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282 Cards in this Set
- Front
- Back
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Frontal Cortex Cognitive Function? (4)
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Calculation, Reasoning, Interference, Learning
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Prefrontal Cortex Cognitive Function? (2)
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Personality, Emotion
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Temporal Cortex Cognitive Function? (3)
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Learning, Memory, Spacial Recognition
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Cortical Areas Controlling Language? (6)
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Primary Auditory Cortex, PVC, Wernike's Area, Arcuate Fasciculus, Primary Motor Cortex, Broca's Area
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Wernike's area function? (Site of..? (2) )
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Site of Comprehension, Site of Generation of Verbal Responses
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Broca's area function?
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Transforms neural code for verbal response into language
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Frontal Lobe Cortical Function? (4)
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Planning, Thinking, Motor Planning, Motor output
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Temporal Lobe Cortical Function? (4)
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Hearing, Smell, Memory, Feelings
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Occipital Lobe Cortical Function? (2)
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Vision, Visual Processing
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Parietal Lobe Cortical Function? (3)
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Spatial Processing, Spatial Orientation, Somatosensory Function
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Cortical function - symmetrical/asymmetrical? Bilateral/unilateral?
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Largely Symmetrical, Bilateral Cortical Function
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Left motor cortex controls which side of the body?
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Right
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Left somatosensory cortex receives information from right periphery?
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Right
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Left VF projects bilaterally/unilaterally (?) to Which visual cortex?
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Bilaterally, Right
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Subcortical areas of brain? (8)
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Corpus Callosum, Basal Ganglia, Hypothalamus, Thalamus, Hippocampus, Cerebellum, Brainstem, Spinal Cord
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Corpus Callosum Function?
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Connecting the two cortical hemispheres
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Basal Ganglia Function?
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Control of behavioural patterns
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Hypothalamus Function? (3)
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Homeostasis, Emotion, Control of endocrine (hormone system)
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Thalamus Function?
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Interface between Cortex and rest of nervous system
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Hippocampus Function? (2)
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Learning and Memory
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Cerebellum Function? (3)
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Movement, Balance, Posture
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Brainstem Function?
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Control of autonomic function
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Spinal Cord Function?
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Nerves going to and from the rest of the body
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What are the Lobes of the Cerebral Cortex? (7)
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Central Sulcus (Fissure) frontal lobe, lateral (sylvian) fissure, Temporal lobe, Parietal Lobe, Occipital Lobe, Cerebellum
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What are Brodmann's areas based on? (2)
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Structure, not function; cytoarchitecture
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Two ways to understand cortical function?
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Brain damaged patients and functional neuroimaging
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What is in charge of interhemispheric communication?
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corpus callosum
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What is the Corpus Callosum?
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A large bundle of fibres connecting the left and right cortices
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Sperry, 1981?
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Split brain patients: If patient is presented with word "ball on screen in LFV.
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What happens if SPB is presented with word "ball" on screen in LFV (in term of what it can say, which hand he can/cannot pickout the ball)
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Unable to say what the object is, can pick out ball with the left hand
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Which Visual Cortex (es) receive(s) information from Left Visual Cortex?
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Only right visual cortex
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If SPB is presented with the word 'ball' on screen in LFV, why can SPB pick out the ball with left hand?
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RIGHT (left hand) somatosensory cortex knows what it is looking for
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Left hemisphere dominance in terms of vision? (2)
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Words, letters
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Right hemisphere dominance in terms of vision? (3)
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Faces, geometri patterns, emotional expressions
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Left hemispheric dominance in terms of audition?
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Language sounds
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RHD in terms of Audition? (2)
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Non-language sounds, music
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LHD in terms of touch?
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none
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RHD in terms of touch?
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Tactual Pattern, Braille
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LHD in terms of movement? (2)
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Complex movement, Ipsilateral movement
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RHD in terms of movement?
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Movement in spatial terms
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LHD in terms of Memory? (2)
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Verbal memory, Finding meaning in memories
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RHD in terms of memory? (2)
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Nonverbal memory, perspectual aspects of memory
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LHD in terms of language? (4)
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Speech, reading, writing, arithmetic
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RHD in terms of language?
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emotional content
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LHD in terms of space?
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none
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RHD in terms of space? (4)
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Mental rotation of shapes, geometry, direction, distance
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3 general functional adjectives for Left hemisphere?
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Logical, analytical, reductionist
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2 general functional adjectives for Right hemisphere?
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Synthesiser, holistic
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5 properties that neurons have in common with other cells?
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Cell membrane, nucleus, organelles and machinery for translating genetic code into proteins, structural and metabolic proteins, metabolic machinery enabling glucose oxidation to provide energy
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What does the nucleus contain (neurons -in common with other cells)? (2)
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DNA, genetic blueprint for the structure and function of the cell
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Example of organelles and machinery for translating genetic code into proteins (neurons - in common with other cells) (3)?
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Golgi apparatus, endoplasmic reticulum, ribosomes
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What are dendrites?
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a network of fine processes derived from cell body
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What is the synapse?
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Connection between two neurons
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What is the axon hillock the site of?
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The site of action potential generation
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What is the axon?
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Elongated neural process, specialised for rapid signal transmission
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What is Myelenation?
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Fatty sheath around axon
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(Membrane Potential) - What is the neuronal cell differentially permeable to?
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To intracellular and extracellular chemical constituents
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(Membrane Potential) - Do ions pass through membrane easily?
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some do, some with more difficulty, some do no pass at all
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(Membrane Potential) - what is the result of differential permeability to ions?
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An uneven distribution of charge across the membrane
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What is an uneven distribution of charge across the membrane called?
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Membrane potential
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What is the resting membrane potential of neurones?
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-70mv
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What are the main ions contributing to membrane potential? (4)
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Positively charged sodium (Na+) and potassium (K+), and negative charged chloride (Cl-) and proteins (A-)
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Three important figures who won the Novel Prize in Physiology or Medicine?
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Sir John Eccles, Sir Alan Hogkin, Sir Andrew Huxley
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(Membrane potential) - what do incoming signals cause? how?
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Incoming signals cause changes in dendritic membrane potential by altering permeability to the membrane of ions
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What does increasing the permeability to sodium (Na+) cause the membrane potential to become? What is this called?
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Increasing Permeability to sodium (Na+) causes membrane potential to become less negative, depolarisation
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(membrane potential) What happens when sodium channels open? What does it generate?
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When the sodium channels open, there is an influx of sodium ions, creating the excitatory post-synaptic potential (EPSP)
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What does increasing the permeability to chloride (Cl-) cause the membrane potential to become? What is this called?
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Increasing Permeability to chloride (Cl-) causes membrane potential to become more negative, hyperpolarisation
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(membrane potential) What happens when Chloride channels open? What does it generate?
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When Chloride channels open, there is an influx of chloride ions, creating the inhibitory post-synapitic potential (IPSP)
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How do change in charges diffuse in the membrane?
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They diffuse passively along the membrane from the point of origin. They are relatively slow and decay over distance
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At any one point, what is the membrane potential determined by?
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By the sum of all individual depolarising and hyperpolarising events originating nearby
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What is signal integration? (membrane potential)
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When the membrane potential is dependent of the sum of all EPSPs and IPSPs occuring nearby
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What is spatial summation?
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When polarising events occurring within a localised area of membrane will add together
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After excitatory (Na+) post-synaptic potential or inhibitory (Cl-) post-synaptic potential, how long does it take for the membrane to return to resting potential?
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A short time, around 5-10ms
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What is temporal summation?
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When polarising events occurring close together in time will add together, as another polarising event (EPSP or IPSP) occurring during the time period when the membrane is returning to the resting state wil cause an additional change in membrane potential
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Two types of signal integration?
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Spatial and temporal summation
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What point is the axon hillock?
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It is the point where the axon leaves the cell body
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What is the axon hillock specialised for?
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For the generation of action potentials
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When is an action potential generated? (And what is the threshold potential?)
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When the net depolarisation at the axon hillock reaches the threshold potential (around -50mv), an action potential is generated. Anything lower than -50mv, and no action potential
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What does the action potential do?
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It propogates electric signal along the axon
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What is the action potential?
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An electric 'spike' caused by reversal of membrane polarity
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What is the action potential mediated by?
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It is mediated by rapid changes in membrane permeability to sodium and potassium
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What is the refactory period, in terms of the action potential?
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After the AP spikes from -50mv to -30mv, it goes back a bit below to -70mv, then to resting potential
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What is the 'all or none phenomenon' in terms of action potential?
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The Action potential is always the same size, does NOT decay over distance, and is the same size when it reaches the terminal as it was when it left the axon hillock
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Name four different classes of primary different axons and their conduction velocities.
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A-alpha fibre (~450mph), A - beta fibre (210mph), A-delta fibre (20 mph), C-fibre (5mph)
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In the presynaptic membrane, where are the neurotransmitters located?
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In vesicles
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In the postsynaptic membrane, after being released into the synaptic cleft, where are the neurotransmitters received?
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In postsynaptic receptors, then by neurotransmitter reuptake sites
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Where are neurotransmitters synthesized?
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In the neurones, close to the site of release
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Until required for release, where are the neurotransmitters stored?
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Stored on the terminal
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When are neurotransmitters released into the synaptic cleft?
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In the response to an action potential
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where to neurotransmitters bind to in the post-synaptic membrane?
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to receptors
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When is change in membrane potential caused?
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When neurotransmitters bind to receptors in post-synaptic membrane
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What do excitatory receptors cause?
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Depolarisation
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What do inhibitory receptors cause?
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Hyperpolarisation
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What does the neurotransmitter evoke when it binds to the receptor
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Either excitatory or inhibitory response
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What does the agonist do?
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It binds to the receptor and evokes the same response as the native transmitter
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What does the antagonist do?
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It binds to the receptor and does NOT evoke any response, and prevents native transmitter or any agonist from binding to the receptor
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Therapeutic drugs (2) affecting synthesis of neurotransmitters?
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Trytophan, L-Dopa
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Therapeutic drug affecting release of neurotransmitter?
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Amantidine
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Therapeutic drugs (3) affecting the receptor of neurotransmitters?
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Neuroleptics, Anxiolytics, Anticolvusants
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Therapeutic drugs (2) affecting the clearance of neurotransmitters?
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Tricyclic antidepressants, GABA + inhibitor
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6 classifications of movement?
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Simple reflex (knee jerk); posture and postural change (standing); Locomotion (walking); Sensory orientation (head and eye movement); Species specific action patterns (ingestion and courtship); acquired skills (speech)
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Where does the motor output come from?
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The motor Cortex
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What does the motor output project through?
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Projects through pyramidal tracts to spinal cord, where it synapses with peripheral motor neurones
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What is the extrapyramidal system?
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From the motor output, other pathways run parallel from the cortex, basal ganglia, and cerebellum via brain stem and spinal cord. these run outside the pyramidal tract and are called the extrapyramidal system
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Name four spinal motor pathways
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Pyramidal tract, tectospinal tract, vestibulospinal tract, reticulospinal tract
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What does the pyramidal tract control?
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Most of our fine movements
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Function of tectospinal tract?
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Coordinating head and eye movements as part of the optic reflexes
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Function of vestibulospinal tract?
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Influences postural muscles
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Function of reticulospinal tract? Where does it project from?
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Projects from reticular formation, controls inhibition/fascilitation of movement
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3 motor control systems in the cortex?
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Primary motor cortex, supplementary motor cortex, premotor cortex
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Primary Motor Cortex?
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Source of pyramidal tract neurons
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Supplementary Motor Cortex?
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Conception and initation of movement
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In the supplementary motor cortex, what do lesions cause?
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lesions cause impairments in stability of stance, gait, and had coordination
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Motor control systems outside the cortex ? (2)
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Cerebellum and Basal Ganglia
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Function of cerebellum in terms of motor control?
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Controls neural 'programs' for the execution of skilled movements
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What is the basal ganglia? (4)
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A group of subcortical forebrain nuclei (caudate nucleus, putamen/striatum, globus palladus, subthalamic nucleus)
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What does the basal ganglia do?
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Modulate patterns of motor activity
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Where are spinal reflexes mediated?
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At the level of the spinal cord
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Do spinal reflexes require any cortical input?
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No
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Elaborate on knee jerk reflex
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Tapping the knee tendon stimulates tendon stretch receptors, the sensory neuron synapses directly to motor neurone, the muscle contracts causing limb extension
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Name 7 neurological diseases of the motor system
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Paralysis, Apraxia, Decomposition of movement, Parkinson's Disease, Hunington's Disease, Duchenne's muscular dystrophia, Myesthenia gravis
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Two ways of getting Paralysis?
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Either damage to motor neurons or damage to primary motor cortex
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Can damage to motor neurons be viral?
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YEs
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Two ways of getting damage to motor neurons?
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Toxins and/or hereditary; Injury
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Two types of injury to damage motor neurons?
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Severing of Spinal cord (permanent), bruising or compression of spinal cord (transient)
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An example of hereditary damage to motor neurons?
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Amyotrophic Lateral Sclerosis - degeneration of motorneurons in the brainstem and spinal cord
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What does damage to primary motor cortex result in?
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Either paralysis or partial paralysis of voluntary movement on one side of the body (controlateral to damage)
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In paralysis (as a result of damage to PMC damage), what does the extent of the paralysis depend on? what is it often accompanied by? (2)
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Extent of paralysis depends on extent of damage. Often accompanied by spacticity and abnormal reflexes
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What is Apraxia?
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The inability to carry out movements in respons to commands
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Apraxia does not show signs of: (3)
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Paralysis, loss of comprehension, loss of motivation
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What may Apraxia be due to?
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May be due to disconnection of primary motor cortex from supplementary motor cortex, and premotor cortex
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What is Decomposition of movement?
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It is the inability to perform 'motor patterns' (eg walking), and are broken up into individual segments instead of being executed smoothly, and require thought and are not automatic
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What is decomposition of Movement due to?
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Due to Cerebral Damage
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Name (3) symptoms of Parkinson's disease (I)
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Resting TREMOR in limbs (disappears on movement or in sleep), muscle RIGIDITY (resistance to passive movement, jerky movement), AKINESIA - General paucity of involuntary movement
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Name (5) symptoms of Parkinson's disease (II)
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Stooped Posture, shuffling gait, excessive sweating and salvation, micrographia, altered cognitive function (depression and/or dementia)
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What are deficits in movemnt controlled by?
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Extra-pyramidal motor pathways
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How does the Parkinson's Disease occur? Which pathways are degenerated?
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Degeneration of nigro-striatal pathway, and some degeneration of other dopamine pathways
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What does degeneration of nigro-striatal pathway lead to?
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To a depletion of striatal dopamine (parkinson's)
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What is increased to treat Parkinson's disease?
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Brain dopamine
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How is Dopamine injected into the brain? why?
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It cannot cross itself from blood to brain, so precursor L-Dopa is used, which enters the brain and is converted into Dopamine
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What are the potential side effects of L-Dopa?
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Dyskinetic movements, psychoticism
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What alternative therapies are under investigation for Parkinson's? (2)
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Surgical interventions and neural transplantation
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What is Huntington's Disease?
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Progressive disease causing involuntary muscle-jerks, ultimately affecting whole body
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Name 3 potential symptoms/effect of Huntington's Disease apart from muscle jerks
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Intellectual deterioration, depression, occasionally psychoticism
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When are the onset of Huntington's symptoms usually displayed?
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usually at 30 to 45 years
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How do you get Huntington's Disease?
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Genetically determines (single dominant gene)
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What does Huntinton's disease cause (biologically) ?
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Degeneration of the output neurones from the striatum, reducing inhibitory modulation of motor function
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What is the treatment of Huntington's Disease?
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No effective treatment, but GABA replacement or dopamine replacement cause some relief. No means of halting progression of disease
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What is the organisation of the sensory system, from the peripheral sensory receptors to multimodal association C?
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Peripheral sensory receptors - spinal cord - sensory thalamus - primary sensory cortex - unimodal association C - multimodal association C
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What are the nerves associated with touch, sight, and hearing respectively?
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Spinal Cord, Optic II, Vestibulocochlear VIII
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What are the nerves associated with taste (3) and smell respectively?
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Facial VII, Glossoph IX, Vagus X; Olfactor I
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What is Gustatory perception?
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Taste perception
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What are the 5 tastes?
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Salty, Sour, Sweet, Bitter, Unami
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What is the link between taste and smell?
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Smelling food also helps us to taste our food
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What is the Gustatory Pathway?
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Tastebuds - Taste Receptor Cells/ Touch, pain receptors - Facial VII, Glosso-Pharangeal IX, Vaus V - Brainstem - Thalamus - Taste central of somatosensory cortex / somatosensory cortex
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Olfactory Perception pathway?
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Olfactory receptors in olfactory epithelium of nose - Olfactory Nerve (II) - Olfactory Bulb (-to hypothalamus) - Olfactory Cortex (- to hypothalamus)
NOT via thalamus! |
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What is the Area V1? (vision)
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Primary Visual Cortex (striate cortex)
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What is the first level of input to the visual cortex?
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Area V1
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What do Cells in V1 respond to?
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They respond to different aspects of the visual signal (eg. orientation, size, colour)
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What are the cells in v1 involved in?
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Involved in characterisation, and not analysis. Sense independent outputs to several other areas
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What does damage to V1 lead to?
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Total or partial blindness, depending on extent of damage
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What is blindsight?
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When subjects are blind due to damage to area v1 but can "guess" direction of travel of a moving object or colour
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How does blindsight happen?
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Movement and colour are not analysed in V1, so information can bipass v1 to reach visual cortex
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Area v3 - what is it the first stage of?
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First stage of building object form
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Area v3 - what is it code for ? (eg?)
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Code for component aspects of the object (eg edges, orientation, spatial frequency)
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Area V4-what is it in charge of?
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Colour recognition - indidvidual neurones in v4
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What does area V4 respond to?
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A variety of wavelengths
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What do PET & MRI studies show regarding V4 and greyscale?
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Activation in v4 to coloured patterns, but not to greyscale
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What is Achromatopsia?
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Inability to perceive colour, cannot remember of imagine colour
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How is Achromatopsia caused?
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Damage to V4
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What lobe has the highest level of processing of visual information?
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Temporal lobe (TEO, TE, STS)
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What does recognition of objects depend on?
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Their form
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What is recognition of objects independent of? (3)
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Of scale (distance), orientation, illumination
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Visual memory - 3 subsections of face recognition?
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Features of a face (subject specific)
Expressions on a face (independent of subject) Gaze direction |
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Associative visual Agnosia?
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Normal visual acuity, but cannot name what they see
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Aperceptive visual agnosia?
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Normal visual acuity, but cannot recognise objects visually by shape
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Where is movement perceived?
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Area V5
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PET and fMRI studies show activation in V5 to what?
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to moving patterns, but not to stationary ones
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Bilateral damage to V5 - potential consequence?
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Unable to perceive continuous motion, only successive positions
Unaffected in colour, perception, object recognition, etc Able to judge movement of tactile or auditory stimuli |
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Balint's Sydrome: damage to what?
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Posterior Parietal Cortex
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Optic ataxia?
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Deficit in reaching for a an object (misdirected movement)
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Ocular aplaxia? (A: Deficit in... B:Difficulty in... C: Unable to perceive... D: No difficulty in...)
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Deficit in visual Scanning
Difficulty in fixation on an object Unable to perceive the location of an object in space No difficulty in overall perception or object recognition |
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Posterior Parietal Cortex: Dorsal or Ventral?
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Dorsal
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TEO & TE: Dorsal or Ventral?
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Ventral
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V5: Dorsal or Ventral?
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Dorsal
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V4: Dorsal or Ventral?
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Ventral
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Primary Auditory Pathway?
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Cochlea - - (Vestibulo-cochlear nerve (CN VIII) )- - Cochlear Nucleus, Superior Olivary Nucleus (Pons) ; - - Inferior Colliculus , Medial Geniculate Nucelus (Thalamus); - - Auditory Cortex (Cortex)
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Where are sound waves converted into vibration?
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Basilar Membrane
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What do hair cells in organ of Corti do?
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Transduce movement of basilar membrane into electrical signal
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Where is high frequency sound transduced?
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Base
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Where is low frequency sound transduced?
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Apex
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Where is (sound) information transmitted along?
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Vestibulo-cochlear nerve
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Is auditory discrimination possible in the absence of the auditory cortex?
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Yes
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Where does initial auditory processing occur?
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In pons and thalamus
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What aspects of sound does auditory cortex analyse?
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Complex aspects of sound
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What does the dorsal stream (Parietal lobe) analyse in terms of sound?
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Spatial analysis
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What does the ventral stream (Temporal lobe) analyse in terms of sound\?
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Component analysis
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What are the three main causes/types of deafness
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Conduction deafness, sensorineural deafness, central deafness
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What is Conduction deafness?
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Disorders of the outer of middle ear, which prevent sound vibrations reaching the cochlea
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What is Sensorineural deafness?
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An inability of the auditory nerve fibres to be excited in the normal manner
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What is Central deafness?
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Damage to auditory brain centres, seldom a simple loss of hearing
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What is localisation of sound dependent on?
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Dependent on different characteristics of a sound arriving at each ear
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What is intensity difference (in terms of sound) ?
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Difference in intensity of sound between the two ears
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What is Latency (in terms of sound), what is it due to?
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A phase shift between the two ears, due to slightly different distance to reach each ear
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What is duplex theory?
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That sound location depends on a combination of intensity and latency
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In the vestbiular organs, what do the semicircular canals do?
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Detect head rotation and tilt around three axes
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Pathway from headmovement to information being transmitted to brain?
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Head movement -> movement of endolymph -> displacement of capula -> stimulation of hair cells -> activation of CN VIII -> Information transmitted to brain
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Vestibular Pathway to balance/vestibulo-ocular reflexes via cerebellum?
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Vestibulocochlear nerve (CN VIII) --> Cerebellum --> Cortex --> Balance reflex/vestibulo-oclar reflex
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Vestibular pathway to balance/vestibulo-ocular reflexes via motorthalamus? (2)
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Vestibulocochlear nerve (CN VIII) --> Vestibular nuclei in brainstem (rest is optional) -- > Motor thalamus --> Cortex (optional) --> Reflexes
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What can motion sickness be caused by?
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May be caused by a mismatch between visual information and information from the vestibular organ
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Balance reflex: Medial?
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Vestibular organ --> Vestibular nuclei, Medial --> Neck muscles --> head orientation
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Balance reflex: Lateral?
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Vestibular organ --> Vestibular nuclei, Lateral --> Peripheral muscles --> Postural muscles Balance
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Sensory perception pathways (from Peripheral or cranial sensory receptors to cingulate cortex)
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Sensory receptors (peripheral/cranial) --> spinal cord --> brainstem --> thalamus --> somatosensory cortex --> Cingulate cortex/other cortical areas
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Name 6 Peripheral sensory receptors
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Free nerve endings, Merkel's disc, Meissner's corpuscle, Pacinian corpuscle, Ruffini's ending, Hair follicle receptor
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What are free nerve ending receptors in charge of?
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Pain, temperature
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What is Merkel's disc in charge of?
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Touch
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What is Meissner's corpuscle in charge of?
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Touch
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What is the Pacinian corpuscle in charge of?
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Vibration
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What is Ruffini's ending in charge of?
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Stretch
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What is Nociception?
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Ther perception of a noxious stimulus
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What is Pain?
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the subjective 'feeling' due to a noxious stimulus
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What is Analgesia?
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The modulation of nociception of pain
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A noxious stimulus is X into electrical activity in appropriate nerve endings?
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Transduced
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Electrical signals are X through nerves to the spinal cord and brain?
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Transmitted
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Pain signal is X at various levels
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Modulated
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In the tranduction level of nociception, what do noxious stimuli activate?
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Peripheral nociceptors
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In the transduction level of nociception, activated peripheral nociceptors are mostly what kind, and responding to what (3) stimuli?
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Mostly polymodal (some unimodal), repsonding to mechanical, thermal, and chemical stimuli
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What are transduction noxious stimuli resposnsed mediated through? (3)
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Histamine, prostoglandins, and others
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In peripheral transmission, where do peripheral nociceptive fibres enter the spinal cord through? And where do they dorminate?
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They enter the through the dorsal root and terminate in the dorsal horn
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What does the synapse in the dorsal horn have?
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Ascending axons and spinal interneurones
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What are the neurotransmitters at the spinal cord? (2)
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Glutamate and substance P
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In the central transmission of nociception, where do ascending axons ascend to prior to terminating?
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Ascending axons cross midline and ascend through anteroelateral column of the spinal cord
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Where do ascending axons in central transmission terminate?
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In ther ventral posterior nucleus of the thalamus
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Where are collateral terminations of ascending axons in central transmission of nociception?
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Brain stem
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Where does thalamus project to? (3) (In terms of nociception central transmission)
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From brainstem to thalamus,
Thalamus to somatosensory and cingulate cortices |
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There are recriprocal connections between the somatosensory cortex and what cortex?
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Cingulate
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Where is perception of pain, as it is activated in people during illusory pain?
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Cingulate cortex
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Pain is a subjective experience based on what?
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On the information received from nociceptive fibres
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Can the brain think something is painful if no tissue damage has occured?
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Yes
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What is one of the earlierst known drugs used by man, which comprises the dried sap of the opium poppy?
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Opium
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What is Opium?
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A sedative and analgesic
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What are two maiin active components of opium?
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Morphine (~10%) and Codeine (~0.5%)
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Is Morphine better absorbed orally or injected?
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injected
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What are two other opioid durgs other than opium?
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heroine and methadone
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What does Morphine act through?
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Binding sites in the brain and spinal cord
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Is morphine an agonist or antagonist?
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Agonist (first beleived to be antagonist)
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What are effects of morphine blocked by?
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Naloxone
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Is morhine endogenous?
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No
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What happened to endogenous opiods in the 1970s?
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They were isolated
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what are three receptors that have been found for opiods?
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Mu, Delta, and Kappa Receptors
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What are Mu receptors most sensitive to?
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To morphine and to endorphins
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What are Delta receptors most sensitive to?
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Enkephalins
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What are Kappa receptors most sensitive to?
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Dynorphins
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Morphine injected into which ventricles relieves sever pain?
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Lateral ventricals
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What doses is morhine effective at when injected?
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Effective at doses 10-fold lower that for systemic injection
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What does intracerebral injection of morphine induce?
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Analgesia
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In which parts does intracerebral injection of morphine induce analgesia (3) ?
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Periaqueductal grey matter (PAG)
Periventricular grey matter (PVG) Rostroventral medulla (RVM) |
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Naloxone injected into PAG, PVG or RVm partially reduces what ?
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Analgesic action of systematically administered morphine
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Whatcan electrical stimulation of localised brain areas do to pain perception?
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Suppress it
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Is analgesia a passive process?
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No, it is active
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Six similarities between opioid analgesia and stimulation produced analgesia?
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Effective loci are the same place in each case, both are blocked by naloxone, both are combining sub-analgesic levels of both produces analgesia, cross-tolerance develops between the two, both effects cause blockade of spinal reflexes, both effects activate the same descending spinal pathway.
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Where are analgesia effects mediated?
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At the level of the spinal cord
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Which descending spinal pathway is acitvated by opioid/stimulation produced analgesia?
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Dorsolateral funiculs
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What is stimulus produced analgesia mediated through?
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Opioid mechanisms
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Three levels of opioid analgesia?
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Supraspinal, spinal, and hormonal
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Elaborate on supraspinal level of opioid analgesia
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Opioid receptor acitivation in brain stem, mediated via spinal cord mechanisms, mu-receptor mediated (i.e. endorphins)
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Elaborate on spinal level of opioid analgesia
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Opioid receptors activation in spinal cord, delta and kappa receptor mediated (enkephalins and dynorhpins )
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Elaborate on hormonal level of opioid analgesia
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Stress-induced analgesia is reversed by naloxone, also reversed by removal of adrenal glands
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What modulates non-opioid brainstem analgesia (2), espeically in which two brain areas?
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Noradrenaline and 5HT, espeically in PAG and PVG
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What does noradrenaline injeicted into spinal cord block response too ? (In terms of Non-opioid analgesia)
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Noxious stimuli
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As 5HT injected into spinal cord is analgesic, what neurones (2) does it block?
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Nocicelptive neurones and Spino-thanlamic neurones
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Name 6 Alternative methods of analgesia
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Transcutaneous electrical nerve stimulation (TENS), Acupuncture, Placebo, Hypnosis, Stess, Cognitive
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In Transcutaneou Electrical Nerve Stimulation, what does it alter? And what it may activate ?
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Alters nociceptive signal to brain, or brain's perception of pain. May activate endogenous opiate systems
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How much increase of a pain threshold does acupuncture do?
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80%
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What hormone levels (and biosynthesis of ) are increased in the brain due to acupuncture?
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Enkephalins
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What are the effected that are enhanced by enkephalinase ihbibotrs mediated via (in acupuncture) ?
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Via release in PAG and PVG
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What may placebo and cognitive do in terms of an alternative method to analgesia?
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May activate endogenous pain-control systems
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What does hypnosis do in terms of an alternative method to anaglesia?
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Alters brain perception of pain
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What is homeostasis ?
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Maintenance of equilibrium by active regulation of internal states
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What internal states are regulated in homeostasis?
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Cordiovascular function (blood pressure, heart rate), body temperature, food and energy regulation, fluid regulation
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What does the fact that multiple mechanisms control homeostasis emphasise?
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emphasizes the importance to survival
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two types of biorthyms (with examples)?
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Circadian rhythms (daily cycle) - body temperature, heart rate, respiration, sleep; Circaunnu
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