Auditory Information Processing Research Articles

Receptive-field nonlinearities in primary auditory cortex: a comparative perspective.

Cortical processing of auditory information can be affected by interspecies differences as well as brain states. Here we compare multifeature spectro-temporal receptive fields (STRFs) and associated input/output functions or nonlinearities (NLs) of neurons in primary auditory cortex (AC) of four mammalian species. Single-unit recordings were performed in awake animals (female squirrel monkeys, female, and male mice) and anesthetized animals (female squirrel monkeys, rats, and cats). Neuronal responses were modeled as consisting of two STRFs and their associated NLs. The NLs for the STRF with the highest information content show a broad distribution between linear and quadratic forms. In awake animals, we find a higher percentage of quadratic-like NLs as opposed to more linear NLs in anesthetized animals. Moderate sex differences of the shape of NLs were observed between male and female unanesthetized mice. This indicates that the core AC possesses a rich variety of potential computations, particularly in awake animals, suggesting that multiple computational algorithms are at play to enable the auditory system's robust recognition of auditory events.

‛Until you're in the chair and executing your role, you don't know': A qualitative study of the needs and perspectives of people with stroke-related communication disabilities when returning to vocational activity.

People with communication disability after stroke experience low rates of return to vocational roles. Vocational rehabilitation is recommended; however, there are no clear guidelines informing vocational rehabilitation for people with communication disability. Understanding the needs and experiences of this population is critical to improving vocational stroke rehabilitation outcomes. This study aimed to: (1) investigate the experience of vocational rehabilitation for people with communication disability after stroke, (2) identify gaps and, (3) provide preliminary recommendations for tailored service delivery. Seven participants with an identified communication impairment following stroke were recruited from a larger clinical trial of early vocational rehabilitation (20% of total sample, n = 34). To address the study aims, a qualitative design was employed. Semi-structured, in-depth interviews were conducted and analysed using thematic analysis. Data were integrated with demographic and intervention audit data to contextualise participant experiences, identify vocational rehabilitation gaps and inform preliminary recommendations. Participants were five men and two women aged 24-69 years whose communication profiles included difficulties with auditory comprehension and information processing, reading comprehension, thinking, executive function and self-regulation, as well as difficulties with verbal and written expression. Vocational rehabilitation was perceived as beneficial but participants identified gaps including limited access to psychological and peer-based support during early rehabilitation, limitations to accessing specialist vocational rehabilitation programs, barriers to accessing ongoing rehabilitation after resumption of vocational activity, and limited preparedness for the degree of impact that their communication changes had on execution of vocational roles and responsibilities. Vocational environments are communicatively demanding and people living with acquired communication difficulties face a range of vocation-related participation barriers even when communication difficulties are mild. Greater emphasis on evaluating the vocational communication environment and targeted communication training and preparation for colleagues within the workplace is recommended to reduce barriers faced. Interdisciplinary rehabilitation, inclusive of psychological care, may support working-age stroke survivors to recognise and acknowledge changes in their communication function, lead to improved engagement in the rehabilitation process, and ensure early identification of factors likely to influence successful return-to-vocational activity. What is already known on the subject Stroke is common amongst people of working age yet fewer than half of stroke survivors will return to pre-stroke vocational roles. Communication difficulties affect anywhere between 24% and 45% of people after stroke and include changes to language abilities, motor speech, vision, hearing and cognition. This group experiences much lower rates of return to vocational roles when compared to people with stroke who do not have a concomitant communication difficulty. Vocational rehabilitation is recommended. However, currently there is limited evidence to inform vocational rehabilitation guidelines for people with stroke and communication difficulties. Achieving a successful return to vocational activity is associated with improved life satisfaction for people with communication difficulties after stroke and is a key research priority for this population. What this study adds This study investigated the experiences of people with communication difficulty after stroke who reported a goal of returning to pre-stroke vocational activity. Data associated with types of interventions received, the experiences and perceptions of vocational rehabilitation, and experiences of returning to vocational activity were analysed to identify core rehabilitation needs and develop preliminary recommendations to inform future vocational rehabilitation guidelines for this population. What are the clinical implications of this work? The present study provides preliminary evidence that people experiencing communication difficulties after stroke require a more integrated rehabilitation pathway. During early stages of vocational rehabilitation psychological and peer-based support is indicated to support adjustment to changed communication function and to enable productive goal setting and engagement in rehabilitation. Clinicians need to complete a detailed analysis of the vocational communication environment and consider the communication activities involved in the individual's future vocational duties in order to plan meaningful rehabilitation. A multidisciplinary approach is required and additional training for clinicians is indicated to support clinicians to work collaboratively within the vocational setting.

Retigabine, a potassium channel opener, restores thalamocortical neuron functionality in a murine model of autoimmune encephalomyelitis

BackgroundMultiple Sclerosis (MS) is an autoimmune neurodegenerative disease, whose primary hallmark is the occurrence of inflammatory lesions in white and grey matter structures. Increasing evidence in MS patients and respective murine models reported an impaired ionic homeostasis driven by inflammatory-demyelination, thereby profoundly affecting signal propagation. However, the impact of a focal inflammatory lesion on single-cell and network functionality has hitherto not been fully elucidated. ObjectivesIn this study, we sought to determine the consequences of a localized cortical inflammatory lesion on the excitability and firing pattern of thalamic neurons in the auditory system. Moreover, we tested the neuroprotective effect of Retigabine (RTG), a specific Kv7 channel opener, on disease outcome. MethodsTo resemble the human disease, we focally administered pro-inflammatory cytokines, TNF-α and IFN-γ, in the primary auditory cortex (A1) of MOG35-55 immunized mice. Thereafter, we investigated the impact of the induced inflammatory milieu on afferent thalamocortical (TC) neurons, by performing ex vivo recordings. Moreover, we explored the effect of Kv7 channel modulation with RTG on auditory information processing, using in vivo electrophysiological approaches. ResultsOur results revealed that a cortical inflammatory lesion profoundly affected the excitability and firing pattern of neighboring TC neurons. Noteworthy, RTG restored control-like values and TC tonotopic mapping. ConclusionOur results suggest that RTG treatment might robustly mitigate inflammation-induced altered excitability and preserve ascending information processing.

Errors in the Assumptions of Bekesy's Traveling Wave Theory

This article examines the fundamental statements of Bekesy's traveling wave theory in hearing and proposes an updated perspective on auditory information processing mechanisms. It argues that the traditional theory does not adequately account for non-mammalian auditory mechanisms, as many species effectively perceive sound without a basilar membrane or cochlear fluids. It suggests alternative pathways for sound signal reception directly to the receptor, bypassing traditional structures like the basilar membrane. This reevaluation raises significant doubts about the resonance capability and the actual role of the basilar membrane in hearing, suggesting that current understandings of auditory processing may be fundamentally limited and not universally applicable across different species.

Repetition-Dependent Adaptation and Prediction Error Signalling in Schizophrenia Patients With Auditory Hallucinations: A Roving Mismatch Negativity Study

BackgroundDysregulated prediction error-signalling may explain auditory hallucinations in schizophrenia (SZ-AH). Roving mismatch negativity (rMMN) is an event-related potential (ERP) index where the deviant tone becomes the new standard with repetitions. Longer repetitions of standard stimuli yield a more positive sensory-adaptation response (Repetition Positivity–RP), elicit a stronger deviance-detection when interrupted (deviant negativity–DN), and the difference waveform between them reflects the strength of prediction-error signalling (mismatch negativity–MMN). MethodsTwenty-three SZ-AH patients and twenty-three healthy controls (HC) underwent rMMN assessment. Various standard stimuli were repeated in sets of 3, 8 and 33 yielding three components for RP (RP3, RP8, RP33), DN (DN3, DN8, DN33), and MMN (MMN3, MMN8, MMN33). Amplitudes and latencies were compared across groups. Correlation between (a) rMMN amplitudes and latencies, and clinical variables in SZ-AH, and (b) the RP-DN amplitude pair for all three repetition sets (3, 8, 33) were also examined. ResultsAll DN and MMN33 amplitudes were significantly suppressed in SZ-AH, while RP amplitudes were not. MMN33 latency was significantly longer in SZ-AH than HC. A few amplitudes and latencies significantly correlated with the frequency of AH. HC showed a significant positive correlation between RP-DN amplitude pairs for sets of 3 and 8 but not for 33; SZ-AH group’s correlation profile was opposite to this. DiscussionThe link between repetition-dependent sensory-adaptation and deviance-detection is perturbed in SZ-AH. The unimpaired RP profile in SZ-AH is due to potential interference of AH with auditory information processing, and does not indicate a preserved short-term plasticity of the echoic memory trace.

The temporal dynamics of conscious and unconscious audio-visual semantic integration

We compared the time course of cross-modal semantic effects induced by both naturalistic sounds and spoken words on the processing of visual stimuli, whether visible or suppressed form awareness through continuous flash suppression. We found that, under visible conditions, spoken words elicited audio-visual semantic effects over longer time (−1000, −500, −250 ms SOAs) than naturalistic sounds (−500, −250 ms SOAs). Performance was generally better with auditory primes, but more so with congruent stimuli. Spoken words presented in advance (−1000, −500 ms) outperformed naturalistic sounds; the opposite was true for (near-)simultaneous presentations. Congruent spoken words demonstrated superior categorization performance compared to congruent naturalistic sounds. The audio-visual semantic congruency effect still occurred with suppressed visual stimuli, although without significant variations in the temporal patterns between auditory types. These findings indicate that: 1. Semantically congruent auditory input can enhance visual processing performance, even when the visual stimulus is imperceptible to conscious awareness. 2. The temporal dynamics is contingent on the auditory types only when the visual stimulus is visible. 3. Audiovisual semantic integration requires sufficient time for processing auditory information.

The Dorsal Part of the Anterior Tuberal Nucleus Responds to Auditory Stimulation in Zebrafish (Danio rerio).

The zebrafish, a widely used model in neurobiology, relies on hearing in aquatic environments. Unfortunately, its auditory pathways have mainly been studied in larvae. In this study, we examined the involvement of the anterior tuberal nucleus (AT) in auditory processing in adult zebrafish. Our tract-tracing experiments revealed that the dorsal subdivision of AT is strongly bidirectionally connected to the central nucleus of the torus semicircularis (TSc), a major auditory nucleus in fishes. Immunohistochemical visualization of the ribosomal protein S6 (pS6) phosphorylation to map neural activity in response to auditory stimulation substantiated this finding: the dorsal but not the ventral part of AT responded strongly to auditory stimulation. A similar response to auditory stimulation was present in the TSc but not in the nucleus isthmi, a visual region, which we used as a control for testing if the pS6 activation was specific to the auditory stimulation. We also measured the time course of pS6 phosphorylation, which was previously unreported in teleost fish. After auditory stimulation, we found that pS6 phosphorylation peaked between 100 and 130 min and returned to baseline levels after 190 min. This information will be valuable for the design of future pS6 experiments. Our results suggest an anatomical and functional subdivision of AT, where only the dorsal part connects to the auditory network and processes auditory information.

Deafness causing neuroplastin missense variants fail to promote plasma membrane Ca2+-ATPase levels and Ca2+ transient regulation in brain neurons

Hearing, the ability to sense sounds, and the processing of auditory information are important for perception of the world. Mice lacking expression of neuroplastin (Np), a type-1 transmembrane glycoprotein, display deafness, multiple cognitive deficiencies, and reduced expression of plasma membrane calcium (Ca2+) ATPases (PMCAs) in cochlear hair cells and brain neurons. In this study, we transferred the deafness causing missense mutations pitch (C315S) and audio-1 (I122N) into human Np (hNp) constructs and investigated their effects at the molecular and cellular level. Computational molecular dynamics show that loss of the disulfide bridge in hNppitch causes structural destabilization of immunoglobulin-like domain (Ig) III and that the novel asparagine in hNpaudio-1 results in steric constraints and an additional N-glycosylation site in IgII. Additional N-glycosylation of hNpaudio-1 was confirmed by PNGaseF treatment. In comparison to hNpWT, transfection of hNppitch and hNpaudio-1 into HEK293T cells resulted in normal mRNA levels but reduced the Np protein levels and their cell surface expression due to proteasomal/lysosomal degradation. Furthermore, hNppitch and hNpaudio-1 failed to promote exogenous PMCA levels in HEK293T cells. In hippocampal neurons, expression of additional hNppitch or hNpaudio-1 was less efficient than hNpWT to elevate endogenous PMCA levels and to accelerate the restoration of basal Ca2+ levels after electrically-evoked Ca2+ transients. We propose that mutations leading to pathological Np variants, as exemplified here by the deafness causing Np mutants, can affect Np-dependent Ca2+ regulatory mechanisms and may potentially cause intellectual and cognitive deficits in humans.

Spatial distribution of parameters of auditory cognitive evoked potentials P300 in young adults with myopia

BACKGROUND: Myopia typically presents itself between the ages of 18 and 29, affecting both women (35%) and men (59.9%). The prevalence of impaired accommodation and refraction in modern individuals can be attributed to the increased strain on visual sensory systems resulting from the widespread digitalization of various aspects of human life. This increased strain poses a potential risk for alterations in cortical processes related to perception and information processing, increasing the risk of cognitive impairment. AIMS: To study the differences in the characteristics of evoked potentials P300 in 21–23 years old individuals with myopia compared to those without ophthalmic pathology. MATERIAL AND METHODS: An ophthalmological examination was conducted on a group of young individuals aged 21–23 years (average age 22.3±0.1 years) residing in the city of Arkhangelsk. The participants were university students, totaling 54 individuals of both genders (34 females and 20 males). During the examination, uncorrected visual acuity, best-corrected visual acuity, and clinical refraction value (in diopters) were assessed for each participant, along with qualitative changes. Additionally, the reserve of relative accommodation (in diopters) was estimated based on the results of the accommodation study. The study sample consisted of 32 participants without ophthalmic pathology and 22 individuals diagnosed with myopia. The parameters of cognitive evoked auditory potential P300 were measured using an electroencephalograph «NeuronSpectrum- 4/VPM» (Neurosoft, Russia) in both groups. The data were analyzed using the SPSS statistical software package. RESULTS: Students with myopia had longer decision-making times compared to individuals with normal vision, as indicated by auditory evoked potentials P300. This effect was observed in the temporal, mid-frontal, and left frontal regions of the brain. Additionally, the anterior-occipital gradient of P300 amplitude was attenuated, with a high amplitude P300 in the left occipital region. CONCLUSION: Assessment of myopia should be complemented with an examination of the functional status of the cerebral cortex. Extended auditory processing time, activation of both hemispheres and involvement of the occipital regions during the processing of auditory information may be a result of functional reorganization of the cerebral cortex in individuals with myopia.

Low-Level Auditory Processing Correlates With Language Abilities: An ERP Study Investigating Sequence Learning and Auditory Processing in School-Aged Children.

Auditory processing and procedural learning deficits have been associated with language learning difficulties. We investigated the relationship of these skills and school-age language abilities in children with and without a history of late talking using auditory event related potentials (ERPs). Late talking (i.e., slow early language development) increases the risk of persistent language difficulties, but its causes remain unknown. Participants in this study were children with varying language abilities (n = 60). Half of the participants (n = 30) had a history of late talking. We measured procedural learning by manipulating the predictability of sine tone stimuli in a passive auditory ERP paradigm. Auditory processing was tested by examining how the presence of noise (increasing perceptual demands) affected the ERPs. Contrary to our hypotheses on auditory processing and language development, the effect of noise on ERPs did not correlate with school-age language abilities in children with or without a history of late talking. Our paradigm failed to reveal interpretable effects of predictability leaving us unable to assess the effects of procedural learning. However, better language abilities were related to weaker responses in a 75-175 ms time window, and stronger responses in a 150-250 ms time window. We suggest that the weak early responses in children with better language ability reflect efficient processing of low-level auditory information, allowing deeper processing of later, high-level auditory information. We assume that these differences reflect variation in brain maturation between individuals with varying language abilities.

423. Biomarkers of Auditory Information Processing and Neural Synchrony Predict Targeted Cognitive Training Exercise Completion in a Transdiagnostic Population

423. Biomarkers of Auditory Information Processing and Neural Synchrony Predict Targeted Cognitive Training Exercise Completion in a Transdiagnostic Population

Effects of Metrical Context on the P1 Component.

The temporal structure of sound, characterized by regular patterns, plays a crucial role in optimizing the processing of auditory information. The meter, representing a well-organized sequence of evenly spaced beats in music, exhibits a hierarchical arrangement, with stronger beats occupying higher metrical positions. Moreover, the meter has been shown to influence behavioral and neural processing, particularly the N1, P2, and mismatch negativity components. However, the role of the P1 component in the context of metrical hierarchy remains unexplored. This study aimed to investigate the effects of metrical hierarchy on the P1 component and compare the responses between musicians and non-musicians. Thirty participants (15 musicians and 15 non-musicians) were enrolled in the study. Auditory stimuli consisted of a synthesized speech syllable presented together with a repeating series of four tones, establishing a quadruple meter. Electrophysiological recordings were performed to measure the P1 component. The results revealed that metrical position had a significant effect on P1 amplitude, with the strongest beat showing the lowest amplitude. This contrasts with previous findings, in which enhanced P1 responses were typically observed at on-the-beat positions. The reduced P1 response on the strong beat can be interpreted within the framework of predictive coding and temporal prediction, where a higher predictability of pitch changes at the strong beat leads to a reduction in the P1 response. Furthermore, higher P1 amplitudes were observed in musicians compared to non-musicians, suggesting that musicians have enhanced sensory processing. This study demonstrates the effects of metrical hierarchy on the P1 component, thereby enriching our understanding of auditory processing. The results suggest that predictive coding and temporal prediction play important roles in shaping sensory processing. Further, they suggest that musical training may enhance P1 responses.

Lack of habituation of visual-evoked potential in the interictal period is not a consistent neurophysiological marker of migraine: A cross-sectional analytical study

Objectives: Migraine is a frequent incapacitating neurovascular illness characterized by severe headache bouts. Individuals suffering from migraine appear to process auditory and visual information differently from those without migraine. The visual-evoked potential (VEP) is a commonly used standardized test to measure excitability in the occipital cortex. Patients with migraine exhibit amplification rather than habituation of stimulus-induced brain responses, between attacks. Our objective is to compare the amplitude of P100 and the latencies of N75, P100, and N145 (N and P represent negative and positive peaks, respectively, with average latency being subscripted with the alphabet) in the fourth block between migraine patients and controls and to determine the various clinical factors associated with the P100 mean amplitude and latency differences between the first and the fourth block in migraine patients. Materials and Methods: The study compared 20 migraine patients (with or without aura) and 20 apparently healthy subjects with no history of migraines or secondary headaches, focusing on the habituation of the VEP. Four blocks of 200 responses were recorded during the headache-free period, and the latencies and amplitudes of N75, P100, and N145 components were analyzed. Results: There was a statistically significant (P < 0.05) decrement in the P100 amplitude in the fourth block when compared to the first block in both eyes in the controls as well as migraine patients. In addition, there was no statistically significant difference between controls and migraine sufferers in the P100 amplitude of the fourth block in either eye. The N145 latency in the fourth block was shorter in both eyes in migraine patients compared to controls (P < 0.05). The mean P100 amplitude difference between the first and fourth block correlated negatively with age and positively with headache frequency, while there was a moderate negative correlation with headache duration. The mean P100 latency difference between the first and fourth block correlated positively with age and negatively with headache frequency, while there was a moderate positive correlation with headache duration. Conclusion: In our study, VEP habituation was not lacking in migraine patients which means that habituation of the P100 wave was noted in migraineurs. The VEP reveals neurological changes due to ischemia injury or neurotransmitter imbalances. Migraine alters cortical excitability, but it is unclear if these changes are due to altered excitatory connections, damaged inhibitory networks or subcortical pre-activation. Our findings suggest that at least during the interictal period, lack of habituation cannot be employed as a consistent neurophysiological marker of migraine across laboratories.

Early auditory processing abnormalities alter individual learning trajectories and sensitivity to computerized cognitive training in schizophrenia.

Auditory system plasticity is a promising target for neuromodulation, cognitive rehabilitation and therapeutic development in schizophrenia (SZ). Auditory-based targeted cognitive training (TCT) is a 'bottom up' intervention designed to enhance the speed and accuracy of auditory information processing, which has been shown to improve neurocognition in certain SZ patients. However, the dynamics of TCT learning as a function of training exercises and their impact on neurocognitive functioning and therapeutic outcomes are unknown. Forty subjects (SZ, n = 21; healthy subjects (HS), n = 19) underwent comprehensive clinical, cognitive, and auditory assessments, including measurements of auditory processing speed (APS) at baseline and after 1-h of TCT. SZ patients additionally completed 30-hours of TCT and repeated assessments ~10-12 weeks later. SZ patients were deficient in APS at baseline (d = 0.96, p < 0.005) relative to HS. After 1-h of TCT, analyses revealed significant main effects of diagnosis (d = 1.75, p = 0.002) and time (d = 1.04, p < 0.001), and a diagnosis × time interaction (d = 0.85, p = 0.02) on APS. APS learning effects were robust after 1-h in SZ patients (d = 1.47, p < 0.001) and persisted throughout the 30-h of training. Baseline APS was associated with verbal learning gains after 30-h of TCT (r = 0.51, p = 0.02) in SZ. TCT learning metrics may have prognostic utility and aid in the prospective identification of individuals likely to benefit from TCT. Future experimental medicine studies may advance predictive algorithms that enhance TCT-related clinical, cognitive and functional outcomes.

Changes in Cortical Grey Matter Volumes After Plasticity-based Auditory Information Processing Remediation Training in Adults with a Chronic Traumatic Brain Injury: A Pilot Study

Changes in Cortical Grey Matter Volumes After Plasticity-based Auditory Information Processing Remediation Training in Adults with a Chronic Traumatic Brain Injury: A Pilot Study

The Correlation between HUIT English Majors’ Short - Term Memory and Listening Comprehension Skills at Different Language Proficiency Levels

The study of short-term memory (STM) is crucial to the study of second language acquisition. STM plays an important role in language acquisition and development since it is an on-line capacity for processing and elaborating new information. A fundamental skill in learning English is listening comprehension. The ability to listen is crucial when learning a foreign language because receiving language input is the key to language learning. More and more academics at home and abroad have started to focus on the relationship between STM and listening comprehension in recent years. STM has been demonstrated to be a crucial component of listening comprehension, making it extremely vital to increase listening comprehension in second languages. STM helps in the immediate processing of incoming auditory information when listening in a second language. This essay investigates the relationship between short-term memory and listening comprehension skills of English - majored students from Ho Chi Minh City University of Industry and Trade. The results' implications suggest that improving short-term memory capacity is necessary to get students ready for the listening IELTS examination.

근원적 인지 메커니즘을 통한 난독증 탐구

Objectives The purpose of this paper is to identify dyslexia among various types of learning disabilities, explain its manifestation mechanism, and demonstrate it clinically.&#x0D; Methods This paper shows that through the fundamental cognitive mechanism, not only can the characteristics of dyslexia be understood in the most fundamental, essential, and holistic way, but also a better understanding of how dyslexia is fundamentally manifested. For clinical proof, non-verbal intelligence test (K-CTONI-2), Korean version of Children's Visual Perception Development Test (K-DTVP-3), the Korean Reading Test (KOLRA), and speech hearing test were administered to 7 elementary school students who continued to experience difficulties despite receiving reading education.&#x0D; Results Dyslexia begins with an excessively imbalanced structure of the brain's large visual and small auditory cognitive spaces. Due to the imbalance between the two cognitive spaces, visual acuity and visual memory appear strong, while auditory acuity and auditory memory appear weak, resulting in auditory internal attention deficit, which is the most important cognitive condition for language development. Auditory internal attention deficit in turn interferes with auditory information processing, resulting in serious difficulties in written language development and various symptoms observed in dyslexic children. The test results showed a low auditory function score compared to a high visual function score.&#x0D; Conclusions Dyslexia occurs due to functional defects in hierarchical cognitive processes such as auditory sensation, memory, and thought processing caused by an imbalance between the brain's small auditory cognitive space and large visual cognitive space. This paper presents directions for effective dyslexia treatment based on research results.&#x0D;

Sleep- and sleep deprivation-related changes of vertex auditory evoked potentials during the estrus cycle in female rats

The estrus cycle in female rodents has been shown to affect a variety of physiological functions. However, little is known about its presumably thorough effect on auditory processing during the sleep–wake cycle and sleep deprivation. Vertex auditory evoked potentials (vAEPs) were evoked by single click tone stimulation and recorded during different stages of the estrus cycle and sleep deprivation performed in metestrus and proestrus in female rats. vAEPs showed a strong sleep-dependency, with the largest amplitudes present during slow wave sleep while the smallest ones during wakefulness. Higher amplitudes and longer latencies were seen in the light phase during all vigilance stages. The largest amplitudes were found during proestrus (light phase) while the shortest latencies were seen during estrus (dark phase) compared to the 2nd day diestrus baseline. High-amplitude responses without latency changes were also seen during metestrus with increased homeostatic sleep drive. More intense and faster processing of auditory information during proestrus and estrus suggesting a more effective perception of relevant environmental cues presumably in preparation for sexual receptivity. A 4-h sleep deprivation resulted in more pronounced sleep recovery in metestrus compared to proestrus without difference in delta power replacement suggesting a better tolerance of sleep deprivation in proestrus. Sleep deprivation decreased neuronal excitability and responsiveness in a similar manner both during metestrus and proestrus, suggesting that the negative consequences of sleep deprivation on auditory processing may have a limited correlation with the estrus cycle stage.

The effective connectivity analysis of fMRI based on asymmetric detection of transfer brain entropy.

It is important to explore causal relationships in functional magnetic resonance imaging study. However, the traditional effective connectivity analysis method is easy to produce false causality, and the detection accuracy needs to be improved. In this paper, we introduce a novel functional magnetic resonance imaging effective connectivity method based on the asymmetry detection of transfer entropy, which quantifies the disparity in predictive information between forward and backward time, subsequently normalizing this disparity to establish a more precise criterion for detecting causal relationships while concurrently reducing computational complexity. Then, we evaluate the effectiveness of this method on the simulated data with different level of nonlinearity, and the results demonstrated that the proposed method outperforms others methods on the detection of both linear and nonlinear causal relationships, including Granger Causality, Partial Granger Causality, Kernel Granger Causality, Copula Granger Causality, and traditional transfer entropy. Furthermore, we applied it to study the effective connectivity of brain functional activities in seafarers. The results showed that there are significantly different causal relationships between different brain regions in seafarers compared with non-seafarers, such as Temporal lobe related to sound and auditory information processing, Hippocampus related to spatial navigation, Precuneus related to emotion processing as well as Supp_Motor_Area associated with motor control and coordination, which reflects the occupational specificity of brain function of seafarers.

Dbx1 is a dorsal midbrain-specific determinant of GABAergic neuron fate and regulates differentiation of the dorsal midbrain into the inferior and superior colliculi.

The mechanism underlying the differentiation of the dorsal midbrain into two morphologically and functionally distinct compartments, the inferior colliculus (IC) and superior colliculus (SC), which process auditory and visual information, respectively, remains largely unexplored. By using null and conditional alleles, we uncover the roles of a homeodomain transcription factor Dbx1 in the regulation of IC and SC differentiation. We show that Dbx1 regulates GABAergic neuron development in the dorsal midbrain. In the absence of Dbx1 function, the dorsal-most m1-m2 progenitor domains in the midbrain fail to activate GABAergic neuron-specific gene expression and instead switch to a glutamatergic phenotype. These results identify Dbx1 as a dorsal midbrain-specific GABAergic determinant that regulates the selector genes, Helt, Gata2, and Tal2. Furthermore, we demonstrate that maturation of the dorsal midbrain into the IC and SC is dependent on Dbx1. Null mutation of Dbx1 impairs the identity and fate of IC and SC neurons. Surprisingly, Dbx1 is required for preventing IC into SC fate switch and thus Dbx1-deficient IC neurons undergo acquisition of SC identity. Conditional inactivation of Dbx1 at late developmental phase leads to alteration in the identity and fate of the IC, but not the SC. These results suggest that SC differentiation is dependent on the early function of Dbx1, and that the IC requires the prolonged action for its normal formation. Furthermore, we uncover that Tcf7l2 acts downstream of Dbx1 selectively to promote IC differentiation. Altogether, our study identifies a molecular mechanism underlying spatial and temporal control of dorsal midbrain development.