Fig. 2.

Pyramidal neurons in the agranular RSC. a Confocal z-stack image of the anterior RSC immunostained for the neuronal marker NeuN. The short discontinuous line indicates the limit between the agranular RSC (aRSC, dorsal) and the granular RSC (gRSC, ventral). b Left, Imaris reconstruction of the position of NeuN positive somas from neurons in the columnar inset shown in A (546 NeuN positive cells); right, NeuN positive cell density across an aRSC column measured with a 50 µm bin width (n = 7 slices from four mice; selected columns were 300–400 µm wide, mean number of NeuN positive cells per column: 466). Grey traces represent individual cases and the black trace the mean. c DIC microphotographs of the agranular RSC in a slice placed in a recording chamber showing the sizes of the bodies of the neurons found in each layer. Note the presence of neurons with medium–small sizes (marked with asterisks) in all layers and the presence of two L5BL neurons (soma marked with arrowheads) in layer 5B whose soma was clearly larger. d Membrane voltage responses from a L2/3, L5A, L5Bm, L5BL and a L6 pyramidal neuron to 1500 ms current pulses. Responses were recorded at resting membrane potential (I _holding = 0 pA). e First action potential from the first suprathreshold response shown at larger scales. Scale bars 250 and 20 µm in a and c, respectively