1. The use of a negative allosteric modulator GABA A α5 for the treatment, prevention and / or delay of development of central nervous system (CNS) conditions caused by defects in the development of the nervous system that lead to excessive GABA (gamma-aminobutyric acid) -ergic inhibition in the cortex and hippocampus .2. The use according to claim 1, where the specified state of the central nervous system is selected from cognitive disorders in Down syndrome, with autism or with neurofibromatosis type I.3. The use of claim 1, wherein said CNS state is a cognitive disorder in Down syndrome. The use of claim 1, wherein said CNS state is a cognitive disorder in autism. The use of claim 1, wherein said CNS state is a cognitive disorder in type I.6 neurofibromatosis. The use according to claim 1, wherein said negative allosteric modulator GABA A α5 binds to the α5β3γ2 subtype of the human GABA A receptor with 10-fold or greater binding selectivity compared to the binding affinities of the α1β2 / 3γ2, α2β3γ2 and α3β3γ2 human GABA A.7 receptor subtypes . The use according to claim 1, wherein said negative allosteric modulator GABA A α5 demonstrates functional selectivity, acting as an inverse agonist on the α5β3γ2 subtype of the human GABA A receptor by reducing the GABA effect by more than 30% and, in addition, affecting the GABA effect on the α1β2 subtypes / 3γ2, α2β3γ2 and α3β3γ2 of the human GABA A receptor by less than 15% .8. The use according to claim 1, wherein said negative allosteric modulator GABA A α5 is selected from a compound of formula (I) or a compound of formula (II), where R is hydrogen, halogen, alkyl, halogenated or �1. Применение негативного аллостерического модулятора GABA A α5 для лечения, предупреждения и/или задержки развития состояний центральной нервной системы (ЦНС), вызванных дефектами развития нервной системы, которые приводят к избыточному GABA (гамма-аминомасляная кислота)-эргическому торможению в коре и гиппокампе.2. Применение по п.1, гд
