The locus cerulean is an anatomical region in the brain stem involved in the response to panic and stress. As the main source of the neurotransmitter norepinephrine, it helps us control our focus of attention. Its name in Latin means ‘the blue place’, which derives from the pigmentation caused by the content of melanin granules within this structure..
Bringing together evidence from animal and human studies, scientists at the Max Planck Institute for Human Development and the University of Southern California have developed a novel framework that describes how the cerulean locus regulates our brain’s sensitivity to relevant information. in situations that require attention.
A surge of norepinephrine
Our attention fluctuates. Sometimes we get distracted and things slip away, while other times we can easily focus on what is important. Sometimes we act in automatic mode but, in the face of an unexpected event, we take control. ButHow does the brain change from a state of inattention to one of concentrated attention?
During states of inattention, our brain is governed by slow and rhythmic fluctuations in neural activity. In particular, neural rhythms at a frequency around 10 Hz, called alpha waves, are believed to suppress active processing of sensory inputs during inattention. Therefore, alpha waves can be understood as a filter that regulates the sensitivity of our brain to external information.
To explore this question, the researchers focused on the locus ceruleus, a small cellular structure found in the brain stem, hidden deep within the cortex. This group of cells is only about 15 millimeters in size.But it is connected to most of the brain through an extensive network of long-range nerve fibers. The locus cerulean is made up of neurons that are the main source of the neurotransmitter norepinephrine. By regulating neuronal communication, norepinephrine contributes to stress control, memory, and attention.
To study whether norepinephrine at the cerulean locus could be a factor that regulates alpha waves, the researchers combined recordings of pupil size and neural oscillations as the participants solved a demanding attention task. As expected, during moments of larger pupil size, indicative of increased noradrenergic activity, alpha waves disappeared. In addition, participants who showed stronger alpha and student responses did better on the attention task.
Therefore, during situations that require a sudden shift in attention, a surge of norepinephrine helps us refocus and quickly dodge the oncoming car.