Networks of neurons in the prefrontal cortex generate persistent firing to keep information "in mind" even in the absence of cues from the environment. This process is called "working memory," and it allows us to recall information, such as where the car keys were left, even when that information must be constantly updated. This ability is the basis for abstract thought and reasoning, and is often called the "Mental Sketch Pad." It is also essential for executive functions, such as multi-tasking, organizing, and inhibiting inappropriate thoughts and actions.
Arnsten and her team studied the firing of prefrontal cortical neurons in young, middle-aged and aged animals as they performed a working memory task. Neurons in the prefrontal cortex of the young animals were able to maintain firing at a high rate during working memory, while neurons in older animals showed slower firing rates. However, when the researchers adjusted the neurochemical environment around the neurons to be more similar to that of a younger subject, the neuronal firing rates were restored to more youthful levels.and: 'Super' Aged Brains Reveal First Secrets Of Sharp Memory In Old Age