Transcript Neurophysiological Monitoring November 16, 2006

Neurophysiological
Monitoring
February 20, 2007
Group Members:
Greg Apker
Vern Huang
Nazriq Lamien
Andrew Lin
Emma Sirajudin
Advisors:
Daniel Polley, Ph.D.
Mark Wallace, Ph.D.
Project Statement
The Polley/Wallace Lab:
 Neuronal probes used in animal models (rats, cats) to
measure multi-sensory neural response:
 Characterize complex neuronal interactions
 Study developmental pathologies
Problem Statement:
 There is a need to create a system which is capable of
real-time data acquisition from a subject presented with
precise, configurable multi-sensory stimuli.
Project Objectives/Goals
• Development of multi-sensory environment hardware for use
in neuronal response characterization in rats and cats
• Produce 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
Performance/Present Status
• Electrical shielding of the backpack hardware system
• Inadequate coverage of the transducer in the earphone
• Arrival of the somatosensory stimulator components
• Testing/validating performance
• Design of mounting apparatus
• Awaiting linear amplifier demonstration
• Increased usability/durability of hardware components
• BNC cable connection for pneumatic driver
• LED driver powered by AC power supply
• Functionality of PPI protocol in simple modes
• Efforts to increase options
• Flowchart of visual software & development of auditory software
• Image stitching with click-and-drag functionality
• Label locations of probe penetration
System and Environment
PL 127.10
Operating voltage [V]
0 - 60
Nominal displacement [µm] ±20%
900
Free length [mm]
27
Dimensions L x W x T [mm]
Blocking Force [N]
Electric Capacitance [µF] ±20%
Resonant Frequency [Hz]
Costs:
Bending Actuator: $305
Flexbar®:
$ 65
Linear Amplifier: $3000
Total:
$3370
31.0 x 9.6 x 0.65
1
2 x 3.4
380
X
9.6 mm
31 mm
System and Environment
Data Analysis
Spike sorting w/ wavelet
analysis
Example of analysis in
frequency domain
Performance Goals
• Hardware
• 0-70 dBSPL dynamic range for audio system
• LEDs bright enough to startle
• Pneumatic strength enough to startle
• Sound frequencies up to 100 kHz
• 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
Informal Observations/Conclusion
• Buying commercially available equipment can save
time and money
• Coding background interfacing mechanisms can be
more demanding than the computational algorithms
 While the hardware and software have not reached
full maturity and integration, progress is being made
toward the development of a comprehensive system
Recommendations
• Measure attenuation of different frequencies in surgically
modified rat’s ear canal
• Create customizable probe tip extender for actuator
• Build programs for four modalities (time, intensity, binaural,
frequency) as generally as possible to facilitate code recycling
• Present fully functioning software in a flowchart
• Increase efficiency within ‘waveclus’
• Develop multi-sensory software for non-sedated animals
Thank you...

Questions/Comments?