Quantifying neural efficiency and neural capacity across the brain during a working memory task using a quadratic model of neural‐cognitive relationships

Author(s):  
Jason Steffener ◽  
Syrina Al Aïn ◽  
Johannes Frasnelli
2004 ◽  
Vol 29 (6) ◽  
pp. 1203-1214 ◽  
Author(s):  
R A E Honey ◽  
G D Honey ◽  
C O'Loughlin ◽  
S R Sharar ◽  
D Kumaran ◽  
...  

2021 ◽  
Author(s):  
Paul Gomez

In this research we explore in detail how a phenomenon called sustained persistent activity is achieved by circuits of interconnected neurons. Persistent activity is a phenomenon that has been extensively studied (Papoutsi et al. 2013; Kaminski et. al. 2017; McCormick et al. 2003; Rahman, and Berger, 2011). Persistent activity consists in neuron circuits whose spiking activity remains even after the initial stimuli are removed. Persistent activity has been found in the prefrontal cortex (PFC) and has been correlated to working memory and decision making (Clayton E. Curtis and Daeyeol Lee, 2010). We go beyond the explanation of how persistent activity happens and show how arrangements of those basic circuits encode and store data and are used to perform more elaborated tasks and computations. The purpose of the model we propose here is to describe the minimum number of neurons and their interconnections required to explain persistent activity and how this phenomenon is actually a fast storage mechanism required for implementing working memory, task processing and decision making.


2020 ◽  
Author(s):  
Max Michael Owens ◽  
Nicholas Allgaier ◽  
Sage Hahn ◽  
Dekang Yuan ◽  
Matthew Albaugh ◽  
...  

Attention deficit/hyperactivity disorder is associated with numerous neurocognitive deficits including poor working memory and difficulty inhibiting undesirable behaviors that cause academic and behavioral problems in children. Prior work has attempted to determine how these differences are instantiated in the structure and function of the brain, but much of that work has been done in small samples, focused on older adolescents or adults, and used statistical approaches that were not robust to model overfitting. The current study used cross-validated elastic net regression to predict a continuous measure of ADHD symptomatology using brain morphometry and activation during tasks of working memory, inhibitory control, and reward processing, with separate models for each MRI measure. The best model using activation during the working memory task to predict ADHD symptomatology had an out-of-sample R2 = 2% and was robust to residualizing the effects of age, sex, race, parental income and education, handedness, pubertal status, and internalizing symptoms from ADHD symptomatology. This model used reduced activation in task positive regions and reduced deactivation in task negative regions to predict ADHD symptomatology. The best model with morphometry alone predicted ADHD symptomatology with an R2 = 1% but this effect dissipated when including covariates. The inhibitory control and reward tasks did not yield generalizable models. In summary, these analyses show, with a large and well-characterized sample, that the brain correlates of ADHD symptomatology are modest in effect size and captured best by brain morphometry and activation during a working memory task.


2021 ◽  
Author(s):  
Mateusz Woźniak ◽  
Timo Torsten Schmidt ◽  
Yuan-hao Wu ◽  
Felix Blankenburg ◽  
Jakob Hohwy

AbstractThe question how the brain distinguishes between information about oneself and the rest of the world is of fundamental interest to both philosophy and neuroscience. This question can be approached empirically by investigating how associating stimuli with oneself leads to differences in neurocognitive processing. However, little is known about the brain network involved in forming such self-associations for, specifically, bodily stimuli. In this fMRI study, we sought to distinguish the neural substrates of representing a full-body movement as one’s movement and as someone else’s movement. Participants performed a delayed match-to-sample working memory task where a retained full-body movement (displayed using point-light walkers) was arbitrarily labelled as one’s own movement or as performed by someone else. By using arbitrary associations we aimed to address a limitation of previous studies, namely that our own movements are more familiar to us than movements of other people. A searchlight multivariate decoding analysis was used to test where information about types of movement and about self-association was coded. Movement specific activation patterns was found in a network of regions also involved in perceptual processing of movement stimuli, however not in early sensory regions. Information about whether a memorized movement was associated with the self or with another person was found to be coded by activity in the left middle frontal gyrus (MFG), left inferior frontal gyrus (IFG), bilateral supplementary motor area, and (at reduced threshold) in the left temporoparietal junction (TPJ). These areas are frequently reported as involved in action understanding (IFG, MFG) and domain-general self/other distinction (TPJ). Finally, in univariate analysis we found that selecting a self-associated movement for retention was related to increased activity in the ventral medial prefrontal cortex.


NeuroImage ◽  
2009 ◽  
Vol 47 ◽  
pp. S144
Author(s):  
K Stingl ◽  
M Rogic ◽  
K Porubska ◽  
C Canova ◽  
O Tschritter ◽  
...  

2021 ◽  
pp. 003151252199828
Author(s):  
Eunbi Jeong ◽  
Jinhan Park ◽  
Yujin Kim ◽  
Minjung Woo

This study examined the electroencephalograpy (EEG) coherence and working memory performance effects of a 9-week exercise program on a small group of adolescents at high suicide risk. We randomly assigned 26 adolescents at high suicide risk (based on their scores on the Adolescents Mental Health Inventory- AMHI) into equal sized exercise and no-exercise groups. Before and after the 9-week exercise program, all participants performed the Sternberg working memory task, during which we recorded their EEGs, with electrodes placed at F3, F4, C3, C4, P3, P4, T3, T4, O1, and O2 regions (using the International 10-20 system of EEG electrode placement). We measured working memory performance and inter-hemispheric (F3-F4, C3-C4, T3-T4, P3-P4, O1-O2) and intra-hemispheric (F3-C3, F3-T3, F3-P3, F3-O1, F4-C4, F4-T4, F4-P4, F4-O2) EEG coherence as an index of the participants’ underlying neural efficiency. While we found no significant group differences in working memory performances, the exercise group, relative to the no-exercise group, exhibited lower inter- and intra-hemispheric EEG coherence while performing the working memory task. These EEG differences may reflect a mediating effect of aerobic exercise on these participants’ neural efficiency.


2021 ◽  
Author(s):  
Quan Wan ◽  
Jorge A. Menendez ◽  
Bradley R. Postle

How does the brain prioritize among the contents of working memory to appropriately guide behavior? Using inverted encoding modeling (IEM), previous work (Wan et al., 2020) showed that unprioritized memory items (UMI) are actively represented in the brain but in a “flipped”, or opposite, format compared to prioritized memory items (PMI). To gain insight into the mechanisms underlying the UMI-to-PMI representational transformation, we trained recurrent neural networks (RNNs) with an LSTM architecture to perform a 2-back working memory task. Visualization of the LSTM hidden layer activity using Principle Component Analysis (PCA) revealed that the UMI representation is rotationally remapped to that of PMI, and this was quantified and confirmed via demixed PCA. The application of the same analyses to the EEG dataset of Wan et al. (2020) revealed similar rotational remapping between the UMI and PMI representations. These results identify rotational remapping as a candidate neural computation employed in the dynamic prioritization within contents of working memory.


2019 ◽  
Author(s):  
Roman Trepp ◽  
Raphaela Muri ◽  
Lenka Bosanska ◽  
Stephanie Abgottspon ◽  
Michel Hochuli ◽  
...  

Abstract Background The population of adult patients with early-treated phenylketonuria (PKU) following newborn screening is growing substantially. The ideal target range of blood Phe levels in adults outside pregnancy is discussed controversially. Therefore, prospective intervention studies are needed to evaluate the effects of an elevated Phe concentration on cognition and structural, functional and neurometabolic parameters of the brain. Methods The PICO (Phenylalanine and Its Impact on Cognition) Study evaluates the effect of a 4-week phenylalanine (Phe) load on cognition and cerebral parameters in 30 adults with early-treated PKU in a double-blind, randomized, placebo-controlled, crossover, non-inferiority trial. The primary objective of the PICO Study is to prospectively assess whether a temporarily elevated Phe level influences cognitive performance in adults with early-treated PKU. As secondary objective, the PICO Study will elucidate cerebral and neurometabolic mechanisms, which accompany changes in Phe concentration using advanced neuroimaging methods. In addition to the intervention study, cognition, structural and functional parameters of the brain of adult patients with early-treated PKU will be cross-sectionally compared to healthy controls, who will be comparable with regard to age, gender and education level. Advanced MR-techniques will be used to investigate intensity of neural activation during the working memory task (fMRI), strength of functional connectivity between brain regions related to performance in working memory (rsfMRI), white matter integrity (DTI), cerebral blood flow (ASL) and brain Phe concentrations (MRS). Discussion Using a combination of neuropsychological and neuroimaging data, the PICO study will considerably contribute to improve the currently insufficient level of evidence on how adult patients with early-treated PKU should be managed.


Author(s):  
Adam Eichenbaum ◽  
Daphne Bavelier ◽  
C. Shawn Green

Neural plasticity, or the ability of the brain to reorganize its structure and activity, is of critical importance. For nearly 50 years, the dominant framework in the field of learning and neural plasticity held that the brain was capable of truly large-scale changes only early in life. However, emerging evidence suggests that plasticity that had assumed to be “lost” due to age, injury, or disease may be at least partially re-established via genetic, pharmacological, and/or behavioral means. Yet, while it is true that humans retain a significant capacity to learn throughout the life span, a second roadblock frequently stands in the way of translating learning gains into practical real-world benefits. This obstacle is the “curse of specificity.” While it is true that, given appropriate training, humans will tend to improve on almost any task, the improvements that are observed are often confined to the exact training task, with little to no benefits of the training being observed for even seemingly very similar tasks. This chapter discusses the trend toward task-specific training on one working memory task, as well as the finding that action video game training does appear to lead to more generalizable improvements in cognitive performance.


2005 ◽  
Vol 16 (5) ◽  
pp. 609-617 ◽  
Author(s):  
Seema Sayala ◽  
Joseph B. Sala ◽  
Susan M. Courtney

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