(c) Hole exploration frequency in the goal sector
(GS): the sum of the number of explorations for
holes 1, 0, and 1 divided by 3, during a PT.
(d) Hole exploration frequency in the non-goal sector
(NGS): the sum of explorations of the 17 nongoal
holes (i.e., all except holes 1, 0, +1) divided
by 17, in a single PT.
(e) Goal Sector Preference: ratio between GS
explorations per hole and NGS explorations per
hole. Provides an index of the accuracy with which
rats of the same age group remember the GS.
Unlike hole exploration frequency, this index is independent
from the target-seeking activity level of the
animals in a given age group.
(f) Total exploratory activity: the sum of all
explorations of a rat in the first AT. This parameter
represents the nonspecific exploratory activity of
the rats (before they become aware of the presence
of an escape box).
(g) Target-seeking activity: the sum of explorations
for all holes in a PT, divided by 20 (ie. mean explorations
per hole).
(h) Path length: distance (in cm) covered by an animal
during a given trial, estimated on the basis of reconstructing
the route using Image Pro Plus v5.1 software
(every 2 s the position of the body center of
the rat was followed by manual track object tool in
order to reconstruct the route).
(i) Mean velocity: path length divided by escape box
latency (in cm/s). Path length was divided by trial
duration during acquisition and probe trials. This
measurement does not discriminate between activity
and inactivity periods. Path length and mean
velocity are reference parameters for locomotion
performance.