Fig. 4. (A) Morphology of the neurobiotin-filled local interneurones (LNs) reconstructed by projecting optical sections (2.5 µm thick) prepared using a confocal microscope. The two LNs were selected to show homogenous (number 97) and heterogeneous (number 98) branching patterns. Scale bar, 100 µm. (B) Typical response of a local interneurone to benzaldehyde and control (blank). The thick horizontal bar indicates the time at which the compound was applied.