SLC16A1 and Cognitive impairment: Similarly, down-regulation of astrocytic lactate transporters MCT1 or MCT4 by intra-hippocampal oligodeoxynucleotide injections could also disrupt long-term memory formation and be reversed by exogenous supplementation of L-lactate; in contrast, injection of exogenous lactate or glucose could not counteract cognitive impairment resulting from inhibition of neuronal lactate transporter MCT2 expression, implying that MCT2-mediated transport of lactate to neurons is required for LTP and long-term memory formation.