Pay attention to rats
Norepinephrine medications improve attention and the ability to ignore distracting stimuli. Although norepinephrine also affects sensory cortex neurons, current theories suggest the prefrontal cortex is the site of norepinephrine-induced control. The EU-funded project WHISKERATTENTION (The effects of spatial attention on stimulus encoding in rat barrel cortex and on relationships between barrel cortex and locus coeruleus norepinephrine neuron spiking) hypothesised that norepinephrine may affect attention via direct action in the sensory cortex. To test this theory, the team developed a novel task to measure rodent attention. The task involved exposing a stationary rat to sensory stimuli, and measuring the rat's reactions and brain activity. First, the study tested the attention and reaction to a stimulus in different layers of the brain's sensory cortex. These showed that the locus coeruleus (the norepinephrine-producing part of the brain) reacts differently to stimulation in specific layers of the sensory cortex. When influenced by sensory stimuli, the locus coeruleus has specific timing mechanisms according to which it releases norepinephrine spikes. In addition, the locus coeruleus has the ability to communicate between different layers of the sensory cortex. Another part of the study tested how attention to different stimuli affected the relationship between the locus coeruleus and the sensory cortex. Project researchers found that attention to audio and visual stimuli affects communication between the prefrontal cortex and the norepinephrine-producing area in different ways. The compounds used in WHISKERATTENTION are also used in humans, and the results expand the knowledge of human brain function and interaction with norepinephrine medication.
Keywords
Norepinephrine, brain, attention, sensory cortex, locus coeruleus, sensory stimuli
