7.20 : Role of Cerebellum and Prefrontal Cortex in Memory

The cerebellum, while traditionally associated with motor control, also plays a crucial role in memory, particularly in procedural memory, which involves learning motor tasks that become automatic through repetition. For example, studies have shown that when the cerebellum is damaged, individuals or animals lose the ability to learn conditioned motor responses, such as the conditioned eye-blink response in classical conditioning experiments with rabbits. This study demonstrates the cerebellum's involvement in motor learning and nonverbal skill memory.

The cerebellum also contributes to non-motor tasks that occur subconsciously. It assists in processing sensory information and involves the timing and coordination necessary for various cognitive functions such as attention and language processing. For example, when estimating the duration of an activity, the cerebellum processes the passage of time. Similarly, when dealing with subtle sensory experiences, such as slight changes in texture or sound, the cerebellum coordinates this sensory input. It manages these tasks automatically, providing precise timing and coordination for smooth cognitive processing without conscious effort.

While the cerebellum plays a crucial role in procedural and sensory memory, the prefrontal cortex (PFC) governs higher-order cognitive functions, including working memory, decision-making, and the processing of new memories. The PFC is heavily involved in tasks that require judgment, planning, and organizing information. For example, brain imaging studies have shown that different parts of the PFC are activated depending on the task type, such as semantic categorization or perceptual tasks. The left PFC is more involved in encoding new information, while the right PFC retrieves previously learned information.

Damage to the prefrontal cortex can significantly impair an individual's ability to plan and execute tasks, even if other cognitive functions remain intact. An example is the famous case of Phineas Gage, who survived a severe accident causing significant damage to his frontal lobe. Before the accident, he was known as responsible and well-mannered. However, after the injury, Gage exhibited dramatic personality changes, becoming impulsive, irritable, and unable to plan or make sound decisions. This case demonstrated how the PFC is crucial for integrating memory, social behavior, and emotional regulation, influencing personality and complex decision-making processes.