Fig. 1.

Intracellular somatic spiking and its extracellular reflection as measured by the 32-site silicon probe recordings in rat somatosensory slices from a L23 pyramidal neuron (L23PC; A), L4 pyramidal neuron (L4PC; B), L5 pyramidal neuron (L5PC; C), and L3 basket cell (L3BC; D). Left: images of the reconstructed neural morphology (dendrites: black; axon: red; horizontal lines indicate cortical layers) and location of silicon probe from individual experiments. (The arrow in A shows the patched L23 neuron.) Somatic spiking is induced via administration of a suprathreshold 9-s DC intracellular step of variable strength. Administration of small amplitude DC current (weak stimulation) resulted in slow spiking (middle) while an increase in the amplitude (strong stimulation) gives rise to faster spiking (right). Intracellular current stimulus is shown on top (black), intracellular somatic voltage response (blue) in the middle, extracellular voltage (as recorded from electrode of the silicon probe closest to the soma; red) at the bottom.