Related by context. Frequent words. (Click for all words.) 46 sleep 46 cognitive 45 REM sleep 44 cognitive functioning 44 wakefulness 43 cognition 41 circadian 40 melatonin 39 sleepiness 39 cognitive functions 39 cognitive deficits 39 ADHD symptoms 39 prefrontal cortex 39 sleep disturbances 39 cognitive function 39 cortisol levels 38 physiologically 38 cognitive abilities 38 brain 38 daytime sleepiness 37 brain scans 37 dopamine 37 impairs 37 neurobiological 36 perceptual 36 physiological 36 mood disorders 36 naps 36 exercising 36 circadian rhythms 36 glucose metabolism 36 circadian rhythm 35 thyroid function 35 neuropsychological 35 serotonin 35 impulsivity 35 developmentally 35 metabolic 35 frontal lobes 35 visual cortex 35 cognitively 35 Melatonin 34 neural 34 cortex 34 nap 34 arousal 34 amygdala 34 fMRI 34 physiologic 34 bedtime 34 hippocampus 34 Brain scans 33 relaxation techniques 33 auditory 33 cerebellum 33 neurogenesis 33 alertness 33 sleep disordered breathing 33 biological clocks 33 exercisers 33 amblyopia 33 sleep deprivation 33 depressive symptoms 33 overeat 33 cognitive decline 32 aerobic exercise 32 cognitive impairment 32 sleep disorders 32 hyperactivity 32 exercise 32 brainstem 32 overeating 32 synaptic 32 sleeping pill 32 snooze 32 drowsiness 31 neurodegeneration 31 neuronal 31 neuroscientists 31 disorders 31 Sleep 31 frontal lobe 31 neurological 31 Sleep deprivation 31 atrophy 31 sleep deprived 31 metabolism 31 awakenings 30 treadmill 30 BDNF 30 snore 30 neurons 30 synapses 30 therapeutic interventions 30 Exercising 30 meditate 30 cognitive behavioral therapy 30 bedtimes 30 ADHD 30 Cognitive 30 tryptophan