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Design & Neuroscience - The Brain

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Design & Neuroscience - The Brain

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2nd presentation of the series Design&Neuroscience, focused on the Brain. Talking about neurons, visual areas, receptive fields, optical illusions and visual field.

2nd presentation of the series Design&Neuroscience, focused on the Brain. Talking about neurons, visual areas, receptive fields, optical illusions and visual field.


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Design & Neuroscience - The Brain

  2. 2. Neurons are about 100 billions, the connections between each neuron are between 1000 and 10,000. It’s estimated that the number of permutations and combinations of a single brain exceeds the number of elementary particles of the universe. (It’s surely the structure more complex we know.)
  3. 3. Longer arm departing from the nucleus. It transmits the information in centrifugal direction. Arms departing from the nucleus. They gather information moving in centripetal direction. Structure that permits a neuron to pass an electrical or chemical signal to another neuron. AXON: DENDRIDES: SYNAPSES:
  4. 4. It has been often asserted that a lot of the connections (synapses) depend on the genetic, they spoke about the gene of jealousy, the gene of mathematic, the passion for chocolate, etc. However this is not demonstrated anywhere and would make the DNA almighty. It’s enough to see the behaviour of two monozygotic twins, where the genetic is identical.
  6. 6. I.E. The first months of life are fundamental for visual areas, if the brain of a child doesn’t receive the necessary external stimuli those synapses will never create. After 25 weeks the brain is already very similar to what it would be in adult age.
  7. 7. Humans are the only animals born without an instict. Spiders know how to weave a net, cat know how to hunt without lessons, etc..
  8. 8. Intellettive skills are ready at the beginning of the adolescence, but the emotions are completely ready only after 20-22 years. 1st walking 2nd abstract thinking 3rd language 4th emotions Humans’ maturation process is very slow and requires learning phases:
  9. 9. DIVISION OF THE BRAIN FRONTAL LOBE Thinking / Imagination PREFRONTAL LOBE Executive & Cognitive Fuction, Personality PARIETAL LOBE Kinestehtic OCCIPITAL LOBE Visual Processing TEMPORAL LOBE Sound & Speech Processing
  10. 10. Theory of Paul MacLean of the three brains, controverse because too simplificatory. 2nd brain LYMBIC SYSTEM Emotional Feel - Remember Interact with other 1st brain REPTILIAN BRAIN Instinctual Survive - React - Repeat 3rd brain NEOCORTEX Rational Talk - Think - Move Create - Learn THE THREE BRAINS
  11. 11. Portion of the lymbic system (2nd brain) with the of an almond. Here are the emotive responses and the fear. It’s where pleasure for food and sex are elaborated. Through a TAC has been demonstrated how the amygdala reacts to a face which induce fear and how it calms down as soon as the face smiles. AMYGDALA FACT: For men the hypothalamus switches on during the orgams, so for it it’s enough only the second brain. For women instead also part of the cortex is activated during the orgams.
  12. 12. VISUAL AREAS OF THE BRAIN Named with the letter V they are over 40 in humans. Squirrels have 4, cats 12, monkey 20 V1 V4 V2 V3 V3A
  13. 13. Given by a damage to V4, area which takes care of the colour. The world is seen in black and white. ACHROMATOPSIA
  14. 14. A damage to V5 prevents the elaboration of the movement and the world appears as a series of frames in succession.
  15. 15. People affected by cortical blindness have no vision. However if they are asked to touch a bright point in front of them they will always manage in the task. They might believe it’s just luck, but it’s not. Indeed their brain is damaged, but their eyes work perfectly. BLIND VISION
  16. 16. Ways to see the brain (TAC, PET, NMR) LOOKING AT THE BRAIN
  17. 17. Saying the world walking we can see motor neurons activate.
  18. 18. Math is in the old part of the brain. Birds know how to count till 5. They would soon notice if a chick is missing from the nest. Same is for the elephant which however can count only till 3, after that they perceive many.
  19. 19. VISUAL NEURONS VENTRAL PATHWAY the “what” pathway (more recent) shape, colour and identity of things space, environment and movementDORSAL PATHWAY the “where” pathway (more ancient)
  20. 20. If we try to grab the two orange dots, as the fingers get closer the dorsal pathway (where pathway) adjusts the aim and calibrates the grabbing so that the hand is not deceived by the optical illusion. TITCHENER ILLUSION
  21. 21. Color is perceived before than the shape. Shape before the movement. Between colour and movement there are about 60-80 milliseconds. We’re not conscious about that because the neuroal times are very quick compared to our consciousness.
  22. 22. All the mammals have an area which elaborates the luminosity, but only the primates have an area for the colours.
  23. 23. The older pathway (the where pathway) is blind to the colour, this means that the spatial elaboration thinks only in terms of quantity of reflected light (so in greyscale). That’s why if we add a colored item on a background of a different colour but of the same luminosity, the image tends to flicker. RED TEXT ON GREEN BACKGROUND RED TEXT ON GREEN BACKGROUND
  24. 24. The flickering is given by two information crossing from a pathway to the other. So the brain answers to two signals apparently contradictory. The use of vibrant colours is a classic in graphic design, especially between the complimentary cold and warm colours. It increase the attention although the readability is obviously quite low.
  25. 25. Claude Monet Impression, soleil levant (1872)
  26. 26. “They asked me why the ice-cream on the book cover is pistachio, chocolate and strawberry. The reason - both technical and aesthetic - is that those three colours once converted into black and white correspond to the same “grade of grey” (equiluminant tints) and, since our eyes read the light difference independently from the colour, in this way the lettering is always more readable in every point. There are two harmonic layers: the one of the figure and the one of the text. Furthermore, chocolate and strawberry are a playful and unscrupulous match, very United States”. (Riccardo Falcinelli) EQUILUMINANT COLORS: the lettering lays on an unique grade of grey NOT EQUILUMINANT: lettering is not very readable anymore
  27. 27. Classic exercise in arts schools is to portrait a model before in greyscale and then using only tints, but of the same luminosity. In this way the brain trains itself to differentiate the tonal values from the chromatic ones, taking advantage of the functional segregation in the brain.
  28. 28. Differentiate tonal and chromatic values is important for whoever works with visual languages. Like one of the best Hollywood costume designer of the last century, Edith Head (1897-1981)
  29. 29. RECEPTIVE FIELD Part of a body which cause the reaction a neuron when stimulated. activate + -inhibit
  30. 30. On the retina these fields are not sitting side by side, but they overlap each other. So the perception is given by the combination of hundreds of bodies. Visually every cell has its own receptive field which corrisponds to a specific part of the scene.
  31. 31. For the on-center cell, whatever goes in the centre activates it, whatever goes in the surrounding center inhibits it. For the off-center cell is obviously the opposite. ON-OFF CELLS ON-CENTER, OFF-SURROUND OFF-CENTER, ON-SURROUND
  32. 32. On-off cells are sensitive to lines of borders of things. End-stop are more sensitive to corners, sharp edges, dashed lines, etc. END-STOP CELLS
  33. 33. All the cells are more sensitive to brightness discontinuity than to the light quantity. In general, light quantity, is not that important in biology and neurons answer better to net jumps than to gradients. The brain did not evolve to appreciate absolute tonal values, but to survive in a world where scene changes are cru-
  34. 34. I.E. DIGITAL IMAGES More an image is compressed less are the colour used and so the gradients, there is only a drastic change of colour which however allow us to recognise the figure.
  36. 36. MACH BANDS In the gradient passages from light to dark (and opposite), the brain sees the reinforce bands before darker and then lighter.
  37. 37. In classic painting they used to teach that when portraing the real three things must be included: A) THE BODIES OWN SHADOW B) THE SHADOW BROUGHT BY THE BODIES C) A DARKER LINE AS REINFORCEMENT IN THE SHADOW PASSAGES Without knowing it they were painting a product of the brain rather than a quality of light. A B C
  38. 38. A black flickering is perceived in the corners, but only in periferic area, in fact the flickering disappears when fixing the corner. Cells on the intersection receive the inhibition on 4 sides, producing a weaker answer (and so less white) than the one obtained when inhibited only on two sides. B A THE HERMANN GRID
  39. 39. In the environment the gradual fadings are almost always characteritics of the illuminating light and not of the things themselves.
  40. 40. Parthenon original colours. They wanted the colours to change as less as possible during the day.
  41. 41. Verticality and horizontality are the most simple orientations to recognise by the brain. Surely it depends also on the fact that we stand up on the Earth, that we feel the gravity and that we have two eyes horizontally aligned.
  42. 42. EACH EYE HAS A VISUAL FIELD OF ABOUT 90º Having more than one eye is needed for two things: - enlarge the visual field - to see in three dimensions
  43. 43. Some animals have visual field which don’t overlap each other, so they can’t see the depth. PREY Have an almost 360º field which allows them to check on every side if a predator is approaching. PREDATORS Can see the distance to the prey.
  44. 44. Crossing the eyes you can make overlap the border of a tile seen by the right eye, with the border of another tile (just next to it) seen by the left eye. Being the tiles perfectly identical, the brain is deceived and tries to rebuild the tridimensionality although starting from altered data - like if the distance between the two eyes was different from the human one. The resulting perception is to feel physically smaller, feeling very close to the wall. Basically seeing the tiles from the point of view of a fly. BRAIN DECEPTION ON THE TRIDIMENSIONALITY TILES DIVERGENT FOCUS SPACE BETWEEN TILES NATURAL FOCUS CROSSED FOCUS (the wall looks closer)
  45. 45. If you try to overlap the two images crossing the eyes the result will be a series of moving and intermittent spots, due to the binocular antagonism.
  46. 46. COMING NEXT #3 - MIMESIS