Activation of γ‐aminobutyric acid B (GABAB) and 5‐hydroxytryptamine (5‐HT) receptors
produces presynaptic inhibition at glutamatergic terminals in the rat neocortex. To evaluate
interactions between these metabotropic receptors, field potentials were recorded in layer
2/3 of somatosensory cortex. In addition, the paired pulse (PP) protocol was used to
measure changes in the ratio of the second/first extracellular synaptic potentials (S2/S1
ratio) as an index of glutamate release probability in the area. Lowering extracellular [Ca2+] …

The authors mistakenly stated that all records were done in ''somato-sensory cortex''when in
fact some of the records in the report were actually done in motor cortex. Thus,''somato-
sensory cortex''should be replaced by ''sensory-motor cortex''throughout the piece. The
authors regret this mistake.