Researchers at the University of California, Riverside mapped a circuit that helps the brain abandon an old rule and adopt a new one. Cognitive flexibility is the ability to shift rules or plans when conditions change, and problems with this ability appear in disorders such as ADHD, depression, obsessive-compulsive disorder, schizophrenia and Alzheimer’s disease.
The study focuses on a small brainstem structure called the locus coeruleus (LC), the brain's primary source of norepinephrine. This chemical is involved in attention, arousal, learning, stress responses and decision-making. The authors write that the LC acts as a regulator that helps the brain transition between behavioral states efficiently.
To test this, the team trained mice on a rule-switching task. Animals first found food using one sensory cue, then the rule changed and they had to use a new cue. The researchers recorded activity in the prefrontal cortex with miniature microscopes that tracked hundreds of neurons. When the team used a method to reduce LC activity, mice struggled to adapt, continued to use outdated strategies and needed many more attempts to learn the switch.
LC disruption also made the prefrontal network noisier: more neurons fired and individual cells responded to broader, mixed information. Machine learning analyses showed brain activity no longer clearly reflected learning stage or predicted upcoming choices. The authors note the LC is affected early in neurodegeneration, so the findings have implications for aging and Alzheimer’s disease and may point to neural targets for therapies.
Difficult words
- cognitive flexibility — Ability to change rules or plans when needed.
- locus coeruleus — Small brainstem area that makes norepinephrine.
- norepinephrine — Chemical in the brain for attention and arousal.
- prefrontal cortex — Front brain area involved in thinking.
- regulator — Component that controls or adjusts activity.
- neurodegeneration — Progressive loss of nerve cells and function.
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Discussion questions
- Can you give a daily example when cognitive flexibility is important?
- How might understanding the locus coeruleus help doctors treat memory or attention problems?
- What simple activities could help a person become more flexible in thinking?
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