Week 09 SOLUTION - Lamprey Place-code to Rate-code conversion

SOLUTION

  due date: Tue Mar 14 by 9:00 PM
  email to: mcb419@gmail.com
  subject: hw09
  email contents:
    1) jsbin.com link to your project code (THIS FILE)
    2) answer all the questions at the bottom of this page in the email
  

Introduction

This week’s homework explores the use of spike-based models in visuomotor circuits. You will be implementing two neural circuits for place-code to rate-code conversion from Fig. 3 of the paper by Kamali-Sarvestani et al. (2012).

To get started, you should review the Braitenberg spiking demo and understand how it works. Then you can move on to the main part of the assignment decribed here. Most of the code has been provided for you in the template file. You need to complete the wiring diagram for two cases: prey and predator, as controlled by the ‘predator/prey’ checkbox in the user interface.

Assignment

Part 1) Implement Circuitry for Prey Approach Mode
Based on Fig. 3A, complete the wiring diagram and specify appropriate connection weights, such that a wheeled vehicle would display an appropriate orienting response to prey.

• When the prey is located near the midline (between sensors SL8 and SR8), both wheels should turn at approximately the same speed. This would correspond to a straight approach toward the prey.
• When the prey is positioned to the far left (in front of sensor SL1), the right wheel should turn much faster than the left wheel, which would correspond to a sharp turn toward the left, toward the prey.
• When the prey is positioned to the far right (in front of sensor SR1), the left wheel should turn much faster than the right wheel, which would correspond to a sharp turn toward the right, toward the prey.

Part 2) Implement Circuitry for Predator Escape Mode
Based on Fig. 3B, complete the wiring diagram and specify appropriate connection weights, such that a wheeled vehicle would display an appropriate orienting response to a predator.

• When the predator is positioned just to the right of the midline (in front of sensor SR8), the right wheel should turn MUCH FASTER than the left wheel, which would correspond to a sharp turn to the left, away from the predator.
• When the predator is positioned further to the right in front of sensor SR1, the right wheel should turn SLIGHTLY FASTER than the left wheel, which would correspond to a gradual turn to the right, away from the predator.
• Similar relationships hold on the left side.