1. Neurophysiological Monitoring January 18, 2007
Group Members: Advisors:
Greg Apker Daniel Polley, Ph.D.
Vern Huang Mark Wallace, Ph.D.
Nazriq Lamien
Andrew Lin
Emma Sirajudin
Emma

2. Problem Statement There is a need to create a system which is capable
of real-time data acquisition while presenting an
environment with precise, configurable multi-sensory stimuli.
Emma

3. Project Objectives
Development of multi-sensory environments for use in
neuronal response characterization in rats and cats
Combine visual, auditory, and somatosensory stimulation
Modulate location and intensity of stimulation
Integrate hardware to receive and deliver information
Development of environment specific software for closed
loop control of the environment
Allow user defined stimulation parameters
Initiate coordinated sensory stimulation
Record, associate, and organize system output
Emma

4. Performance Criteria Hardware Software Sound frequencies up to 100 kHz
0-70 dBSPL dynamic range for audio system
Sound frequencies up to 100 kHz
Brightness of LEDs maximized
Rat backpack weight minimized
1-300 mm/sec actuator velocity
1-inch max actuator deformation with high resolution
Software
Spike sorting process reduced from 3 minutes to <1 minute
Emma

5. Solution Description Sound Fidelity LED Brightness Rat Backpack Weight
Bluetooth wireless transmitter-receiver system
LED Brightness
Driver providing optimal current
Rat Backpack Weight
Custom-designed backpack from private designer
Somatosensory Stimulation
Driver-controlled piezoelectric bending actuator
Software Efficiency
Distribution of analysis tasks to appropriate programming languages
Vern

6. Factors Complexity and functionality of equipment yields higher cost
Reusability of equipment reduces cost
Biocompatibility of materials/equipment affect the quality of the data
High sampling rates will produce a higher SNR but will also increase process time
High throughput will facilitate inter-lab collaboration and data pooling
Vern

7. Performance Metrics Hardware: Software:
Degree of synchronization of stimuli
msec
Stimulus intensity (target vs. actual)
mm, N (somatosensory), dB
(audio)
Software:
Time for data processing
seconds to minutes
File size (kB-MB)
Greg

8. System and Environment
Piezoelectric Bending Actuator
Controlled motion
Precise deflection
Silent operation
Cost-effective
Greg

9. System and Environment
Andrew
Sound Chamber:
Containment box
Stimulus equipment
Force plate
Rack Hardware:
DSP unit
Audio amps
Controllers

10. Performance/Present Status
Ear plugs provide an improved seal and a higher level of comfort for the rat ear
Preparatory work on the pre-pulse inhibition program can produce linear
frequency sweeps and white noise with randomized trial intervals on test
speakers
LED banks and driver can produce bright flashes with little delay after trigger
Software for evaluating visual stimuli is complete, but auditory and
somatosensory analysis tools are still in progress
Spike sorting program can perform rudimentary separation between neuron
signatures and export data that works with other existing programs
Spectral analysis program lets the user delineate several characteristics of the
tuning curve with visualization options
Andrew
don’t need to screw molds into the ear

11. Informal Observations/Conclusion
Buying commercially available equipment can save
time and money
Coding background interfacing mechanisms can be
more demanding than the computational algorithms
Nazriq
While the hardware and software have not reached
full maturity and integration, progress is being made
toward the development of a comprehensive system

12. Recommendations
Investigate ways to reduce animal interference with hardware
Study methods to control actuator deflection range
Present fully functioning software in a flowchart
Identify inefficient processes within ‘waveclus’
Create a similar program for behavior of an animal
Nazriq
waveclus is a program that looks at the electrical signal and counts and separates action potentials

13. Thank you...
Questions/Comments?
Nazriq