Biology subjects

Hernandez-Perez, H.

Publications and source records attributed to Hernandez-Perez, H..

4 recordsLinked to original sources

bioRxiv2026

Objective markers of altered neural gain dissociate tinnitus and self-reported listening problems in individuals with exceptional hearing thresholds

Many individuals experience problems that are undetected by standard hearing tests, such as persistent tinnitus and difficulties understanding speech in background noise. Here, we report evidence of altered neural gain in young adults with self-reported listening problems despite exceptional hearing thresholds. Individuals reporting persistent tinnitus (the daily percept of sound in the absence of an external source) exhibited elevated thresholds of the middle ear muscle reflex, suggestive of altered gain in brainstem reflexive circuits, and reduced cortical responses to auditory spatial cues conveyed in the temporal fine structure of low-frequency sounds. Moreover, in both groups, greater self-reported speech-in-noise difficulties were associated with higher magnitude cortical responses, particularly at the highest stimulus intensity, consistent with elevated neural gain. Using a conceptual model, we demonstrate how damage to high-threshold auditory nerve fibres innervating cochlear nuclei can account for reduced activity of binaural neurons sensitive to the temporal fine structure of low-frequency sounds, generating a compensatory increase in neural gain in higher brain centres that impacts listening in complex environments.

neuroscience↗

bioRxiv2026

Disruption of prefrontal cortex accelerates sensory anchoring but dissociates online recognition from implicit consolidation of sound sequences

The auditory brain excels at extracting predictive regularities from sound, but the neural and temporal mechanisms mediating long-term learning of these regularities remain poorly understood. Here, using a perceptual anchoring paradigm, we investigate whether the dorsolateral prefrontal cortex (dlPFC) is causally required to transform transient regularities into stable internal templates (anchors). We characterized the behavioural dynamics of anchoring to predicable acoustic events using sensitivity (d) and decision bias (c) metrics, alongside growth curve analysis (GCA) to model trial-by-trial learning. Listeners exhibited a robust anchoring effect, showing significantly higher sensitivity in decision strategy for recurring acoustic regularities compared to novel ones. This implicit anchoring was driven selectively by specific features in regular sequences--the local repetition of an acoustic motif--whereas explicit memory indiscriminately encoded the entire acoustic episode. To test for causality, we applied inhibitory continuous theta-burst stimulation (cTBS) to the dlPFC. Crucially, not only did this not impair anchoring, but significantly accelerated the rate of anchoring for predictable patterns, suggesting the dlPFC may act as a source of top-down interference in implicit learning. In contrast to predictable sequences, inhibition of dlPFC disrupted the initial precision of online comparisons for novel sequences, though insulating against the rapid, interference-driven reduction in performance or novel sequences in observed in listeners subjected to a sham cTBS procedure. These findings reveal a functional dissociation. Whilst dlPFC provides an essential buffer for novel sensory comparisons, long-term consolidation of regularities in acoustic sequences relies on a robust implicit pathway independent of prefrontal control.

neuroscience↗

bioRxiv2025

Listening to the room: disrupting activity of dorsolateral prefrontal cortex impairs learning of room acoustics in human listeners

Navigating complex sensory environments is critical to survival, and brain mechanisms have evolved to cope with the wide range of surroundings we encounter. To determine how listeners learn the statistical properties of acoustic spaces, we assessed their ability to perceive speech in a range of noisy and reverberant rooms. Listeners were also exposed to repetitive transcranial stimulation (rTMS) to disrupt the dorsolateral prefrontal cortex (dlPFC) activity, a region believed to play a role in statistical learning. Our data suggest listeners rapidly adapt to statistical characteristics of an environment to improve speech understanding. This ability is impaired when rTMS is applied bilaterally to the dlPFC. The data demonstrate that speech understanding in noise is best when exposed to a room with reverberant characteristics common to human-built environments, with performance declining for higher and lower reverberation times, including fully anechoic (non-reverberant) environments. Our findings provide evidence for a reverberation "sweet spot" and the presence of brain mechanisms that might have evolved to cope with the acoustic characteristics of listening environments encountered every day.

neuroscience↗

bioRxiv2022

Dogma and belief: the primary lesion in age-related hearing loss is old news

Presbycusis, or age-related hearing loss, is the most common sensory deficit globally, and the biggest modifiable risk factor for a later dementia diagnosis. Despite its ubiquity, however, the primary pathology contributing to presbycusis is reportedly contentious, particularly the relative role of damage to the sensory outer hair cells compared to the stria vascularis, an important inner ear structure that maintains the ionic concentration of inner ear fluids that surround it. To determine what might be the "dogma" of the field regarding the primary pathology in presbycusis, we conducted an online Google survey (https://forms.gle/GPreoePmRxBBkchc7) asking relevant respondents in the field their opinions on the matter. In Question (Q1), respondents were asked to rate in your opinion from least likely to most likely (on a scale 1 to 4 [being most likely]) what is the primary pathology contributing to presbycusis? in terms of damage to: i) the inner hair cells, ii) outer hair cells (OHCs), iii) spiral ganglion, iv) stria vascularis. The term dogma suggests that the proportion of people in the field who believe that the main cause of presbycusis is damage to the stria vascularis is at least 50%. The results of our survey estimated this proportion to be 19/101 = 0.188 (95% CI [0.124 0.275]) and a two-sided test of the null hypothesis that this proportion is at least 0.5 was rejected (p < 10-10). When it came to opining what other professionals in the field consider to be the primary pathology contributing to presbycusis (Q2), the tendency to rank damage to OHCs as being the primary pathology was 45%. Stria vascularis was least likely to be ranked 4 (11%) by professionals in the field opining about the beliefs of others. Even when noise damage was excluded as a factor (Q3), the most likely contributing factor to presbycusis was stated to be damage to the OHCs (42%). Our data suggest the dogma of the field is that damage to outer hair cells is the primary pathology in presbycusis.

neuroscience↗