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Multi-Channel Gustometer

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Presentation on theme: "Multi-Channel Gustometer"— Presentation transcript:

1 Multi-Channel Gustometer
Kevin A. Johnson Advisor: Dr. David H. Zald Neuroimaging Engineer: Patrick Henry

2 Multi-Channel Gustometer
General Design Objective Device to present an array of taste stimuli. Delivery of stimuli must be in a controlled manner. Intended for functional neuroimaging (fMRI) studies on human participants. Adaptable to a variety of experiment protocols.

3 Gustometer Background
Multi-channel gustometers have been used for psychophysical studies on monkeys. (Reilly et al. 1994)  Computer Automated Current gustometers for neuroimaging provide only a few (generally 1 or 2) taste stimuli. (Zald et al & 2002)  NOVELTY: Multi-channel gustometer for functional neuroimaging.

4 fMRI Background Strong magnet field environment (3T).
 Safety and interference considerations. Time course of neural-physiological response to be measured is quite rapid.  Requires precise control of stimuli delivery and response measurement. Imaging technique is very sensitive to physical movement of participant.  Need passive reception of stimuli.

5 Specification Demands
1. fMRI Friendly No ferrous materials within 10 ft. of participant (preferably farther than 10ft). Minimal electronics close to subject. Note: In past experiments, this demand has been achieved by delivering fluid stimulus through extended tubing.

6 Specification Demands (cont.)
Ability to deliver up to 10 different fluids. Ability to deliver from 0.5 – 5 ml discrete boluses of liquid. (Accuracy:  15%) Safety: consider amount intake.

7 Specification Demands (cont.)
Ability to switch in a relatively constant flow (no more than 250 ms pause) from one stimulus to another. Note: It is fine if there is a time lag (< 1 s) between a stimulus pulse (stimulus switch) and the time it reaches the participant, as long as the timing is consistent ( 250 ms).

8 Specification Demands (cont.)
A fixed flow rate of 0.5 ml/s is acceptable. Ability to deliver up to 50 cc in a session for each stimulus, with one stimulus (for saline) able to deliver more (up to 200 cc). Ability to exchange stimulus containers quickly (exchange all 10 in less than 5 minutes).

9 Specification Wishes Expandable to deliver more than 10 different fluids. Ability to vary flow rate (as low as .25 ml/s or as high as 1 ml/s). Easily to sanitize (contamination resistant).

10 Specification Wishes (cont.)
Easily portable. Protective covering. User-friendly. Quick development time of device. 8. Reasonable cost.

11 Innovative Approaches?
Electrical Simulation of Taste?  Perceptual Problems Single pump with stimuli prearranged in single tube?  Contamination Problems Solid taste stimuli?  Numerous Problems Pneumatic-Controlled Pumps Closer  More components, re-setup time  Use concept, possible alternative

12

13 Probable Merging Unit Configuration

14 Delay = (Distance)/(Speed)
Stimulus Delay Delay = (Distance)/(Speed) Max Delay: 1 second Max Pump Speed: cm/mn (?)  Max Tubing Distance

15 Current Status Verified pump/syringe specifications.
Verified pump control via computer. Need to finalize merging design and order tubing components.  Spoke concept.


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