Tim-principles Of Neuroscience Flashcards
Galileo views
Link between mind and brain, the world is heliocentric, heart mentioned more than brain in the bible
philosophical standpoints- ancient Egyptians
Ancient Egyptian 1600bce-300bce, brain written on pyrus, damage causes change in behaviour. Left heart as the only organ in the body as heart weighed in the afterlife against feathers but didn’t care about the brain
Ancient Greece
Plato and Aristotle 429-322 bce. Plato said mind has 3 parts (higher thinking, emotions and Eros/desire). Aristotle said sensus cominus (common sense where they come together). Source of sensation is heart as first to develop, die immediately, central . Psyche and Eros - Eros mum is Venus, psyche is pretty, Venus gets jealous and gets psyches father to be eaten by monster (mind is immortal)
Hippocrates and materialism 400 BCE-100ACE:
feelings arise from the brain and the brain alone. Galon: physician for the gladiators, brain injuries had behaviour deficits. Noticed nerves went to diff parts of the body. The 4 humours were sent from the brain via these nerves- led to diff personalities/ mental illnesses
Leonardo, Michelangelo and the Renaissance 1400-1600:
thought the brain has ventricles to combine the senses, cognitition, memory. good artist but less understanding of the the brain. Giving life to Adam painting by Michelangelo may have actually been a Picture of the brain. Henry more: brain has no role in behaviour. Shakespeare: where is fancy bread in the heart or in the head
Descartes and dualism 1596-1650:
mechanical part of brain and another part with higher thinking (the mind and the brain). Mechanical: info to the pineal gland sends info to the mind then makes an action via nerves and fluid . Mental illness lost their link between the mind and the brain, children had undeveloped mind and animals had no mind. Jon jarqueo: mental illness caused by brain damage. West riding pauper lunatic asylum - bi lateral control
Relationship between structure and function
Thomas Willis 1600s-father of neuroscience had anatomically correct brain with cortex being memory, cc with thinking and imagination-localisation. Gall:phrenology 1800: feeling brain to tell personality. Flourens:quipotentiality challenged localisation as size of legion not located dictated deficits in pigeons. Karl lashley found size of legion on rags more important for mazes. Broca’s area=aphasia, saying language and wernciks for understanding, nick gage . Golgi first to get image, created stain, everything thanked. Cajal said nerve cells separated. Broadman:neurones organised diff in diff parts (cytoarchitectonics)
Techniques for brain activity
Single neurone recordings:stim in visual field and record AP (hubel and Wiesel but need electrode). Quiroga Jennifer Anniston effect. Electro/magneto encephalography-response of many neurones show localisation. Fmri and tms
Galvanni and mitsugoro
lightning struck metal attached to frog legs, made them move. His nephew got dead criminal bodies and sent electricity through them- deduced messages sent via electricity
Bando Mitsugoro 8th: wanted livers of puffer fish and died (rip) because it had toxin (VGC Na+ inhibitor)
Resting membrane potential
Neurone: cell body, nucleus, axon, dendron, dendrites, myelin sheath,nodes of ranvier, terminal buttons and synapse, lipid bilayer (has ion channel and na/k pump, specific/complementary to Na+ and K+).
Conc diffusion force e.g gradient and electrical force (+ and - attracted but equal each other out to -60mv): at rest, leak K+ are open
na/k pump: 3Na+ out 2K+ in, overall means inside is -, outside is + (polarised) and ATP hydrolysed, pump is phosphorylated
Action potential
Threshold value has to be reached (-50mv),triggers AP, Na+ vgc open, Na+ diffuses down gradient and down electric force, becomes depolarised (more+),. At +40mv ,na+ vgc close, K+ vgc open, K+ diffuses out (axon gets more -), more k+ leaves, becomes hyperpolarised to -75mv, K+ vgc closed, leak channels and pumps restore resting
APs only increase in freq not siz
History of the synapse
vagus nerve attached to heart in solution connected via tube to another heart. If vagus stim- causes HR to decrease, found that heart 2 also slowed. Means vagus nerve supplies chemical (NT)- led to development of drugs for MH disorders
Action of the synapse
Synapse is between the presynaptic membrane of the axon and the post of the dendrite. AP causes Ca2+ vgc to open and ca to diffuse in, binds to vesicles which causes them to bind to the presynaptic membrane and fuse w it. They release NT into the synapse which diffuse across and bind to NT receptors on post. Opens ion/Na vgc, Na diffuse in, creates an AP
Action of drugs on the synapse.
Drugs can be agonist-mimic NT as similar structure so bind to protein receptor or can be antagonist/ inhibitory as bind to protein receptor and blocks it
NT removal and summation
Removal: NT is taken up into pre or by degrading the NT via enzymes, if this doesn’t happen, NT can make the neurone toxic
Spatial summation: if two excitatory but if one excitatory and one inhibitory-no threshold reached (happens on the post)