Limits...
From creation to consolidation: a novel framework for memory processing.

Robertson EM - PLoS Biol. (2009)

View Article: PubMed Central - PubMed

Affiliation: Berenson-Allen Centerfor Non-Invasive Brain Stimulation, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. emrobert@bidmc.harvard.edu

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

These studies have contrasted the patterns of activation before and after consolidation to reveal how the brain has been changed by consolidation... Yet just because the activation of a brain area is changed by consolidation does not mean that area was responsible for supporting consolidation... Disrupting the function of these activated areas, by using TMS or through lesion studies, would determine which areas are necessary for consolidation... Thus, the challenge for future studies is to identify those circuits activated during consolidation, as opposed to those circuits altered by consolidation, and use this as a foundation to define those circuits making a functional contribution to consolidation... These motor skill components are processed offline over different brain states (i.e., sleep versus wakefulness), and so differences in the relative size of these component may restrict the benefits of consolidation to a specific brain state... Potentially, this leads to motor skill acquisition that is predominately goal-based, and as this component is preferentially processed over sleep, to a task that shows sleep-dependent consolidation (; see also )... These heterogeneous changes in functional connectivity during NREM sleep may support reduced connectivity between memory systems, allowing disengagement, while simultaneously supporting enhanced or maintained connectivity within memory systems, allowing the offline processing necessary for memory consolidation... Alternatively, a decrease in functional connectivity may be associated with a specific sleep stage—such as NREM—while other sleep stages support the offline processing within specific memory systems... This alternative implies that when declarative and procedural memories are acquired simultaneously, consolidation will be dependent upon NREM sleep when memory systems are disengaged... Consistent with this prediction are observations that the consolidation of motor skills, when acquired along with declarative knowledge for the skill, is correlated with NREM sleep, whereas when the same motor skill is acquired in isolation, its subsequent consolidation is correlated with REM sleep... Evidence that the memory processing benefits of sleep can be replicated over wakefulness through the loss of declarative knowledge (, Figure 3) implies that the loss of declarative knowledge may be critical for memory processing during sleep... Yet the sleep-related memory processing benefits can occur without a permanent loss of declarative knowledge... Yet this unique framework extends beyond accounting for observations by also making experimentally testable predictions for future work (Box 6)... Direct evidence for a differential organization supporting the offline processing of declarative memories is awaited, and a greater understanding of the relationship between biological events, such as decreases in functional connectivity and the disengagement between memory systems during sleep, is required.

Show MeSH
A Motor Skill Memory Has Classically Been Split into Two ComponentsOne component encodes the spatial goal of the movement, and the other encodes the movements needed to achieve that goal [84–86]. For example, the goal of playing out a sequence of spatial positions—2-3-1—can be achieved by a sequence of finger movements. The goal of a motor skill is encoded within a circuit that includes the dorsolateral prefrontal cortex (DLPFC), the inferior parietal lobule (IPL), and perhaps the mediotemporal lobe (MTL); whereas the movements associated with a skill are encoded within a circuit that includes the primary motor cortex (M1) and subcortical areas such as the striatum [12,13]. Other memories can be split into similar components. For example, navigating around a city relies upon learning the spatial location of landmarks plus learning the sequence of right-and-left turns needed to get to the landmark.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2631067&req=5

pbio-1000019-g001: A Motor Skill Memory Has Classically Been Split into Two ComponentsOne component encodes the spatial goal of the movement, and the other encodes the movements needed to achieve that goal [84–86]. For example, the goal of playing out a sequence of spatial positions—2-3-1—can be achieved by a sequence of finger movements. The goal of a motor skill is encoded within a circuit that includes the dorsolateral prefrontal cortex (DLPFC), the inferior parietal lobule (IPL), and perhaps the mediotemporal lobe (MTL); whereas the movements associated with a skill are encoded within a circuit that includes the primary motor cortex (M1) and subcortical areas such as the striatum [12,13]. Other memories can be split into similar components. For example, navigating around a city relies upon learning the spatial location of landmarks plus learning the sequence of right-and-left turns needed to get to the landmark.

Mentions: Important clues about the offline processing of memories can be gleaned from understanding how the brain initially encodes memories. The motor skill memories acquired by a squash player, for example, ensure the production of rapid and powerful arm movements, either backhand or forehand, to hit a ball. The goal is always the same—to hit a ball; however, the exact movements can be very different. This classical distinction between goal and movement can be mapped onto distinct brain circuits (Figure 1, [3,12,13]). These distinct circuits are differentially affected by wakefulness and sleep: activity within the goal-component circuit changes substantially between wakefulness and sleep, with far smaller changes in activity occurring within the movement-based circuit [14]. Having differential changes in activity may produce a differential processing of the motor skill components during wakefulness and sleep. Consistent with this idea, experimental work has shown that only the movement component is processed during wakefulness; whereas only the goal component is processed during sleep (Figure 2, [15]). Converging with this behavioral work are observations from functional imaging and transcranial magnetic stimulation (TMS) studies showing that distinct circuits are engaged during wakefulness and sleep to support offline processing (Figure 2, [16–20]).


From creation to consolidation: a novel framework for memory processing.

Robertson EM - PLoS Biol. (2009)

A Motor Skill Memory Has Classically Been Split into Two ComponentsOne component encodes the spatial goal of the movement, and the other encodes the movements needed to achieve that goal [84–86]. For example, the goal of playing out a sequence of spatial positions—2-3-1—can be achieved by a sequence of finger movements. The goal of a motor skill is encoded within a circuit that includes the dorsolateral prefrontal cortex (DLPFC), the inferior parietal lobule (IPL), and perhaps the mediotemporal lobe (MTL); whereas the movements associated with a skill are encoded within a circuit that includes the primary motor cortex (M1) and subcortical areas such as the striatum [12,13]. Other memories can be split into similar components. For example, navigating around a city relies upon learning the spatial location of landmarks plus learning the sequence of right-and-left turns needed to get to the landmark.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2631067&req=5

pbio-1000019-g001: A Motor Skill Memory Has Classically Been Split into Two ComponentsOne component encodes the spatial goal of the movement, and the other encodes the movements needed to achieve that goal [84–86]. For example, the goal of playing out a sequence of spatial positions—2-3-1—can be achieved by a sequence of finger movements. The goal of a motor skill is encoded within a circuit that includes the dorsolateral prefrontal cortex (DLPFC), the inferior parietal lobule (IPL), and perhaps the mediotemporal lobe (MTL); whereas the movements associated with a skill are encoded within a circuit that includes the primary motor cortex (M1) and subcortical areas such as the striatum [12,13]. Other memories can be split into similar components. For example, navigating around a city relies upon learning the spatial location of landmarks plus learning the sequence of right-and-left turns needed to get to the landmark.
Mentions: Important clues about the offline processing of memories can be gleaned from understanding how the brain initially encodes memories. The motor skill memories acquired by a squash player, for example, ensure the production of rapid and powerful arm movements, either backhand or forehand, to hit a ball. The goal is always the same—to hit a ball; however, the exact movements can be very different. This classical distinction between goal and movement can be mapped onto distinct brain circuits (Figure 1, [3,12,13]). These distinct circuits are differentially affected by wakefulness and sleep: activity within the goal-component circuit changes substantially between wakefulness and sleep, with far smaller changes in activity occurring within the movement-based circuit [14]. Having differential changes in activity may produce a differential processing of the motor skill components during wakefulness and sleep. Consistent with this idea, experimental work has shown that only the movement component is processed during wakefulness; whereas only the goal component is processed during sleep (Figure 2, [15]). Converging with this behavioral work are observations from functional imaging and transcranial magnetic stimulation (TMS) studies showing that distinct circuits are engaged during wakefulness and sleep to support offline processing (Figure 2, [16–20]).

View Article: PubMed Central - PubMed

Affiliation: Berenson-Allen Centerfor Non-Invasive Brain Stimulation, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. emrobert@bidmc.harvard.edu

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

These studies have contrasted the patterns of activation before and after consolidation to reveal how the brain has been changed by consolidation... Yet just because the activation of a brain area is changed by consolidation does not mean that area was responsible for supporting consolidation... Disrupting the function of these activated areas, by using TMS or through lesion studies, would determine which areas are necessary for consolidation... Thus, the challenge for future studies is to identify those circuits activated during consolidation, as opposed to those circuits altered by consolidation, and use this as a foundation to define those circuits making a functional contribution to consolidation... These motor skill components are processed offline over different brain states (i.e., sleep versus wakefulness), and so differences in the relative size of these component may restrict the benefits of consolidation to a specific brain state... Potentially, this leads to motor skill acquisition that is predominately goal-based, and as this component is preferentially processed over sleep, to a task that shows sleep-dependent consolidation (; see also )... These heterogeneous changes in functional connectivity during NREM sleep may support reduced connectivity between memory systems, allowing disengagement, while simultaneously supporting enhanced or maintained connectivity within memory systems, allowing the offline processing necessary for memory consolidation... Alternatively, a decrease in functional connectivity may be associated with a specific sleep stage—such as NREM—while other sleep stages support the offline processing within specific memory systems... This alternative implies that when declarative and procedural memories are acquired simultaneously, consolidation will be dependent upon NREM sleep when memory systems are disengaged... Consistent with this prediction are observations that the consolidation of motor skills, when acquired along with declarative knowledge for the skill, is correlated with NREM sleep, whereas when the same motor skill is acquired in isolation, its subsequent consolidation is correlated with REM sleep... Evidence that the memory processing benefits of sleep can be replicated over wakefulness through the loss of declarative knowledge (, Figure 3) implies that the loss of declarative knowledge may be critical for memory processing during sleep... Yet the sleep-related memory processing benefits can occur without a permanent loss of declarative knowledge... Yet this unique framework extends beyond accounting for observations by also making experimentally testable predictions for future work (Box 6)... Direct evidence for a differential organization supporting the offline processing of declarative memories is awaited, and a greater understanding of the relationship between biological events, such as decreases in functional connectivity and the disengagement between memory systems during sleep, is required.

Show MeSH