SIO/UCSD Mouse Lickometer

The Lickometer Device

Real Lickometer Device Built by Our Teamk

Real Lickometer Device (Top View)

Meet the Team

Rat Pack

Our team is composed of senior Mechanical Engineering students at Univeristy of California, San Diego

Project Overview

Research Background

It has been debated how alcohol addiction regulates neural brain circuits. This particular study uses fiber photometry to regulate neural activity in response to level of intoxication. An overview of the usage of fiber photometery is as follows:

▹A wavelength of light is transmitted through a fiber optic that is physically connected to a portion of the brain

▹In response to the wavelength, GCaMP (a green fluorescent protein fused with calmodulin and M13 in the targetted brain) will emit a green wavelength that idicates that calcium is present and neurons are active

▹Computer will show intensity of green wavelength emitted - which indicates more/less neural activity

Project Objective

To properly implement fiber photometery and sync the neural activity to physica mice drinking behavior, a device to record the amount of alcohol the mouse consumes in real time is necessary

This project aims to create a device that records the volume of alcohol drank by a mouse using pressure sensor attached to a microcontroller to regulate the amount of alcohol consumed.

Project Timeline

1st Priority Objective

Design Lickometer that records time-stamps and duration of each mouse lick

○ NIH Prototype is available on open source website

2nd Priority Objective

Improve prototype to measure volume of liquid in real time

○ Alcohol consumption will be synchonized with fiber photometry

○ Implementation of pressure sensor to measure the height of the fluid at all times

WOW Design Solution

Completely hands off device that transmits real-time liquid consumption data to computer

○ USB Connection or Wifi Transmitted data is ideal to simplify data collection

Constraints and Issues

Physical and Sponser requirements of project

○ Device must be compatible with home cage

○ All components and materials used must be resistant to mice chewing

○ Minimum resolution of measurements is 50μL

Foundational Design

1. Air Buffer Column

▹Column of air and water that can be pressurized by closing the toggle valve

▹Liquid consumption will result in a pressure difference caused by the difference in height of the water columns

▹Height remains constant even when liquid is consumed

5. Toggle Valve

▹Toggles between on and off positions that allows

and disallows air passageway into the air buffer tube

▹Used to "tare" pressure in the system between tests

2. Water Column

▹Water column that is open to atmosphere

▹Liquid consumption results in decrease of fluid height

6. Custom PCB

▹Contains amplifier circuit that multiplies output signal by 2

▹Contains filter to reduce noise in output

3. TE Connectivity Pressure Sensor

▹Pressure sensor rated at 0.07psi for low pressure applications

▹Used to detect pressure differences caused by a height change in the water column from liquid consumption.

7. ESP 32 Microcontroller

▹Microcontroller utilized to collect output data nd transfer it to "home base" computer

▹Includes on board ADC to read pressures sensor

▹Includes on board WiFi to wirelessly transmit data

4. Edstrom Sipper Valve

▹Sipper valve designed for small animal liquid consumption

▹Allows for an adjusable flow rate

▹Tested for minimal leakage.

Key Design Components

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