Complex memories induced by intracranial electrical brain stimulation are related to complex networks.

The precise and fleeting moment of rich recollection triggered by an environmental cue is difficult to reproduce in the lab. However, epilepsy patients can experience sudden reminiscences after intracranial electrical brain stimulation (EBS). In these cases, the transient brain state related to the activation of the engram and its conscious perception can be recorded using intracerebral EEG (iEEG).

An insight from the default mode network in patients with amnesia following left thalamic infarction involving the mediodorsal nucleus and mammillothalamic tract.

The role of the medial part of the thalamus, and in particular the mediodorsal nucleus (MD) and the mammillothalamic tract (MTT), in memory has long been studied, but their contribution remains unclear. While the main functional hypothesis regarding the MTT focuses on memory, some authors postulate that the MD plays a supervisory executive role (indirectly affecting memory retrieval) due to its dense structural connectivity with the prefrontal cortex (PFC). Recently, it has been proposed that the MD, MTT and PFC form part of the DMN the default mode network (DMN).

Detecting fast-ripples on both micro- and macro-electrodes in epilepsy: A wavelet-based CNN detector.

Background: Fast-ripples (FR) are short (∼10 ms) high-frequency oscillations (HFO) between 200 and 600 Hz that are helpful in epilepsy to identify the epileptogenic zone. Our aim is to propose a new method to detect FR that had to be efficient for intracerebral EEG (iEEG) recorded from both usual clinical macro-contacts (millimeter scale) and microwires (micrometer scale).

New Method: Step 1 of the detection method is based on a convolutional neural network (CNN) trained using a large database of > 11,000 FR recorded from the iEEG of 38 patients with epilepsy from both macro-contacts and microwires.

A roadmap towards standardized neuroimaging approaches for human thalamic nuclei.

The thalamus has a key role in mediating cortical-subcortical interactions but is often neglected in neuroimaging studies, which mostly focus on changes in cortical structure and activity. One of the main reasons for the thalamus being overlooked is that the delineation of individual thalamic nuclei via neuroimaging remains controversial. Indeed, neuroimaging atlases vary substantially regarding which thalamic nuclei are included and how their delineations were established.