The Investigation Of Dorsolateral Prefrontal Cortex (DLPFC) Activity In Item And Associative Memory Using Transcranial Direct Current Stimulation (tDCS)

Though the dorsolateral prefrontal cortex (DLPFC) has been shown to be important for working and item memory, recent neuroimaging research has suggested that the DLPFC is more important in relational processing for associative memory than initially thought. It has been found that individuals with depressive symptoms often have less activity in the DLPFC; it has also been found that these individuals experience associative memory deficits. However, it remains unclear if associative memory deficits in depression are related to DLPFC activity. Transcranial direct current stimulation (tDCS) can modify cortical excitability and has thus been used in the examination of brain regions and their related functions. The present study used tDCS in individuals with depression to investigate if associative memory deficits were related to DLPFC activity. Only the High Depression group showed a selective enhancement of associative memory after tDCS, whereas the Low Depression group received no benefits from tDCS. The present study suggests that DLPFC activity is related to associative memory deficits in depression. This adds further evidence to the existing body of literature on the DLPFC’s function in associative memory.