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Temudo, A.

Publications and source records attributed to Temudo, A..

6 recordsLinked to original sources

Children exhibit greater persistence of motor learning-related patterns of hippocampal activity into post-task wake epochs

Previous research has demonstrated that children exhibit superior - as compared to adults - consolidation of newly acquired motor sequences across post-learning periods of wakefulness. Given that consolidation is thought to be supported by the reactivation of learning-related patterns of brain activity during the rest periods following active task practice, we hypothesized that the childhood advantage in offline consolidation may be linked to greater reactivation during post-learning wakefulness. Twenty-two children (7-11 years) and 23 adults (18-30 years) completed two sessions of a motor sequence learning task, separated by a 5-hour wake interval. Multivoxel analyses of task-related and resting-state functional magnetic resonance imaging data were employed to assess the persistence of learning-related patterns of neural activity into post-task rest epochs, reflective of reactivation processes. Behavioral results demonstrated the previously reported childhood advantage in offline consolidation over a post-learning wake interval. Imaging results revealed that children exhibited greater persistence of task-related hippocampal - but not putaminal - activity into post-learning rest as compared to adults. These findings suggest that the childhood advantage in awake motor memory consolidation may be supported, at least partially, by enhanced reactivation of task-dependent hippocampal activity patterns during offline epochs.

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The order, but not the structure, of cross-domain learning influences memory consolidation

Everyday activities often require learning sequences that necessitate the involvement of both the declarative and the procedural memory domains. Previous research has shown that a learning structure that is common across tasks from different domains can improve learning and resistance to interference. However, it remains unknown whether such shared learning structure can enhance longer-term memory retention. To address this question, forty-eight healthy adults participated in a pre-registered study in which they learned both an object sequence task (declarative learning) and a motor sequence task (procedural learning) in two separate sessions separated by 4h. Participants were assigned to either an associated group, where the two tasks shared a common learning structure - that consisted of a specific mapping between finger movements and object categories across learning sessions - or an unassociated group with no such cross-domain shared structure. Memory retention was assessed with a 24h retest session on both tasks. Contrary to our predictions, a shared higher-order structure between tasks from different domains did not enhance memory retention. Exploratory follow-up analyses revealed that the order the tasks were learned (i.e., object or motor first), rather than their structural overlap, influenced performance. Specifically, learning the motor task before the object task impaired the consolidation of the object task irrespective of whether the tasks shared a common learning structure or not. This effect was unidirectional as learning the object task before the motor task had no effect on the consolidation of the motor task. Altogether, the current findings suggest that the order of cross-domain learning experiences rather than their structure influences memory consolidation.

neuroscience↗

Neural correlates of motor sequence learning and enhanced offline consolidation in 7- to 11-year-old children

IntroMany daily activities involve series of interrelated movements and thus the capacity to learn new motor sequences is vital for everyday functioning. Although learning new skills is especially prominent throughout childhood, remarkably few studies have examined the neural underpinnings of motor sequence learning (MSL) and memory consolidation in children. MethodsTwenty-two children (7-11 years) and 23 adults (18-30 years) underwent functional magnetic resonance imaging while completing two sessions of a MSL task, separated by a 5-hour offline period of wakefulness. ResultsAnalyses of the behavioral data revealed comparable initial learning in children and adults. However, and consistent with previous research, children exhibited superior motor memory consolidation over the 5-hour offline epoch. Neuroimaging analyses revealed that children exhibited smaller modulations in brain activity between task and rest epochs in a widespread network, including the sensorimotor cortex, supplementary motor area, cerebellum, putamen and regions associated with the default mode network. Similar levels of activity during task and rest epochs in the hippocampus, dorsolateral prefrontal cortex and somatosensory cortex were associated with better motor memory consolidation in children. ConclusionResults potentially suggest that the continued engagement of the developing brain during interleaved rest contributes to the childhood advantage in motor memory consolidation.

neuroscience↗

The capacity of the medial temporal lobe to represent memory items in their ordinal position in a sequence is domain-general

Memory systems in humans are less segregated than initially thought as learning tasks from different memory domains (e.g., declarative vs. procedural) can recruit similar brain areas. However, it remains unclear whether the functional role of these overlapping brain regions - and the hippocampus in particular - is domain-general. Here, we test the hypothesis that the hippocampus encodes and preserves the temporal order of sequential information irrespective of the nature of that information. We used multivariate pattern analyses (MVPA) of functional magnetic resonance imaging (fMRI) data acquired in young healthy individuals during the execution of learned sequences of movements and objects to test whether the hippocampus represents information about the temporal order of items in a learned sequence irrespective of their nature. We also examined such coding in brain regions involved in both motor (primary and premotor cortices) and object (perirhinal cortex and parahippocampus) sequence learning. Our results suggest that hippocampal and perirhinal multivoxel activation patterns do not carry information about specific items or temporal position in a random series of objects or movements. Rather, these regions code for the representation of items in their learned temporal position in sequences irrespective of their nature (i.e., item-position coding). In contrast, although all other ROIs showed evidence of item-position coding, this representation could - at least partially - be attributed to the coding of other information such as position information. Altogether, our findings indicate that the capacity of regions in the medial temporal lobe to represent the temporal order of sequential information is domain-general. Our data suggest that these regions contribute to the development of item-position maps that might provide a cognitive framework to order sequential behaviors irrespective of their nature.

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Alpha phase-coding supports feature binding during working memory maintenance

The ability to successfully retain and manipulate information in working memory (WM) requires that objects individual features are bound into cohesive representations; yet, the mechanisms supporting feature binding remain unclear. Binding (or swap) errors, where memorized features are erroneously associated with the wrong object, can provide a window into the intrinsic limits in capacity of WM that represent a key bottleneck in our cognitive ability. We tested the hypothesis that binding in WM is accomplished via neural phase synchrony and that swap errors result from perturbations in this synchrony. Using magnetoencephalography data collected from human subjects in a task designed to induce swap errors, we showed that swaps are characterized by reduced phase-locked oscillatory activity during memory retention, as predicted by an attractor model of spiking neural networks. Further, we found that this reduction arises from increased phase coding variability in the alpha-band over a distributed network of sensorimotor areas. Our findings demonstrate that feature binding in WM is accomplished through phase coding dynamics that emerge from the competition between different memories. SignificanceWe investigate the neural basis of working memory, focusing on how feature binding is accomplished and how binding or swap errors arise. Using magnetoencephalography, we found that stable phase-locking of alpha oscillations supports correct feature binding, while swap errors correlate with reduced alpha phase preservation, localized to specific brain areas. These findings align with a biologically-plausible computational model predicting that temporal synchrony in neuronal firing underpins feature binding. This work advances our understanding of the neural mechanisms of working memory, providing empirical support for theories of time-based binding and demonstrating the utility of biophysically-realistic models in human neuroimaging studies.

neuroscience↗

Across-area synchronization supports feature integration in working memory

Working memory function is severely limited. One key limitation that constrains the ability to maintain multiple items in working memory simultaneously is so-called swap errors. These errors occur when an inaccurate response is in fact accurate relative to a non-target stimulus, reflecting the failure to maintain the appropriate association or "binding" between the features that define one object (e.g., color and location). The mechanisms underlying feature binding in working memory remain unknown. Here, we tested the hypothesis that features are bound in memory through synchrony across feature-specific neural assemblies. We built a biophysical neural network model composed of two one-dimensional attractor networks - one for color and one for location - simulating feature storage in different cortical areas. Within each area, gamma oscillations were induced during bump attractor activity through the interplay of fast recurrent excitation and slower feedback inhibition. As a result, different memorized items were held at different phases of the networks oscillation. These two areas were then reciprocally connected via weak cortico-cortical excitation, accomplishing binding between color and location through the synchronization of pairs of bumps across the two areas. Encoding and decoding of color-location associations was accomplished through rate coding, overcoming a long-standing limitation of binding through synchrony. In some simulations, swap errors arose: "color bumps" abruptly changed their phase relationship with "location bumps". This model, which leverages the explanatory power of similar attractor models, specifies a plausible mechanism for feature binding and makes specific predictions about swap errors that are testable at behavioral and neurophysiological levels.

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