European Journal of Neuroscience最新文献

Transcranial alternating current stimulation (tACS) has been proposed to modulate neural activity through two primary mechanisms: entrainment and neuroplasticity. The current study aimed to probe both of these mechanisms in the context of the sensorimotor μ-rhythm using transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to assess entrainment of corticospinal excitability (CSE) during stimulation (i.e., online) and immediately following stimulation, as well as neuroplastic aftereffects on CSE and μ EEG power. Thirteen participants received three sessions of stimulation. Each session consisted of 90 trials of μ-tACS tailored to each participant's individual μ frequency (IMF), with each trial consisting of 16 s of tACS followed by 8 s of rest (for a total of 24 min of tACS and 12 min of rest per session). Motor-evoked potentials (MEPs) were acquired at the start and end of the session (n = 41), and additional MEPs were acquired across the different phases of tACS at three epochs within each tACS trial (n = 90 for each epoch): early online, late online and offline echo. Resting EEG activity was recorded at the start, end and throughout the tACS session. The data were then pooled across the three sessions for each participant to maximise the MEP sample size per participant. We present preliminary evidence of CSE entrainment persisting immediately beyond tACS and have also replicated the plastic CSE facilitation observed in previous μ-tACS studies, thus supporting both entrainment and neuroplasticity as mechanisms by which tACS can modulate neural activity.

Nekhoroshev, E., Kleshchev, M., Volgin, A., Shevlyakov, A., Bao, X., Wang, S., Abreu, M., Amstislavskaya, T. and Kalueff, A. (2025), Laser-Induced Olfactory Bulbectomy in Adult Zebrafish as a Novel Putative Model for Affective Syndrome: A Research Tribute to Brian Leonard. European Journal of Neuroscience, 61: e16660.

In the paper by Nekhoroshev et al. (2025), the author's name Anton Shevlyakov was misspelled.

We apologize for this error.

Repetition suppression (RS) refers to the reduction of neuronal responses to repeated stimuli as compared to nonrepeated stimuli. The predictive coding account of RS proposes that its magnitude is modulated by repetition probability (P(rep)) and that this modulation increases with prior experience with the stimulus category. To test these proposals, we examined RS and its modulation by P(rep) for three stimulus categories for which participants had different expertise (Asian faces, written Chinese words and animals) using EEG. Cantonese speakers watched paired stimuli (S1–S2) of a given category with S2 being the same or a different stimulus as S1. Attributes of S1 (e.g., the sex of the first face) served as a cue for the repetition probability of S2. There were significant repetition effects and distinct topographic distributions across stimulus categories. Repetition effects in the N250 component were present in all stimulus categories, but in words, they appeared earlier and showed distinct topographic patterns compared to faces and animals. These results suggest that repetition effects differ between stimulus categories, presumably depending on prior experience and stimulus properties, such as spatial frequency. Importantly, we failed to find evidence for effects of P(rep) across any of the three categories. These null findings of P(rep) effects are putatively indicating an absence of expectancy modulation of repetition effects.

Episodic memory benefits from arousal, with better retrieval linked to arousing to-be-remembered information. Arousal's impact on subsequent memory processes, particularly for nonarousing stimuli, remains unclear. Healthy ageing is associated with emotion regulation changes and declines in episodic memory, which may influence how arousal affects memory processes. This functional Magnetic Resonance Imaging (fMRI) study examined the effects of valence on episodic memory in young and old adults, focusing on memory of neutral information following arousal exposure. Neural activity was assessed at three time points: during exposure to arousing and nonarousing images, encoding of neutral videos following image exposure, retrieval of the encoded videos. We hypothesised that valence would induce distinct neural activation across task stages, and exposure to negative stimuli would be associated with worse retrieval. Old adults were expected to show stronger neural responses to positive valence and less disruption from negative valence on memory performance. Behavioural results revealed that only negative valence was associated with impaired retrieval. fMRI results replicated age-related differences in memory performance, with old adults compensating through increased hippocampal and frontal gyri activity. Negative valence was associated with increased activity in the occipital cortex and precentral gyri, also affecting upcoming encoding with heightened activity in the left insula, precuneus and middle temporal gyrus. In old adults, positive valence prompted increasing neural engagement from initial exposure to retrieval, reflecting changes in emotion regulation strategies. Findings emphasise the enduring impact of negative valence on subsequent cognitive processes and suggest that age-related changes in emotional regulation influence memory-related neural processes.

Verbal fluency provides a unique index of the functional architecture of control functions because it reflects the interactions between executive processes and lower-level language processes. However, an evaluation of the number of correct words alone does not enable one to determine precisely which processes are impaired. This study investigates post-stroke fluency impairments, focusing on previously unexplored indices and their neuroanatomical correlates using voxel-based lesion symptom mapping (VLSM). In total, 337 patients and 851 controls performed letter and semantic fluency tests. Analyses included overall performance (correct responses) and strategic indices (errors, time course, frequency, switches, and cluster size). Stroke patients produced fewer correct responses, more rule-breaking errors, fewer words after 15″, fewer infrequent words, fewer switches, and smaller clusters in letter fluency. Switching was strongly associated with letter fluency, while clustering was more related to semantic fluency. VLSM identified left-hemisphere structures, particularly frontal tracts (e.g., anterior thalamic and frontostriatal tracts), associated with switching, and a smaller set of left-hemisphere structures linked to clustering.

Conceptually, the findings suggest stroke-related fluency disorders primarily arise from impairments in executive strategic search, as indicated by switching impairments, with weaker impairment on lexicosemantic abilities. The rarity of rule-breaking and perseverative errors indicates that inhibition and working memory deficits do not significantly contribute to poor fluency. The patients' production of infrequent words and fluency worsened over time, although the precise contributions of the three core processes to these additional changes require further investigation. Our results highlight the importance of detailed fluency evaluations in stroke patients for optimized rehabilitation.

Deterioration in the peripheral and central auditory systems is common in older adults and often leads to hearing and speech comprehension difficulties. Even when hearing remains intact, electrophysiological data of older adults frequently exhibit altered neural responses along the auditory pathway, reflected in variability in phase alignment of neural activity to speech sound onsets. However, it remains unclear whether challenges in speech processing in aging stem from more fundamental deficits in auditory and timing processes. Here, we investigated if and how aging individuals encoded temporal regularities in isochronous auditory sequences presented at 1.5Hz, and if they employed adaptive mechanisms of neural phase alignment in anticipation of next sound onsets. We recorded EEG in older and young individuals listening to simple isochronous tone sequences. We show that aging individuals displayed larger event-related neural responses, an increased 1/F slope, but reduced phase-coherence at the stimulation frequency (1.5Hz) and a reduced slope of phase-coherence over time in the delta and theta frequency-bands. These observations suggest altered top-down modulatory inhibition when processing repeated and predictable sounds in a sequence and altered mechanisms of continuous phase-alignment to expected sound onsets in aging. Given that deteriorations in these basic timing capacities may affect other higher-order cognitive processes (e.g., attention, perception, and action), these results underscore the need for future research examining the link between basic timing abilities and general cognition across the lifespan.