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Journal of the Association For Research... Jun 2021The ability to process and perceive sensory stimuli is an essential function for animals. Among the sensory modalities, audition is crucial for communication, pleasure,... (Review)
Review
The ability to process and perceive sensory stimuli is an essential function for animals. Among the sensory modalities, audition is crucial for communication, pleasure, care for the young, and perceiving threats. The auditory cortex (ACtx) is a key sound processing region that combines ascending signals from the auditory periphery and inputs from other sensory and non-sensory regions. The development of ACtx is a protracted process starting prenatally and requires the complex interplay of molecular programs, spontaneous activity, and sensory experience. Here, we review the development of thalamic and cortical auditory circuits during pre- and early post-natal periods.
Topics: Animals; Auditory Cortex; Auditory Perception; Sound; Thalamus
PubMed: 33909161
DOI: 10.1007/s10162-021-00794-3 -
Nature Reviews. Neuroscience Oct 2019Humans and other animals use spatial hearing to rapidly localize events in the environment. However, neural encoding of sound location is a complex process involving... (Review)
Review
Humans and other animals use spatial hearing to rapidly localize events in the environment. However, neural encoding of sound location is a complex process involving the computation and integration of multiple spatial cues that are not represented directly in the sensory organ (the cochlea). Our understanding of these mechanisms has increased enormously in the past few years. Current research is focused on the contribution of animal models for understanding human spatial audition, the effects of behavioural demands on neural sound location encoding, the emergence of a cue-independent location representation in the auditory cortex, and the relationship between single-source and concurrent location encoding in complex auditory scenes. Furthermore, computational modelling seeks to unravel how neural representations of sound source locations are derived from the complex binaural waveforms of real-life sounds. In this article, we review and integrate the latest insights from neurophysiological, neuroimaging and computational modelling studies of mammalian spatial hearing. We propose that the cortical representation of sound location emerges from recurrent processing taking place in a dynamic, adaptive network of early (primary) and higher-order (posterior-dorsal and dorsolateral prefrontal) auditory regions. This cortical network accommodates changing behavioural requirements and is especially relevant for processing the location of real-life, complex sounds and complex auditory scenes.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Pathways; Hearing; Humans; Sound Localization
PubMed: 31467450
DOI: 10.1038/s41583-019-0206-5 -
Neuroscience and Biobehavioral Reviews Jan 2022The auditory system provides us with extremely rich and precise information about the outside world. Once a sound reaches our ears, the acoustic information it carries... (Review)
Review
The auditory system provides us with extremely rich and precise information about the outside world. Once a sound reaches our ears, the acoustic information it carries travels from the cochlea all the way to the auditory cortex, where its complexity and nuances are integrated. In the auditory cortex, functional circuits are formed by subpopulations of intermingled excitatory and inhibitory cells. In this review, we discuss recent evidence of the specific contributions of inhibitory neurons in sound processing and integration. We first examine intrinsic properties of three main classes of inhibitory interneurons in the auditory cortex. Then, we describe how inhibition shapes the responsiveness of the auditory cortex to sound. Finally, we discuss how inhibitory interneurons contribute to the sensation and perception of sounds. Altogether, this review points out the crucial role of cortical inhibitory interneurons in integrating information about the context, history, or meaning of a sound. It also highlights open questions to be addressed for increasing our understanding of the staggering complexity leading to the subtlest auditory perception.
Topics: Acoustic Stimulation; Auditory Cortex; Auditory Perception; Interneurons
PubMed: 34822879
DOI: 10.1016/j.neubiorev.2021.11.021 -
Neuron Aug 2023The brain can combine auditory and visual information to localize objects. However, the cortical substrates underlying audiovisual integration remain uncertain. Here, we...
The brain can combine auditory and visual information to localize objects. However, the cortical substrates underlying audiovisual integration remain uncertain. Here, we show that mouse frontal cortex combines auditory and visual evidence; that this combination is additive, mirroring behavior; and that it evolves with learning. We trained mice in an audiovisual localization task. Inactivating frontal cortex impaired responses to either sensory modality, while inactivating visual or parietal cortex affected only visual stimuli. Recordings from >14,000 neurons indicated that after task learning, activity in the anterior part of frontal area MOs (secondary motor cortex) additively encodes visual and auditory signals, consistent with the mice's behavioral strategy. An accumulator model applied to these sensory representations reproduced the observed choices and reaction times. These results suggest that frontal cortex adapts through learning to combine evidence across sensory cortices, providing a signal that is transformed into a binary decision by a downstream accumulator.
Topics: Animals; Mice; Visual Perception; Acoustic Stimulation; Auditory Perception; Photic Stimulation; Frontal Lobe; Auditory Cortex
PubMed: 37295419
DOI: 10.1016/j.neuron.2023.05.008 -
Nature Nov 2020Infant cries evoke powerful responses in parents. Whether parental animals are intrinsically sensitive to neonatal vocalizations, or instead learn about vocal cues for...
Infant cries evoke powerful responses in parents. Whether parental animals are intrinsically sensitive to neonatal vocalizations, or instead learn about vocal cues for parenting responses is unclear. In mice, pup-naive virgin females do not recognize the meaning of pup distress calls, but retrieve isolated pups to the nest after having been co-housed with a mother and litter. Distress calls are variable, and require co-caring virgin mice to generalize across calls for reliable retrieval. Here we show that the onset of maternal behaviour in mice results from interactions between intrinsic mechanisms and experience-dependent plasticity in the auditory cortex. In maternal females, calls with inter-syllable intervals (ISIs) from 75 to 375 milliseconds elicited pup retrieval, and cortical responses were generalized across these ISIs. By contrast, naive virgins were neuronally and behaviourally sensitized to the most common ('prototypical') ISIs. Inhibitory and excitatory neural responses were initially mismatched in the cortex of naive mice, with untuned inhibition and overly narrow excitation. During co-housing experiments, excitatory responses broadened to represent a wider range of ISIs, whereas inhibitory tuning sharpened to form a perceptual boundary. We presented synthetic calls during co-housing and observed that neurobehavioural responses adjusted to match these statistics, a process that required cortical activity and the hypothalamic oxytocin system. Neuroplastic mechanisms therefore build on an intrinsic sensitivity in the mouse auditory cortex, and enable rapid plasticity for reliable parenting behaviour.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Excitatory Postsynaptic Potentials; Female; Housing, Animal; Maternal Behavior; Mice; Neural Inhibition; Neuronal Plasticity; Oxytocin; Synapses; Time Factors; Vocalization, Animal
PubMed: 33029014
DOI: 10.1038/s41586-020-2807-6 -
Hearing Research Nov 2022Sensory processing is frequently conceptualized as a linear flow of information from peripheral receptors through hierarchically organized brain regions, ultimately... (Review)
Review
Sensory processing is frequently conceptualized as a linear flow of information from peripheral receptors through hierarchically organized brain regions, ultimately reaching the cortex. In reality, this ascending stream is accompanied by massive descending connections that cascade from the cortex toward more peripheral subcortical structures. In the central auditory system, these feedback connections influence information processing at virtually every level of the pathway, including the thalamus, midbrain, and brainstem, and exert influence even at the level of the cochlea. The auditory cortico-collicular system, which connects the auditory cortex to the auditory midbrain, mediates manifold functions ranging from tuning shifts to defense behavior. In this review, we first summarize recent findings regarding the anatomical organization and physiological properties of the auditory cortico-collicular pathway. We then highlight several new studies that show that this projection system mediates high-level cognitive processes, acoustico-motor behaviors, and auditory plasticity, and discuss the circuit mechanisms through which they are mediated. Finally, we discuss remaining unanswered questions regarding cortico-collicular circuitry and function and potential avenues for future exploration.
Topics: Acoustic Stimulation; Auditory Cortex; Auditory Pathways; Inferior Colliculi
PubMed: 35351323
DOI: 10.1016/j.heares.2022.108488 -
Neuroscience and Biobehavioral Reviews Mar 2019How and where sensory stimuli, such as tones or lights, are linked to valence is an important unresolved question in the field of neuroscience. The auditory cortex is... (Review)
Review
How and where sensory stimuli, such as tones or lights, are linked to valence is an important unresolved question in the field of neuroscience. The auditory cortex is essential to analyse the identity and the behavioural importance of tones paired with emotional events. On the contrary, whether the auditory cortex may also encode information on the emotional-motivational valence of sounds is much more controversial. Here, we reviewed recent studies showing that the activity of cortical neurons reflects information about the content of emotional stimuli paired with tones. Critically, the blockade of these neuronal processes prevents animals from recognising sounds as aversive or pleasant. Based on these findings, we proposed a conceptual model in which the auditory cortex may incorporate ascending information from subcortical nuclei about the valence of sounds in sound representations and may consequently drive the activity of subcortical structures towards emotionally laden tones. This hypothesis may also have important implications in the characterisation of neural circuits engaged by maladaptive affective disorders, such as phobias.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Perception; Emotions; Fear; Humans; Motivation
PubMed: 30664888
DOI: 10.1016/j.neubiorev.2019.01.018 -
Cerebral Cortex (New York, N.Y. : 1991) May 2023To understand auditory cortical processing, the effective connectivity between 15 auditory cortical regions and 360 cortical regions was measured in 171 Human Connectome...
To understand auditory cortical processing, the effective connectivity between 15 auditory cortical regions and 360 cortical regions was measured in 171 Human Connectome Project participants, and complemented with functional connectivity and diffusion tractography. 1. A hierarchy of auditory cortical processing was identified from Core regions (including A1) to Belt regions LBelt, MBelt, and 52; then to PBelt; and then to HCP A4. 2. A4 has connectivity to anterior temporal lobe TA2, and to HCP A5, which connects to dorsal-bank superior temporal sulcus (STS) regions STGa, STSda, and STSdp. These STS regions also receive visual inputs about moving faces and objects, which are combined with auditory information to help implement multimodal object identification, such as who is speaking, and what is being said. Consistent with this being a "what" ventral auditory stream, these STS regions then have effective connectivity to TPOJ1, STV, PSL, TGv, TGd, and PGi, which are language-related semantic regions connecting to Broca's area, especially BA45. 3. A4 and A5 also have effective connectivity to MT and MST, which connect to superior parietal regions forming a dorsal auditory "where" stream involved in actions in space. Connections of PBelt, A4, and A5 with BA44 may form a language-related dorsal stream.
Topics: Humans; Auditory Cortex; Temporal Lobe; Parietal Lobe; Semantics; Language
PubMed: 36573464
DOI: 10.1093/cercor/bhac496 -
Annual Review of Psychology Jan 2018Auditory perception is our main gateway to communication with others via speech and music, and it also plays an important role in alerting and orienting us to new... (Review)
Review
Auditory perception is our main gateway to communication with others via speech and music, and it also plays an important role in alerting and orienting us to new events. This review provides an overview of selected topics pertaining to the perception and neural coding of sound, starting with the first stage of filtering in the cochlea and its profound impact on perception. The next topic, pitch, has been debated for millennia, but recent technical and theoretical developments continue to provide us with new insights. Cochlear filtering and pitch both play key roles in our ability to parse the auditory scene, enabling us to attend to one auditory object or stream while ignoring others. An improved understanding of the basic mechanisms of auditory perception will aid us in the quest to tackle the increasingly important problem of hearing loss in our aging population.
Topics: Acoustic Stimulation; Auditory Cortex; Auditory Perception; Hearing Loss; Humans; Pitch Perception; Sound; Speech Perception
PubMed: 29035691
DOI: 10.1146/annurev-psych-122216-011635 -
Nature Reviews. Neuroscience Jul 2019There are functional and anatomical distinctions between the neural systems involved in the recognition of sounds in the environment and those involved in the... (Review)
Review
There are functional and anatomical distinctions between the neural systems involved in the recognition of sounds in the environment and those involved in the sensorimotor guidance of sound production and the spatial processing of sound. Evidence for the separation of these processes has historically come from disparate literatures on the perception and production of speech, music and other sounds. More recent evidence indicates that there are computational distinctions between the rostral and caudal primate auditory cortex that may underlie functional differences in auditory processing. These functional differences may originate from differences in the response times and temporal profiles of neurons in the rostral and caudal auditory cortex, suggesting that computational accounts of primate auditory pathways should focus on the implications of these temporal response differences.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Pathways; Auditory Perception; Humans
PubMed: 30918365
DOI: 10.1038/s41583-019-0160-2