|
The boxes in the center
of the diagram are coincidence detectors. A box lights up when it receives
two inputs simultaneously. The time it takes an input to travel from the
right ear to the coincidence detectors is longer for the ÒlaterÓ branches,
so the .4 ms box will receive right ear inputs .4 of a ms later than the 0
ms box does. The inputs from the left ear travel along equal length
branches, so they all arrive at all the coincidence detectors at the same
time. Now if the message from the left ear arrives a little later than the
message from the right, then the message from the left ear will arrive at
all the boxes at the same time as the message from the right ear arrives at
one of the boxes, determined by the interaural delay. The action potentials
from each ear are phase-locked to the same frequency-- so the delay weÕre
talking about is the time between action potentials coming from the two
ears. If the sound continues, then after a time coincidence detectors for
longer delays will respond, but no coincidence detectors for shorter delays
will respond.
|