Cognitive deficits in the autosomal dominant disorder Neurofibromatosis type 1 (NF1) typically consist of a lower than average IQ, impaired visual-spatial learning, attention problems and impaired executive functioning. These deficits have a substantial influence on the daily life of pediatric and adolescent individuals with NF1. One of the key underlying mechanisms of these deficits is an increased gamma-aminobutyric acid (GABA)-ergic inhibition and a subsequent decrease in synaptic plasticity. The ENCORE laboratory has recently shown that loss of the NF1-gene is associated with attenuated function of the hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1). These channels, enriched in membranes of inhibitory interneurons, play an important role in the pathophysiology underlying the cognitive deficits in NF1. Lamotrigine, an HCN-agonist, restored function of HCN1, together with the electrophysiological and visual-spatial learning deficits in Nf1-mice. Thus, lamotrigine is a novel candidate drug for treating cognitive deficits associated with NF1.