cues during sleep initiate reactivation, an essential part of long term memory consolidation that improves later recall performance. Spindles generated in the thalamus have been shown to aid sleeping in the presence of disruptive external sounds. A correlation has been found between the amount of brainwave activity in the thalamus and a sleeper's ability to maintain tranquility. Spindles play an essential role in both sensory processing and long term memory consolidation because they are generated in the TRN. During sleep, these spindles are seen in the brain as a burst of activity immediately following muscle twitching. Researchers think the brain, particularly in the young, is learning about what nerves control what specific muscles when asleep. Sleep spindle activity has furthermore been found to be associated with the integration of new information into existing knowledge as well as directed remembering and forgetting (fast sleep spindles). During NREM sleep, the brain waves produced by people with schizophrenia lack the normal pattern of slow and fast spindles. Loss of sleep spindles are also a feature of familial fatal insomnia, a prion disease. Changes in spindle density are observed in disorders. There are some studies that show an increase in sleep spindles in autistic children. Also some studies suggest a lack of sleep spindles in epilepsy./ Research is currently underway to develop a web-based automatic sleep spindle detection system by using machine learning techniques. The results of the present study show that the automatic sleep spindle detection system has great potential in practical application. Evolution No sleep spindles have been observed in reptiles and birds so far. In most mammals sleep spindles were described at face value, but the existence of pseudo-spindles invites uncertainty around these observations. Spindle-like oscillations, that show additional analogies (e.g. apparent involvement in learning or thalamic dependence) are currently only known from humans, rats, mice, cats, and dogs. In these species spindles invariantly oscillate between 9 and 16 Hz, with minor variations (e.g. 7-14 Hz in the cat). Clearly distinct frontal and posterior sleep spindles (i.e. "slow" and "fast") were only confirmed outside humans in the rat and dog. Sex differences Sleep spindles play a crucial role in declarative memory consolidation, however, most studies neglect to control for sex , although both sex and menstruation affect sleep and online learning periods. Studies have shown that the influence of sleep spindles during the declarative memory process may be affected by modulatory