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Understanding the brain: a work in progress

Understanding the brain: a work in progress. The brain performs an incredible range of functions. Controls body functions and motivates us to obtain appropriate resources to maintain life Movement Detect and interpret sensory information and social cues

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Understanding the brain: a work in progress

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  1. Understanding the brain: a work in progress

  2. The brain performs an incredible range of functions • Controls body functions and motivates us to obtain appropriate resources to maintain life • Movement • Detect and interpret sensory information and social cues • Attend to specific things rather than others • Learn and remember information and integrate it with past knowledge • Guide behaviour through emotional responses • Generate conscious awareness of the external environment, self and others

  3. 0.5 5

  4. High speed supercomputers 2000-2010 • 2000IBMASCI White 7.226 TFLOPS DoE-Lawrence Livermore National LaboratoryUSA • 2002NECEarth Simulator 35.86 TFLOPS Earth Simulator Center, Japan • 2004IBMBlue Gene/L 70.72 TFLOPS DoE/IBM • 2005 136.8 TFLOPS DoE/U.S. National Nuclear Security, Lawrence Livermore National Laboratory 280.6 TFLOPS • 2007/8 478.2 TFLOPS IBMRoadrunner 1.026 PFLOPS DoE-Los Alamos National Laboratory 1.105 PFLOPS • 2009CrayJaguar 1.759 PFLOPS DoE-Oak Ridge National Laboratory, USA

  5. IBM Sequoia Supercomputer 20 PFLOPS speed 1.6 PFLOPS memory 318m2 96 racks 7megawatts

  6. Neurons

  7. Neuroglial cells Astrocytes - anchor neurons to blood vessels and transport of nutrients/ waste. Have receptors, produce growth factors and modulate synaptic transmission. Signal to one another via gap junctions using calcium. Microglia - defence against pathogens and monitor the condition of neurons. Ependymalcells- line the fluid-filled cavities in brain and spinal cord. Produce, transport, and circulate the cerebrospinal fluid. Oligodendrocytes- produce the myelin sheath in the CNS which insulates and protects axons.

  8. The molecular brain! Growth Factors iGLUR GLUR (Group-II,III) GLUR (Group-I) Growth Factor Receptor GPCR Gb Ga Ga Gb Gg GRB2 Ac Gg SOS Gas PKC Ca++ Ga Gb PLC Ca++ PI3K ATP Gg c-Raf PI DAG PKC Akt P P P P P P I P 3 R IP3 MEKs Ca++ cAMP CamK-II CamK-II CamK-IV ERK1/2 PKA p90RSK Co-factor CREB CREB p300 RNA Pol-II 2009 ProteinLounge.com TFIIB Elk1 TBP SRE TATA CRE Ras Glu C PresynapticTerminal Ca++ Glu Hormones/Neurotransmitters Glu CaCn CREB Pathway Calm Neuron CBP Gene Expression S133 S133

  9. Major subdivisions of the brain

  10. Reticular activating system

  11. Neural plasticity Neural plasticity Learning – turning the gain up and the noise down

  12. Imitating the actions of others (mirror neurons) Control Autistic

  13. How is information represented in the brain?

  14. Advantages/disadvantages of spatial encoding

  15. Advantages and disadvantages of temporal encoding A B C D DABC pre-stimulus during stimulus Correlationand pattern changes

  16. 247ms Inhale 5 sec

  17. Complexity of inhale-related sequences Incidence of inhale-related sequences 16 14 400 12 Number of elements in sequences 10 300 Number of sequences detected 8 6 200 4 100 2 0 0 Prestimulus During stimulus Prestimulus During stimulus 14 400 13 300 Number of elements in sequences 12 Number of Sequences detected 200 11 100 10 0 1 2 3 4 1 2 3 4 Odor Concentration Odor Concentration

  18. Complexity of inhale-related sequences Incidence of inhale-related sequences 16 14 400 12 Number of elements in sequences 10 300 Number of sequences detected 8 6 200 4 100 2 0 0 Prestimulus During stimulus Prestimulus During stimulus 14 400 13 300 Number of elements in sequences 12 Number of Sequences detected 200 11 100 10 0 1 2 3 4 1 2 3 4 Odor Concentration Odor Concentration

  19. Combined spatial and temporal encoding • Most robust solution, allowing brains to be a reasonable size • Makes it easier to both separate, integrate and decode information

  20. The Sensory Brain

  21. Sensory maps - vision

  22. Sensory maps - hearing

  23. Somatosensory and motor maps

  24. The somatosensory homunculus

  25. Integration of sensory information Multisensory brain areas One sense can influence interpretation of another one (see a mouth shape the word “bait” and hear the word “gate”, you think you hear “date”) – McGurk Illusion Facial expressions, even if not consciously perceived, modify the perception of emotion in the voice of the speaker

  26. The brain as an interpreter Illusions

  27. Synaesthesia

  28. Synaesthesia

  29. Synaesthesia

  30. Synaesthesia We may all start off experiencing the world through synaesthesia

  31. Neural encoding of faces "Who are you?", "how do you feel?" "do i like you"?” Answers in <300 milliseconds!

  32. Face processing in the brain

  33. Face processing in the brain

  34. Single cell vs population encoding

  35. Quian-Quiroga et al (2005) Nature

  36. Andrews et al J Neurosci (2010)

  37. The brain as an interpreter

  38. Encoding face identity and face emotion cues simultaneously

  39. Face discrimination learning Operant discrimination between different faces

  40. Brain rhythms and face recognition learning 30-120Hz 4-8Hz

  41. Coupling between fast and slow oscillations (theta and gamma)

  42. Phase locking between IT neuronal activity and theta

  43. >75% of IT electrodes show coupling between theta phase and gamma amplitude I 5µV

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