Learning and Plasticity

Transcript

1. The Human Brain in the Animal Kingdom (HEB 1339) | lecture 15 Learning and Plasticity Suhas Vijayakumar postdoc | evolutionary neuroscience lab @neuroacademic @neuroacademic a Learning and Plasticity | April 01, 2020 suhas_vijayakumar@harvard.edu
2. part I: introduction @neuroacademic a Learning and Plasticity | April 01, 2020
3. @neuroacademic a Learning and Plasticity | April 01, 2020 < discuss > Learning and Plasticity
4. @neuroacademic a Learning and Plasticity | April 01, 2020 Definitions Experience Memory (LTP - LTD) Development Aging Adaptation Problem solving Lesion
5. @neuroacademic a Learning and Plasticity | April 01, 2020 Definitions ¯\_(ツ)_/¯ learning plasticity acquiring new experience changes the brain
6. Learning and Plasticity @neuroacademic a Learning and Plasticity | April 01, 2020
7. Learning and Plasticity @neuroacademic a Learning and Plasticity | April 01, 2020 the one about how acquiring new information changes the brain
8. Learning is how you acquire new information about the world, and memory is how you store that information over time Eric R. Kandel “ @neuroacademic a Learning and Plasticity | April 01, 2020
9. Learning @neuroacademic a Learning and Plasticity | April 01, 2020 ‣ preferential strengthening ‣ non-associative permanent change to repeated stimulus habituation and sensitization ‣ associative stimulus => behavior classical conditioning operant conditioning
10. Learning Plasticity ‣ produce more neurons ‣ produce more glial cells ‣ capillary growth (increase O2 ) ‣ synaptic connections @neuroacademic a Learning and Plasticity | April 01, 2020 ‣ preferential strengthening ‣ non-associative permanent change to repeated stimulus habituation and sensitization ‣ associative stimulus => behavior classical conditioning operant conditioning
11. Learning ‣ preferential strengthening ‣ non-associative permanent change to repeated stimulus habituation and sensitization ‣ associative stimulus => behavior classical conditioning operant conditioning Plasticity ‣ produce more neurons ‣ produce more glial cells ‣ capillary growth (increase O2 ) ‣ synaptic connections @neuroacademic a Learning and Plasticity | April 01, 2020 change across generations “adaptation” Krubitzer & Dooley 2013 Front in Hum NeuroSci [link]
12. Learning ‣ preferential strengthening ‣ non-associative permanent change to repeated stimulus habituation and sensitization ‣ associative stimulus => behavior classical conditioning operant conditioning Plasticity ‣ produce more neurons ‣ produce more glial cells ‣ capillary growth (increase O2 ) ‣ synaptic connections @neuroacademic a Learning and Plasticity | April 01, 2020
13. Recap Learning: how we process and acquire incoming new information Plasticity: changes to the nervous system (usually within one’s lifetime) Both can be studied at multiple levels Both have highly specific and specialized mechanisms (outside the scope of this talk) @neuroacademic a Learning and Plasticity | April 01, 2020 Any learning will likely result in some plasticity
14. part II: absence of input and plasticity case of the visual system nervous system has evolved to expect certain kinds of inputs but can certainly be repurposed @neuroacademic a Learning and Plasticity | April 01, 2020
15. ‣ auditory localization task Evidence for reorganization in humans Weeks et al., 2000 JNeuroSci [link] @neuroacademic a Learning and Plasticity | April 01, 2020
16. ‣ auditory localization task ‣ reading Braille Evidence for reorganization in humans Sadato et al., 1996 Nature letters [link] @neuroacademic a Learning and Plasticity | April 01, 2020
17. ‣ auditory localization task ‣ reading Braille ‣ auditory discrimination task ‣ faster in processing language . . . Evidence for reorganization in humans *Not limited to visual cortex. There are reorganizations of the auditory cortex of deaf individuals. @neuroacademic a Learning and Plasticity | April 01, 2020
18. Visual cortex organization ‣ Hubel & Wiesel https://www.youtube.com/watch?v=8VdFf3egwfg @neuroacademic a Learning and Plasticity | April 01, 2020
19. Extent of reorganization ‣ Hubel & Wiesel, LGN Hubel & Wiesel, 1970 J Physiol [link] @neuroacademic a Learning and Plasticity | April 01, 2020 right eye closed (d23 - d26) right eye closed (d23 - d29)
20. Extent of reorganization ‣ Hubel & Wiesel, recordings from left visual cortex right eye closed (d23 - d26) normal development right eye closed (d23 - d29) @neuroacademic a Learning and Plasticity | April 01, 2020 Hubel & Wiesel, 1970 J Physiol [link]
21. Cnops et al., 2008 Cerebral Cortex [link] Extent of reorganization ‣ at layer-level ‣ protein expression @neuroacademic a Learning and Plasticity | April 01, 2020
22. back to system-level plasticity @neuroacademic a Learning and Plasticity | April 01, 2020
23. Extent of reorganization in short-tailed opossums (Monodelphis domestica) ‣ n = 6 ‣ enucleated ‣ postnatal day 4 area X: auditory + somatosensory Kahn & Krubitzer, 2002 PNAS [link] @neuroacademic a Learning and Plasticity | April 01, 2020
24. Recap Parts of the brain have evolved to expect certain kinds of inputs In absence of such typical input, cortical function is often altered @neuroacademic a Learning and Plasticity | April 01, 2020
25. part III: learning and plasticity nervous system has evolved to expect certain kinds of inputs but can certainly be repurposed by training @neuroacademic a Learning and Plasticity | April 01, 2020
26. @neuroacademic a Learning and Plasticity | April 01, 2020 Extent of reorganization ‣ auditory localization task ‣ reading Braille ‣ auditory discrimination task ‣ faster in processing language . . . *natural adaptations. What about active training?
27. @neuroacademic a Learning and Plasticity | April 01, 2020 echolocation Plasticity through active adaptation ‣ EB, early blind - 13 months ‣ LB, late blind - 14 years ‣ fMRI * Thaler et al., 2011 PlosOne [link]
28. @neuroacademic a Learning and Plasticity | April 01, 2020 echolocation Plasticity through active adaptation Thaler et al., 2011 PlosOne [link] ‣ echo > silence blind visual cortex control auditory cortex
29. echolocation Plasticity through active adaptation @neuroacademic a Learning and Plasticity | April 01, 2020 Thaler et al., 2011 PlosOne [link] ‣ echo > silence blind visual cortex control auditory cortex ‣ more than normal hearing blind visual cortex control none
30. @neuroacademic a Learning and Plasticity | April 01, 2020 echolocation Plasticity through active adaptation Thaler et al., 2011 PlosOne [link] ‣ echo > silence blind visual cortex control auditory cortex ‣ more than normal hearing blind visual cortex control none ‣ lateralization blind contralateral preference for EB control auditory
31. Extent of reorganization due to phantom limb ‣ V S Ramachandran @neuroacademic a Learning and Plasticity | April 01, 2020 Side note: TED talk “3 clues to understanding your brain” https://www.youtube.com/watch?v=Rl2LwnaUA-k
32. ‣ V S Ramachandran Ramachandran & Rogers-Ramachandran, 2000 ArchNeurol [link] @neuroacademic a Learning and Plasticity | April 01, 2020 Extent of reorganization due to phantom limb face hand upper arm right hemi left hemi
33. @neuroacademic a Learning and Plasticity | April 01, 2020 Okay, but shouldn’t this be in part II?
34. ‣ V S Ramachandran Ramachandran & Rogers-Ramachandran, 2000 ArchNeurol [link] @neuroacademic a Learning and Plasticity | April 01, 2020 Extent of reorganization due to phantom limb plasticity through training
35. @neuroacademic a Learning and Plasticity | April 01, 2020 Hand grafts! Plasticity through active adaptation
36. @neuroacademic a Learning and Plasticity | April 01, 2020 Hand grafts! Plasticity through active adaptation Giraux et al., 2001 NatNeuro [link]
37. part III: learning and plasticity nervous system has evolved to expect certain kinds of inputs but can certainly be repurposed by training @neuroacademic a Learning and Plasticity | April 01, 2020
38. @neuroacademic a Learning and Plasticity | April 01, 2020 String instrument players Plasticity through active training Elbert et al., 1995 Science [link]
39. @neuroacademic a Learning and Plasticity | April 01, 2020 The taxi driver study Plasticity through active training Maguire et al., 2000 PNAS [link] ‣ Hippocampus ‣ “the knowledge” ‣ VBM (voxel-based morphometry)
40. @neuroacademic a Learning and Plasticity | April 01, 2020 The taxi driver study Plasticity through active training Maguire et al., 2000 PNAS [link] ‣ Hippocampus ‣ “the knowledge” ‣ VBM (voxel-based morphometry)
41. @neuroacademic a Learning and Plasticity | April 01, 2020 The juggling study Plasticity through active training Scholz et al., 2000 NatNeuro [link] supplementary material ‣ Juggling training juggling patterns (ranks) 0: 2-ball pattern 1: 1 cycle of 3-ball cascade 2: 2 cycles 3: 3 cycles 4: 60 s 3-ball cascade.
42. @neuroacademic a Learning and Plasticity | April 01, 2020 The juggling study Plasticity through active training Scholz et al., 2000 NatNeuro [link] ‣ Juggling training ‣ White matter changes (FA:= fractional anisotropy) ‣ Grey matter changes (VBM)
43. @neuroacademic a Learning and Plasticity | April 01, 2020 The toolmaking study Plasticity through active training Hecht et al., 2015 BSAF [link] ‣ Paleolithic stone tool
44. @neuroacademic a Learning and Plasticity | April 01, 2020 The toolmaking study Plasticity through active training ‣ Paleolithic stone tool ‣ White matter changes (FA:= fractional anisotropy) Hecht et al., 2015 BSAF [link]
45. @neuroacademic a Learning and Plasticity | April 01, 2020 The toolmaking study Plasticity through active training ‣ Paleolithic stone tool ‣ White matter changes (FA:= fractional anisotropy) ‣ Tractography Hecht et al., 2015 BSAF [link]
46. Recap Cortical function is changed due to various reasons! (echolocation, lost effector, regained effector, skill training…) Both grey matter and white matter changes have been observed Changes seem to be related to the intensity of training @neuroacademic a Learning and Plasticity | April 01, 2020
47. part IV: can we “enhance” function? @neuroacademic a Learning and Plasticity | April 01, 2020
48. @neuroacademic a Learning and Plasticity | April 01, 2020 The tDCS study Enhancing function, transient plasticity ‣ transcranial direct current stimulation Wikimedia
49. @neuroacademic a Learning and Plasticity | April 01, 2020 The tDCS study Enhancing function, transient plasticity ‣ transcranial direct current stimulation ‣ effect lasted ~30 minutes
50. @neuroacademic a Learning and Plasticity | April 01, 2020 Okay, but what does it do?! ¯\_(ツ)_/¯
51. @neuroacademic a Learning and Plasticity | April 01, 2020 Thank you! @neuroacademic suhas_vijayakumar@harvard.edu