Neurophysiological Monitoring

March 13, 2007Group Members: Advisors:Greg Apker Daniel Polley, Ph.D.Vern Huang Mark Wallace, Ph.D.Nazriq LamienAndrew LinEmma Sirajudin

Neurophysiological Monitoring

Studies of plasticity and multisensory interactions must be improved.

They drive our understanding of pathologies and perception.

Other analogous studies presently have these limitations: Anaesthetized recording no behavioral results Simple stimuli no real-world situations simulated

The Polley/Wallace Labs want to address these limitations: Awake recording capabilities will yield behavioral results. Refined stimuli will better elicit realistic responses.

Accuracy of stimuli Association of stimuli in location and time

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

Neuroscience meets Engineering…

• Bluetooth transmitter-receiver system• Frequency range, spectral fidelity, and channel crosstalk impact

• Ground-up development of somatosensory stimulator system• Design of stimuli delivery and mounting apparatus• Component compilation

• Increased usability/durability of hardware components• BNC cable for pneumatic driver • LED driver powered by AC power supply

• Increasing functionality of Pre-Pulse Inhibition protocol

• Development of visual and auditory software

System and EnvironmentPL 127.10  

Operating voltage [V] 0 - 60

Nominal displacement [µm] ±20% 900

Free length [mm] 27

Dimensions L x W x T [mm] 31.0 x 9.6 x 0.65

Blocking Force [N] 1

Electric Capacitance [µF] ±20% 2 x 3.4

Resonant Frequency [Hz] 380

X

Costs:Bending Actuator: $305Flexbar®: $ 65Linear Amplifier: $3000Total: $3370

31 mm

9.6 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• Silent actuator deflection• 1-inch max actuator deformation with high

resolution

• Software• Spike sorting process reduced from 3 minutes to <1 minute

Additional System Developments

• Electrical shielding of the backpack hardware system

• Develop customizable probe tip extender for actuator

• Build programs for four modalities (time, intensity, binaural, frequency) as generally as possible to facilitate code recycling

• Increase efficiency within ‘waveclus’

• Image stitching with click-and-drag functionality• Label locations of probe penetration to improve multiple testing

Thank you... Questions/Comments?