The maintenance of letters in verbal working memory (WM) activates the phonological loop. It relies on a widespread network of cortical areas and hippocampus. We record from epilepsy patients with intracranial electrodes and EEG. We showed that single neuron firing in the hippocampus predicts the participants’ performance and WM workload. Synchronization between the recordings reflects functional coupling. When the sounds of letters are recalled, information flows from hippocampus to auditory cortex. Our goal is to understand how verbal memory items unconsciously enter long term memory.