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Despite the critical link between visual exploration and memory, little is known about how neuronal activity in the human mesial temporal lobe (MTL) is modulated by saccades. Here, we characterize saccade-associated neuronal modulations, unit-by-unit, and contrast them to image onset and to occipital lobe neurons. We reveal evidence for a corollary discharge (CD)-like modulatory signal that accompanies saccades, inhibiting/exciting a unique population of broad-/narrow-spiking units, respectively, before and during saccades and with directional selectivity. These findings comport well with the timing, directional nature, and inhibitory circuit implementation of a CD. Additionally, by linking neuronal activity to event-related potentials (ERPs), which are directionally modulated following saccades, we recontextualize the ERP associated with saccades as a proxy for both the strength of inhibition and saccade direction, providing a mechanistic underpinning for the more commonly recorded saccade-related ERP in the human brain. • Single-unit activity in the human hippocampus is modulated with saccades • This single-unit activity modulation is dominated by inhibition • The magnitude of modulation is correlated with peri-saccadic-evoked response amplitude • Human mesial temporal lobe structures receive a corollary discharge during saccades Katz et al. characterize single-unit activity during saccadic eye movements in the human mesial temporal lobe. They demonstrate that this activity contains directional information and is inhibitory. These findings lead them to conclude that human memory structures receive a corollary discharge mediated by a circuit including the nucleus reuniens. [ABSTRACT FROM AUTHOR]