Behavioural Processes, 5 (1980)227—249
227
Elsevier Scientific Publishing Company, Amsterdam — Printed in Belgium
DISCRIMINATORY APPROACH TO AUDITORY STIMULI IN GUINEA
FOWL (NUMIDA MELEAGRIS) AFTER HYPERSTRIATAL∕HIPPOCAMP-
AL BRAIN DAMAGE
ROBERT D. OADES
Institut fur Zoologie der T.H., Schmttspahnstrasse 3, 6100 Darmstadt (Federal Republic
of Germany)
Present address: Max-Planck-Institut fiir Hirnforschung, Deutschordenstrasse 46, 6000
FrankfurtZMain 71 (Federal Republic of Germany)
(Accepted 25 January 1980)
ABSTRACT
Oades, R.D., 1980. Discriminatory approach to auditory stimuli in Guinea fowl (Numida
meleagris) after hyperstriatal∕hippocampal brain damage. Behaυ. Processes, 5: 227—249.
Guinea fowl were trained to approach, feed and retreat from a food dish after hearing
a species-specific food-trill. An ethogram including approach, search, locomotion and ten-
sion behaviour was recorded before and after operation for a training and a test regime of
variations of the natural calls and other sounds. Experimental groups consisted of sham-
controls and birds with lesions in the hyperstriatum∕hippocampus anterior and posterior
to the anterior commissure.
Both the ‘anterior’ and ‘posterior’ groups showed impaired recognition of the stimulus
variations as shown by increases of approach by the posterior group and of search behav-
iour by both lesion groups. The long approach of the posterior group was followed by a
long period of arousal (high tension). This was more quickly habituated in the anterior
group (search behaviour changed to low tension).
It is hypothesised that in the anterior group, where activation is followed by a disen-
gagement, there may have been changes in thresholds for matching learned specifications
with new sensory input. The more generalised approach responses of the posterior group
may show an impairment of the rules for the selection of input.
INTRODUCTION
There are areas in the forebrain of birds and mammals that are likely to be
involved in the use of polysensory information because they are directly con-
nected to more than one sensory projection field. Prominent among these is
the hippocampal complex of the limbic forebrain. There is much behavioural
and neurophysiological evidence that the mammalian hippocampus takes
part in the attentional processes associated with the recognition of significant
stimuli (reviews: Kemp and Kaada, 1975; Pribram and McGuinness, 1975;
Oades, 1979). Pribram and Isaacson (1975) suggest that the hippocampal cir-
cuit determines whether inputs have occurred to which attention must be
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