Figure 1

Laminar profile of fEPSPs in CA1 area of the hippocampus recorded by a multi-electrode array. A) A 350 μm thick hippocampal slice was placed over 8 × 8 3D MEA and a suitable electrode (red circle) was selected for stimulation of Schäffer collateral/commissural fibres. A column of electrodes (yellow circles) aligned in parallel with the direction of apical dendrites of CA1 pyramidal neurones was chosen to record synaptic responses in stratum lacunosum-moleculare (electrode 1), stratum radiatum (electrodes 2–4) and stratum pyramidale/stratum oriens (electrode 5). Layers of cell bodies are delineated by green dashed line. Distance between electrodes was 100 μm. B) Waveforms of fEPSPs recorded by electrodes 1–5 in response to a voltage step (biphasic positive/negative 3.5 V pulse, 100 μs/phase) applied to stimulation electrode. Initial small, negative deflections are the stimulus artefacts.