In an example, an apparatus can include an array of memory cells and a neural memory unit controller coupled to the array of memory cells and configured to assert respective voltage pulses during a first training interval to memory cells of the array to change respective threshold voltages of the memory cells from voltages associated with a reset state to effectuate respective synaptic weight changes. The neural memory unit controller can be configured to initiate a sleep interval, during which no pulses are applied to the memory cells, to effectuate respective voltage drifts in the changed respective threshold voltages of the memory cells from a voltage associated with a set state toward the voltage associated with the reset state, and determine an output of the memory cells responsive to the respective voltage drifts in the changed respective threshold voltages after the sleep interval.