Memory is the process through which the brain encodes, retains and reuses information from past experiences. This process results from the synaptic junction of neurons, and by performing repetitive tasks, thereby creating links or networks of neurons capable of containing information for short and long time periods. Humans have three types of memory: sensory memory, long term memory and short term memory. The last is responsible for storing the interpretation of the experiences acquired by the senses and for keeping the information in a conscious way, but its duration is limited to few minutes; also, its capacity is reduced to five or six items. This paper presents the results of analyzing bioelectric signals, captured with a brain-computer interface. Such signals are generated in the cerebral cortex when the areas and processes involved in the use of the short-term memory are stimulated. The signal processing was performed using the EEGLab tool, which operates under the MATLAB programming environment, and it allows to conduct the spectral and statistical analysis of EEG signals. The results show that the brain areas directly associated with the short-term memory, had a significant increase after a certain number of repetitions for the stimulation activity.