- Montreal procedure
- over 30 years
- 1000 patients
- lab experiment, clinical case studies
- severely epileptic Ps
- surgeon probed different cortex areas with gentle electrical stimulation - painless as brain has no pain receptors
- Ps asked to report what they experienced
- local anaesthetic used
- method of control - surgeon said they would stimulate areas again but not, patients reported no experiences
- qualitative + primary data
Penfield’s study of the interpretive cortex RESULTS
- visual area stimulation - saw colours/shadows
- somatosensory area stimulation - tingling sensation, false sense of movment
- temporal lobe stimulation - past memories relived, deja vu feeling, e.g- patient heard song being played on piano
Penfield’s study of the interpretive cortex CONCLUSION
- there is evidence for localisation of function
- temporal lobe has role in storing memories, specifically episodic
Penfield’s study of the interpretive cortex STRENGTH
- precise method of studying brain
- precise brain areas stimulated to see consequences, able to stimulate exact same areas again to find same detailed results
- benefited neuroscience by establishing map of brain function to be created
Penfield’s study of the interpretive cortex WEAKNESSES
- biased sample
- Ps all had severe epilepsy, could have changed structure/function of brain, affecting results collected when stimulated
- results can’t be generalised to non-epileptic brains, lacks validity
+ - results of Penfield’s later research didn’t always support original findings
- later study - 40 of 520 patients studied reported recall of past memories when temporal lobe stimulated
- suggests interpretive cortex doesn’t always respond in same way, conclusions lack validity
Cognitive neuroscience
Scientific study of how mental processes and brain activity/biological structures of the brain are connected/influence one another
Example of brain structure relating to behaviour
Amygdala in the temporal lobe linked to emotional responses like fear
Example of brain structure relating to cognition
Right prefrontal cortex linked to perception of time
CT scans
- person lies still in large doughnut-shaped scanner
- scanner slowly rotates, taking large number of x-rays of brain from many different angles
- each image is cross section of brain
- images put together to make detailed image of brain
CT scans STRENGTHS
- can identify abnormal structures in brain like tumours/structural damage
- higher quality images than from traditional x-ray
CT scans WEAKNESSES
- require more radiation than traditional x-rays, more detailed/complex mean more radiation exposure, can’t be used often
- only provide structural information, unlike PET scans, don’t give info of activity in ‘live’ brain, just still images
PET scans
- measure metabolic activity in brain to see which parts are most active at one time
- patient injected with radioactive substance (radiotracer) like glucose, more active areas of brain absorb more
- info sent to computer, red/yellow represent more active areas
PET scans STRENGTHS
- shows brain in action - more useful
- show localisation of function, e.g- person can be asked to think about memory and linked brain area can be identified
PET scans WEAKNESSES
- very expensive
- results not easy to interpret - scans on people doing same task have shown different brain activity in different people
- ethical issues with injection of radioactive glucose - technique can only be used few times
fMRI scans
- measure changes in blood oxygen levels in brain
- active brain areas use more oxygen so more blood directed to them (haemodynamic response)
- this picked up through radio signals, producing 3D images on computer screen
fMRI scans STRENGTHS
- live info about what area of brain being used
- don’t use radiation, very safe
- produce clear images, show brain activity to millimetre
fMRI scans WEAKNESS
- expensive
- only effective if person perfectly still, problem for people like children
- about 5 second lag between activity in brain and showing on screen, problems in interpretation of info received
Tulving’s ‘gold’ memory study DATE
1989
Tulving’s ‘gold’ memory study AIM
See if thinking about episodic memories produced blood flow in different parts of brain to semantic memories
Tulving’s ‘gold’ memory study METHOD
- 6 volunteers (including Tulving + wife) - opportunity sample
- Ps injected with small amount of radioactive gold (half-life of 30 seconds - little risk), when substance taken up by brain, active areas showed up on PET scan using gamma rays
- 8 trials (4 semantic + 4 episodic) in random order - Ps told what memory to think
- semantic - recalling historical facts
- episodic - childhood holiday
- repeated measures
Tulving’s ‘gold’ memory study RESULTS
- clear differences in blood flow patterns for 3/6 Ps
- semantic - greater blood flow concentration towards back of brain (parietal/occipital lobes)
- episodic - greater blood flow concentration towards front of brain (frontal lobe)
Tulving’s ‘gold’ memory study CONCLUSION
- semantic + episodic memories are different forms of LTM located in different parts of brain
- supports idea memory has biological basis
Tulving’s ‘gold’ memory study STRENGTH
- produced objective scientific evidence
- in lab studies, Ps often find out aims of study and behave falsely (may display demand characteristics), difficult to do in Tulving’s study as (provided Ps thought correct memory) impossible to fake brain scan
- evidence unbiased + more reliable
Tulving’s ‘gold’ memory study WEAKNESSES
- restricted sample
- only 6 Ps used including Tulving himself, only blood flow differences for 3/6 Ps
- difficult to generalise results to all people
+ - semantic/episodic memories often very similar
- difficult to say if memory in semantic/episodic, some memories include both aspects
- as often not clear diving line, may explain why results from study were inconclusive
Neurological damage
- event (like illness/injury) which leads to neuron damage in brain
- can lead to loss of function or change in behaviour
Effect of stroke on motor abilities
- if stroke hits left hemisphere, will impair movement on right side of body, vice versa
- stroke in frontal lobe - difficulty writing, walking, picking things up ect.
- extent of movement impairment depends on severity of stroke
Effect of stroke on behaviour
- suffer aphasia - language impairment/disability - struggle with language production + comprehension
- struggle producing intelligible speech, understanding what people are saying, reading and/or writing
- stroke in left hemisphere - could affect 2 areas - Broca’s area + Wernicke’s
- Broca’s - Broca’s aphasia - difficulty producing speech
- Wernicke’s - Wernicke’s aphasia - difficulty understanding speech, reading/writing
