A generalised ability to recognise the identity and hence also the non-identity (or oddity) chara... more A generalised ability to recognise the identity and hence also the non-identity (or oddity) characterising pairs of stimuli is essential for many cognitive operations. It is established that the necessary same-different distinctions must neurally be based on relative assessments of sameness. The criteria by which a concept-like application of identity-oddity discrimination can be empirically demonstrated are stated. The experimental evidence on whether pigeons and more generally birds can command this twin concept is reviewed. It is shown that the only weak evidence yielded by earlier studies is ascribable to procedural defects underestimating the by-rote memory capacities of pigeons. The employment of an increased number of training stimuli enhances the transfer of the matching-non-matching distinction to novel stimuli. The conceptualisation is in fact best demonstrated when the task is turned into a straight stimulus familiarity-novelty discrimination. Based on this insigqt, it is argued that the competence for identity-oddity discrimination of birds and mammals (including humans) may be derived from a very basal, phylogenetically primitive stimulus-specific habituation mechanism controlling the orienting response and alternative specific responses.
Pigeons were subjected to an apparent heat (44 ~ or cold (30 ~ load by means of a thermode locate... more Pigeons were subjected to an apparent heat (44 ~ or cold (30 ~ load by means of a thermode located next to their thermosensitive spinal cord. They were then able to obtain brief thermonormality (40 ~ spells if they changed their heart-rate by a preset amount above (or below) their baseline heartrate. In the final experiments the animals increased (or decreased) their heart-rate by about 25% within 12 training sessions, thereby achieving a partial thermoregulation : they were able to maintain their spinal temperature at a normal level for about 25% of the time. Extinction sessions, in which the heart-rate changes did not have any thermoregulatory effect, and control sessions, in which thermonormality periods were given independently of the heart activity, yielded baseline heart-rates. It is concluded that the cardiac activity related to thermoregulation may be subject to modification through learning and thus may not differ fundamentally in this respect from some homeothermic behavioural responses.
The afferent pathways to the nucleus basalis prosencephali of the pigeon were studied by use of t... more The afferent pathways to the nucleus basalis prosencephali of the pigeon were studied by use of the horseradish peroxidase (HRP) technique. It was confirmed that this nucleus receives a direct pathway from the nucleus sensorius principalis nervi trigemini and that, as in the starling, it receives a direct input from the nucleus lemnisci lateralis, pars ventralis, an auditory relay. Totally novel is the finding that the nucleus basalis prosencephali is the target of a direct pathway originating in the medullary nucleus vestibularis superior. All three pathways bypass the thalamus. From within the telencephalon the nucleus basalis prosencephali also receives fibres from the tuberculum olfactorium and the peri-ectostriatal belt, suggestive of olfactory and visual input. Marked cell bodies were also found in the neostriatum frontolaterale. It is assumed that these arose from HRP uptake by axons of the tractus fronto-archistriatalis that course through the nucleus basalis prosencephali to the anterodorsal archistriatum. Marked fibres and bouton-like formations were observed in the latter structure. The afferents to the nucleus basalis prosencephali are discussed in conjunction with the probable role of the nucleus as a sensorimotor coordinator of the pecking/feeding behaviour of the pigeon.
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