Biology subjects

Cespon, J.

Publications and source records attributed to Cespon, J..

3 recordsLinked to original sources

bioRxiv2024

Electrophysiological correlates of cognitive reserve in healthy older adults at different cognitive states

High cognitive reserve (CR) is associated with a set of lifestyle factors such as high education level and occupational attainment. Studies suggest that CR is linked to enhanced executive control functions. Nevertheless, it is unclear what are the functional neural activity patterns linked to high CR and to what extent they are steady across different cognitive states. The aim of the present study was to investigate electrophysiological differences between low CR (LCR) and high CR (HCR) at rest and during the performance of two cognitive control tasks with different difficulty level. Thus, 67 older adults performed an experimental session consisting of two spatial stimulus-response compatibility (SRC) tasks (i.e., the Simon task, and the more demanding spatial Stroop task), and a resting state during an electroencephalogram (EEG) recording. Cognitive control was better in HCR than LCR group, as revealed by higher accuracy in HCR compared to LCR group in incongruent conditions of the tasks. Moreover, event-related brain potentials (ERP) showed earlier latencies (P300) in HCR than LCR and time/frequency analysis showed higher alpha activity in HCR than LCR during the performance of the tasks, while no differences were observed at rest within any of the analyzed frequency bands. Higher P300 frontalization was observed in LCR than HCR in the more difficult task but it was not related to frontalization within a specific frequency band. Overall, results showed that electrophysiological differences between high and low CR depend on the cognitive state, with greater CR-related differences emerging at increased task demands.

neuroscience↗

bioRxiv2023

Cognitive reserve counteracts typical neural activity changes related to ageing

Studies have shown that older adults with high Cognitive Reserve (HCR) exhibit better executive functioning than their low CR (LCR) counterparts. However, the neural processes linked to those differences are unclear. This study investigates (1) the neural processes underlying enhanced executive functions in older adults with HCR and (2) how executive control differences are modulated by task difficulty. We recruited 74 participants, who performed two executive control tasks with different difficulty levels while recording the electroencephalogram. The accuracy on both tasks requiring inhibition of irrelevant information was better in the HCR than the LCR group. Also, in the more demanding task, event-related potentials (ERP) latencies related to inhibition and working memory update were faster in HCR than LCR. Moreover, the HCR, but not the LCR, showed larger P300 amplitude in parietal than frontal regions and in the left than right hemisphere, suggesting a posterior to anterior shift of activity and loss of inter-hemispheric asymmetries in LCR participants. These results suggest that high CR counteracts neural activity changes related to ageing. Thus, high levels of CR can be related to maintenance of neural activity patterns typically observed in young adults rather than to deployment of neural compensatory mechanisms.

neuroscience↗

bioRxiv2023

Cognitive control activity is enhanced by single pulse transcranial magnetic stimulation over prefrontal and premotor areas

Cognitive control, which includes a set of processes to implement goal directed actions and flexible behaviour, is related to a set of brain areas comprising prefrontal, premotor, and parietal cortex. However, the functional relationships between these areas and the neural correlates underlying the specific cognitive processes linked to cognitive control (e.g., inhibition and working memory update) are still unclear. In the present study, participants performed a spatial cognitive control task (i.e., a Simon task) during a transcranial magnetic stimulation electroencephalogram (TMS-EEG) co-registration. In different blocks of the task, single pulse TMS was applied over the left prefrontal, premotor, and parietal regions (a sham TMS condition was also included) at 180ms after the stimulus onset. Behavioural differences between the four TMS conditions were not observed. Accordingly, activity to inhibit the response toward the attended location was not modulated by TMS, as indexed by the contralateral central negativity (N2cc), even if TMS over parietal regions accelerated the visuospatial processing, as evidenced by faster contralateral posterior negativity (N2pc). Importantly, we observed larger P300 amplitude when delivering TMS over prefrontal and premotor cortex compared to the sham condition. These results suggest that TMS applied over the left prefrontal and premotor regions could enhances working memory processes linked to switch-and-update of the stimulus-response binding and align with the existence of prefrontal-premotor connections.

neuroscience↗