Instituto Interuniversitario de Neurociencias de Castilla y León (INCyL)

Auditory Sensitivity in Autism: A Systematic Review of Mismatch Negativity and Mismatch Field Responses

Sun, 17 May 2026 00:00:00 GMT

Auditory mismatch responses—mismatch negativity (MMN) and mismatch fields (MMF)—are well established electrophys-iological markers of automatic auditory discrimination supported by short-term sensory memory. These responses, typicallyelicited using passive oddball paradigms, are increasingly used to investigate sensory and language processing in autism. Thissystematic review synthesizes findings from 55 studies comparing MMN and MMF responses in autistic and typically developing(TD) individuals across childhood, adolescence, and adulthood. Using the Synthesis Without Meta-analysis (SWiM) framework,we identified consistent evidence for smaller MMN amplitudes and reduced MMF power in autistic children and adolescentsrelative to TD peers, particularly in response to frequency, duration, and speech-based deviants. Studies also frequently reportedlonger mismatch latencies in autistic participants and associated these delays with language difficulties and heightened auditorysensitivity. Although some studies reported age-related convergence in MMN and MMF measures between autistic and TDgroups in later childhood or adolescence, greater right-hemisphere lateralization in autistic individuals emerged as a consistentfinding across both speech and non-speech paradigms, suggesting differences in hemispheric weighting for auditory process-ing of linguistic and non-linguistic cues. To explain interindividual and developmental variability in mismatch responses, wepropose a precision-weighted predictive coding account, in which divergent assignment of confidence to sensory predictionerrors may contribute to autism-related differences. While study quality was generally fair, methodological heterogeneity, un-derrepresentation of females, and limited cross-cultural sampling constrain generalizability. Future research should prioritizelongitudinal, sex-stratified, and culturally diverse designs, using standardized protocols and collaborative data practices. MMNand MMF responses hold promise as non-invasive translational biomarkers of early-stage sensory prediction and neurodevelop-mental variation in autism

Temporal dynamics of contextual processing in the inferior colliculus of a rat model of autism: Sex- and age-dependent trajectories

Sun, 10 May 2026 00:00:00 GMT

[EN] In autism, sensory differences have been linked to altered contextual processing and to how temporal structure supports the formation of regularities and predictions. Here, we examined how temporal and contextual auditory processing are shaped by sex, development, and prenatal valproic acid (VPA) exposure in the non-lemniscal inferior colliculus at low sound levels. Single-unit recordings from control and VPA-exposed rats were obtained using oddball and cascade paradigms, allowing dissociation of mismatch (iMM), repetition suppression (iRS), and prediction-error (iPE) components in both response magnitude and latency.In control animals, maturation selectively reorganized contextual and predictive processing in females, shifting responses toward reduced repetition suppression and increased prediction-error signaling. This shift was accompanied by longer response latencies, indicating a broader temporal integration window. Compared to male rats, adult females displayed prediction-driven, with reduced adaptation bias, of mismatch responses.In contrast, prenatal VPA exposure disrupted this sex- and age-dependent pattern, particularly in females, producing reduced response magnitude together with earlier response peaks. These findings reveal a female-specific reorganization of subcortical contextual processing and demonstrate that sex, age, and prenatal VPA exposure-related effects can dissociate response strength from temporal deployment. Collectively, our results highlight the role of temporal dynamics in contextual computation within the auditory midbrain and support the contribution of early subcortical circuits to autism-related sensory processing

MSK1 mediates BDNF-dependent MeCP2-S421 phosphorylation in postnatal striatal development and psychiatric-relevant behaviours

Mon, 18 May 2026 00:00:00 GMT

Brain-derived neurotrophic factor (BDNF) is a master regulator of neuronal differentiation and inhibitory circuit maturation in the mammalian brain. Yet, its downstream mediators in distinct neuronal populations remain incompletely defined. Here, we identify mitogen- and stress-activated kinase 1 (MSK1) as a critical mediator of BDNF signalling during postnatal striatal development. MSK1 expression predominates in GABAergic neurons across the cortex and striatum, with region-specific dynamics: MSK1 expression in cortical GABAergic interneurons declines from postnatal day 5 (P5) to day 30 (P30), while expression in striatal GABAergic medium spiny neurons (MSNs) persists into adulthood. Using a novel Msk1IV KO mouse model, generated by deleting exon IV of Msk1, we find that striatal volume and MSN dendritic complexity decrease by P60, without cortical neuron alterations, underscoring MSK1´s striatal-specific role. Mechanistically, MSK1 drives BDNF-induced MeCP2 phosphorylation at serine 421 in MSNs via MAPK/ERK, independently of CaMKII, forming a nuclear complex with MeCP2, thus amplifying MSK1´s role in transcriptional regulation. This MSK1-MeCP2 signalling is also involved in BDNF-dependent and independent morphological developmental processes of cultured striatal neurons. Accordingly, Msk1IV KO striatum shows dysregulated GABAergic (Gad1, Gabrg3) and dopaminergic (Drd1, Drd2, Drd3) gene expression, mirroring profiles in MeCP2 deficient models. Behaviourally, Msk1IV KO mice display hypersociability, impaired nest-building, and increased depressive-like behaviour in the forced swimming test, contributing to striatal circuit dysfunction. These findings link MSK1-mediated molecular disruptions to inhibitory circuit imbalances and behaviours reminiscent of psychiatric disorders, positioning MSK1 as a potential therapeutic target for neurodevelopmental and psychiatric disorders, including those associated with MeCP2 dysfunction.

Ndfip2 in TrkA-expressing sensory neurons regulates noxious mechanosensation through control of TrkA signaling and protein levels

Tue, 31 Mar 2026 00:00:00 GMT

[EN]Nociception, the neural process underlying pain detection, is modulated by the NGF/TrkA signaling axis. Although anti-NGF antibodies can alleviate chronic pain, their clinical application is limited by adverse effects, underscoring the need to identify downstream regulators of this pathway. One such mechanism involves TrkA ubiquitination mediated by Nedd4 E3 ubiquitin ligases, whose activity is modulated by Nedd4 family interacting protein 2 (Ndfip2). Notably, Ndfip2 expression is regulated by TrkA signaling under pain conditions. Here, we characterize the physiological and molecular roles of Ndfip2 in sensory neurons. We demonstrate that Ndfip2 localizes to the endoplasmic reticulum and Golgi apparatus and interacts with TrkA in sensory neurons. Conditional deletion of Ndfip2 in TrkA-expressing cells selectively alters mechanical nociception. Mechanistically, loss of Ndfip2 decreases total TrkA protein levels, downstream activation, and cell-surface exposition, particularly in male-derived dorsal root ganglia neurons. Conversely, Ndfip2 expression reduces mature glycosylated TrkA and promotes the accumulation of non-glycosylated forms, consistent with impaired receptor maturation. Together, these findings identify Ndfip2 as a post-translational regulator of TrkA in TrkA-lineage sensory neurons and establish its in vivo role in mechanical nociception.

Genetically modified bone marrow cells halt mitral cell loss by modulating inflammation and protecting against DNA damage

Sat, 16 May 2026 00:00:00 GMT

[EN]Cell therapy is a promising strategy for tackling neurodegenerative diseases. The most outstanding results with this approach usually involve neuroprotection of damaged neurons at risk of death, but only with limited success. Current therapies are often based on the idea of “one gene, one disease, one drug” for single targets, a concept that limits their actual effectiveness. In contrast, combining different strategies can establish an advanced cell therapy that can slow down neuronal degeneration. In this study, we took advantage of the combination of cell and gene therapy, by transplanting bone marrow stem cells genetically modified to overexpress insulin-like growth factor 1 (IGF1) into a model of selective neurodegeneration, the PCD mouse. This animal is characterized by progressive neuronal loss in the olfactory bulb and alterations in IGF1 levels, among other symptoms. Using different techniques (cell cultures, viral transduction, cell transplants, flow cytometry, qPCR, ELISA, immunohistochemistry, advanced image analysis), our findings showed that neuronal death was virtually blocked, even 130 days after cell transplantation, a result clearly more successful than previous studies. The effects of this transplant are based in part on the regulation of neuroinflammation, increasing the proportion of reactive microglia and reducing that of proinflammatory microglia. In addition, IGF1 overexpression dramatically reduced DNA damage in mutant animals via IGF binding protein 3 pathway: this enhances neuroprotection by complementing the basal effect of cell therapy itself. In summary, our work supports the idea that combining therapeutic approaches and their synergies is a more effective tactic for combating neuronal loss.

Audiogenic Kindling Stimulation Fails to Induce Cerebral Overexpression of P-Glycoprotein and Limbic Crises in the GASH/Sal Model of Epilepsy

Thu, 09 Apr 2026 00:00:00 GMT

[EN] Experimental evidence indicates that a high seizure burden can induce cerebral overexpression of P-glycoprotein (P-gp) at the blood–brain barrier, a phenomenon associated with drug-resistant epilepsy under the “transporter hypothesis”, but also at the neuronal level, linked to a reduced seizure threshold, increased seizure severity (SS), status epilepticus (SE), and a high spontaneous death (SD) rate. In contrast, we recently described a progressive reduction in SS and the absence of SE and SD in GASH/Sal hamsters subjected to 45 audiogenic seizures. Here, we examined SS, SE, and the SD, and the expression of P-gp, erythropoietin receptor (EPO-R), hypoxia-inducible factor 1 alpha subunit (HIF-1α) and cyclooxygenase 2 (COX-2), in the brains of GASH/Sal hamsters following 20 audiogenic kindling stimulations (AUK-20). SS was evaluated using the midbrain and limbic severity scales; gene expression was assessed by RT-qPCR and P-gp protein levels were measured by immunohistochemistry and Western blot (IHC/WB) analysis. A modest decrease in midbrain SS was observed, without an increase in the already low limbic SS scores, and no SE or SD events occurred. P-gp levels remained low in both IHC and WB analyses. At the mRNA level, we detected increased EPO-R expression, decreased HIF-1α, and increased COX-2 without an accompanying increased in Abcb1b. Unlike findings from other experimental epilepsy models, AUK-20 in GASH/Sal hamsters does not enhance limbic SS, trigger SE or SD, or induce P-gp overexpression in the brain. Independently of the implications for drug resistance, the lack of cerebral P-gp overexpression without increased SS in the AUK-20-GASH/Sal model supports a potential role of P-gp in modulating seizure severity and epilepsy-associated mortality risk.

Specific Glutamylation Patterns of the Cytoskeleton Confer Neuroresistance to Lobe X of the Cerebellum in a Model of Childhood-Onset Neurodegeneration with Cerebellar Atrophy

Wed, 01 Jan 2025 00:00:00 GMT

[EN]The cytoskeleton relies heavily on the dynamic nature of microtubules, regulated by posttranslational modifications such as polyglutamylation and deglutamylation. Disruption of its internal balance, particularly through the absence of cytosolic carboxypeptidase 1 (CCP1), leads to cytoskeletal collapse and cell death. An example of this occurrence exists in the Purkinje Cell Degeneration (PCD) mouse, a direct animal model for childhood-onset neurodegeneration with cerebellar atrophy (CONDCA) human disease. Both CONDCA patients and PCD mice suffer a dramatic degeneration of Purkinje cells. Intriguingly, lobe X appears less vulnerable to this insult. This study revealed in wild-type mice that lobe X expresses less Ccp1 compared to other lobes, correlating with its delayed degeneration in PCD mice. Further expression analysis of other deglutamylating enzymes (CCP4 and CCP6) and glutamylating enzymes (TTLL1) revealed distinctive patterns: Ccp4 showed minimal relevance in cerebellum, while Ccp6 displayed a compensatory increase during critical stages. Meanwhile, Ttll1 expression remained consistent across lobes, suggesting that the resistance of lobe X may be related to a more dynamic, hyperglutamylated cytoskeleton. Unraveling the neuroresistance mechanisms of Purkinje cells may help mitigate neuronal loss in CONDCA patients and may offer a glimmer of hope for alleviating the symptoms of other neurodegenerative diseases.

Sex, age, and etiology effects on auditory processing in two rat models of autism: evidence from auditory brainstem responses and contextual neural and behavioral measures

Thu, 01 Jan 2026 00:00:00 GMT

[ES]La tesis titulada “Sex, age, and etiology effects on auditory processing in two rat models of autism: evidence from auditory brainstem responses and contextual neural and behavioral measures” investiga cómo el procesamiento auditivo varía en función del sexo biológico, la etapa del desarrollo y la etiología en modelos animales de autismo. Partiendo del marco teórico de la codificación predictiva, el trabajo analiza cómo el sistema auditivo extrae regularidades del entorno y detecta desviaciones, integrando niveles de análisis que abarcan desde el tronco encefálico hasta el comportamiento. Para ello, se emplean dos modelos de autismo en rata: uno ambiental, basado en la exposición prenatal al ácido valproico (VPA), y otro genético, mediante deleción heterocigota del gen Grin2b. Además, se incluye un modelo farmacológico basado en la administración del antagonista NMDA MK-801 para estudiar el uso conductual de regularidades auditivas. Metodológicamente, la tesis combina tres aproximaciones complementarias: (1) registros de respuestas auditivas del tronco encefálico (ABRs) para evaluar la sincronía y el tiempo de conducción subcortical; (2) registros de actividad neuronal de unidad única en el colículo inferior para caracterizar el procesamiento contextual auditivo mediante índices de mismatch (iMM), supresión por repetición (iRS) y error de predicción (iPE); y (3) tareas conductuales tipo oddball para evaluar el uso de regularidades auditivas en la toma de decisiones. Los resultados muestran que el procesamiento auditivo no se altera de manera uniforme, sino que depende de la interacción entre sexo, edad y etiología. Se observan diferencias específicas en la latencia y amplitud de las ABRs, así como en los mecanismos neuronales de procesamiento contextual en el colículo inferior, especialmente en regiones no lemniscales. Asimismo, las manipulaciones farmacológicas revelan alteraciones en la capacidad de utilizar regularidades auditivas para guiar la conducta. En conjunto, la tesis demuestra que la variabilidad auditiva en el autismo refleja interacciones estructuradas entre factores biológicos y del desarrollo, y no una alteración única. Estos hallazgos aportan un marco integrador que conecta mecanismos neurofisiológicos con procesos conductuales, contribuyendo a una comprensión multiescala del procesamiento auditivo en el autismo.

Performance assessment of no-fee GNSS augmentation systems for tractor guidance

Tue, 24 Mar 2026 00:00:00 GMT

[EN] This study assesses the performance of no-fee GNSS augmentation systems for tractor guidance. Five no-fee augmentation systems: EGNOS, GLIDE, RTK, VRS-NRTK, and on-site RTK were evaluated in both static and guidance tests over short- and long‑term periods using three GNSS receiver types: low-cost Navilock NL8022MP, mid-range Novatel Smart2, and high-end Harxon TS108PRO. Static tests recorded 24 h of position data from 14 receiver-augmentation configurations on a fixed surface. Guidance tests recorded trajectory data from the 14 configurations during straight-line guidance using a tractor equipped with two GNSS receivers, one under test and one high-precision reference. Results found that: (i) unaugmented GNSS resulted in guidance errors of 2–3 m, reduced below 1 m in pass-to-pass intervals shorter than 15 min; (ii) EGNOS reduced these guidance errors by ∼41%; (iii) GLIDE reduced guidance errors to below 20 cm for pass-to-pass intervals shorter than 15 min, with no long-term improvement; (iv) RTK guidance error decreased as baseline length shortened: >100 km yielded > 17 cm, 20–100 km yielded 3–20 cm, and < 20 km yielded 2–3 cm; (v) VRS-NRTK slightly outperformed RTK with similar baseline lengths; and (vi) on-site RTK enabled 1 cm guidance error. In summary: low-cost receivers without augmentation or with EGNOS result in metre-level errors; mid-range receivers with GLIDE deliver decimetre-level guidance errors in the short term; and high-end receivers using on-site RTK or VRS-NRTK on baselines up to 100 km achieve centimetre-level errors, enabling farmers to replicate tractor trajectories consistently year to year.

Multisession epidural direct current stimulation of the auditory cortex mitigates age-related transcriptomic dysregulation in Wistar rats

Thu, 19 Feb 2026 00:00:00 GMT

[EN]Age-related hearing loss (ARHL) disrupts ascending auditory inputs, impairing auditory signal transmission, triggering cortical hyperexcitability, and increasing the risk of age-related cognitive decline. In early aging, multisession epidural direct current stimulation (DCS) of the auditory cortex (AC) preserves auditory thresholds and prevents cortical hyperexcitability in Wistar rats. Here, we hypothesized that multisession DCS could halt transcriptional dysregulation in the AC at the earliest stages of aging. We have characterized age-related transcriptional changes in the AC to assess DCS-mediated effects by RNA-seq. At 18.13 months, non-stimulated, aged rats (NES) showed 194 differentially expressed genes (DEGs) in relation to young controls (YG), with enrichment in pathways associated with GABAergic, glutamatergic, and dopaminergic synapses, long-term potentiation/depression, inflammaging, autophagy, apoptosis and neurodegeneration. The upregulated genes included Gabrb1, Grin2b, Rac3c, Tnr, and Ndst1, suggesting compensatory hyperactivity, excitatory/inhibitory imbalance, and stiffening of perineuronal nets (PNN) around parvalbumin (PV) interneurons. Electrically stimulated (ES) rats showed 86 DEGs in relation to YG, with no significant enrichment in aging-related pathways. By contrast, NES vs ES showed 1393 DEGs, with strong enrichment in aging-related pathways. Also, many of the 121 common DEGs across comparisons, which are upregulated in NES and downregulated in ES, are related to neurotransmission (Gabrb1, Grin2b), synaptic scaffolding (Dlg2, Prkca), trophic signaling (Ntrk2, Igf1r) and PNN (Tnr, Ndst1). Based on these findings, multisession DCS curbs maladaptive genomic reprogramming in the aged AC most likely by preserving excitatory/inhibitory balance and maintaining PNN integrity, thereby protecting the AC from ARHL and cognitive vulnerability.

Sex- and etiology-specific effects on predictive processing in the inferior colliculus of two rat models of autism

Fri, 30 Jan 2026 00:00:00 GMT

[EN] Atypical sensory processing is a common feature of autism, yet the neural computations that give rise to these differences, particularly in relation to biological sex and etiological origin, remain unclear. Here we examine predictive auditory processing at the single-neuron level in the inferior colliculus of two adult rat models of autism: a genetic model with a heterozygous Grin2b deletion (Grin2b + /-) and an environmental model based on prenatal valproic acid exposure. We recorded neuronal responses to an auditory oddball paradigm and a cascade control sequence across lemniscal and non-lemniscal IC divisions under high-intensity stimulation, allowing us to derive indices of repetition suppression, prediction error and neuronal mismatch. Using generalized linear mixed-effects models that accounted for animal identity, inferior colliculus division, sex, and rat model, followed by hierarchical group-level comparisons, we identified robust alterations in predictive processing in both autism-like models. These effects varied across inferior colliculus divisions and differed between sexes, revealing distinct phenotype-specific signatures. The results indicate that sex and etiology jointly modulate early auditory computations in autism. More broadly, our findings highlight the translational value of predictive coding frameworks and support the use of complementary animal models to capture neurobiological heterogeneity across the autism spectrum

Prosodia rítmico frecuencial en lingüística clínica: en búsqueda de biomarcadores fonéticos para alzheimer y depresión mayor

Wed, 01 Jan 2025 00:00:00 GMT

[EN]This paper delves into the prosodic features of speech affected in AD and MD, the type of pathology they are associated with (aphasia, apraxia or aprosodia), as well as the contribution of these alterations to the neurolinguistic field (hemispheric specialization).We used a corpus of spontaneous speech from patients with AD (n=10) and MD (n=10), and a control group with HS (n=10). The results showed a discriminatory significance of VnPVI (in MD), and (Δ)f0 and %V; furthermore, %V is a strong variable to distinguish between speakers with and without pathology, as well as to discriminate between AD and MD along with other variables. There is, however, no correlation with verbal fluency (semantic and phonological) or with MMSE, which would imply a motor type deficit: apraxic type in AD and aprosodic type in MD. These results show certain phonological and typological conditioning, among other issues.

Auditory deviance detection beyond the auditory pathway: Hierarchical predictive coding in the hippocampus and primary visual cortex

Thu, 01 Jan 2026 00:00:00 GMT

[EN] Under the predictive coding framework, perception is understood as an inferential process in which the brain continuously generates predictions about incoming sensory input and updates its internal models when reality deviates from expectation. Auditory deviance detection provides a tractable paradigm to investigate how the brain encodes prediction errors. While these computations are well characterized within the auditory hierarchy, their extension to memory-related and cross-modal structures remains unclear. This thesis examines auditory predictive processing beyond the auditory pathway, focusing on the hippocampus and the primary visual cortex (V1) as potential nodes in a distributed predictive network. Using extracellular recordings in urethane-anesthetized rats, I measured single- and multi-unit activity and local field potentials (LFPs) from hippocampal subfields (dentate gyrus [DG], cornu ammonis 1 [CA1]) and infragranular layers (IV–VI) of V1. Classical oddball paradigms and no-repetition control sequences were employed to dissociate repetition suppression from genuine prediction error components. Approximately one-fifth of hippocampal neurons responded to auditory stimulation, with a subset (~20%) showing enhanced activity to deviant tones. DG neurons displayed shorter latencies and larger mismatch and prediction error indices than CA1, suggesting a distinct contribution to novelty-related processing. Spiking responses reflected prediction error, while LFPs showed distinct contributions from repetition suppression and prediction error that varied across subfields. Early LFP components were enhanced for randomly presented deviants, whereas later components were more pronounced for predictable deviants. In V1, more than half of infragranular neurons responded to tones despite the absence of visual input, 50% showing larger responses to deviant than standard stimuli. These responses predominantly reflected prediction error rather than adaptation and were amplified under temporally uncertain (random) conditions. Layer V neurons exhibited rapid, phasic responses, whereas layer VI responses were broader and more sustained, consistent with laminar specialization in hierarchical predictive coding. Together, these results demonstrate that auditory prediction errors are encoded in both hippocampal and visual circuits, extending predictive processing beyond classical sensory boundaries, positioning both regions as integral components of a distributed predictive coding architecture that underlies hierarchical inference across the brain.

Binaural audio processing to improve speech in noise intelligibility: Design and experimental evaluation with normal-hearing listeners and hearing-aid users

Thu, 01 Jan 2026 00:00:00 GMT

[EN] Understanding speech in noisy environments remains challenging for individuals with hearing loss, particularly in listening scenarios involving multiple competing sound sources. While modern hearing aids incorporate directional microphones and noise reduction methods, their effectiveness is limited by assumptions about the acoustic scene or by the degradation of spatial cues in users of bilateral devices. Current approaches, such as adaptive beamforming or machine learning-based source separation, rely on complex estimations of the location or the characteristics of the target sound. Furthermore, they often require multiple microphones per device or synchronized bilateral processing. These constraints limit their applicability and leave many users with suboptimal performance in multi-talker environments. In this thesis, we present a binaural audio processing method designed to improve speech intelligibility in noisy environments by attenuating contralateral sounds. The method consists of subtracting a weighted version of the contralateral signal from the ipsilateral signal. It operates in the frequency domain, with subtraction weights based on generic head-related transfer functions, and without requiring prior knowledge of the target or noise properties or their location. The method is first evaluated using objective metrics in simulated listening scenarios. Results demonstrate consistent improvements in the signal-to-noise ratio and the short-term objective intelligibility, particularly for spatially separated target and noise sources. These findings confirm the theoretical premise that contralateral sound attenuation can improve speech intelligibility without the need for complex spatial analysis or source tracking. The method is then evaluated experimentally on individuals with normal hearing as well as in users of bilateral hearing aids. In normal-hearing listeners, the method improved intelligibility in unilateral listening but was less effective in bilateral listening due to its altering spatial cues. Hearing-aid users exhibited substantial improvements in both unilateral and bilateral listening, underscoring the method’s potential to compensate for degraded binaural processing. Overall, the findings support the effectiveness and practical relevance of the proposed method. Its simplicity and low computational cost make it a promising candidate for implementation in hearing technologies. The thesis contributes a novel sound processing method for speech enhancement that addresses real-world auditory challenges faced by individuals with and without hearing loss.

The impact of "hidden" hearing loss, reduced inhibition of cognitive interference, and aging on behavioral adaptation to noise

Thu, 01 Jan 2026 00:00:00 GMT

[EN] Understanding speech in noisy environments is challenging but essential for human verbal communication. Fortunately, the auditory system can adapt to background noise, which facilitates speech intelligibility in noisy environments. Behavioral adaptation to noise, however, varies across individuals for reasons that are unclear. The aim of the work presented in this thesis was to investigate whether behavioral adaptation to noise is affected by ‘hidden’ hearing loss (HHL), a reduced ability to inhibit cognitive interference, or aging. Eighty-nine adult speakers of Castilian Spanish (19–86 years old) with clinically normal hearing participated in the experiments. Speech reception thresholds (SRTs), the signal-to-noise ratio at 50 % recognition, were measured for disyllabic words embedded in noise. SRTs were measured for words delayed 50 ms and 800 ms in the noise, for various noises and levels. Adaptation to noise was calculated as the improvement in the long-delay relative to the short-delay condition. Because adaptation is greater for vocoded than for natural words, words were processed through a tone vocoder. The risk of HHL was assessed using the amplitude and the rate of growth (slope) of wave I of the auditory brainstem response (ABR). The ability to inhibit cognitive interference was assessed using the Stroop color and word test. The data revealed that participants exhibited significant adaptation to noise, and that adaptation was greater at higher noise levels and for steady than for fluctuating noises. However, adaptation was not significantly associated with ABR wave I amplitude or slope, age, or Stroop test score, even after controlling for the potential confounding effect of audiometric threshold. Findings suggest that behavioral adaptation to noise is preserved across the adult lifespan and is independent of subclinical auditory deficits or inhibitory control abilities. Findings further suggest that speech-in-noise difficulties experienced by older adults or individuals at risk of suffering from HHL should be attributed to factors other than impaired adaptation to noise.

Anatomía y fisiología del hipotálamo de la oveja, implicaciones en la regulación de la estacionalidad reproductiva

Wed, 01 Jan 2025 00:00:00 GMT

[ES] El presente trabajo de tesis doctoral surge de la necesidad de la búsqueda, en nuestro modelo experimental (oveja Churra), de procedimientos para la evaluación de intervenciones o experimentos enfocados a modificar la estacionalidad y la fertilidad. En este sentido, este trabajo tiene la relevancia de ampliar los conocimientos y las técnicas aplicadas a un campo, el de la producción animal, de la neurociencia. En los últimos años, en el grupo de producción animal de la universidad de Salamanca, a cargo del Prof. Palacios Riocerezo, se han desarrollado proyectos enfocados a la modificación de la estacionalidad mediante cambios en el fotoperiodo, tratamiento hormonales y comportamentales. Los análisis de las variaciones hormonales en sangre sirven de mucha ayuda para estos fines, pero nuestro grupo detectó que el cambio estacional en la oveja se produce en un espacio de tiempo relativamente amplio y difícil de detectar en sus orígenes debido al carácter pulsátil de la liberación de GnRH. Nuestro planteamiento, por tanto, fue que el estudio de los núcleos hipotalámicos con inmunocitoquimica puede permitir un diagnóstico de certeza del cambio estral en nuestras intervenciones. Sin embargo, localizar los núcleos hipotalámicos y su anatomía funcional (inmunocitoquímica) es tarea difícil en una especie (oveja churra) no bien caracterizada anatómicamente. Por ello tuvimos que estudiar primero la anatomía del diencefalo de nuestro modelo (oveja churra) que se publicó en el año 2023 (Merchán M Jr, Coveñas R, Plaza I, Abecia JA, Palacios C. Anatomy of hypothalamic and diencephalic nuclei involved in seasonal fertility regulation in ewes. Front Vet Sci. 2023 Feb 16;10:1101024. doi: 10.3389/fvets.2023.1101024. PMID: 36876003; PMCID: PMC9978410) Q1. Los siguientes pasos fueron dirigidos directamente al propósito de nuestra hipótesis de partida: determinar un proceso objetivo de valoración de la activación estral del hipotálamo. Para ello evaluamos primero con detalle la distribución y cuantificación de la GnRH en un segundo articulo: Merchán M Jr, Plaza I, Nieto J, Plaza J, Abecia JA, Palacios C. Densitometric analysis of GnRH and IBA1 immunocytochemistry in the basal ventromedial hypothalamus of the ewe. Theriogenology. 2024 Oct 1;227:112-119. doi: 10.1016/j.theriogenology.2024.07.012. Epub 2024 Jul 21. PMID: 39053287 Q1. En este articulo demostramos la importancia de valorar la actividad paracrina de la GnRH en relación con la regulación de la microglía inmunoreactiva para esta hormona. Se definió así un procedimiento objetivo que permite la aplicación de morfometría para correlacionar los cambios hormonales y la activación hipotalámica. El tercer artículo, en curso, sobre "Validación inmunocitoquímica de la activación estrogénica hipotalámica de GnRH localizada en el núcleo arcuato de la oveja" (Experiencia 3 en el manuscrito) trata de ser una aplicación práctica de la correlación planteada en nuestra hipótesis de partida. En resumen, nos gustaría enfatizar que este trabajo no solo está enfocado al mejor conocimiento del diencéfalo de la oveja sino más bien a la búsqueda criterios objetivos para evaluar los cambios estrales y la fertilidad vinculado al campo de la producción animal. Abordar este trabajo desde la síntesis de los conocimientos de ámbitos no próximos en los campos de conocimiento como la neurociencia y la producción animal ha resultado en un esfuerzo sustancial. Sin embargo, esperamos que permita en el futuro hacer estas técnicas accesibles a los investigadores del campo de la Ingeniería agrícola en nuestro entorno mas proximo