Acquisition and retention of motor sequences: the effects of time of the day and sleep.
OBJECTIVE
We used a sequence-learning task to assess whether: 1. The time interval between awakening and training equally affects the rate of acquisition of sequence order, a declarative component, and the kinematic optimization process, an implicit component; 2. Sleep enhances the retention of both these aspects of sequence learning.


METHODS
For aim 1, we compare the acquisition rate of a new motor sequence in a group trained in the morning and another in the evening. For aim 2., we tested retention of the same motor sequence twelve hours later, either without sleep (normal day activity or a night of sleep deprivation) or with interposed sleep (afternoon napping or regular full night sleep).


METHODS
Training and Testing were performed in a controlled laboratory setting.


METHODS
Thirty-six right-handed normal subjects (age range 18-24 years; 16 women).


RESULTS
During the training, acquisition rate of the sequence order was significantly higher in the AM-trained than in the PM-trained group, without differences in the kinematic optimization processes. Both declarative and implicit learning indices were significantly higher in the subjects tested after sleep compared to those tested without interposed sleep.


CONCLUSIONS
The best time for fast and efficient acquisition of new declarative material is the morning, while the kinematic aspects of skill acquisition are not sensitive to the time of day. However, better retention of both declarative material and motor skills requires two conditions: a period of post-training sleep and the achievement of performance saturation during training.
Department of Physiology and Pharmacology, Sophie Davis School of Biomedical Education, [corrected] The City University of New York Medical School, 138th Street and Convent Avenue, New York, NY, [corrected] USA. lice.mg79@gmail.com
Svetlana
S
Kvint
Brian
B
Bassiri
April
A
Pruski
John
J
Nia
Israel
I
Nemet
Melissa
M
Lopresti
Bernardo
B
Perfetti
Clara
C
Moisello
Giulio
G
Tononi
M Felice
MF
Ghilardi
D000293:Adolescent; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000502:physiology; D009068:Movement / Q000502:physiology*; D009483:Neuropsychological Tests; D011930:Reaction Time; D012153:Retention, Psychology / Q000502:physiology*; D012691:Serial Learning / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult