Auditory Neurophysiology publications

Auditory processing in the cerebral cortex is considered to begin with thalamocortical inputs to layer 4 (L4) of the primary auditory cortex (A1). In this canonical model, A1 L4 inputs initiate a hierarchical cascade that propagates to higher-order cortices for slower integration of complex sounds. Here, we identify parallel ascending pathways in mice that bypass A1 and directly reach the secondary auditory cortex (A2), alongside the canonical hierarchical route. We found that layer 6 (L6) of both A1 and A2 receive short-latency (<10 ms) sound inputs via higher-order thalamic nuclei. Additionally, A2 L4 is innervated by a caudal subdivision of the traditionally defined primary thalamus, which we now re-classify as non-primary. Notably, both identified thalamic regions receive projections from distinct subdivisions of the higher-order inferior colliculus, which in turn receive direct projections from cochlear nucleus neurons. Thus, higher-order auditory cortex integrates both slower, pre-processed information and rapid, direct sensory inputs, enabling parallel processing of fast sensory information across cortical areas.

Atypical sensory processing, particularly in the auditory domain, is one of the most common and quality-of-life affecting symptoms seen in autism spectrum disorders (ASD). Fragile X Syndrome (FXS) is a leading inherited cause of ASD and a majority of FXS individuals present with auditory processing alterations. While auditory hypersensitivity is a common phenotype observed in FXS and Fmr1 knockout (KO) rodent models, it is important to consider other auditory coding impairments that could contribute to sound processing difficulties and disrupted language comprehension in FXS. We have shown previously that a Fmr1 KO rat model of FXS exhibits heightened sound sensitivity that coincided with abnormal perceptual integration of stimulus bandwidth, indicative of altered spectral processing. Frequency discrimination is a fundamental aspect of sound encoding that is important for a range of auditory processes, such as source segregation and speech comprehension, and disrupted frequency coding could thus contribute to a range of auditory issues in FXS and ASD. Here we explicitly characterized spectral processing deficits in male Fmr1 KO rats using an operant conditioning tone discrimination assay and in vivo electrophysiological recordings from the auditory cortex and inferior colliculus. We found that Fmr1 KO rats exhibited poorer frequency resolution, which corresponded with neuronal hyperactivity and broader frequency tuning in auditory cortical but not collicular neurons. Using an experimentally informed population model, we show that these cortical physiological differences can recapitulate the observed behavior discrimination deficits, with decoder performance being tightly linked to differences in cortical tuning width and signal-to-noise ratios. Together, these findings indicate that cortical hyperexcitability in Fmr1 KO rats may act to preserve signal-to-noise ratios and signal detection threshold at the expense of sound sensitivity and fine feature discrimination, highlighting a potential mechanistic locus for a range of auditory behavioral phenotypes in FXS.

Identifying neural signatures of loss of consciousness is a major goal of neuroscience. The local/global auditory novelty paradigm has been useful in characterizing sensory processing across arousal states. Propofol suppresses responses to long‐term novelty (global deviance, GD) at subhypnotic doses; suppression of responses to short‐term novelty (local deviance, LD) outside auditory cortex may represent a biomarker of loss of consciousness. Dexmedetomidine is an alpha‐2 adrenergic agonist that induces sleep‐like sedation. This study examined whether the changes in auditory novelty processing observed with propofol, a GABA‐ergic agent, also occur with dexmedetomidine and during sleep. Intracranial recordings were obtained in neurosurgical patients undergoing monitoring for refractory epilepsy. Stimuli were vowel sequences incorporating LD and GD. Neural activity was recorded during wakefulness, administration of dexmedetomidine, and sleep and was examined as the averaged evoked potential (AEP) and high gamma (70–150 Hz) power. AEP responses were more broadly distributed than high gamma activity. Results previously observed with propofol were replicated with dexmedetomidine. Subhypnotic doses led to decreased LD effects and a precipitous decline in GD effects. Loss of responsiveness was associated with loss of LD effects outside the auditory cortex. Likewise, daytime sleep was associated with cessation of GD effects and confinement of LD effects to the auditory cortex. Results support the generalizability of changes in auditory novelty processing to dexmedetomidine and sleep. Preservation of LD effects in the auditory cortex indicates that the auditory cortex continues to monitor the environment following loss of responsiveness.

Analyzing the functional connectivity of the brain is an enormous challenge, as deciphering functional connectivity requires knowledge of functional responses and connections. One promising strategy is analyzing the spatial pattern of activity correlations across cell populations. In the primary auditory cortex (A1), cells respond to different sound features. On the large scale, there exists a tonotopic map, which is fractured at the small scale, raising the question of whether functional connections are spatially ordered or disordered. To test whether functional connectivity on a local and a global scale is also disordered, we first designed a robust statistical model to estimate parameters and test for the significance of the estimated correlation maps. We developed an inference method that allows efficient model fitting and statistical testing to project the correlation maps to 2D space. We then performed in vivo two-photon calcium imaging in layer 2/3 of A1 with pure tones (PT) or a combination of two tones (TT; harmonically related or not). We found that the spatial patterns of signal correlations (SCs) depend on the type of sound stimuli that were presented. The functional 2D maps of PT-driven SCs are more restricted to local neurons than TT signal correlations which showed more global textures. 2D SC patterns for harmonic stimuli showed spatially distinct relationships. TT SCs revealed spatially precise functional connectivity between harmonically related neurons. Thus, even though the frequency preference of neighboring neurons in A1 is functionally diverse, the functional connection pattern of these neurons is functionally precise and harmonically related.

Insects’ sound and vibration detection including proprioception rely on the scolopidium—a mechanosensory unit enclosing the sensory cilium of chordotonal organ neurons. The cilium, enclosed by a scolopale cell, contains mechanosensitive ion channels with the ciliary tip embedded in a cap. Despite knowledge of the scolopidial structure in multiple insects, the mechanism by which mechanical force elicits transduction remains speculative. We examined scolopidia in the auditory Müller’s organ of the desert locust and present a comprehensive three-dimensional (3D) ultrastructure of a scolopidium using Focused Ion Beam Scanning Electron Microscopy (FIB-SEM). Next, we characterised sound-evoked motions of Müller’s organ and the scolopidium using Optical Coherence Tomography (OCT) and high-speed light microscopy. Finally, we measured transduction currents via patch clamp electrophysiology during mechanical stimulation of individual scolopidia. By combining ultrastructure, sound-evoked motions, and transduction current recordings, our finding suggests that the scolopidium is activated best by stretch along the ciliary axis.

Negative feedback of the cochlear efferent system plays a critical role in control of hearing sensitivity and protection from noise trauma. Type II auditory nerves (ANs) innervate outer hair cells (OHCs) in the cochlea and provide an input to the cochlear efferent system to achieve hearing sensitivity controlling and protection; in particular, medial olivocochlear efferent nerves innervate OHCs to control OHC electromotility, which is an active cochlear amplifier in mammals. However, little is known about channel information underlying type II AN activity and consequent function. Here, we report that ATP-gated P2x7 receptor had a predominant expression at type II spiral ganglion (SG) neurons and the synaptic areas under inner hair cells and OHCs with lateral and medial olivocochlear efferent nerves. Knockout (KO) of P2x7 increased hearing sensitivity with enhanced acoustic startle response, auditory brainstem response, and cochlear microphonics by increasing OHC electromotility. P2x7 KO also increased susceptibility to noise and exacerbated ribbon synapse degeneration. Middle-level noise exposure could impair active cochlear mechanics resulting in hearing loss in P2x7 KO mice. These data demonstrate that P2x7 receptors have a critical role in type II SG neuron’s function and the cochlear efferent system to control hearing sensitivity; deficiency of P2x7 receptors can impair type II SG neuron’s function and the cochlear efferent suppression leading to increase of active cochlear amplification and hearing oversensitivity, i.e., hyperacusis, and susceptibility to noise, which may also associate with other hearing disorders, such as tinnitus.

Introduction Prenatal exposure to valproic acid (VPA) is a common environmental cause of autism spectrum disorder (ASD) and often leads to expressive and receptive language impairments. Similar communication difficulties among individuals with ASD are often linked to abnormal subcortical and cortical sound processing. Rodents prenatally exposed to VPA exhibit degraded cortical responses to speech and an impaired ability to behaviorally discriminate speech sounds. Methods We sought to determine whether sound processing could be restored with paired vagus nerve stimulation (VNS). In a first experiment, we evaluated whether sound-paired VNS would alter in vivo extracellular multi-unit responses to tones, noise burst trains, and speech sounds from the anterior auditory field. We next sought to evaluate whether improvements to neural sound processing led to improvements in sound discrimination ability. In a second experiment, rats underwent go/no-go sound discrimination testing where VNS was paired with successful trials. Results We found that VPA-exposed rats had degraded spectral, temporal, and speech sound processing compared to saline-exposed control rats. VPA-exposed rats which received sound-paired VNS exhibited a partial or full restoration of processing across sound types. However, across several sound discrimination tasks, we did not observe changes in behavioral performance in response to prenatal exposure to VPA or VNS. Discussion Our study is the first to show that speech-paired VNS leads to a generalized improvement in cortical sound processing across sound types, rescuing neural processing among VPA-exposed rats. These results provide a framework for future studies to develop VNS-based interventions for communication disorders.

The mediodorsal thalamic nucleus (MD) forms neural circuits with various brain regions, including the prefrontal cortex (PFC), the reticular thalamic nucleus (TRN), and the midbrain reticular nucleus (MRN). However, the specific roles and underlying mechanisms in auditory information processing remain unclear. Here, we perform multi-channel electrophysiological recordings in awake mice to investigate the response patterns of the MD to auditory stimuli, as well as the regulatory effects of PFC, MRN, and TRN inputs. We identify two distinct types of sound-evoked responses. The Phasic-response features a transient burst firing to the stimulus with short latency, rapidly adapting to baseline and corresponding to the onset fluctuation of the local field potential. The Sustained-response is marked by prolonged firing with longer latency and is accompanied by persistent enhancement of oscillatory power following stimulus offset. The response patterns of MD neurons remain consistent across different types of auditory stimuli. Optogenetic inactivation of the MRN suppresses both response types in the MD. The Sustained-response is attenuated by PFC inactivation but enhanced by TRN inactivation, while the Phasic-response remains unaffected by inactivation of either the PFC or TRN. Our findings expand the understanding of the MD's role in sound information integration and auditory cognitive regulation.

A crucial aspect of auditory perception is the ability to use sound cues to predict future events and to time actions accordingly. For example, the sound of an approaching vehicle signals when it is safe to cross the street; distinct smartphone notification sounds reflect a call that needs to be answered within a few seconds, or a text that can be read later. Other animals similarly use sounds to plan, time and execute behaviors such as hunting, evading predation and tending to offspring. However, the neural mechanisms that underlie sound-guided prediction of upcoming salient event timing are not well understood. To address this gap, we employed an appetitive sound-triggered reward time prediction behavior in head-fixed mice. We find that mice trained on this task reliably estimate the time from a sound cue to upcoming reward on the scale of a few seconds, as demonstrated by learning-dependent well-timed increases in predictive licking for reward. Moreover, mice showed a dramatic impairment in their ability to use sound to predict delayed reward when the auditory cortex was inactivated, demonstrating its causal involvement. To identify the neurophysiological signatures of auditory cortical reward-timing prediction, we recorded local field potentials during learning and performance of this behavior and found that the magnitude of auditory cortical responses to the sound prospectively encoded the duration of the anticipated sound-reward time interval. Next, we explored how and where these sound-triggered time interval prediction signals propagate from the auditory cortex to time and initiate consequent action. We targeted the monosynaptic projections from the auditory cortex to the posterior striatum and found that chemogenetic inactivation of these projections impaired animals’ ability to predict sound-triggered delayed reward. Simultaneous neural recordings in the auditory cortex and posterior striatum during task performance revealed coordination of neural activity across these regions during the sound cue predicting the time interval to reward. Collectively, our findings identify an auditory cortical-striatal circuit supporting sound-triggered timing-prediction behaviors.

Noise-induced hearing loss (NIHL) poses an emerging global health problem with only ear protection or sound avoidance as preventive strategies. The cochlea receives some protection from medial olivocochlear efferent neurons, providing a potential target for therapeutic enhancement. Cholinergic efferents release acetylcholine (ACh) to hyperpolarize and shunt the outer hair cells (OHCs), reducing sound-evoked activation. The (α9)2(α10)3 nicotinic ACh receptor (nAChR) on the OHCs mediates this effect. Transgenic knockin mice with a gain-of-function nAChR (α9L9'T) suffer less NIHL. α9 knockout mice are more vulnerable to NIHL but can be rescued by viral transduction of the α9L9'T subunit. In this study, an HA-tagged gain-of-function α9 isoform was expressed in wild-type mice to reduce NIHL. Synaptic integration of the virally expressed nAChR subunit was confirmed by HA immunopuncta localized to the postsynaptic membrane of OHCs. After noise exposure, AAV2.7m8-CAG-α9L9'T-HA (α9L9'T-HA)-injected mice had less hearing loss (auditory brainstem response [ABR] thresholds and threshold shifts) than did control mice. ABRs of α9L9'T-HA-injected mice also had larger wave-1 amplitudes and better recovery of wave-1 amplitudes post noise exposure. Thus, virally expressed α9L9'T combines effectively with native α9 and α10 subunits to mitigate NIHL in wild-type cochleas.

Socially effective vocal communication requires brain regions that encode expressive and receptive aspects of vocal communication in a social context-dependent manner. Here, we combined a novel behavioral assay with microendoscopic calcium imaging to interrogate neuronal activity (regions of interest [ROIs]) in the posterior insula (pIns) in socially interacting mice as they switched rapidly between states of vocal expression and reception. We found that largely distinct subsets of pIns ROIs were active during vocal expression and reception. Notably, pIns activity during vocal expression increased prior to vocal onset and was also detected in congenitally deaf mice, pointing to a motor signal. Furthermore, receptive pIns activity was modulated strongly by social context. Lastly, tracing experiments reveal that deep-layer neurons in the pIns directly bridge the auditory thalamus to a midbrain vocal gating region. Therefore, the pIns is a site that encodes vocal expression and reception in a manner that depends on social context.

The neural processes that change when falling asleep are only partially understood. At the cortical level, features of both spontaneous neural activity and sensory responses change between wakefulness and sleep. For example, in the early auditory cortex, sleep increases the occurrence of postonset silent (OFF) periods and elevates population synchrony. However, it remains unknown whether such changes occur abruptly or gradually around sleep onset and awakening. Here, we recorded spontaneous and sound-evoked neuronal spiking activity in the early auditory cortex along with polysomnography during thousands of episodes when male rats fell asleep or woke up. We found that when falling asleep, stimulus-induced neuronal silent periods (OFF periods), characteristic of nonrapid eye movement sleep, increased within a few seconds around sleep onset. In contrast, a gradual increase in neuronal population synchrony built up over tens of seconds until reaching maximal levels. EEG auditory-evoked potentials likely representing stimulus-triggered “K-complexes” changed along with postonset neuronal firing, whereas ongoing EEG slow-wave activity was associated with neuronal population synchrony. Similar effects, but with opposite direction, were observed around awakenings. The results highlight late stimulus-induced neuronal silence as a key feature changing abruptly around transitions between vigilance states, likely reflecting neuronal bistability and manifesting also in EEG-evoked potentials. More generally, these findings emphasize the added value of going beyond monitoring ongoing activity and perturbing the nervous system to reveal its state—an insight that could also help guide the development of more sensitive noninvasive monitors of falling asleep in humans.

The entire auditory system downstream of the cochlea features pronounced offset responses, which follow the termination of sounds. Because of their ubiquity, it is still an unsolved question whether offset responses are generated early in the auditory system and then propagated or recomputed at each processing stage. Here, we analysed large-scale sound responses datasets acquired in the cochlear nucleus, inferior colliculus, medial geniculate nucleus and auditory cortex of awake mice. All brain regions showed a significant proportion of offset responses often combined with onset and sustained responses in the same neuron. However, using population activity decoders, we observed that neural representations after the sound offset show a three-fold increase in sound encoding accuracy in the cortex relative to subcortical areas. This result indicates that cortical offsets encode a more precise short-term memory of the elapsed sound than subcortical offsets and that they likely result from specific computational steps. Key points summary Offset responses are found throughout the central auditory system Offset responses are often combined to sustained and onset responses at all central auditory system stages Offset responses provide richer information about elapsed sounds in the auditory cortex

Purpose Present-day cochlear-implant (CI) users can achieve high levels of speech reception in quiet surroundings. Nevertheless, sensitivity to the temporal pitch of sounds is limited, which contributes to deficits in speech reception amid multiple talkers and in appreciation of musical melodies. Short-term, invasive neurophysiological studies in animals have demonstrated limitations in neural phase locking in the tonotopic range of the auditory pathway that is activated by CIs. It remains an open question, however, whether those neural limitations can account for perceptual deficits in those animal species, let alone in human CI users. For that reason, we have evaluated non-invasive recordings of phase locking from cats chronically implanted with a CI. Methods Ten deafened cats (eight female) were implanted with an animal version of a clinical CI array. The electrically evoked frequency following response (eFFRs) was recorded from the scalps of sedated animals at ≥ 10 weeks post-implantation. Stimuli consisted of constant-amplitude electrical pulse trains at rates from ~ 40 to 640 pulses per second. Results Recordings of the eFFR demonstrated robust responses synchronized to electrical pulse trains across all stimulus rates. Analyses of eFFR amplitude and phase transfer functions confirmed that the eFFR, as with its normal-hearing counterpart, originates from multiple subcortical and cortical generators. The slopes of segments of eFFR phase transfer functions revealed stimulus-to-response latencies of generators that dominated the eFFR across restricted ranges of pulse rates. Those rate ranges must coincide with the limits of phase locking by putative generators at successive levels of the auditory neuroaxis and could inform our understanding of the limits to perceptual temporal acuity. Conclusion The eFFR demonstrated here in an animal model provides a valuable non-invasive measure of temporal processing in electric cochlear stimulation that can be related to ongoing perceptual measures in the same animals and is well-suited to evaluate novel modes of auditory prosthesis for enhancing temporal acuity.

For patients with severe and profound hearing loss, cochlear implant (CI), a common and effective modality for restoring hearing, directly stimulates spiral ganglion neurons (SGNs) to generate electrical activity and form auditory perception. However, the postoperative outcome of CI is significantly influenced by the number of surviving SGNs, ​​which is a key focus of preoperative evaluation​​. Existing audiologic function and radiographic tests cannot directly demonstrate the integrity of inner ear primary neurons. In this study, ​​we developed and validated​​ a radionuclide‐labeled anti‐vesicular glutamate transporter 1 (anti‐VGLUT1) antibody‐drug and achieved animal‐level in vivo imaging of cochlear SGNs using nuclear imaging. By screening the public single‐cell sequencing database, it is found that VGLUT1 can serve as a representative cell membrane marker for SGN in the cochlea. The potential of anti‐VGLUT1 conjugated to the long half‐life 177 Lu as a molecular probe to detect the relative number of SGNs in SGN‐injured mouse and pig models is explored. The study provides a novel method for assessing cochlear nerve integrity in vivo by visualizing target antigen expression levels through nuclear imaging. This approach is promising to help CI candidates with preoperative inner ear SGN integrity assessment, contributing to clinical decision‐making.

Animals have evolved complex auditory systems to extract acoustic information from natural environmental noise, yet they are challenged by rising levels of novel anthropogenic noise. Songbirds adjust their vocal production in response to increasing noise, but auditory processing of signals in noise remains understudied. Auditory processing characteristics, including auditory filter bandwidth, filter efficiency and critical ratios (level-independent signal-to-noise ratios at threshold), likely influence auditory and behavioral responses to noise. Here, we investigated the effects of noise on auditory processing in three songbird species (black-capped chickadees, tufted titmice and white-breasted nuthatches) that live in mixed-species flocks and rely on heterospecific communication to coordinate mobbing behaviors. We determined masked thresholds and critical ratios from 1 to 4 kHz using auditory evoked potentials. We predicted that nuthatches would have the lowest critical ratios given that they have narrowest filters, followed by titmice and then chickadees. We found that nuthatches had the greatest sensitivity in quiet conditions, but the highest critical ratios, suggesting their auditory sensitivity is highly susceptible to noise. Titmice had the lowest critical ratios, suggesting relatively minor impacts of noise on their auditory processing. This is not consistent with predictions based on auditory filter bandwidth, but is consistent with both recent behavioral findings and predictions made by auditory filter efficiency measures. Detrimental effects of noise were most prevalent in the 2–4 kHz range, frequencies produced in vocalizations. Our results using the critical ratio as a measure of processing in noise suggest that low levels of anthropogenic noise may influence these three species differently.

The postnatal brain undergoes substantial plasticity in order to represent features and statistics of the sensory world. To date, for technical reasons it has been difficult to examine experience-dependent changes over the course of postnatal development. Here we perform longitudinal two-photon calcium imaging of hundreds of neurons in the auditory cortex of young mice, from postnatal day (P) 12 into adulthood. Auditory cortical neurons started responding to tonal stimuli by P13-14 with an initial tonotopic organization that expanded over the next few days. We documented the daily variation in tuning curves and best frequency, and while some neurons gradually changed their frequency representation across days, altogether our findings support the functional maturation of a largely stable auditory map at the population level. We then compared the representation of mouse pup ultrasonic vocalizations to pure tone responses. Ultrasonic pure tone tuning developed with a delay, coinciding with emerging responses to ultrasonic vocalizations. Vocalization responses initially were observed in neurons tuned to ultrasonic frequencies, but over later development the vocalization responses became independent from ultrasonic frequency tuning. Our results show how varied sensory representations at the single-cell and population levels in the postnatal auditory cortex emerge and change over the course of early-life development.

Severe to profound sensorineural hearing loss seriously affects the communication and cognitive ability of the patients. Cochlear implantation (CI) is currently the most effective treatment, while it may damage the remaining inner ear function due to its poor biocompatibility and the resultant fibrosis. Herein, a porous methacrylated poly(dimethylsiloxane) (MA‐PDMS)‐coated cochlear electrode is presented for CI and hearing protection. The porous MA‐PDMS is filled with a hybrid hydrogel system made of dexamethasone sodium phosphate (Dex), Ti 3 C 2 T x MXene (MXene), and methacrylate gelatin (GelMA). The coating shows good biocompatibility and drug loading and release capacity in vitro, protective effects on hair cells (HCs) and spiral ganglion neurons (SGNs) of the inner ear, as well as the residual hearing protection and the effective fibrosis reduction in vivo. It is anticipated that this porous electrode drug‐loading coating may provide a valuable reference strategy for the future cochlear electrode transplantation system.

In utero nicotine exposure from maternal smoking is linked to increased risk of auditory processing deficits. This study investigated the impact of developmental nicotine exposure during the critical period on nicotinic acetylcholine receptor (nAChR) functional expression, glutamatergic synaptic transmission and auditory processing in the mouse auditory brainstem. We assessed nAChR function at a central synapse and the consequences of perinatal nicotine exposure (PNE) on synaptic currents and auditory brainstem responses (ABRs) in mice. Our results indicate developmentally regulated changes in nAChR expression in medial nucleus of the trapezoid body (MNTB) neurons and presynaptic calyx of Held terminals. PNE led to increased ACh‐evoked postsynaptic currents and impaired glutamatergic neurotransmission, underscoring the importance of nAChR activity in early auditory synaptic development. PNE also increased ABR thresholds and reduced ABR peak amplitudes, indicating impaired central auditory processing without cochlear dysfunction. Our study provides new insights into the synaptic disruptions underlying auditory deficits from prenatal nicotine exposure. image Key points In utero nicotine exposure leads to increased risk of sensory processing deficits and elevated expression of nicotinic acetylcholine receptors (nAChRs). nAChRs are essential for auditory processing and are present in the auditory brainstem. Within the medial nucleus of the trapezoid body in the auditory brainstem, the patterning of nicotinic receptor expression during development and how nicotine exposure might affect this are unknown. Nicotinic receptors are expressed postsynaptically before hearing onset and switch to presynaptic expression after hearing onset. Perinatal nicotine exposure disrupts physiological nicotinic receptor patterning and impairs synaptic transmission at the calyx of Held.

The control of speech and vocal production involves the calculation of error between the intended vocal output and the resulting auditory feedback. This model has been supported by evidence that the auditory cortex (AC) is suppressed immediately before and during vocal production yet remains sensitive to differences between vocal output and altered auditory feedback. This suppression has been suggested to be the result of top-down signals about the intended vocal output, potentially originating from frontal cortical (FC) areas. However, whether FC is the source of suppressive and predictive signaling to AC during vocalization remains unknown. Here, we simultaneously recorded neural activity from both AC and FC of marmoset monkeys during self-initiated vocalizations. We found increases in neural activity in both brain areas from 1 to 0.5 s before vocal production (early pre-vocal period), specifically changes in both multi-unit activity and theta-band power. Connectivity analysis using Granger causality demonstrated that FC sends directed signaling to AC during this early pre-vocal period. Importantly, early pre-vocal activity correlated with both vocalization-induced suppression in AC as well as the structure and acoustics of subsequent calls, such as fundamental frequency. Furthermore, bidirectional auditory-frontal interactions emerged during experimentally altered vocal feedback and predicted subsequent compensatory vocal behavior. These results suggest that FC communicates with AC during vocal production, with frontal-to-auditory signals that may reflect the transmission of sensory prediction information before vocalization and bidirectional signaling during vocalization suggestive of error detection that could drive feedback-dependent vocal control.