EN
Local field potentials recording is a tool well suited for the chronic monitoring of neuronal activity. However, due to the widespread propagation of electric field within a brain tissue a signal recorded in one place may possess a substantial contribution of synaptic currents from distant neuronal populations. In the rat vibrissae-barrel system the cortical representation of mystacial vibrissae is located closely above their somatosensory relays in thalamic nuclei. Since the order and dynamics of thalamic EP waves resemble those of cortical ones, it is crucial to determine to what extent these signals are generated locally or whether they reflect the electrotonic component from cortical sources and vice versa. Using two linear multielectrodes (100 µm inter-electrode distances) we recorded series of potentials evoked by deflections of a group of vibrissae, thus obtaining EP profile spanning the tissue from the cortical surface to the level below somatosensory thalamic nuclei. Kernel Current-Source Density analysis revealed that the subcortical EPs recorded in the external capsule and fimbria of the hippocampus comprised mostly of responses of cortical characteristics while those recorded within the thalamus mainly possessed components characteristic to the local, thalamic sources. Research supported by the polish National Science Centre grant N N401 533040.