Harmonicity is a property of complex sounds such as vocalizations or music, but it remains unclear how harmonicity is processed in the auditory cortex (ACtx). Subregions of ACtx are thought to process harmonic stimuli differently. Selective responses to sound features in ACtx emerge hierarchically from primary ACtx (A1) L4 and secondary ACtx (A2) layer (L)2/3, which is believed to be the most responsive to harmonic sounds. Since harmonic stacks can range from 2 to >10 components, being more similar to naturalistic vocalizations, harmonic sensitivity might also arise hierarchically across layers and areas. We studied responses to harmonic stacks of 2–10 frequencies across A1 L4, A1 L2/3, and A2 L2/3 in adult male and female mice using in vivo two-photon microscopy. We found harmonic-sensitive neurons (HNs) responding only to harmonic stacks but not to individual frequencies in all areas at similar proportions. HNs showed highly nonlinear spectral integration of harmonic frequencies that decreased as the har...

Rapid advancements in artificial intelligence (AI) have enabled text-to-speech (TTS) systems to produce voices increasingly indistinguishable from humans, posing significant societal risks, particularly through potential misuse in fraud and deception. To address this concern, this study combined behavioral assessments and neural measures using electroencephalography (EEG) to examine whether short-term perceptual training enhances people's ability to distinguish AI-generated from human speech. Thirty participants (of either sex) listened to sentences produced by human speakers and corresponding AI-generated clones, judging each sentence as either human or AI-generated before and after a brief (∼12 min) training session, during which voices were explicitly labeled as “human” or “AI.” Behaviorally, participants showed consistently poor discrimination before and after training, with only minimal improvement. However, neural analyses revealed substantial training-induced changes. Specifically, temporal response...

Rodent hippocampal power spectra comprise periodic and aperiodic components. The periodic components (brain rhythms) contain information about the behavioral or cognitive state of the animal. The aperiodic components are rarely studied, and their functionality is not well understood, though they have shown to be correlated with animal's age or the excitation–inhibition ratio of the brain region. To study these components in the mouse hippocampus, we modified the existing open-source FOOOF toolbox, which was originally optimized for EEG data. First, using simulated data, we show that our modifications decrease the error in assessment of the low frequency periodic components from 3 to 0.1%. Second, using tetrode electrophysiological signals from adult males, we compare the aperiodic activity within mice hippocampal subregions, CA1 and dentate gyrus (DG). Our optimization of FOOOF improved the aperiodic assessment errors by ∼50% and were critical in making the first assessment of the aperiodic components in t...

Forming a long-term memory requires changes in neuronal transcription. What happens, though, as the memory is forgotten? And how does the transcriptional state relate to the maintenance and recall of the long-term memory? To answer these questions, we have been systematically tracing the time course of transcriptional changes evoked by long-term sensitization in the marine mollusk Aplysia californica . Our approach captures transcriptional changes in neurons of known behavioral relevance using a within-subject design, delineating patterns of transcriptional change that are comprehensive and reproducible. We have previously reported that within 1 d of long-term sensitization training, there is a widespread transcriptional response involving robust changes in over 5% of tested transcripts (1,198 of ∼22 k; [Conte et al., 2017][1]). Within 1 week, however, memory strength fades, and nearly all transcriptional changes relapse to baseline ( [Perez et al., 2018][2]). Here we report microarray analysis ( N  = 16) ...

A possible mechanism of temporal lobe epilepsy is insufficient inhibition of hippocampal dentate granule cells. Precipitating injuries that kill interneurons in the dentate gyrus might result in fewer inhibitory synapses with granule cells. To test this hypothesis, previous studies evaluated numbers or densities of interneurons, γ-amino butyric acid (GABA)ergic boutons, and inhibitory synapses in tissue from human patients with temporal lobe epilepsy and rodent models. However, those studies have limitations. Some of those limitations can be addressed by a large animal model. Sea lions ( Zalophus californianus ) can develop temporal lobe epilepsy naturally. Like humans, epileptic sea lions exhibit bilateral or unilateral hippocampal sclerosis (neuron loss) with granule cell vulnerability, but sea lions permit optimal tissue preservation and sampling, and good control subjects. To label interneuron cell bodies and GABAergic synaptic boutons, sea lion hippocampal tissue from both sexes was processed with imm...

The current treatment for drug-resistant epilepsy is surgical intervention, which relies on accurate identification of the seizure onset zone (SOZ) using intracranial electroencephalography (iEEG) data. iEEG analysis with computational epileptogenic zone identification algorithms (CEZIAs) is a promising step toward better SOZ localization and surgical outcomes. A key step in validation and adoption of CEZIAs is to allow for widespread shared development and validation of code and data. To achieve this, we developed an ecosystem of seizure localization methods that includes a straightforward analysis pipeline, standardized data formatting and storage, and completely documented and open-source code. The TableContainer package provides standardized storage of tabular data and serves as a foundational data structure for the ecosystem. Building on this, the Epoch package enables cropping, resampling, and visualization of iEEG data and provides publicly downloadable datasets for reproducibility. The public iEEG ...

Social media (SM) use is typically regarded as a technological tool which might negatively impact physical fitness and cognitive function, especially in critical developmental stages. In this opinion paper, we argue that specific forms of SM content might be beneficial for promoting motor skill acquisition and function. Furthermore, we suggest that SM use might be a promising innovative tool for educational purposes in optimizing skills not only in sports but also in academia. As a prerequisite, future research is needed to clarify the optimal type of content, its use, and how these parameters are affected by age. Therefore, longitudinal studies across the lifespan are necessary for a thorough understanding of the potential beneficial effects of SM use. The use of social media (SM) has rapidly accelerated due to technological progress and the release of the first SM platforms such as Facebook in the early 2000s. During the Covid-19 pandemic, lockdowns and social distancing acted as catalysts, contributing...

Accurate time estimation is essential for optimizing our perception and actions. Previous neuroimaging and transcranial magnetic stimulation (TMS) studies have suggested that the right inferior parietal lobule (IPL) and supplementary motor area (SMA) are involved in time perception. However, it remains inconclusive whether the activity in these regions is crucial for time perception, partly due to the possible spread of TMS effects across anatomically connected brain regions. Such a remote effect is less likely to happen with transcranial static magnetic stimulation (tSMS), as the static magnetic field is expected to modulate the firing threshold of neurons rather than directly triggering an action potential. In this study, we aimed to determine the causal relevance of local activities in the right IPL and the SMA for temporal processing using tSMS. Forty-eight human volunteers (26 males and 22 females) participated in the study. We measured duration discrimination thresholds, along with orientation discri...

Implicit adaptation recalibrates movements based on sensory prediction errors. It is often characterized as automatic and resource-independent, suggesting that it is insulated from cognitive influence. Here, we asked whether implicit adaptation is sensitive to goal-directed attentional demands imposed by a concurrent visual task. Across two experiments, we used clamped visual feedback to measure implicit adaptation while human adults (49 females, 23 males) monitored a rapidly changing visual stream for targets. In Experiment 1, participants performing the visual task showed modest early enhancement in implicit adaptation relative to a single-task control condition. In Experiment 2, adding response-contingent feedback to the visual task led to stronger and more sustained enhancement. Visual task accuracy and implicit adaptation were uncorrelated, arguing against resource competition. Model-based analyses revealed elevated error sensitivity under dual-task conditions, with individual differences reflecting a...

Reward prediction errors (RPEs) guide learning by comparing expected and obtained outcomes. In mammals, ventral tegmental area (VTA) activity is closely linked to RPE-like signaling, yet how avian VTA dynamics evolve during reinforcement learning remains less well characterized. Here we recorded VTA spiking in pigeons (two females and one male) performing a cue-guided operant task in which a green cue (cue+) predicted reward contingent on a key peck, whereas a red cue (cue−) was unrewarded. Using a 16-channel microwire array, we analyzed pooled channel-level multiunit activity (MUA) aligned to task events. Across sessions, cue+ trials showed a learning-related redistribution of event-locked modulation: outcome-locked activity was more prominent early in training, while cue-locked modulation became stronger as performance stabilized, consistent with a temporal-difference–like shift of prediction-related signals. Cue− trials were sparse after early learning and showed limited cue-locked modulation in the ava...