Biopsychology Flashcards
What are neurons?
The basic building blocks of the nervous system - they process and transmit messages through electrical and chemical signals
What are the different functions of the neuron?
- Dendrites: branchlike structures that receive signals from other neurons or sensory receptor cells
- Axon: carries impulses away from cell body down length of neuron
- Myelin sheath: insulates the axon so that the electrical impulses travel faster along the axon
- Terminal button: connects the neuron to other neurons using synaptic transmission
What is action potential?
- A tiny electrical impulse that is triggered by a change in the electrical ‘potential’ of the neuron itself
- The inside of the neuron goes from being negatively charged to positively charged
What is the structure and function of the 3 types of neurons?
- Motor: found in the CNS, and connects CNS to effectors like muscles and glands, to control muscle movements - short dendrites & long axons
- Sensory: found in receptors cells (e.g. skin) + carry nerve impulses to the spinal cord and brain - when these nerve impulses reach the brain, they are translated into ‘sensations’ (e.g. touch) - longer dendrites & short axons
- Relay: found in between sensory input and motor response + connect sensory neurons to motor or other relay neurons - short dendrites & short axons
What is synaptic transmission?
The process by which one neuron communicates with another
What are the stages of synaptic transmission?
1) An electrical signal called an action potential arrives at the presynaptic neuron
2) This stimulates vesicles containing neurotransmitters to move down and bind to the wall of the presynaptic neuron
3) Neurotransmitters are released from the vesicles into the synaptic cleft
4) Neurotransmitters are received by receptors on the post-synaptic receptors via a lock and key mechanism
What are the functions of the 2 elements of the CNS?
- Brain: centre of awareness - divided into 2 hemispheres - outer layer is more distinguishes us from animals (cerebral cortex)
- Spinal cord: an extension of the brain - transports messages to and from the brain to the PNS - responsible for reflexes
What are the functions of the 2 subsystems of the PNS?
- Autonomic nervous system: responsible for vital functions such as heart rate, breathing, digestion
- Somatic nervous system: receives info from the senses and transmits it to the CNS - also transmits info from CNS to direct muscle movement
What is the role of the endocrine system?
Works alongside the nervous system to regulate bodily functions through the release of hormones
What are hormones?
A chemical secreted by the endocrine glands into the bloodstream which then distributes it around the body
What are the differences between the endocrine and nervous system?
- Endocrine: chemical messengers, long-lasting effects, takes longer, more permanent and wide
- Nervous: electrical impulses, short-lived effects, quick, localised
Explain the process of the fight or flight response?
- The endocrine and ANS work in parallel e.g. during a parallel event
- When a stressor is perceived the hypothalamus triggers the sympathetic nervous system and the ANS changes from its usual resting state (the parasympathetic state)
- Adrenaline is released from the adrenal medulla into the bloodstream resulting in the physical arousal needed for fight/flight
What are the differences between the sympathetic and parasympathetic state?
- Sympathetic state- increased heart rate, increased breathing rate, dilates pupils, inhibits digestion etc
- Parasympathetic state- decreases heart rate, decreases breathing rate, constricts pupils, stimulates digestion etc
What is localisation of function in the brain?
Different parts of the brain are involved in different tasks and are associated to different behaviours
What is the opposite of localisation of function?
Holism - the whole brain is implicated in behaviours and functions
What is the structure of the brain?
- Two symmetrical hemispheres
- Psychological & physical functions are controlled/dominated by a particular hemisphere
- Left-side of body -> controlled by right hemisphere and vice versa
- Outer layer - cerebral cortex - separates us from animals (more developed)
What are the 4 main brain centres in the cerebral cortex?
- Motor area (back of frontal lobe) - controls voluntary movement on the opposite side of body
- Somatosensory cortex (front of parietal lobe) - where information from senses (skin) is represented
- Visual cortex (occipital lobe) - each eye sends info from left and right visual fields to left and right cortex (LVF-> right half of both your eyes + vice versa)
- Auditory area (temporal lobe) - analyses speech based info - damage = partial hearing loss
Where are Wernicke’s area and Broca’s area located and what are their functions
Broca’s area:
- Left frontal lobe
- Speech production
- Broca’s aphasia -> slow laborious speech
Wernicke’s area:
- Left temporal lobe
- Speech comprehension
- Wernicke’s aphasia -> speech production is fine but understanding is poor
What are the strengths of localisation theory? (A03)
- Brain scan evidence: support for localisation of language/memory - Petersen et al used brain scans to show Wernicke’s area was active in a listening task, broca’s in reading (different roles) + Tulving et al’s LTM study showed semantic & episodic reside in different parts of prefrontal -> research conducted with sophisticated & objective methods to measure brain activity
- Neurosurgery: lobotomies used to be common (surgically removing parts of the frontal lobe) - controversially still used - Dougherty et al -> 44pts with OCD underwent a cingulotomy - 32wk follow up, 1/3 showed a successful response
- Case-study evidence: Gage was caught in an explosion where a meter length pole was hurled through his head, tearing most of his frontal lobe - became short-tempered & aggressive -> suggests frontal is responsible for mood regulation
What are the weaknesses of localisation theory?
- Gender differences found within research of cortical specialisation - Harasty et al found women have larger Broca’s & Wernicke’s than men - this difference makes it difficult to map specific areas
What is hemispheric lateralisation?
The idea that both hemispheres are functionally different & that certain mental processes & behaviors are mainly controlled by one hemisphere rather than the other
What was Sperry’s split-brain research?
- A study on a group pf individuals who had undergone a comissurotomy (severing the corpus callosum to control seizures)
- Sperry could see the extent to which 2 hemispheres were specialised for certain functions
What was the procedure of Sperry’s split-brain research?
- An image /word was projected to a patient’s RVF (processed by LH) & the same/different image could be projected to LVF
- Normal brain - corpus callosum would share info between hemispheres -> info couldn’t be conveyed to another in patients
What were the findings of Sperry’s split brain research?
- Describing what you see: if image/word was flashed up in RVF, patient could say what they saw but if flashed into LVF patient reported seeing nothing + couldn’t say what they saw
- Recognition by touch: if image flashed into RVF, could say what they saw, if flashed into LVF they couldn’t say what they saw but could blindly pick an item from a bag matching what they saw with left hand
Composite words: one flashed in LVF, other in RVF e.g. keyring -> patients could say the word ring (it’s in RVF) and used left hand t draw a key + could say key after drawing one
What is a strength of split brain research? (A03)
- Research support: Gazzinga showed split-brain patients performed better than connected control on certain tasks - e.g. they were faster at identifying the odd one out in an array of similar objects than control -> in normal brains, the LH’s better cognitive strategies are watered down by inferior RH (Kingston et al) -> left & right brain are distinct
What is a weakness of split-brain research? (A03)
- Generalisation issues: hard to establish cause&effect in Sperry’s research - the behaviour of Sperry’s split-brain patients was compared to a neurotypical control group (none had epilepsy was the issue - confounding variable) -> any differences observed between the 2 groups may be the result of epilepsy not split-brain -> some of the unique features of split-brain ppts cognitive abilities’ may be due to their epilepsy