The Neural Substrates of a Navigational Guidance System

Lorelei Howard, Rebecca Knight and Hugo Spiers

Goal

PersonNavigating

Goal Proximity

Path Distance

EgocentricGoal Direction

Spiers & Maguire (2007)

Variables

An Example

1

2

3

4 5

1 2 3 4 5

T T

Training:1. Sent Map. Learn street layout, start and goal locations.2. Visit Soho. 2 x 40 min sessions, tested with feedback, direction and distance

judgements.3. Pre-Scan. Tested on start and goal locations. Familiarised with task.

Scanning:NAVIGATION NAVIGATION CONTROL CONTROL

3 MIN 3 MIN

20 SEC (REST)

Event types:NAVIGATION CONTROL

Goal Events

Decision Point

Turns

Direction: L/R?

Direction: L/R/F? Button Press: L/R/F

Food/Drink: Y/N?

Debriefing: - Find out routes taken rather than presuming they chose the optimum route each time

Scanning Details:- 20 healthy participants- 32-channel head coil - Similar sequences to previous- Total time: (3 min x 12) + (20 sec x 11) = 40mins (over 2 sessions)- 10 min structural

Analysis and Predictions:- SPM 8, with parametric modulation- mPFC: positive correlation with Goal Proximity (GP)- MTL: negative correlation with GP- PPC: positive correlation with Egocentric Direction to goal - HC: more active in viewing goals in NAV than CON blocks- PD tracked, possibly PFC?

Questions:- Rest gap: 20 sec long enough?- Multiple parametric variables: issues/things to be aware of?- Eye-tracking: possible? set-up time?