2021 Cortex; a journal devoted to the study of the nervous system and behavior
* Training at asymptote stabilizes motor memories by reducing intracortical excitation.
- Learning similar motor skills in close succession is limited by interference, a phenomenon that takes place early after acquisition when motor memories are unstable. Interference can be bidirectional, as the first memory can be disrupted by the second (retrograde interference), or the second memory can be disrupted by the first (anterograde interference). The heightened plastic state of primary motor cortex after learning is thought to underlie interference, as unstable motor memories compete for neural resources. While time-dependent consolidation processes reduce interference, the passage of time (~6 h) required for memory stabilization limits our capacity to learn multiple motor skills at once. Here, we demonstrate in humans that prolonged training at asymptote of an initial motor skill reduces both retrograde and anterograde interference when a second motor skill is acquired in close succession. Neurophysiological assessments via transcranial magnetic stimulation reflect this online stabilization process. Specifically, excitatory neurotransmission in primary motor cortex increased after short training and decreased after prolonged training at performance asymptote. Of note, this reduction in intracortical excitation after prolonged training was proportional to better skill retention the following day. Importantly, these neurophysiological effects were not observed after motor practice without learning or after a temporal delay. Together, these findings indicate that prolonged training at asymptote improves the capacity to learn multiple motor skills in close succession, and that downregulation of excitatory neurotransmission in primary motor cortex may be a marker of online motor memory stabilization.
Overview of verb observe
The verb observe has 9 senses (first 8 from tagged texts)
1. (39) detect, observe, find, discover, notice -- (discover or determine the existence, presence,
or fact of; "She detected high levels of lead in her drinking water"; "We found traces of lead in
the paint")
2. (17) note, observe, mention, remark -- (make mention of; "She observed that his presentation took
up too much time"; "They noted that it was a fine day to go sailing")
3. (12) note, take note, observe -- (observe with care or pay close attention to; "Take note of this
chemical reaction")
4. (10) observe -- (watch attentively; "Please observe the reaction of these two chemicals")
5. (4) respect, honor, honour, abide by, observe -- (show respect towards; "honor your parents!")
6. (3) observe, celebrate, keep -- (behave as expected during of holidays or rites; "Keep the
commandments"; "celebrate Christmas"; "Observe Yom Kippur")
7. (2) watch, observe, follow, watch over, keep an eye on -- (follow with the eyes or the mind;
"Keep an eye on the baby, please!"; "The world is watching Sarajevo"; "She followed the men with the
binoculars")
8. (1) observe, keep, maintain -- (stick to correctly or closely; "The pianist kept time with the
metronome"; "keep count"; "I cannot keep track of all my employees")
9. observe, keep -- (conform one's action or practice to; "keep appointments"; "she never keeps her
promises"; "We kept to the original conditions of the contract")
Overview of adj observed
The adj observed has 1 sense (first 1 from tagged texts)
1. (7) ascertained, discovered, observed -- (discovered or determined by scientific observation;
"variation in the ascertained flux depends on a number of factors"; "the discovered behavior norms";
"discovered differences in achievement"; "no explanation for the observed phenomena")
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