Authors
- Vaheed Jahedi 1
- Hamidreza Taheri Torbati 2
- Ehsan Vafaei Noghabi 3
- Mersad Khodashenas 3
- Ensie Nasiri 4
1 PhD student of Motor Behavior, Ferdowsi University of Mashhad
2 Professor of Motor Behavior Department, Ferdowsi University of Mashhad
3 Motor Behavior Department, Ferdowsi University of Mashhad, Iran
4 Motor Behavior Department,،Ferdowsi University of Mashhad, Iran
Abstract
Background and Aim:
Consolidation is a set of neural processes by which a memory both becomes more stable and improves over time. At least two events occur as a result of consolidation: consolidation and enhancement. During consolidation, a new and fragile memory can become strong and stable; this event is called consolidation. During consolidation, a memory may not only be consolidated but also enhanced. Enhancement can also occur offline between training sessions. Such offline learning can often be supported by the passage of time or by a night of sleep. In the neuroscience and behavioral sciences literature, consolidation has two subprocesses; the first process, which occurs in the first minutes and hours, involves changes and exchanges of materials within and between two neurons. These initial changes are referred to as “synaptic consolidation” or rapid and early consolidation. Another type of consolidation takes many hours, days, weeks, or perhaps months. It is believed that this type of consolidation involves the reorganization of brain and systemic circuits over time, such this engram can be transferred to new locations in the brain and lose its dependence on the circuits and initial consolidation points. This type of process is called “system consolidation” or delayed consolidation. This review article is based on two research questions. In the first research question, we sought to understand where motor memory consolidation occurs and which brain regions it involves. We then sought to understand how long the process of motor memory consolidation takes. Therefore, in this review article, we seek to examine the neural processes of consolidation in general, and the spatial neural substrates and temporal trends of each of the subprocesses.
Research Method:
This research is a narrative review study. Based on the keyword consolidation, the search for the following terms was started: consolidation, memory consolidation, motor memory, motor memory consolidation. Regarding the types of motor memory consolidation and stages of motor memory consolidation, the terms cognitive consolidation (news), procedural consolidation, motor memory consolidation, offline promotion, synaptic consolidation, and systemic consolidation were searched. In this review study, four databases of English articles were consulted: Sciencedirect, PubMed, Sage, and Google Scholar, and the time period was considered from 1996 to 2024. Persian research was also searched in Irandoc and Jihad Daneshgahi (SID) databases, and the time period was considered from 1375 to 1403. A total of 147 articles related to the above keywords were found. First, the authors eliminated duplicate studies between databases (23 cases). Second, the titles of all 124 remaining articles were read and those that were clearly irrelevant (some of these studies were on computers, artificial intelligence, and robots) were excluded (26 cases). Then, by reading the abstracts of the remaining articles, the authors determined that 53 articles were suitable for full-text review. Finally, by reading the full-text articles, with particular focus on the methodology and results obtained, and based on agreement between the authors of this text, 37 core articles were selected for this review study.
Findings:
There are three physiological explanations for synaptic consolidation in the early minutes (short-term memory). First, many physiologists believe that this consolidation is due to the continuous activity of neural signals that are created around a temporary memory trace and form a circuit of reflex neurons. The second explanation is that synaptic consolidation can be the result of presynaptic facilitation or inhibition. This action occurs in the presynaptic neuron, not the postsynaptic neuron. Neurotransmitters released at such terminals repeatedly and repeatedly cause facilitation or inhibition for several seconds or several minutes. The final explanation is synaptic potentiation, which can strengthen synaptic conduction. After training or acquisition, as more time passes without training, the new memory becomes resistant to all kinds of interference. According to the results of the reported research, the process of synaptic consolidation seems to take its longest time during the first four to six hours after training. It is believed that long-term memory (system consolidation process) results from actual structural changes, rather than mere chemical changes in synapses, and these changes cause the enhancement or suppression of signal conduction. The most important structural changes produced in long-term memory are: 1. An increase in the number of vesicle release sites for transmitter secretion; 2. An increase in the number of released vesicles; 3. An increase in the number of presynaptic terminals; 4. A change in the structure of dendritic spines. Several areas of the brain are responsible for the long-term consolidation of non-novel skills, including the primary motor cortex (M1), parts of the neocortex, the cerebellum and deep nuclei, and the striatum. Offline consolidation of newly learned motor skills is a multi-stage and dynamic process. Many studies on systemic consolidation have reported that improvements are often associated with sleep deprivation, with improvements occurring more significantly if the period of non-practice is accompanied by sleep (especially at intervals of 12 to 24 hours). In general, depending on the type of skill and task, systemic consolidation of a skill requires 24 to 72 hours after acquisition to occur, such as consolidation (12 hours), promotion (24 hours, accompanied by sleep), and spatial transfer (48 to 72 hours).
Discussion and Conclusion:
According to the results of the reported studies and their comparison with each other, it was shown that the temporal and spatial contexts of motor memory consolidation can vary depending on the type of task or training provided. Therefore, the results of this study can be a refutation of the idea that motor memory consolidation, like cognitive memory consolidation, has a single cortical area and a specific duration. According to Newell's constraint-based perspective, the development, control, and learning of a movement should be considered with respect to the three constraints of the individual, the environment, and the task. Therefore, the variability of the spatial and temporal infrastructures of movement consolidation with respect to the type of task can indicate the different post-training needs of different motor skills. Finally, it is suggested that more detailed studies and research be conducted in the future on the spatial and temporal contexts of motor memory consolidation with respect to the constraints of the individual and the environment.
Keywords
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