Temporal representation in spiking neurons

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Temporal representation in spiking neurons
Biomedical engineering Group School of Electrical
Engineering Sharif University of Technology

• TEMPORAL CODES

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TEMPORAL CODES IN NEURONS

• Neurons output Code
• Rate Code
• Timing Code
• On-Off Code
• Real Value Code
• Need a General Model
• Inputs from Others
• A resultant Voltage/Soma Current
• Threshold
• Action Potential
• Transmission
• Neurotransmitter Release

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A Complete model of a Network of Neurrons
j
ij Neuron
hi Neuron
h
i
ik Neuron
k
il
l
gi Neuron
f
fi Neuron
g
im Neuron
Names of Nodes Representing a Synapse/ a Sensor/
an Effector A link between two nodes A
neuron Notice the Direction and naming Strategy
m
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A Nuron Parameters
ij Neuron
i
j

• Delay Associated with each Neuron
• Soma Current
• Node Voltage
• Threshold Voltage
• Refractory period
• Output Function Code

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Schematic Diagram
Neurotransmitter Release
Soma Voltage
i
j
Soma Current
Axon Voltage
Soma Current of j caused by i
Quiz 1 Determine/Explain all the values of
Blocks for LIF Neurons
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Possible Neurotransmitter Release Functions

• On-Off Code
• Spike-Train Code
• Unit-Spike Code
• Rate Code

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Rate Code

• Integral period? (100 ms)!?
• Rapid Movements (below ms)
• Dependent to interval
• Evidence that different input spike trains with
  the same mean rate, but different temporal
  structure produce significantly different output
  from the same cell

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Timing Code

• 1/ISI 1/ InterSpike Interval

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DECODING NEURAL SPIKES

• Properties of neural spike trains
• Attempts to decode neural spike trains have been
  largely successful
• No need to develop a completely new means of
  understanding neural representation
• Methods discussed are a variation on past themes

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Temporal encoding and decoding process
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HW3

• Try to test if you can represent a signal x(t)
  with Not Equally-Spaced Unit Impulse Trains
• Discuss how realistic is your proposal
• Subject HW3 NeuroScience1386 IDxxx
• DueDate 27 Aban

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Neuron pairs
adding a second neuron that increases firing with
decreasing stimulus intensity
A push-pull amplifier
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Representing time dependent signals with spikes