Complex sentence: Research in enhancing working memory has been done by the use of transcranial direct current stimulation (tDCS) to the DLPFC which is believed to excite the shift in membrane potential in either a depolarization or hyperbolizing direction.
Split into simpler sentences: Research in enhancing working memory has been done by the use of transcranial direct current stimulation (tDCS) to the DLPFC. Which tDCS is believed to excite the shift in membrane potential in either a depolarization or hyperbolizing direction.