Neural Recording System

1
Neural Recording System

• By
• Ivana Duvnjak
• Stephen Kilpatrick
• Dawit Fsiha

2
Outline

• What is a Neural Network Recording System?
• Why are they important?
• How can they be improved?
• Some possible solutions
• Analysis of some solutions
• Conclusions

3
Neural Network Recoding Systems

• Brain sends electrical signals - Neurons
• Sent through axons
• Electrical Signals processed by synapses
• Mapping the brain

4
Applications

• Medical Research
• Mental Performance
• Mental Illness
• Sleep Disorders
• Etc.

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Subsystems

• Electrode
• Amplifier
• Multiplexer
• Transmitter
• Receiver

6
Block Diagram of System
MUX
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Possible Improvements

• Areas to improve in the neural recording system
• Electrodes
• Amplifier
• Multiplexer
• Transmitter
• Receiver

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Neural LNA Amplifier

• Functions
• Power dissipation must kept low
• Must reject noise ( flicker noise)
• Amplifying a weak signal received from the
  electrodes
• Must reject the DC offset created at the
  electrodes-Tissue interface

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Neural Amplifier Requirements

• Power dissipation
• Bandwidth requirement
• Gain
• Stability
• Overall size

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Amplifier Solutions Design I

OTA Design
Neural Amplifier Circuit
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Amplifier Solutions Design II
Neural Amplifier Circuit
OTA Design
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Design I Simulation Results

• 10 pW power consumption
• 39.974dB gain
• Low-cutoff frequency 0.4Hz
• High-cutoff frequency 7.852kHz
• Area 0.16mm2
• Stable

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Design II Simulation Results

• 11.5 pW power consumption
• 40.362dB gain
• Low-cutoff frequency 83.114Hz
• High-cutoff frequency 32.526kHz
• Area 0.091mm2
• Stable

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Comparison of Designs

Table 1. Summary of simulation results for the
neural amplifiers
Parameter Expected Circuit 1 Simulation Circuit 2 Simulation
Supply voltage /-2.5V /-2.5V /-1.5V
Power dissipated lt5mW 10pW 11.5pW
Gain 40dB 39.974dB 40.362dB
Bandwidth 7.0kHz 7.852kHz 32.443kHz
Low-frequency cutoff 0.025Hz 0.4Hz 83.144Hz
High-frequency cutoff 7.0kHz 7.852kHz 32.526kHz
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Conclusions

• Both designs meet the requirements of
• Power consumption
• Stability
• Size
• DC offset rejection
• Design I is significantly better, due to the more
  desirable bandwidth requirements.

16
Implementation
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References

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Exit(0)

• Questions?