Scientists find hidden targeted norepinephrine signaling in the brain

Researchers at the Allen Institute report in Nature that the locus coeruleus does not broadcast norepinephrine brain-wide but sends signals along distinct pathways. Dorsal neurons connect to the cortex and are active during learning, while ventral neurons project to the brainstem and spinal cord. The study imaged about 35,000 mouse neurons and found an axon 70.32 cm long.

• Dorsal LC neurons link to the cortex and are active during learning
• Ventral LC neurons govern whether animals respond to cues
• About 35,000 neurons and nearly 400,000 cell profiles analyzed
• One reconstructed axon measured 70.32 cm, a mouse record