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Homeostasis and Receptive Field Plasticity RF plasticity with the CaDP model Synaptic scaling

Homeostasis and Receptive Field Plasticity RF plasticity with the CaDP model Synaptic scaling Metaplasticity RF plasticity with CaDP + Metaplasticity. correlated. uncorrelated. rate. 0 50 100. Assume: CaDP model as in previous class. 1. 2. 3.

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Homeostasis and Receptive Field Plasticity RF plasticity with the CaDP model Synaptic scaling

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  1. Homeostasis and Receptive Field Plasticity • RF plasticity with the CaDP model • Synaptic scaling • Metaplasticity • RF plasticity with CaDP + Metaplasticity

  2. correlated uncorrelated rate 0 50 100 Assume: CaDP model as in previous class 1. 2. 3. Input structure: How is this done?

  3. 10 Hz 12 Hz 8 Hz 1 1 1 0.8 0.8 0.8 final 0.6 0.6 0.6 synaptic 0.4 0.4 0.4 weight 0.2 0.2 0.2 0 0 0 20 40 60 80 100 20 40 60 80 100 20 40 60 80 100 Input Neuron Input Neuron Input Neuron Model Consequences at system level: Input structure: correlated uncorrelated rate 0 50 100 The system is not robust

  4. Review of Homeostatic mechanisms 1. Synaptic scaling Review by Turrigiano and Nelson 2000

  5. Synaptic scaling is a description of a phenomena, not a mechanism Possible Mechanism:

  6. Metaplasticity: The experience dependent change in the functional form of synaptic plasticity. There are many examples, we will concentrate on one type of metaplasticity. Kirkwood et al 1996

  7. Possible molecular basis for this change in threshold: • Change in NMDAR composition (Quinlan et al 1999, Philpot et. al 2001) or number (Watt et. al. 2004) produced by dark rearing. • Activity dependent change in Ih previous lecture by Dan Johnston.

  8. NMDAR extracellular membrane intracellular Correlated channel final weights Voltage-dep transition rates 0.05 uncorrelated channel 0 20 40 40 Input (Hz) Metaplasticity: activity dependent change in synaptic plasticity

  9. Excitatory inhibitory 100x …20 x … Effects of metaplasticity with poisson inputs

  10. Different time scales for plasticity and metaplasticity

  11. Plasticity with correlated and uncorrelated group The spike-triggered presynaptic event density (STPED)

  12. Segregation between correlated and uncorrelated channels is robust.

  13. Segregation with two correlated groups

  14. Selectivity to non-static, non-overlapping square patterns of input rate distribution.

  15. Selectivity to non-static, overlapping Gaussian patterns of input rate distribution.

  16. Summary

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