Spike timing-dependent plasticity Guoqiang Bi Department of Neurobiology University of Pittsburgh School of Medicine
Dec 18, 2015
Spike timing-dependent plasticity
Guoqiang Bi
Department of Neurobiology University of Pittsburgh School of Medicine
When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased.
— Donald O. Hebb, 1949
“Cells that fire together, wire together”
Question:
How precise do the cells need to fire together in order to wire together?
1. Spike-timing-dependent synaptic plasticity
• How does the timing of pre- and postsynaptic activity affect synaptic modification?
2. STDP in neuronal networks
• How may a network change its configuration according to the temporal structure of in input stimuli?
3. Temporal integration of STDP
• How is a synapse modified by natural spike trains?
+ bicuculline
+ CNQX & bicuculline
A. Glu - Glu
+ CNQX
+ bicuculline & CNQX
B. Glu - GABA
S1 S2
R2
R1*
S1 S2
R2
R1
Synaptic connectivity between cultured neurons
0 10 20 30 40 500.2
0.4
0.6
0.8
1.0
EP
SC
am
plit
ude (
nA
)
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Norm
aliz
ed E
PS
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Time (min)
0 10 20 30 40 500
50
100
150
200E
PS
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mplit
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A
B
C
LTP induced by paired spiking with positive timing
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0.2
0.3
0.4
0.5
EP
SC
am
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0.6
0.8
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1.2
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Norm
aliz
ed E
PS
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Time (min)
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0.2
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PS
C a
mplit
ude (
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LTD induced by paired spiking with negative timing
1. Spike-timing-dependent synaptic plasticity
• Paired pre- and postsynaptic spiking induces LTP and LTD, depending on the precise spike timing
• STDP is sensitive to neuronal cell type• STDP requires NMDA receptors
2. STDP in neuronal networks• How may a network change its configuration according to the
temporal structure of in input stimuli?
3. Temporal integration of STDP• How is a synapse modified by natural spike trains?
1. Spike-timing-dependent synaptic plasticity
• Paired pre- and postsynaptic spiking induces LTP and LTD, depending on the precise spike timing
• STDP is sensitive to neuronal cell type• STDP requires NMDA receptors
2. STDP in neuronal networks• How may a network change its configuration according to the
temporal structure of in input stimuli?
3. Temporal integration of STDP• How is a synapse modified by natural spike trains?
Correlated spiking at remote synapses through convergent polysynaptic pathways – a “delay-line” mechanism
IPI'
(i) (ii)
positively spike timing negative spike timing
IPI
t
IPI
t
IPI'
0 20 40 60 80
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3
Polysynaptic pathways in small neural networks
B
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Time (min)
Tim
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ms)
1
3
2
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EPSC700 pA
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20
40
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80
Time (min)
Tim
e (
ms)
321S
4
IPI(ms): 60 40
Long-term pathway remodeling inducedby repetitive paired-pulse stimulation
0 20 40 60 80 100 1200
10
20
30
40
Time (min)
Tim
e (m
s)
IPI(ms): 100 5020
3
2
1
S
Sensitivity of pathway remodeling to inter-pulse interval (IPI) of input stimuli
0 20 40 60 80 100
0
20
40
60
80
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Time (min)
Tim
e (m
s)
IPI(ms): 150 65 65 55
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S
4
Dependence of pathway remodeling on inter-pulse interval (IPI) of input stimuli
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-0.4
-0.2
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Inter-pulse interval (ms)
Pathway remodeling induced bypaired-pulse stimuli of different IPIs
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**
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Abs
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)
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LTP and LTD at remote synapses induced by local paired pulse stimulation
A1 A2
B1 B2
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50
100
Time (min)
EP
SC
am
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de (
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0 10 20 30 40 50 600
50
100
150
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de (
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1. Spike-timing-dependent synaptic plasticity
• Paired pre- and postsynaptic spiking induces LTP and LTD, depending on the precise spike timing
• STDP is sensitive to neuronal cell type• STDP requires NMDA receptors
2. Remote STDP in neuronal networks
• STDP occurs at synaptic sites remote to network input nodes• Spike timing within the network can be coordinated by delay-lines
formed by polysynaptic pathways.
3. Temporal integration of STDP
1. Spike-timing-dependent synaptic plasticity
• Paired pre- and postsynaptic spiking induces LTP and LTD, depending on the precise spike timing
• STDP is sensitive to neuronal cell type• STDP requires NMDA receptors
2. Remote STDP in neuronal networks
• STDP occurs at synaptic sites remote to network input nodes• Spike timing within the network can be coordinated by delay-lines
formed by polysynaptic pathways.
3. Temporal integration of STDP
Temporal integration of STDP – theoretical considerations
“Pan-spike” interaction
“Near-neighbor” interaction
-20 -10 0 10 20 30
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Norm
aliz
ed E
PS
C
Time (min)
0 10 20 30 40 500.0
0.2
0.4
0.6
EP
SC
am
plit
ute
(nA
)A
B
LTP induced by a special case of “triplet” spiking
Bi & Poo 1998
1. Spike-timing-dependent synaptic plasticity
• Paired pre- and postsynaptic spiking induces LTP and LTD, depending on the precise spike timing
• STDP is sensitive to neuronal cell type• STDP requires NMDA receptors
2. Remote STDP in neuronal networks
• STDP occurs at synaptic sites remote to network input nodes• Spike timing within the network can be coordinated by delay-lines
formed by polysynaptic pathways.
3. Temporal integration of STDP
• In hippocampal cultures, LTP- and LTD-inducing processes integrate asymmetrically
• Different systems with the same spike-timing window may have different integration rules.