The "conductor" neurons: key to our brain's power

Our brain is a maestro of cognition, capable of juggling multiple tasks effortlessly. This astonishing ability relies on a type of neurons called "mixed-selectivity neurons," which act like conductors, orchestrating various functions simultaneously.


Mixed-selectivity neurons can integrate multiple types of information and participate in multiple computations. Neuroscientists have long sought to understand how our brain achieves such cognitive flexibility. In a study published in Neuron, a team delved deep into this question, revealing that neurons with mixed selectivity are crucial for integrating necessary information without being overwhelmed by irrelevant details.

Earl K. Miller, co-author of the study and professor at the Picower Institute for Learning and Memory at MIT, explains that this capability of neurons to engage in various computations simultaneously is essential for flexible cognition. According to Miller, these neurons "wear many hats," allowing our brain to create a representation space as complex as needed.

The idea of mixed selectivity emerged in 2000, when researchers observed that many neurons in the prefrontal cortex were involved in sorting categories of images. This discovery showed that neurons could be flexible and participate in multiple computations.

The mechanisms for recruiting neurons for specific tasks are only partially understood. The recent study identifies forms of mixed selectivity and discusses how brain oscillations and neuromodulators, like serotonin and dopamine, recruit neurons into computational ensembles.

Understanding mixed selectivity is crucial for grasping how cognition works. Researchers conclude that this property is ubiquitous across species and functions, from high-level cognitive processes to automatic sensorimotor processes, highlighting its fundamental role in the brain's processing power.