Biology Reference
In-Depth Information
The various parameters used to measure open-field behavior were derived
from computer-based trajectometric analysis of video images (see
Mills
et al. 1990
), and direction observation of behavior (
Launay, 1993
). During
the first 10-minute period of the open field test, the behavior of short TI
(low fear) and high SR lines was of an active type (i.e. short latencies,
high activity), whereas the behavior of chicks of the long TI (high fear)
and low SR lines was the inverse (
Figure 8.11
). Immediately after being
placed in the open field, the short TI (low fear) and the high SR line
birds walked or ran around the arena whereas the long TI (high fear) and
the low SR birds did just the opposite. These birds took a long time to
start moving around the open field , and they moved very little during the
first 10 minutes of the rest.
During the second 10-minute period of the test, discriminant analysis
(a powerful statistical test) permitted discrimination between lines. At least
for certain behavior patterns, long TI and low SR line chicks began to resem-
ble short TI and high SR line chicks (
Figure 8.12
). However, during the third
10-minute period of the test, high SR and low SR lines could still be dis-
criminated, but the long TI and short TI lines could not. These results indi-
cate that even though the behavior of short TI and high SR (or of long TI
and low SR) were similar during the first period of the test, the motivational
(a)
30
(b)
800
20
600
400
10
200
0
0
1
2
3
1
2
3
Period
Period
(c)
400
(d)
400
300
300
200
200
100
100
0
0
1
2
3
1
2
3
Period
Period
FIGURE 8.11
Changes in four behavior patterns in three successive 10-minute periods in
open-field test. (a) Number of jumps, (b) distance run, (c) number of peeps, (d) time in the
median zone. (
&
) HSR, (
'
) LSR, (
x
) LTI, (
K
) STI.
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