Effect of forebrain ablation on the performance of a conditioned avoidance response in the teleost fish, Tilapia h. macrocephala

The Fish Telencephalon and Its Relation to Learning

“…Much of the recent behavioral work on the telencephalon has centered on the study of active avoidance, since it became apparent to several workers that, if the lesion impaired some functions such as speed of decision, avoidance tasks would be ideal for demonstrating this. Aronson and Kaplan (1965;Kaplan and Aronson, 1967) examined instrumental avoidance learning in Tilapia macrocephala. Animals were placed in aquaria divided into two halves and were trained to swim through a 4-cm-diameter hole in the dividing partition, when an overhead light came on, to avoid shock.…”

“…Retention. Aronson and Kaplan (1963;Kaplan and Aronson, 1967) Tilapia macrocephala removed the telencephalon from fish trained with the schedule described above. Following operation, animals which were previously avoiding consistently ceased to do so, and maintained only a low avoidance level despite several hundred further trials.…”

The Behaviour and Brain Function of the Cichlid FishHemihaplochromis Philander

“…They drew support for their hypothesis from the electro-encephalographic (EEG) recordings of Enger (1957), and Schade and Wieler {1959), in which the EEG activation was associated with reduced reaction time {=arousal). Furthermore, an anatomical examination of the brain of T macrocephala revealed major fibre tracts running from the telencephalon to the diand mesencephalon, which suggested to Aronson and Kaplan (1967) that the forebrain might exert a "dynamic influence <;m the midbrain". Probably it is the midbrain which organises the behavioural motor-patterns.…”

Long-term habituation to spatial novelty in blind cave fish (Astyanax hubbsi): role of the telencephalon and its subregions.

“…The nature of this deficit can most easily be explained in terms of the hypothesis that the telencephalon of fish may serve as an "activator" or "energizer" of lower brain centers (Aronson 1948;Kaplan and Aronson 1967). It is thus conceivable that the telencephalon determines the level of arousal of the animals.…”