Brain Chooses Between Classical and Operant Conditioning

Groundbreaking research from Tel Aviv University reveals that the brain cannot simultaneously learn through classical conditioning and operant conditioning, reshaping our understanding of how humans and animals form memories.

The study, led by Prof. Moshe Parnas and Ph.D. student Eyal Rozenfeld, uncovers a fascinating “tug-of-war” between these two learning systems. Classical conditioning involves forming passive associations between stimuli, like Pavlov’s famous dog experiment, where a bell signaled food. In contrast, operant conditioning is active, teaching behaviors based on the outcomes of actions—reward or punishment.

Using fruit flies (Drosophila) as a model, the researchers demonstrated that the brain suppresses one learning system when the other is active. In their experiment, flies exposed to an odor associated with an electric shock displayed freezing behavior under classical conditioning. Meanwhile, flies trained using operant conditioning learned to flee from the odor to avoid the shock. However, when both learning systems were engaged simultaneously, the flies failed to learn either response. This suggests that the brain actively prioritizes one type of memory while blocking the other to prevent cognitive confusion.

The team further discovered that the brain’s “navigation center” intervenes in this decision-making process, ensuring only one memory type is active at a time. This mechanism prevents clashes between competing responses and optimizes learning efficiency.

Prof. Parnas explains, “Our findings show the brain can’t handle two conflicting learning processes at once. It’s a protective mechanism that prevents cognitive overload and ensures clarity in responses.”

Interestingly, while fruit flies have simpler brains, their neural processes closely mirror those of mammals, including humans. This research offers insight into learning disorders, such as ADHD and Alzheimer’s disease, suggesting potential pathways for treatment by targeting these competing memory systems. Join Effective Management of Common Psychiatric Conditions for the latest inputs.

As Eyal Rozenfeld notes, “Understanding how the brain prioritizes one learning system over another could open doors to innovative therapies for cognitive and memory disorders.”

This discovery not only deepens our understanding of brain function but also highlights the limitations of multitasking when it comes to memory formation and learning efficiency.

More Information: Eyal Rozenfeld et al, Neuronal circuit mechanisms of competitive interaction between action-based and coincidence learning, Science Advances (2024). DOI: 10.1126/sciadv.adq3016