CREB Downregulation In The Laterodorsal Thalamic Nucleus Deteriorates Memory Consolidation In Rats

As a multisensory nucleus,laterodorsal thalamic nucleus(LD)plays an significant part in the process of spatial orientation and learning tasks due to its mutual effect with the hippocampus and the cortical areas of cognition and somatosensory.Recent researches referred to the extensive interactions between the thalamus and vestibular apparatus,and neurons in the laterodorsal thalamic nucleus responded to various stimuli,particularly associated with somatosensory and proprioceptive ones,which involved in the space orientation after integrating the internal and environmental information.Plenty of animal experiments suggested that the LD participated in multimodal learning or memory tasks,and this study aimed to further explore the relationship between the LD and learning and memory process of location awareness and space navigation.In the previous experiment of bilaterally lesion on the LD which was pinpoingting,rats showed different degrees of spatial navigation and memory impairment.Thus we selected c AMP regulated element binding protein(CREB),a transcription factor that has been known to be tightly associated with memory shaping in the hippocampus,and its phosphorylated form(p-CREB),to detected whether the behavioral tendency of rats is closely relevant to the expression of p-CREB in the LD.The si RNA against CREB was synthesized to downregulate the expression of CREB m RNA in the LD,in contrast to wild-type and controlled injection rats.As a consequence of Morris water maze sessions,CREB si RNA rats exhibited a memory deficiency,and expression of p-CREB wasattenuated simultaneously,significantly diverging from the control groups.In brief,our results implied a correlation between behavioral performance of rats during spatial tasks and expression of p-CREB in the LD.These results support the hypothesis that CREB-related signaling pathway contributes to memory facilitation and consolidationin the LD,not merely in the hippocampus.