The accurate estimation of limb state is necessary for movement planning and execution. While state estimation requires both feedforward and feedback information, we focus here on the latter. Prior literature has shown that integrating visual and proprioceptive feedback improves estimates of static limb position. However, differences in visual and proprioceptive feedback delays suggest that multisensory integration could be disadvantageous when the limb is moving. We formalized this hypothesis by modeling feedback-based state estimation using the longstanding maximum likelihood estimation model of multisensory integration, which we updated to account for sensory delays. Our model predicted that the benefit of multisensory integration was largely lost when the limb was passively moving. We tested this hypothesis in a series of experiments in human subjects that compared the degree of interference created by discrepant visual or proprioceptive feedback when estimating limb position either statically at the e...

The auditory brainstem response (ABR) is a measure of subcortical activity in response to auditory stimuli. The wave V peak of the ABR depends on stimulus intensity level, and has been widely used for clinical hearing assessment. Conventional methods to estimate the ABR average electroencephalography (EEG) responses to short unnatural stimuli such as clicks. Recent work has moved towards more eco­logically relevant continuous speech stimuli using linear deconvolution models called Temporal Response Functions (TRFs). Investigating whether the TRF waveform changes with stimulus intensity is a crucial step towards the use of natural speech stimuli for hearing assessments involving subcortical responses. Here, we develop methods to estimate level-dependent subcortical TRFs using EEG data collected from 21 participants listening to continuous speech presented at 4 different intensity levels. We find that level-dependent changes can be detected in the wave V peak of the subcortical TRF for almost all par­ticipan...

Long-term aluminum (Al) exposure increases the risk of mild cognitive impairment (MCI). The aim of present study was to investigate the neural mechanisms of Al-induced MCI. In our study, a total of 52 individuals with occupational Al exposure > 10 years were enrolled and divided into two groups: MCI (Al-MCI) and healthy controls (Al-HC). Plasma Al concentrations and Montreal Cognitive Assessment (MoCA) score were collected for all participants. And diffusion tensor imaging and resting-state functional magnetic resonance imaging were used to examine changes of white matter (WM) and functional connectivity (FC). There was a negative correlation between MoCA score and plasma Al concentration. Compared with the Al-HC, fractional anisotropy value for the right fornix (cres)/stria terminalis (FX/ST) was higher in the Al-MCI. Furthermore, there was a difference in FC between participants with and without MCI under Al exposure. We defined the regions with differing FC as a “pathway”, specifically the connectivity ...

Peak-alpha frequency varies across individuals and mental states, but it also forms a negative gradient from posterior to anterior regions in association with increases in cortical thickness and connectivity, reflecting a cortical hierarchy in temporal integration. Tracking the spatial standard deviation of peak-alpha frequency in scalp EEG, we observed that a posterior-to-anterior gradient dynamically formed and dissolved. Periods of high spatial standard deviation yielded robustly negative posterior-to-anterior gradients—the “gradient state”—while periods of low spatial standard deviation yielded globally converged peak-alpha frequency—the “uniform state.” The state variations were characterized by a combination of slow (0.3 Hz-0.5 Hz) oscillations and random-walk-like fluctuations. They were relatively independently correlated with peak-alpha frequency variations in anterior regions and peak-alpha power variations in central regions driven by posterior regions (together accounting for ∼50% of the state ...

Public outreach can expand your professional perspective, make you a stronger communicator, and strengthen public support for science. There are many ways to get involved. In this webinar, experienced neuroscientists share ways to find outreach activities that connect to your personal strengths and interests and offer you a chance to educate the public about neuroscience.

This resource was featured in the NeuroJobs Career Center. Visit today to search the world’s largest source of neuroscience opportunities. Six seconds. That’s all it takes for a reviewer to put your resume or CV in the “keep” or “discard” pile. So to be a successful candidate, you need to make a strong impression. Watch this webinar to learn the strategies that will best showcase your value on a CV or resume and earn you that coveted position.

Sensory axons projecting to the central nervous system are organized into topographic maps that represent the locations of sensory stimuli. In some sensory systems, even adjacent sensory axons are arranged topographically, forming “fine-scale” topographic maps. Although several broad molecular gradients are known to instruct coarse topography, we know little about the molecular signaling that regulates fine-scale topography at the level of two adjacent axons. Here, we provide evidence that trans-synaptic BMP signaling mediates local inter-neuronal communication to regulate fine-scale topography in the nociceptive system of Drosophila larvae. We first show that the topographic separation of the axon terminals of adjacent nociceptors requires their common postsynaptic target, the A08n neurons. This phenotype is recapitulated by knockdown of the BMP ligand, Dpp, in these neurons. In addition, removing the type-II BMP receptors or their effector (Mad transcription factor) in single nociceptors impairs the fine...

Adolescent inhibition of thalamo-cortical projections from postnatal day P20-50 leads to long-lasting deficits in prefrontal-cortex function and cognition in the adult mouse. While this suggests a role of thalamic activity in prefrontal-cortex maturation, it is unclear how inhibition of these projections affect prefrontal circuitry during adolescence. Here, we used chemogenetic tools to inhibit thalamo-prefrontal projections in male/female mice from P20-35 and measured synaptic inputs to prefrontal pyramidal neurons by layer (either II/III or V/VI) and projection target (MD, NAc or callosal mPFC) twenty-four hours later using slice physiology. We chose mPFC and MD-projecting cells as they are largely distinguished by cortical layer (II/III versus V/VI, respectively) and NAc-projecting cells as they span both layers and therefore provide a within-layer comparison for the other two populations. We found a decrease in the frequency of excitatory and inhibitory currents in layer-II/III-nucleus-accumbens (NAc) ...

This resource was featured in the NeuroJobs Career Center. Visit today to search the world’s largest source of neuroscience opportunities. If you’re looking at career options, or wondering where to start, an Individual Development Plan (IDP) can help. The IDP is a tool to help you critically assess your skills and values, which will help you address your career goals in an achievable way. Get a step-by-step guide for the AAAS myIDP tool by one of the creators and hear from two postdocs about their experiences using the IDP.

Reverberation, a ubiquitous feature of real-world acoustic environments, exhibits statistical regularities that human listeners leverage to self-orient, facilitate auditory perception, and understand their environment. Despite the extensive research on sound source representation in the auditory system, it remains unclear how the brain represents real-world reverberant environments. Here, we characterized the neural response to reverberation of varying realism by applying multivariate pattern analysis to electroencephalographic (EEG) brain signals. Human listeners (12 male and 8 female) heard speech samples convolved with real-world and synthetic reverberant impulse responses and judged whether the speech samples were in a “real” or “fake” environment, focusing on the reverberant background rather than the properties of speech itself. Participants distinguished real from synthetic reverberation with ∼75% accuracy; EEG decoding reveals a multistage decoding time course, with dissociable components early in ...