Magnetoencephalography can reveal deep brain network activities linked to memory processes

López‐Madrona, Víctor J.; Villalon, Samuel Médina; Badier, Jean‐Michel; Trébuchon, Agnès; Velmurugan, J; Bartolomei, Fabricē; Carron, Romain; Barborică, Andrei; Vulliémoz, Serge; Alario, F.‐Xavier; Bénar, Christian

doi:10.1002/hbm.25987

Cited by 16 publications

(10 citation statements)

References 116 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 e ). A similar facilitation pattern was found in MEG during the same task ( López-Madrona et al, 2022 ). In that work, the combined activity of the hippocampus and the rhinal cortex presented earlier latencies for old items, although the onset time of the differential activity was not measured.…”

Section: Discussionsupporting

confidence: 80%

“…This result has suggested that the hippocampus is mainly involved in a slower process that retrieves complementary information ( Despouy et al, 2020a ), although early activations have also been identified for specific source memory effects ( Staresina et al, 2012 ). A similar result was found in a recent magnetoencephalography (MEG) study, with higher amplitudes for recognition memory at ∼500 ms ( López-Madrona et al, 2022 ). Interestingly, the responses to old and new elements were different not only in amplitude but also in delay, with faster activations for recognized items.…”

Section: Introductionsupporting

confidence: 87%

“…Together with the absence of clear amplitude differences and the midfrontal topography of the FN400, our results cannot support any major role of Hc250-IC in the scalp ERP. Otherwise, the Hc600-IC potential is visible at the surface in MEG recordings ( López-Madrona et al, 2022 ) and may directly contribute to the LPC component, as both have similar activation time. Our results, with earlier delays for recognition memory in Hc600-IC, indicate that the hippocampus could be also indirectly involved in the generation of the FN400 by activating other areas.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Identification of Early Hippocampal Dynamics during Recognition Memory with Independent Component Analysis

López-Madrona,

Trébuchon,

Mindruta

et al. 2024

eNeuro

Self Cite

View full text Add to dashboard Cite

The hippocampus is generally considered to have relatively late involvement in recognition memory, its main electrophysiological signature being between 400 and 800 ms after stimulus onset. However, most electrophysiological studies have analyzed the hippocampus as a single responsive area, selecting only a single-site signal exhibiting the strongest effect in terms of amplitude. These classical approaches may not capture all the dynamics of this structure, hindering the contribution of other hippocampal sources that are not located in the vicinity of the selected site. We combined intracerebral electroencephalogram recordings from epileptic patients with independent component analysis (ICA) during a recognition memory task involving the recognition of old and new images. We identified two sources with different responses emerging from the hippocampus: a fast one (maximal amplitude at ∼250 ms) that could not be directly identified from raw recordings, and a later one, peaking at ∼400 ms. The earliest component presented different amplitudes between old and new items in 6 out of 10 patients. The latter component had different delays for each condition, with a faster activation (∼290 ms after stimulus onset) for recognized items. We hypothesize that both sources represent two steps of hippocampal recognition memory, the faster reflecting the input from other structures and the latter the hippocampal internal processing. Recognized images evoking early activations would facilitate neural computation in the hippocampus, accelerating memory retrieval of complementary information. Overall, our results suggest that hippocampal activity is composed by several sources with an early activation related to recognition memory.Significance StatementIn the human memory circuit, the hippocampus is considered as a structure with relatively late activation, associated to the retrieval of elaborate memories. However, in most electrophysiological studies, it is characterized by the activity of a single contact, which may not represent the entire dynamics of this structure. Here, we combined intracerebral recordings with independent component analysis to separate the activity from two different neural sources generated in the hippocampus. We analyzed the responses of both sources during the recognition of old and new images. Our results reveal new dynamics associated to different neuronal sources within the hippocampus, with recognition memory occurring much faster than previously reported.

show abstract

Section: Discussionsupporting

confidence: 80%

Section: Introductionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Identification of Early Hippocampal Dynamics during Recognition Memory with Independent Component Analysis

López-Madrona,

Trébuchon,

Mindruta

et al. 2024

eNeuro

Self Cite

View full text Add to dashboard Cite

show abstract

“…This neuronal facilitation would be reflected in the ERP, with earlier latencies for old items (Figure 3e). Interestingly, we identified a similar facilitation pattern in magnetoencephalography (MEG) during the same task (López-Madrona et al, 2022). In that work, the combined activity of the hippocampus and the rhinal cortex presented earlier latencies for old items.…”

Section: Early Memory Recognition System Of the Hippocampussupporting

confidence: 72%

Identification of an early hippocampal recognition system using intracerebral evoked potentials in humans

López‐Madrona

Trébuchon

Mı̂ndruță

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

The role of the hippocampal formation in memory recognition has been well studied in animals, with different pathways and structures linked to specific memory processes. In contrast, the hippocampus is commonly analyzed as a unique responsive area in most electrophysiological studies in humans, and the specific activity of its subfields remains unexplored. We combined intracerebral electroencephalogram recordings from epileptic patients with independent component analysis (ICA) during a memory recognition task involving the recognition of old and new images to disentangle the activities of multiple neuronal sources within the hippocampus. We identified two sources with different responses emerging from the hippocampus: a fast one (maximum at ~250 ms) that could not be directly identified from raw recordings, and a later one, peaking at ~400 ms. The earliest component was found in 12 out of 15 electrodes, with different amplitudes for old and new items in half of the electrodes. The latter component, identified in 13 out of 15 electrodes, had different delays for each condition, with a faster activation (~290 ms after stimulus onset) for recognized items. We hypothesize that both sources represent two steps of hippocampal memory recognition, the faster reflecting the input from other structures and the latter the hippocampal internal processing. Recognized images evoking early activations would facilitate neural computation in the hippocampus, accelerating memory retrieval of complementary information. Overall, our results suggest that hippocampal activity is composed by several sources, including an early system for memory recognition, that can be disentangled with ICA methods.

show abstract

“…We used the same experimental visual memory paradigm as in López-Madrona et al ( 2022 ). In summary, we used 168 images from the database of Duñabeitia et al ( 2018 ) that were organized in blocks of 12 or 24 images, presented on a computer screen.…”

Section: Methodsmentioning

confidence: 99%

Studying memory processes at different levels with simultaneous depth and surface EEG recordings

Barborică

Mı̂ndruță

López‐Madrona

et al. 2023

Front. Hum. Neurosci.

Self Cite

View full text Add to dashboard Cite

Investigating cognitive brain functions using non-invasive electrophysiology can be challenging due to the particularities of the task-related EEG activity, the depth of the activated brain areas, and the extent of the networks involved. Stereoelectroencephalographic (SEEG) investigations in patients with drug-resistant epilepsy offer an extraordinary opportunity to validate information derived from non-invasive recordings at macro-scales. The SEEG approach can provide brain activity with high spatial specificity during tasks that target specific cognitive processes (e.g., memory). Full validation is possible only when performing simultaneous scalp SEEG recordings, which allows recording signals in the exact same brain state. This is the approach we have taken in 12 subjects performing a visual memory task that requires the recognition of previously viewed objects. The intracranial signals on 965 contact pairs have been compared to 391 simultaneously recorded scalp signals at a regional and whole-brain level, using multivariate pattern analysis. The results show that the task conditions are best captured by intracranial sensors, despite the limited spatial coverage of SEEG electrodes, compared to the whole-brain non-invasive recordings. Applying beamformer source reconstruction or independent component analysis does not result in an improvement of the multivariate task decoding performance using surface sensor data. By analyzing a joint scalp and SEEG dataset, we investigated whether the two types of signals carry complementary information that might improve the machine-learning classifier performance. This joint analysis revealed that the results are driven by the modality exhibiting best individual performance, namely SEEG.

show abstract

Magnetoencephalography can reveal deep brain network activities linked to memory processes

Cited by 16 publications

References 116 publications

Identification of Early Hippocampal Dynamics during Recognition Memory with Independent Component Analysis

Identification of Early Hippocampal Dynamics during Recognition Memory with Independent Component Analysis

Identification of an early hippocampal recognition system using intracerebral evoked potentials in humans

Studying memory processes at different levels with simultaneous depth and surface EEG recordings

Contact Info

Product

Resources

About