Age-dependent effects of environmental enrichment on spatial memory and neurochemistry
Fecha
2015
Tipo
artículo original
Autores
Mora Gallegos, Andrea
Rojas Carvajal, Mijail
Salas Castillo, Sofía
Saborío Arce, Adriana
Fornaguera Trías, Jaime
Brenes Sáenz, Juan Carlos
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Resumen
Although aging and environmental stimulation are well-known to affect cognitive abilities, the question
of whether aging effects can be distinguished in already-mature adult rats has not been fully addressed.
In the present study, therefore, young and mature adult rats were housed in either enriched or standard
conditions (EE or SC) for three months. Open-field (OFT) and radial-maze (RM) behavior, and ex-vivo contents
of GABA and glutamate in hippocampus, and of dopamine and DOPAC in ventral striatum (VS) were
analyzed and compared between the four groups. In OFT, young rats were more active than mature adults
irrespective of the housing condition. Surprisingly, in the RM test, mature adults outperformed young
counterparts except for the young-enriched rats, which showed a progressive improvement in RM performance.
At the neurochemical level, young EE rats showed higher hippocampal glutamate and GABA
concentrations, and DA turnover in VS, which correlated with RM performance. Altogether, the behavioral
and cognitive strategies underlying habituation learning and spatial memory seem to be qualitatively
different between the two ages analyzed. These results challenge the assumption that mature
adult animals are always worse in learning and memory tasks. However, young rats benefited more from
the social and physical stimulation provided by the enrichment than mature adult counterparts. The latter
effect was evident not just on behavior, but also on brain neurochemistry.
Descripción
Palabras clave
Age, Environmental enrichment, Habituation, Spatial learning, Working, reference memory, Dopamine, GABA, Glutamate