Functional Neuroanatomy and Neurophysiology

1999 Neural Plasticity  
SPATIAL NETWORK In order to study the role of non cognitive components, such as motivation, attention and emotionality, in the integration of learning and memory processes, and its neural substrates a neurogenetic approach has been followed in two genetic models, the Naples High Excitability (NHE) and Naples Low Excitability (NLE) rats using behavioral and functional imaging analysis. To this aim, adult male rats of the NHE, NLE and random-bred controls (NRB) were used in separate experiments.
more » ... ehavioral analysis: rats were tested in an 8-arm radial maze (Olton-maze) with extra-maze cues. They were either kept at 80-85 % body weight (Exp. 1) or were fed ad-libitum and were given also two pieces of chocolate per day at about the testing time (Exp. 2). In both experiments, non reinforced maze exploration on day was followed by reinforcements of alley visits during shaping sessions and restriction of baited arms to a single arm. The latter was the same for each rat and differed among rats on consecutive days. The behavior was videotaped and analyzed off-line. The results indicate that (i) there was no difference among the three rat lines in working memory during non reinforced maze exploration, independent of the motivational level, (ii) at high motivational level (Exp. 1) rats of all three lines showed a higher working memory in finding the single baited arm than under low motivational level (Exp. 2), (iii) at low motivational level, both NHE/NLE showed a more stable reference memory than controls, and (iv) NHE rats paid little attention towards reinforcement upon visiting the baited arm. Functional imaging_analysis: brains were frozen, sectioned, and stained for quantitative histochemistry of cytochrome oxidase (C.O.) together with standards (brain homogenates) of known C.O. activity. Densitometric measurements converted to C.O. activity units (mmol/min/g wet weight tissue) were carried out across the anterior forebrain. Significant differences were found in medial frontal, entorhinal, and perirhinal cortex, and basolateral amygdala.
doi:10.1155/np.1999.168 fatcat:fubefhqamzf5tenbuqrqjzpvei