A human clinical study published this week in Nature Medicine finds that cognitive lapses after sleep deprivation might be driven by slower and weaker neural activity in the medial temporal lobe of the brain.
Sleep deprivation negatively impacts human health and well-being, and the long-term effects of chronic sleep deprivation have been associated with elevated risk for numerous conditions, including hypertension, diabetes, obesity and depression. The acute effects of a lack of sleep can also cause cognitive and behavioral lapses that contribute to accident-induced injury or death, but it has been difficult to determine precisely how sleep deprivation influences neural activity within the human brain owing to the invasive techniques required to record neural activity.
Yuval Nir and colleagues obtained recordings of single-neuron activity in the medial temporal lobe of participants as they completed a series of facial recognition tests before and after sleep deprivation while also undergoing monitoring for potential neurosurgery. The authors observed that, when sleep deprived, the participants had delayed and reduced neural activity as compared to the activity evoked during rapid completion of the task, leading participants to make slower responses characteristic of cognitive lapses.
Essential next steps include investigation into whether these delayed and reduced patterns of neural activity occur in the rest of the brain as well. Furthermore, additional studies may be required in order to identify the precise mechanisms through which lack of sleep directly influences neuronal activity.