Synaptic Plasticity - Michigan State University

Synaptic Plasticity - Michigan State University

Spike Timing-Dependent Plasticity Presented by: Arash Ashari Woodin MA, Ganguly K, and Poo MM. Coincident pre- and postsynaptic activity modifies GABAergic synapses by postsynaptic changes in Cl- transporter activity, Neuron 39: 807820, 2003. Dan Y, Poo MM. Spike timing-dependent plasticity: from synapse to perception. Physiol Rev. 2006 Jul;86(3):1033-48. Review. Rao, R. and Sejnowski, T. Spike-timing-dependent Hebbian plasticity as temporal difference learning. Neural Comput, 13(10):22212237, 2001. Slides mostly from: www.mbi.osu.edu 1

Outline Neuron, Synapse, Depolarization and Hyperpolarization Long-Term Potentiation and Depression (LTP and LTD) Spike Timing-Dependent Plasticity (STDP) A Mathematical Model for STDP Discussion 2 3 4 Dendrite: 1. Spatial Summation 2. Temporal Summation

5 6 7 Neurotransmitters Amino Acids Glutamate, GABA Biogenic Amines Dopamine, Histamine Neuropeptides LHRH, Proctolin 8 Neurotransmitters Amino Acids Glutamate, GABA

Biogenic Amines Dopamine, Histamine Neuropeptides LHRH, Proctolin NMDA, GABAA are typical receptors Glumatergic: Excitatory GABAergic: Inhabitatory 9 Excitatory (EPSP) or Inhibitory (IPSP) 10 Depolarization: Influx of Na and Ca cations This causes a spike (Action Potential a pulse-like wave of voltage) Hyperpolarization: Outflux of K cations or influx of Cl anion11

Long-Term Synaptic Enhancement Long-Term Potentiation (LTP) ~ Rapid and sustained increase in synaptic efficacy following a brief but potent stimulus Best studied in the hippocampus Induction of LTP occurs at the postsynaptic site and requires the conjunction of pre and post-synaptic activity On the order of hours, days or longer 12 13 Long-term Synaptic Enhancement The mechanisms underlying LTP remain

controversial The existence of Long Term Depression (LTD) A possible way to study LTP might be Spike Time Dependent Plasticity (STDP) 14 Spike Time Dependent Plasticity 15 Synaptic Plasticity Hebbs Postulate: When an axon of cell A... excites cell B and

repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells so that A's efficiency as one of the cells firing B is increased. In standard Hebbian learning, a synaptic weight is increased if presynaptic and postsynaptic neuron are `simultaneously' active. If neurons communicate by spikes, the concept of simultaneity implies the pre- and postsynaptic spikes occur within some time window. Theory predicts that these time windows could have two phases corresponding to an increase (potentitiation) or decrease (depresseion) of the synaptic weight depending on the relative timing of pre- and postsynaptic spike. Such asymmetric learning rules with two phases have been found in recent experiments. 16

Spike Time Dependent Plasticity Weakening Presynaptic Cell Excitatory Synapse Strengthening t Postsynaptic Cell t

17 What do experiments show? % Change in PostSynaptic Current Presynaptic Cell Excitatory Synapse Postsynaptic Cell t = tpost - tpre 18 Guo-qiang Bi and Mu-ming Poo, J. of Neuroscience, December 1998

So, what are the STDP rules? 19 L. F. Abbott and S. B. Nelson, 2000 Nature Review Similar results: Karmarkar and Bunomano, 2002; Abarbanel et. al. 2003; Kitijima and Hara, 2000 (ms) 20

0.1 I peak ( M / ms) .08 .06 LTP B N

.04 +/- LTD .02 0 -50 LTD 0

LTP 50 100 t (ms) 150 LTD 200 21 A Mathematical Model for STDP

Presynaptic Cell V ' Vrest V g ex Eex V m gex is PLASTIC Excitatory Synapse

Postsynaptic Cell g ' ex g ex / ex V Postsynaptic Membrane Potential Vrest Postsynaptic Membrane Resting Potential gex Excitatory Synaptic Conductance Eex Excitatory Synaptic Reversal Potential m Membrane Potential decay time constant ex gex decay time constant

22 Song, Miller, Abbott Model for STDP A exp t / if t 0 F t A exp t / if t 0 Strengthening Weakening t t t

t F(%) F(%) A+ M ' M / P ' P / P(t) t = tpost - tpre

t t M(t) A- 23 Updating P and M When Presynaptic cell fires, Update P When Postsynaptic cell fires, Update M

Presynaptic Cell P P A M M A Excitatory Synapse F(%) F(%) Postsynaptic Cell A+

P(t) t t M(t) A- 24 Updating gex Synaptic conductance gex is updated when there is a presynaptic action potential at excitatory synapse When Presynaptic cell fires

g a g a M g max When Postsynaptic cell fires g a g a P g max g ex g ex g a ga Denotes the peak synaptic conductance (the synaptic conductance immediately after an isolated presynaptic spike) ADDITIVE RULE for Synaptic Modification 25 Putting things into perspective

Vrest V g ex Eex V ' V g ' ex g ex / ex m P ' P / M ' M / When Presynaptic cell fires, When Postsynaptic cell fires,

1. P P A 1. M M A 2. g a g a M g max 2. g a g a P g max

3. g ex g ex g a Strengthening Weakening Presynaptic Cell t Postsynaptic Cell t

Excitatory Synapse t t 26 In the real world Multiple Synapses 1 postsynaptic neuron How about inhibitory synapses!! Hence, the equation for the postsynaptic neuron changes to include the inhibitory synapses V

' V rest V g ex Eex V g in Ein V m g ' in g in / in gin Inhibitory Synaptic Conductance Ein Inhibitory Synaptic Reversal Potential in gin decay time constant

27 1000 Excitatory Synapses 1000 P functions, but only ONE M function!!! 200 Inhibitory Synapses Postsynaptic Cell Presynaptic Excitatory cell fires,

Postsynaptic cell fires, 1. P[1...1000] P[ j ] A 1. 2. g [1...1000] g [ j ] M g max 2. 3.

g ex g ex g [1...1000] M M A g [1...1000] g [ j ] P[ j ] g max Presynaptic Inhibitory cell fires, 1. g in g in g in 28 Discussion How LTP and LTD occur? Can STDP underlie Memory and

Learning? How? Correlated activity can occur purely by chance, rather should be learned than reflecting a causal relationship that STDP as a Reinforcement Learning/ Temporal Difference Learning 29 References Woodin MA, Ganguly K, and Poo MM. Coincident pre- and postsynaptic activity modifies GABAergic synapses by postsynaptic changes in Cltransporter activity, Neuron 39: 807820, 2003. Dan Y, Poo MM. Spike timing-dependent plasticity: from synapse to perception. Physiol Rev. 2006 Jul;86(3):1033-48. Review. Rao, R. and Sejnowski, T. Spike-timing-dependent Hebbian plasticity as

temporal difference learning. Neural Comput, 13(10):22212237, 2001. Song, S., Miller, K. D., & Abbott, L. F. (2000). Competitive Hebbian learning through spike-timing-dependent synaptic plasticity. Nature Neuroscience, 3, 919-926. http://en.wikipedia.org/wiki/ 30 Thank you Any Questions? 31

Recently Viewed Presentations

  • Elementary Logic - Southern Illinois University Carbondale

    Elementary Logic - Southern Illinois University Carbondale

    A truth table that has no lines where the premises are all true and the conclusion false presents a valid argument. A truth table that has . at least one. line where the premises are all true and the conclusion...
  • International Conference Innovation in Teaching, Research and Management

    International Conference Innovation in Teaching, Research and Management

    The other is the 1974 adaptation of a dual-track higher education system in which vocational/technical colleges are introduced to compliment the traditional/academic ones. Government policies on private higher education Firstly, in August of 1972, the Executive Yuan suspended the issuing...
  • Programming Assignment #4 -- Binary Trees

    Programming Assignment #4 -- Binary Trees

    Programming Assignment #4 Binary Trees CS-2303 System Programming Concepts (Slides include materials from The C Programming Language, 2nd edition, by Kernighan and Ritchie and from C: How to Program, 5th and 6th editions, by Deitel and Deitel)
  • Gaius Julius Caesar Caesar had more than a

    Gaius Julius Caesar Caesar had more than a

    Gaius Julius Caesar ... CLEOPATRA Became Queen of Egypt at the age of 17 Joint Ruler of Egypt with her brother Ptolomy XII Egyptian custom meant that she had to marry him Ptolomy was aged 12 He died aged 18...
  • Sistem Informasi dn - restubj.files.wordpress.com

    Sistem Informasi dn - restubj.files.wordpress.com

    Memfokuskan diri pada segmen tertentu yang diterapkan Hotel Hilton dengan menyediakan sistem yang bernama OnQ. Sistem tersebut mampu menganalisis preferensi tamu-tamu yang sudah menjadi pelanggan setia sehingga pihak hotel bisa memberikan layanan terbaik kepda mereka secara induvidual.
  • Leadership and Professional Development DBA leadership lectures ch

    Leadership and Professional Development DBA leadership lectures ch

    The results were similar. Michigan found leadership behaviour varied from Job centred to employee centred, Ohio called the end points Initiating Structure behaviour and Consideration behaviour. Managers that were job centred were very directive, watch subordinates closely, and use formal...
  • Residential Gateway Applications - IEEE

    Residential Gateway Applications - IEEE

    Integrated Access Device Small Business DSLAM MTU/MDU Airport/Hotels MMDS IEEE802.11 Cable SOHO Telecommuter Home Access Networking PSTN Integrated Access Device 37% of broadband subscribers interested in residential Nets* DSL customers: One of the 12 most frequently asked questions" How do...
  • Best Practices in the Treatment of Patients With Multiple ...

    Best Practices in the Treatment of Patients With Multiple ...

    Serum M-protein (absolute increase ≥0.5 g/dL) Urine M-protein (absolute increase of ≥200 mg/24 hours) Bone marrow plasma cell percentage (at least 10 percent absolute increase) in patients who lack measurable M protein levels Difference in the kappa and lambda FLC...