A-type K channels impede supralinear summation of clustered glutamatergic inputs in layer 3 neocortical pyramidal neurons.

A-type K channels restrain the spread of incoming signals in tufted and apical dendrites of pyramidal neurons resulting in strong compartmentalization. However, the exact subunit composition and functional significance of K channels expressed in small diameter proximal dendrites remain poorly understood. We focus on A-type K channels expressed in basal and oblique dendrites of cortical layer 3 pyramidal neurons, in ex vivo brain slices from young adult mice.

Binomial parameters differ across neocortical layers and with different classes of connections in adult rat and cat neocortex.

Binomial model-based analysis compared excitatory connections involving different classes of neurons in different neocortical layers. Single-sweep excitatory postsynaptic potentials (EPSPs) from dual intracellular recordings in adult cat and rat slices were measured. For data subsets corresponding to first EPSPs exhibiting different degrees of posttetanic potentiation and second, third etc.