EN
In laboratory animals, exposure to the enriched environment (EE) induces broad range of modifications in nerve cells at both molecular and anatomical levels. EE also improves animal’s cognitive performance in learning and memory tasks. Despite some progress in revealing the effects of EE on synaptic transmission in the hippocampus, scant and inconsistent data are available on the impact of EE on synaptic properties in the neocortex. The aim of the present study was to examine the influence of the EE exposure on neuronal properties in layer IV of the barrel cortex. Twenty five days old mice (bred under standard laboratory conditions) were put for two weeks to the enriched environment (i.e. to bigger cage with playing tools: tunnels, ladders, a running wheel, spatial maze box and with a set of objects of different shape, made from various fabrics). Control mice were housed in standard laboratory cages during the same period of time. Next, we prepared brain slices containing the barrel cortex and performed visually guided whole-cell recordings from excitatory layer IV neurons within barrels B-D. The results were compared between control and EE-exposed animals. We found that EE experience increased the spontaneous firing rate of excitatory layer IV cells. This phenomenon seems to be due to stronger excitatory synaptic input to these neurons, because both frequency and amplitude of spontaneous excitatory postsynaptic currents were bigger after EE exposure, while kinetic properties of spontaneous inhibitory postsynaptic currents as well as intrinsic excitability remained unchanged. Our results indicate that EE selectively enhances excitatory transmission within the cortical representation of whiskers. The research was supported by the Ministry of Science and Higher Education “PolPostDoc” grant PBZ/MNiSW/07/2006/09 to GY.