Optical Imaging of Intrinsic Cortical Signals Group #24 Shivani Shah, Ania Warczyk, Alia Durrani, Daniel Maxwell, Timothy Chen

Problem Statement Design a miniature camera for optical imaging of the visual cortex area of the brain (awake imaging) Design a miniature camera for optical imaging of the visual cortex area of the brain (awake imaging) Further understand physiology of the brain Further understand physiology of the brain Work with Psychological Sciences Department at Vanderbilt University Work with Psychological Sciences Department at Vanderbilt University Mentor: Dr. Anna Roe Mentor: Dr. Anna Roe

Question/Thesis Problem Statement Problem Statement Design a miniature camera for optical imaging of the visual cortex Design a miniature camera for optical imaging of the visual cortex Without requiring subject immobilization Without requiring subject immobilization To be tested on laboratory rats and monkeys To be tested on laboratory rats and monkeys Performance Criteria Performance Criteria Small head-worn camera Small head-worn camera High resolution High resolution High frame rate High frame rate Primary Objective Primary Objective Measuring hemodynamic signals related to neural activity Measuring hemodynamic signals related to neural activity Could be implanted or detachable Could be implanted or detachable Possibly wireless Possibly wireless

Background and Importance Solution Description Solution Description Build upon previous work by summer intern Build upon previous work by summer intern Clover CCM625 Miniature Security Camera Clover CCM625 Miniature Security Camera

Rat Cortex Imaging: 7/15/2004 Image Courtesy Vanderbilt Psychology Department

Design Constraints System must be attachable to 2 cm diameter well System must be attachable to 2 cm diameter well Lens, CCD or CMOS chip, power source, board, connection to PC Lens, CCD or CMOS chip, power source, board, connection to PC Lighting composed of red and green LEDs or fiber-optics Lighting composed of red and green LEDs or fiber-optics red: lights up vasculature red: lights up vasculature green: reflects off hemoglobin (indicates flow) green: reflects off hemoglobin (indicates flow)

Design Constraints Desired Resolution: 512 x 512 Desired Resolution: 512 x 512 Desired frame rate: 300 fps Desired frame rate: 300 fps Well depth: 12 bits Well depth: 12 bits 3.15 MB / frame 3.15 MB / frame G = 54 MB / sec (standard wireless) G = 54 MB / sec (standard wireless) Maximum wireless frame rate: 10 fps Maximum wireless frame rate: 10 fps Maximum cable frame rate: 30 fps Maximum cable frame rate: 30 fps USB is the only way to get 300 fps USB is the only way to get 300 fps Eventually, wireless frame rate: 100 fps Eventually, wireless frame rate: 100 fps Not before 3 years Not before 3 years

Methods Design camera including: Design camera including: CCD Chip CCD Chip LED or fiber-optic illuminators LED or fiber-optic illuminators Battery for power Battery for power Connection for transmission of data Connection for transmission of data Research other designs: Research other designs: Cell-phone camera designs/web-cams Cell-phone camera designs/web-cams Pill-Cam used for endoscopies Pill-Cam used for endoscopies

Methods Approached GI Lab in Vanderbilt Medical Center Approached GI Lab in Vanderbilt Medical Center Was given two expired Given Imaging © Pill-Cam SB cameras to analyze Was given two expired Given Imaging © Pill-Cam SB cameras to analyze Approached Dr. Duco Jansen for alternative designs Approached Dr. Duco Jansen for alternative designs Necessity of lens in system Necessity of lens in system Use of fiber-optics to provide light versus LEDs Use of fiber-optics to provide light versus LEDs

Status/Results Currently in design phase Currently in design phase Analyzed contents of Pill-Cam for internal design Analyzed contents of Pill-Cam for internal design Small lens Small lens CMOS chip CMOS chip Lower resolution, frequency, but save battery power Lower resolution, frequency, but save battery power Wireless transmitter Wireless transmitter Analyzed contents of webcam Analyzed contents of webcam CCD Chip CCD Chip Higher resolution, frequency, more power consumption Higher resolution, frequency, more power consumption Simple electronics Simple electronics

Next Phase Take pictures with webcam with and without lens Take pictures with webcam with and without lens Determine whether lens is necessary Determine whether lens is necessary Use available CCD chips to reconstruct rough camera with lens Use available CCD chips to reconstruct rough camera with lens Calculate focal point with Lensmaker’s equations for specific well depth Calculate focal point with Lensmaker’s equations for specific well depth Draw sketch and calculate dimensions needed to make miniature camera Draw sketch and calculate dimensions needed to make miniature camera

Conclusions Previous designs can be used as basis for desired device Previous designs can be used as basis for desired device Use higher resolution CCD and applicable lens Use higher resolution CCD and applicable lens Keep other circuit components very similar Keep other circuit components very similar Obtaining diagrams from camera companies will help us design the small, high resolution camera we need Obtaining diagrams from camera companies will help us design the small, high resolution camera we need Wireless capabilities are not currently sufficient for desired data transfer rates Wireless capabilities are not currently sufficient for desired data transfer rates Will use USB connection until other wireless options become available on the market Will use USB connection until other wireless options become available on the market