1 / 48

model system: sea hare ( Aplysia californica ) behavior: the gill & siphon withdrawal reflex

PART 4: BEHAVIORAL PLASTICITY #21: LEARNING & MEMORY of a SIMPLE REFLEX in APLYSIA II. model system: sea hare ( Aplysia californica ) behavior: the gill & siphon withdrawal reflex even more cell biology: learning & memory summary. PART 4: BEHAVIORAL PLASTICITY

wattan
Download Presentation

model system: sea hare ( Aplysia californica ) behavior: the gill & siphon withdrawal reflex

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. PART 4: BEHAVIORAL PLASTICITY #21: LEARNING & MEMORY of a SIMPLE REFLEX in APLYSIA II • model system: sea hare (Aplysia californica) • behavior: the gill & siphon withdrawal reflex • even more cell biology: learning & memory • summary

  2. PART 4: BEHAVIORAL PLASTICITY #21: LEARNING & MEMORY of a SIMPLE REFLEX in APLYSIA II • model system: sea hare (Aplysia californica) • behavior: the gill & siphon withdrawal reflex • even more cell biology: learning & memory • summary

  3. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • convergence of CS & US in sensory neuron • adenylyl cyclase (AC) = coincidence detector? • sensitization: • Ca++ channels closed • Ca++not bound to calmodulin • calmodulin not bound to AC • some cAMP ...

  4. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • convergence of CS & US in sensory neuron • adenylyl cyclase (AC) = coincidence detector? • associative learning: • Ca++ channels open • Ca++ bound to calmodulin • calmodulin bound to AC • lots of cAMP ...

  5. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • glutamate, excitatory transmitter • activates N-methyl-D-aspartate (NMDA) receptor

  6. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • glutamate, excitatory transmitter • activates N-methyl-D-aspartate (NMDA) receptor • no signal... • NMDA channel closed • no Ca++ enters cell

  7. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • glutamate, excitatory transmitter • activates N-methyl-D-aspartate (NMDA) receptor • signal... • glutamate binds to receptor • postsynaptic membrane depolarizes • postsynaptic neuron fires • test this model?

  8. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • differential conditioning

  9. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • differential conditioning • aminophosphonovalerate (APV) block of NMDA receptor…

  10. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • differential conditioning • block NMDA receptor with APV during training

  11. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • differential conditioning • block NMDA receptor with APV during training • associative synaptic facilitation 

  12. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • differential conditioning • block NMDA receptor with APV during training • associative synaptic facilitation  • NMDA receptor necessary

  13. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • differential conditioning • same result during training if • postsynaptic neuron: • hyperpolarized • Ca++ blocked • presynaptic neuron: • PKA blocked • Ca++ 

  14. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • postsynaptic factors • implication that the postsynaptic neuron communicates with the presynaptic neuron • retrograde (backward) signaling • evidence (not shown) – associative facilitation mechanism in postsynaptic neuron changes signaling properties in the presynaptic neuron • neurons communicate in both directions • but... what is the signal?

  15. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • revised model • 2 sites of CS-US coincidence • presynaptic AC

  16. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • revised model • 2 sites of CS-US coincidence • presynaptic AC • postsynaptic NMDA receptor gated channels

  17. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of classical conditioning • revised model • 2 sites of CS-US coincidence • presynaptic AC • postsynaptic NMDA receptor gated channels • retrograde signal (hypothetical)

  18. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • terminology: • long-term memory (LTM) behavioral measure • long-term facilitation (LTF) physiological measure

  19. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training

  20. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training: • siphon withdrawal 

  21. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training • siphon withdrawal  • sensory EPSPs 

  22. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training • siphon withdrawal  • sensory EPSPs  • S-current  (data not given)

  23. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training • siphon withdrawal  • sensory EPSPs  • S-current  • serotonin-induced presynaptic transmitter release  (data not given)

  24. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training • siphon withdrawal  • sensory EPSPs  • S-current  • serotonin-induced presynaptic transmitter release  (data not given) • presynaptic neuronal plasticity

  25. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training • serotonin substitutes for tail shock @ sensory • cell body  LTF • terminal  STF

  26. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • distributed sensitization training • serotonin substitutes for tail shock @ sensory • cell body  LTF • terminal  STF

  27. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • serotonin induces • LTF • intracellular signal • protein synthesis (?) • neural plasticity (?) • STF • locally @ synapse

  28. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • protein synthesis (?) • transcription • translation • transport  synapses

  29. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • protein synthesis inhibited by blockers • also block LTF • during serotonin application only • not before or after... • narrow temporal window

  30. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • protein synthesis inhibited by blockers • also block LTF • during serotonin application only • not before or after... • narrow temporal window • no block of STF

  31. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term synaptic facilitation in sensory neurons • protein synthesis inhibited by blockers • also block LTF • during serotonin application only • not before or after... • narrow temporal window • no block of STF • ... and does block LTM (behavior) • protein synthesis necessary for LTM

  32. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term sensitization / serotonin treatments  molecular changes in sensory neurons: • persistent phosphorylation of existing proteins • synthesis of new proteins • growth of sensory neurons... neural plasticity

  33. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term sensitization / serotonin treatments  molecular changes in sensory neurons: • growth of sensory neurons... neural plasticity • visual examination •  axonal processes, branching, varicosities

  34. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term sensitization / serotonin treatments  molecular changes in sensory neurons: • growth of sensory neurons... neural plasticity • visual examination •  axonal processes, branching, varicosities

  35. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term sensitization / serotonin treatments  molecular changes in sensory neurons: • growth of sensory neurons... neural plasticity • model for synaptic restructuring / plasticity •  varicosities •  terminal active zones • opposite for habituation

  36. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • long-term sensitization / serotonin treatments  molecular changes in sensory neurons: • growth of sensory neurons... neural plasticity • model for synaptic restructuring / plasticity •  varicosities •  terminal active zones •  long-term increase in synaptic transmission • what are the molecular mechanisms?

  37. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • molecular induction of LTF in sensory neurons • cAMP pathway implicated: • cAMP injection ... S-current  • PKA inhibitors ... block serotonin-induced LTF • serotonin application ... PKA catalytic subunit cytoplasmic  nuclear • activity of genes: • immediate early (IEG), transcription factors • late-responsive, leave nucleus

  38. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • molecular induction of LTF in sensory neurons • cAMP pathway implicated: • cAMP response elements (CREs) on DNA • CRE binding protein (CREB) • phosphorylated by PKA... CREBs  IEGs • IEGs  late-responsive genes

  39. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • molecular induction of LTF in sensory neurons • single training event  some PKA, STF • distributed training  more PKA... nucleus, LTF

  40. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • molecular induction of LTF in sensory neurons • competition studies using injected CRE sequences  block CREB binding & LTF 

  41. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • molecular induction of LTF in sensory neurons • competition studies using injected CRE sequences  block CREB binding & LTF 

  42. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • molecular induction of LTF in sensory neurons • competition studies using injected CRE sequences  block CREB binding & LTF  • enhanced CREB + 1 serotonin application  • LTF • structural enhancement • CREB essential for LTF & LTM • similar findings in Drosophila (next chapter)

  43. CELL BIOLOGY OF LEARNING & MEMORY • mechanistic analysis of long-term memory • LTF molecular model • what proteins? • how do they work? • other 2nd messenger cascades? • homology (flies, mice)

  44. CELL BIOLOGY OF LEARNING & MEMORY • middle-term memory... read the section on your own

  45. SUMMARY • defensive withdrawal reflex after stimulation (CS) of • siphon, mantle, gill • shows non-associative learning properties • habituation, dishabituation, sensitization • sensitization: reflex with preceding tail shock • associative learning • reflex (CS) + paired shock (US) • differential conditioning = CS1+ + US, CS2– • distributed training  long-term memory

  46. SUMMARY • tail shock sensitization • interneuron serotonin release  sensory neuron •  K current flow (out of cell) • spike broadening • synaptic facilitation • cAMP cascade mediated • sensory neuron transmitter release

  47. SUMMARY • classical conditioning • interneuron serotonin release  sensory neuron • tail shock US responses augmented by concurrent CS signal... • activity-dependent presynaptic facilitation • postsynaptic process, NMDA receptor in motor neuron

  48. SUMMARY • long-term memory • dispersed training • protein synthesis-dependent • cAMP & CREB  IEGs • IEGs  late-response genes • proteins  neuron terminals • neuronal plasticity

More Related