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Background: The superior colliculus (SC) plays a critical role in auditory-related behaviors, receiving descending inputs from the auditory cortex (AC). However, the modulatory effects of AC projections on SC auditory responses remain unclear. This study focuses on elucidating how AC corticofugal projections modulate SC neuronal activity in response to auditory stimuli in mice.
Methods: We combined viral tracing, in vitro and in vivo electrophysiology, and optogenetics in mice to investigate the corticofugal modulation of SC neurons by AC projections.
Results: Layer 5 (L5) pyramidal neurons in the AC send dense projections to the intermediate and deep layers of the SC. While SC neurons exhibit strong auditory responses to noise, they show weaker frequency selectivity to pure tones compared to SC-projecting neurons in the AC. Optogenetic inhibition of the AC significantly suppressed auditory responses in the SC, reducing firing rates, increasing response thresholds, narrowing frequency bandwidth, decreasing the number of spikes and shifting the best frequency (BF) toward lower frequencies.
Conclusions: These findings reveal that AC corticofugal projections regulate auditory responses in SC neurons in mice, potentially modulating auditory-related behaviors.
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http://dx.doi.org/10.1016/j.brainresbull.2025.111457 | DOI Listing |
Scand J Rheumatol
September 2025
The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Frederiksberg, Denmark.
Objective: Pain hypersensitivity and hypersensitivity to other sensory modalities (visual, auditory, olfactory, and tactile) are considered defining features in nociplastic pain states. A self-report measure of sensory sensitivity may help to characterize sensory profiles across pain populations. This study aimed to evaluate the psychometric properties of a newly developed Danish nine-item Sensory Sensitivity Profile (SSP) questionnaire in patients with fibromyalgia.
View Article and Find Full Text PDFFront Neurosci
August 2025
Acoustics Research Institute, Austrian Academy of Sciences, Vienna, Austria.
Introduction: Spatial hearing enables both voluntary localization of sound sources and automatic monitoring of the surroundings. The auditory looming bias (ALB), characterized by the prioritized processing of approaching (looming) sounds over receding ones, is thought to serve as an early hazard detection mechanism. The bias could theoretically reflect an adaptation to the low-level acoustic properties of approaching sounds, or alternatively necessitate the sound to be localizable in space.
View Article and Find Full Text PDFEar Hear
September 2025
Department of Otorhinolaryngology-Head and Neck Surgery, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
Objectives: In patients with cochlear implants, tools for measuring intracochlear electric environment as well as neural responses to electrical stimulation are widely available. This study aimed to investigate the possible correlation of changes in the responsiveness of the auditory nerve measured by neural response telemetry with changes in the peak and spread of the intracochlear electric field measured by transimpedance matrix (TIM) in patients implanted with straight electrode arrays.
Design: In this retrospective study, we analyzed a cohort of 144 ears of 113 consecutive patients who were implanted with Slim Straight electrode array (Cochlear Ltd.
Eur J Neurosci
September 2025
The Tampa Human Neurophysiology Lab, Department of Neurosurgery, Brain and Spine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA.
Sensory areas exhibit modular selectivity to stimuli, but they can also respond to features outside of their basic modality. Several studies have shown cross-modal plastic modifications between visual and auditory cortices; however, the exact mechanisms of these modifications are yet not completely known. To this aim, we investigated the effect of 12 min of visual versus sound adaptation (referring to forceful application of an optimal/nonoptimal stimulus to a neuron[s] under observation) on the infragranular and supragranular primary visual neurons (V1) of the cat (Felis catus).
View Article and Find Full Text PDFMed Eng Phys
October 2025
Department of Bioengineering, Technological University of Havana "José Antonio Echeverría", Cuba.
Congenital hearing loss is a significant health problem, with a worldwide incidence of >6 per 1000 live births. Late diagnosis will delay appropriate treatment, leading to potential neurodevelopment problems. Early diagnosis requires neonatal hearing screening, where one of the most used techniques is automated Auditory Brainstem Responses (aABR).
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