These results demonstrate an association between physical performance measures and genetic variation in the muscle-specific creatine kinase gene (rs8111989).

Septal innervation of basal forebrain cholinergic neurons to the hippocampus is critical for normal learning and memory and is severely degenerated in Alzheimer's disease. To understand the molecular events underlying physiological cholinergic synaptogenesis and remodeling, as well as pathological loss, we developed an optimized primary septal-hippocampal co-culture system. Hippocampal and septal tissue were harvested from embryonic Sprague-Dawley rat brain and cultured together at varying densities, cell ratios, and in the presence of different growth factors. We identified conditions that produced robust septal-hippocampal synapse formation. We used confocal microscopy with primary antibodies and fluorescent ligands to validate that this system was capable of generating developmentally mature cholinergic synapses. Such synapses were comprised of physiological synaptic partners and mimicked the molecular composition of in vivo counterparts. This co-culture system will facilitate the study of the formation, plasticity, and dysfunction of central mammalian cholinergic synapses. Keyword Septal • Cholinergic • Septal-hippocampal co-culture • Basal forebrain cholinergic neurons • Cholinergic synapse • Primary culture Abbreviations αBTX α-Bungarotoxin AChE Acetylcholinesterase AD Alzheimer's Disease BFCN Basal forebrain cholinergic neurons bFGF Basic fibroblast growth factor BMP9 Bone morphogenetic protein 9 ChAT Choline acetyltransferase CHT1 High-affinity choline transporter CNS Central nervous system DIV Day in vitro GABA Gamma-aminobutyric acid GAD65 Glutamate decarboxylase 65 Geph Gephyrin MAP2 Microtubule associated protein 2 MLA Methyllycaconitine nAChR Nicotinic acetylcholine receptor NGF Nerve growth factor nMDP Normalized mean deviation product PSD-93 Postsynaptic density 93 PSD-95 Postsynaptic density 95 VAChT Vesicular acetylcholine transporter VGAT Vesicular GABA transporter Electronic supplementary material The online version of this article (