The effects of multi-day rTMS and cardiorespiratory fitness on working memory and local GABA concentration

AbstractWorking memory (WM) refers to the capacity to temporarily retain and manipulate finite amounts of information; a critical process in complex behaviours such as reasoning, comprehension, and learning. This cognitive function is supported by a parietal-prefrontal network and linked to the activity of key brain neurotransmitters, such as gamma-aminobutyric acid (GABA). Impairments in WM are seen in a range of psychiatric and neurological disorders, and there are currently no effective methods of remediating WM deficits. In this study, we analysed secondary outcome measures from a trial investigating the effects of multi-day rTMS on cognition. Participants received four days of 20 Hz rTMS to an individualised region of left parietal cortex in one week, and an individualised region of pre-supplementary motor area (pre-SMA) in a separate week. We assessed changes to WM function before and after each week of stimulation (N = 39), and changes to GABA concentration before and after stimulation in week one using MR spectroscopy (N = 18 per stimulation condition). We hypothesised that multi-day parietal rTMS would enhance WM and reduce GABA concentration, but this was not observed. Instead, we report some evidence of improved WM function and increased GABA concentration following pre-SMA rTMS, although this effect was variable across individuals. Additionally, we found that higher cardiorespiratory fitness was associated with greater WM improvement following pre-SMA stimulation. While there are a number of factors known to influence the response to rTMS, increasing cardiorespiratory fitness may provide a novel approach to enhance cognitive outcomes. Given the clinical utility of both exercise and rTMS, future studies are required to determine whether additive effects may be achieved when applied in tandem.

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No evidence for changes in GABA concentration, functional connectivity, or working memory following continuous theta burst stimulation over dorsolateral prefrontal cortex

10.1101/2021.06.17.448448 ◽

2021 ◽

Author(s):

Tribikram Thapa ◽

Joshua Hendrikse ◽

Sarah Thompson ◽

Chao Suo ◽

Mana Biabani ◽

...

Keyword(s):

Working Memory ◽

Functional Connectivity ◽

Memory Performance ◽

Memory Task ◽

Low Frequency ◽

Theta Burst Stimulation ◽

Gaba Concentration ◽

Dorsolateral Prefrontal ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

Continuous theta burst stimulation (cTBS) is thought to reduce cortical excitability and modulate functional connectivity, possibly by altering cortical inhibition at the site of stimulation. However, most evidence comes from the motor cortex and it remains unclear whether similar effects occur following stimulation over other brain regions. We assessed whether cTBS over left dorsolateral prefrontal cortex altered gamma aminobutyric acid (GABA) concentration, functional connectivity and brain dynamics at rest, and brain activation and memory performance during a working memory task. Seventeen healthy individuals participated in a randomised, sham-controlled, cross-over experiment. Before and after either real or sham cTBS, magnetic resonance spectroscopy was obtained at rest to measure GABA concentrations, whereas functional magnetic resonance imaging (fMRI) was recorded at rest and during an n-back working memory task to measure functional connectivity, brain dynamics (low-frequency fluctuations), and task-related patterns of brain activity. We could not find evidence for changes in GABA concentration (P=0.66, Bayes factor [BF10]=0.07), resting-state functional connectivity (P(FWE)>0.05), resting-state low-frequency fluctuations (P=0.88, BF10=0.04), blood-oxygen level dependent activity during the n-back task (P(FWE) >0.05), or working memory performance (P=0.13, BF10=0.05) following real or sham cTBS. Our findings add to a growing body of literature suggesting the effects of cTBS are highly variable between individuals and question the notion that cTBS is a universal 'inhibitory' paradigm.

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Cardiorespiratory fitness, physical activity and pulse pressure as predictors of learning in a multicomponent intervention in healthy older adults

10.31219/osf.io/y3mwe ◽

2021 ◽

Author(s):

Jonna Nilsson ◽

Maria Ekblom ◽

Olga Tarassova ◽

Martin Lövdén

Keyword(s):

Physical Activity ◽

Older Adults ◽

Working Memory ◽

Cardiorespiratory Fitness ◽

Pulse Pressure ◽

Intervention Period ◽

Healthy Older Adults ◽

Multicomponent Intervention ◽

Predictive Role

This project concerns new analyses based on pre-existing data from a randomized controlled multicomponent intervention study combining physical exercise and cognitive training in healthy older adults. The project tests the predictive role of cardiorespiratory fitness, physical activity and pulse pressure for learning in a working memory training context, in combination with physical exercise and in isolation. Specifically, two learning outcomes are considered: change in trained working memory tasks from before to after the intervention period (pre-post change) and day-by-day change in n-back performance during the intervention period (up to 32 timepoints). The results did not support a predictive role of cardiorespiratory fitness, physical activity or pulse pressure for learning in this particular study context. Please note that this document is intended solely as a report of the results pertaining to the registered hypotheses on Open Science Framework (https://osf.io/h5npm), simply to ensure transparency also of the null findings. As such, this document is not intended for formal peer-review or publication. If you are interested in the results, please do not hesitate to contact the author of this document ([email protected]).

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Working Memory, Cognitive Load and Cardiorespiratory Fitness: Testing the CRUNCH Model with Near-Infrared Spectroscopy

Brain Sciences ◽

10.3390/brainsci9020038 ◽

2019 ◽

Vol 9 (2) ◽

pp. 38 ◽

Cited By ~ 6

Author(s):

Nounagnon Agbangla ◽

Michel Audiffren ◽

Jean Pylouster ◽

Cédric Albinet

Keyword(s):

Working Memory ◽

Prefrontal Cortex ◽

Infrared Spectroscopy ◽

Cognitive Load ◽

Cognitive Performance ◽

Cardiorespiratory Fitness ◽

Near Infrared Spectroscopy ◽

Near Infrared ◽

Chronological Age ◽

Functional Near Infrared Spectroscopy

The present study aimed to examine the effects of chronological age and cardiorespiratory fitness (CRF) on cognitive performance and prefrontal cortex activity, and to test the compensation-related utilization of neural circuits hypothesis (CRUNCH). A total of 19 young adults (18–22 years) and 37 older ones (60–77 years) with a high or low CRF level were recruited to perform a working memory updating task under three different cognitive load conditions. Prefrontal cortex hemodynamic responses were continuously recorded using functional near-infrared spectroscopy, and behavioral performances and perceived difficulty were measured. Results showed that chronological age had deleterious effects on both cognitive performance and prefrontal cortex activation under a higher cognitive load. In older adults, however, higher levels of CRF were related to increased bilateral prefrontal cortex activation patterns that allowed them to sustain better cognitive performances, especially under the highest cognitive load. These results are discussed in the light of the neurocognitive CRUNCH model.

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Development of Cardiorespiratory Fitness Standards for Working Memory Using Receiver Operating Curves In 15-Year-Old Adolescents

10.21203/rs.3.rs-88014/v1 ◽

2020 ◽

Author(s):

Vinicius Muller Reis Weber ◽

Daniel Zanardini Fernandes ◽

Leonardo Alex Volpato ◽

Maria Raquel Oliveira Bueno ◽

Marcelo Romanzini ◽

...

Keyword(s):

Working Memory ◽

Cardiorespiratory Fitness ◽

Memory Performance ◽

Cross Sectional Study ◽

Roc Curve Analysis ◽

Cross Sectional ◽

Run Test ◽

Normal Performance ◽

Shuttle Run ◽

Receiver Operating

Abstract Working memory performance is associated with better academic achievements in children and adolescents, and it is positively related to CRF. However, what level of cardiorespiratory fitness (CRF) discriminates higher working memory performance is not known. The purpose of this study was to identify thresholds of CRF linked to working memory in adolescents. Data of 141 adolescents (53.2% girls) were collected (14.9 years) from a cross-sectional study during the year 2019. CRF was assessed by the 20-m shuttle run test, and maximal oxygen uptake were calculated by Mahar´s equation. Working memory was evaluated by the Corsi blocks test and the performance was classified by percentiles. Receiver operating characteristic (ROC) curve analysis was used to identify CRF thresholds. The results of ROC analysis indicated that CRF could be used to discriminate working memory in adolescents. CRF thresholds of ³45.03 ml.kg-1.min-1for boys and ³36.63 ml.kg-1.min-1for girls were found to be indicative of “normal” performance in working memory. ConclusionCRF could discriminate low and normal working memory performance in 14-16 years old adolescents. These thresholds could allow for earlier identification and intervention of low working memory performance by the CRF.

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