Thigmotaxis

An HVS Image user was checking how to calculate the figure to enter for thigmotaxis, the tendency of the subject to keep close to the side of the pool as they swim. This should be the desired thigmotaxis diameter divided by the pool diameter.

In this case the user wanted the thigmotaxis band to be 3 cm from the edge of the pool, and the pool has a 120 cm diameter, so the value to enter is 0.975, i.e. (120-3)/120.

Measuring thigmotaxis gives an indication of whether the subject is using spatial learning or non spatial strategies.

It gives an indication of whether or not the subject is problem-solving, with excessive thigmotaxis suggesting that subject is not recognising that the platform is the goal, or not focussing on the task of finding it. This may be the result of drugs interfering with sensorimotor function.

Some subjects don't search on the basis of place-learning, but instead swim round the edge of the pool and may find the platform this way. Some users suggest that such subjects should be excluded at an early stage.