RT Journal Article SR Electronic T1 A Cellular Mechanism Underlying Enhanced Capability for Complex Olfactory Discrimination Learning JF eneuro JO eNeuro FD Society for Neuroscience SP ENEURO.0198-18.2019 DO 10.1523/ENEURO.0198-18.2019 VO 6 IS 1 A1 Naveen Chandra A1 Richa Awasthi A1 Togba Ozdogan A1 Friedrich W. Johenning A1 Barbara Imbrosci A1 Genela Morris A1 Dietmar Schmitz A1 Edi Barkai YR 2019 UL http://www.eneuro.org/content/6/1/ENEURO.0198-18.2019.abstract AB The biological mechanisms underlying complex forms of learning requiring the understanding of rules based on previous experience are not yet known. Previous studies have raised the intriguing possibility that improvement in complex learning tasks requires the long-term modulation of intrinsic neuronal excitability, induced by reducing the conductance of the slow calcium-dependent potassium current (sIAHP) simultaneously in most neurons in the relevant neuronal networks in several key brain areas. Such sIAHP reduction is expressed in attenuation of the postburst afterhyperpolarization (AHP) potential, and thus in enhanced repetitive action potential firing. Using complex olfactory discrimination (OD) learning as a model for complex learning, we show that brief activation of the GluK2 subtype glutamate receptor results in long-lasting enhancement of neuronal excitability in neurons from controls, but not from trained rats. Such an effect can be obtained by a brief tetanic synaptic stimulation or by direct application of kainate, both of which reduce the postburst AHP in pyramidal neurons. Induction of long-lasting enhancement of neuronal excitability is mediated via a metabotropic process that requires PKC and ERK activation. Intrinsic neuronal excitability cannot be modulated by synaptic activation in neurons from GluK2 knock-out mice. Accordingly, these mice are incapable of learning the complex OD task. Moreover, viral-induced overexpression of Gluk2 in piriform cortex pyramidal neurons results in remarkable enhancement of complex OD learning. Thus, signaling via kainate receptors has a central functional role in higher cognitive abilities.