Biopsychology Flashcards
The nervous system made of?
- specialised network of cells
- primary communication system
- through electrical signals
- consists of CNS + PNS
(Central + peripheral nervous systems)
Functions of nervous system?
- Collect, process + respond to info in the environment
- Co-ordinate the working of different organs + cells
The Central Nervous System (CNS) ?
- Made of brain + spinal cord
- Is the origin of all complex commands + decisions
Role of the brain in the CNS?
- centre of all conscious awareness
- divided - 2 hemisphere
- covered by cerebral cortex
Role of the Spinal Cord in the CNS?
- extension of the brain
- passes messages to + from brain
- Connects nerves to the PNS
- responsible for reflex actions
The peripheral Nervous System?
(PNS)
What’s PNS further divided into?
- transmits messages via millions of neurons to + from CNS
- Divided into Autonomic Nervous System (ANS) + Somatic Nervous System (SNS)
- Autonomic Nervous System (ANS) ?
- governs vital body functions
- involuntary
EG: breathing, heart rate
- Somatic Nervous System (SNS) ?
- governs muscle movement
- receives info from sensory receptors
2 other nervous systems branching from Autonomic Nervous System (ANS) ?
- Parasympathetic Nervous System
- Sympathetic Nervous System
They act in opposition to each other
activity rises in 1 = falls in the other
- Parasympathetic Nervous System?
- ANS’ normal resting state
- relax the body + return us to our ‘normal’ resting state.
- slows down heart rate + breathing rate
- reduces our blood pressure.
- Functions that were previously slowed down during a fight / flight reaction are started again (e.g. digestion).
- Sympathetic Nervous System?
- ANS’ state when body’s preparing for a fight or flight situation from a threat or sudden unexpected stimuli
- Impulses travel from sympathetic nervous system to organs to help us prepare for action in dangerous situation
- increased heart rate = more blood to muscles + push adrenaline around body
- Pupils dilate = better vision from more light
- Liver stimulates Glucose release
- less important functions decrease ( digestion, salivation + urination.)
Endocrine system?
- instructs glands to release hormones into bloodstream carried towards target organs
- communicate via chemicals
The endocrine system’s major endocrine glands?
- Hypothalamus: regulates body temp, hunger, thirst
- Adrenal gland: secretes adrenaline
- Pituitary gland: controls all other endocrine glands + influences growth
- Thyroid gland: thyroxine + regulates metabolism
- Ovaries: oestrogen released
What systems work together in fight or flight situations?
Endocrine + ANS (Autonomic Nervous System) work together stressful events of fight or flight
- Sympathetic nervous system in ANS
Fight or flight situation?
- signals sent to sympathetic branch of ANS
= prepares body for fight/flight (heart rate eg) - sees threat = transmitted via somatic nervous system to brain, amygdala (in brain) sends signals to hypothalamus.
- hypothalamus triggers pituitary gland to send out chemical messages via bloodstream
- Adrenaline released from Adrenal gland
What happens after threat has passed?
parasympathetic nervous system returns body to resting state
What are neurons?
How info flows through neurons?
nerve cells that process + transmit messages within them through electrical signals and with other neurons chemically (synapse)
- Dendrites (collect electrical signals) –>
Cell body ( integrates incoming signals + generates outgoing signals to axons) –>
Axon ( passes electric signals to dendrites of another neuron)
Sensory neuron?
- Carry messages from PNS (Peripheral nervous system) to CNS
- Long dendrites
- Short axons
Relay neuron?
- connects sensory neuron to motor neuron + other relay neurons
- Short dendrites
- Short axons
Motor neuron?
- Connects the CNS to effectors (eg muscle + glands)
- Short dendrites
- Long axon
Synapse?
Synaptic transmission?
Synaptic gap - tiny gap between 2 neurons where neurotransmitters travel across to transfer info.
Synaptic transmission - Process in which neighbouring neurons communicate with each other by sending chemical messages (neurotransmitters) across synapse.
Process of synaptic transmission:
- Electrical impulse reaches end of presynaptic neuron
- Triggers synaptic vesicles to release neurotransmitters (chemical messengers) that carry signals across synapse
- Bind to the receptors on postsynaptic neuron.
- Converted back to electrical signal and travels through neuron
What charge is a neuron in:
- resting state?
- activated by stimulus?
- Neuron in resting state : Negatively charged
- Neuron activated by stimulus : positively charged
What’s action potential?
- When neuron becomes positively charged, causes an action potential to occur - the electrical impulse travels from axon to the end of neuron.
Excitatory neurotransmitters / excitation ?
Effect + example
- These excitatory neurotransmitters increase the positive charge of the postsynaptic neuron
= increase likelihood that the postsynaptic neuron will fire + pass on the electrical impulse.
[ EG: Adrenaline ]
Inhibitory neurotransmitters / Inhibition ?
Effect + example `
Inhibitory neurotransmitters increase the negative charge of the postsynaptic
= decreases likelihood that the postsynaptic neuron will fire + pass on the electrical impulse.
[ EG: Serotonin ]
Studying the brain:
- fMRI
(Functional Magnetic Resonance Imaging)
- brain-scanning technique that measures blood flow in brain when a person performs a task.
- neurons in the brain that are the most active during a task use the most energy = increased blood flow in those areas to supply more oxygen.
= haemodynamic response
Evaluation of fMRI
- Invasive v non-invasive?
- Causation?
- Non-invasive: no radiation or surgery used as person is awake.
- unlike PET scans does not rely on use of radiation = making procedure risk free, non-invasive + straightforward to use. - Causation: no direct measure of neural activity. simply measure changes in blood flow = impossible to infer causation (at a neural level)
- Temporal resolution?
- Spatial resolution?
- Temporal resolution: Poor (1-4 seconds after activity).
- Psychologists are unable to predict with a high degree of accuracy the onset of brain activity - Spatial resolution: good (1-2 mm).
- Psychologists can determine the activity of different brain regions with greater accuracy when using fMRI, compared to EEG / ERP
Economic implications?
Expensive compared to other techniques
= reduced sample sizes/ limited number of patients offered an fMRI
= negatively impacts validity of research + is difficult to generalise findings from this technique to a larger population
= may be necessary to use other brain techniques in addition to fMRI which has economical implications for the NHS (there will be an additional cost).
Studying the brain:
- Post-Mortem examination (autopsy)
Brain analysed after death to determine whether certain observed behaviours during lifetime can be linked to structural abnormalities in the brain.
Case study: Work of Broca
- Examined the brain of a man who displayed speech problems when he was alive.
- Discovered that he had damage in the area of the brain important for speech production = became known as Broca’s area.
Evaluation of Post-Mortem Examination
- Invasive v non-invasive?
- Causation?
- Invasive: brain is cut and person is dead - informed
consent must be given before death (ethical)
Permission is harder to gain = reduced sample size - Causation: issues a patient displays during their lifetime (e.g can’t speak) may not be linked to the deficits found in the brain.
May be result of another illness = psychologists unable to conclude that the deficit is caused by the damage found in the brain.
- Temporal resolution?
- Spatial resolution?
- n/a (no brain activity- minimal neural changes
in the brain after death) - n/a (Low, changes seen by the eye, not much detail compared to other methods of investigation)
Studying the brain:
- EEG (Electroencephalogram)
- recording of electrical activity in brain
- signals picked up by electrodes
(useful for diagnosis of epilepsy)
The brain waves and how they can be examined?
- Alpha
- Beta (most activity)
- Delta (when asleep)
- Theta
Examine:
Amplitude: the intensity or size of the activity
Frequency: the speed or quantity of activity
Evaluation of EEG
- Invasive v non-invasive
- Causation
- Non-invasive: There are no surgical procedures or radiation involved.
- Causation: No causation. Electrical activity identified in multiple regions = difficult to establish cause + effect.
- Temporal resolution
- Spatial resolution
- Temporal resolution: High temporal resolution (1 millisecond) = can accurately detect onset of brain activity quick
- Spatial resolution: low. Can’t pinpoint exact source of neural activity = doesn’t allow researchers to distinguish between activities originating in different but adjacent / close locations.
EEG Practical application?
- Real practical application + valuable diagnostic tools for epilepsy as it can easily be detected.
-epilepsy: brain’s electrical rhythms become imbalanced = causeing seizures as normal electrical pattern is disrupted by sudden bursts of electrical energy - Has contributed to our understanding of sleep + sleep disorders = led to effective treatment + better quality of life for patients.
Studying the brain:
- ERPs (Event-related potentials)
- Electrodes attached to scalp
- Stimuli presented to ps (eg sound/picture)
- Researchers look for electrical activity related to that stimuli
Sensory VS Cognitive ERPs
Sensory ERPs:
- waves occur WITHIN 100 millisecond after stimuli
= reflect sensory response to stimuli
Cognitive ERPs:
- waves occur AFTER 100 milliseconds after stimuli
= demonstrates some information processing
Evaluation of ERPs
- Invasive V non-invasive
- Causation
- Non- invasive: no radiation, no instruments directly into brain, no surgical procedure.
- Causation: Causation can be established
- Temporal resolution
- Spatial resolution
- Temporal resolution: excellent temp resolution = more valid measurement of electrical activity when undertaking specific task = can detect origin of brain activity with greater degree of accuracy.
- Spatial resolution: Poor spatial resolution - unable to provide info on what’s happening in deeper regions of brain, just general areas.
Economic implications?
cheaper compared to FMRIs = more patients can undertake ERPs + EEG = more widely used for research / diagnosis which can be easily generalised to a larger pop.
Localisation of function
- Different areas of brain are responsible for different behaviours/ functions / activities.
- If different areas of brain become damaged (illness/injury) = function associated with that area will be affected.
Flourens
- He systematically removed cerebellum of dog’s brain = gradually lost ability for regular movement but intellectual faculties not affected but couldn’t coordinate movements.
Broca :
- Broca studied patient who could only say ‘Tan’
- Had difficulty in producing speech
-When he died, Broca performed post-mortem + found Broca’s area damaged (language production)