Download or read book Cortical Mechanisms of Adaptation in Auditory Processing written by Ryan G. Natan and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptation is computational strategy that underlies sensory nervous systems' ability to accurately encode stimuli in various and dynamic contexts and shapes how animals perceive their environment. Many questions remain concerning how adaptation adjusts to particular stimulus features and its underlying mechanisms. In Chapter 2, we tested how neurons in the primary auditory cortex adapt to changes in stimulus temporal correlation. We used chronically implanted tetrodes to record neuronal spiking in rat primary auditory cortex during exposure to custom made dynamic random chord stimuli exhibiting different levels of temporal correlation. We estimated linear non-linear model for each neuron at each temporal correlation level, finding that neurons compensate for temporal correlation changes through gain-control adaptation. This experiment extends our understanding of how complex stimulus statistics are encoded in the auditory nervous system. In Chapter 3 and 4, we tested how interneurons are involved in adaptation by optogenetically suppressing parvalbumin-positive (PV) and somatostatin-positive (SOM) interneurons during tone train stimuli and using silicon probes to record neuronal spiking in mouse primary auditory cortex. In Chapter 3, we found that inhibition from both PVs and SOMs contributes to stimulus-specific adaptation (SSA) through different mechanisms. SOM inhibition was stimulus-specific, suppressing responses to standard tones more strongly than responses to deviant tones, and increasing with standard tone repetition. PVs amplified SSA because inhibition was similar for standard and deviant tones and PV mediated inhibition was insensitive to tone repetition. PVs and SOMs themselves exhibit SSA, and a Wilson-Cowan dynamic model identified that PVs and SOMs can directly contribute to SSA in pyramidal neurons. In Chapter 4, we tested how SOMs and PVs inhibition is modulated with the dynamics of adaptation and across frequency tuning, during exposure to single frequency tone trains across the neuron's tuning curve. We found that the magnitude of SOM inhibition correlated with the magnitude of adaptive suppression, while PVs inhibition was largely insensitive to stimulus conditions. Together Chapters 3 and 4 implicate SOM inhibition in actively suppressing responses in a stimulus-specific manner while PV inhibition may passively enhance stimulus-specific suppression. These experiments inform the underlying principles and mechanisms of cortical sensory adaptation.
Download or read book Cortical Subcortical Loops in Sensory Processing written by Max F. K. Happel and published by Frontiers Media SA. This book was released on 2022-02-28 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Auditory Cortex written by Jeffery A. Winer and published by Springer Science & Business Media. This book was released on 2010-12-02 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been substantial progress in understanding the contributions of the auditory forebrain to hearing, sound localization, communication, emotive behavior, and cognition. The Auditory Cortex covers the latest knowledge about the auditory forebrain, including the auditory cortex as well as the medial geniculate body in the thalamus. This book will cover all important aspects of the auditory forebrain organization and function, integrating the auditory thalamus and cortex into a smooth, coherent whole. Volume One covers basic auditory neuroscience. It complements The Auditory Cortex, Volume 2: Integrative Neuroscience, which takes a more applied/clinical perspective.
Download or read book The Inferior Colliculus written by Jeffery A. Winer and published by Springer Science & Business Media. This book was released on 2005-12-05 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Connecting the auditory brain stem to sensory, motor, and limbic systems, the inferior colliculus is a critical midbrain station for auditory processing. Winer and Schreiner's The Inferior Colliculus, a critical, comprehensive reference, presents the current knowledge of the inferior colliculus from a variety of perspectives, including anatomical, physiological, developmental, neurochemical, biophysical, neuroethological and clinical vantage points. Written by leading researchers in the field, the book is an ideal introduction to the inferior colliculus and central auditory processing for clinicians, otolaryngologists, graduate and postgraduate research workers in the auditory and other sensory-motor systems.
Download or read book Visual Mismatch Negativity vMMN a Prediction Error Signal in the Visual Modality written by Gabor Stefanics and published by Frontiers Media SA. This book was released on 2015-06-04 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current theories of visual change detection emphasize the importance of conscious attention to detect unexpected changes in the visual environment. However, an increasing body of studies shows that the human brain is capable of detecting even small visual changes, especially if such changes violate non-conscious probabilistic expectations based on repeating experiences. In other words, our brain automatically represents statistical regularities of our visual environmental. Since the discovery of the auditory mismatch negativity (MMN) event-related potential (ERP) component, the majority of research in the field has focused on auditory deviance detection. Such automatic change detection mechanisms operate in the visual modality too, as indicated by the visual mismatch negativity (vMMN) brain potential to rare changes. VMMN is typically elicited by stimuli with infrequent (deviant) features embedded in a stream of frequent (standard) stimuli, outside the focus of attention. In this research topic we aim to present vMMN as a prediction error signal. Predictive coding theories account for phenomena such as mismatch negativity and repetition suppression, and place them in a broader context of a general theory of cortical responses. A wide range of vMMN studies has been presented in this Research Topic. Twelve articles address roughly four general sub-themes including attention, language, face processing, and psychiatric disorders. Additionally, four articles focused on particular subjects such as the oblique effect, object formation, and development and time-frequency analysis of vMMN. Furthermore, a review paper presented vMMN in a hierarchical predictive coding framework. Each paper in this Research Topic is a valuable contribution to the field of automatic visual change detection and deepens our understanding of the short term plasticity underlying predictive processes of visual perceptual learning.
Download or read book Neuromodulatory Function in Auditory Processing written by R. Michael Burger and published by Frontiers Media SA. This book was released on 2022-06-03 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Auditory Temporal Processing and Its Disorders written by Jos J. Eggermont and published by Oxford University Press, USA. This book was released on 2015 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Auditory temporal processing' determines our understanding of speech, our appreciation of music, our ability to localize a sound source, and even to listen to a person in a noisy crowd. This book reviews the mechanisms for temporal processing in the auditory system, looking at how these underlie specific clinical disorders, and their treatment.
Download or read book Functional Mechanisms of Stimulus specific Adaptation in Neurons of the Auditory Thalamus and Its Cortical Modulation written by Flora María Ferreira Antunes and published by . This book was released on 2011 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuestra hipótesis general de trabajo es que la detección de la novedad es un principio básico de organización funcional del sistema auditivo y que el potencial de disparidad (MMN) y las neuronas detectoras de sonidos novedosos son expresiones distintas pero, correlacionadas, de la activación de este sistema detector de la novedad. El conocimiento sobre los mecanismos neurológicos implicados en la detección de la novedad en el sistema auditivo pasa por establecer las posibles relaciones funcionales entre estas neuronas y el potencial de disparidad (MMN). Para ello, es fundamental caracterizar la naturaleza de las respuestas de estas mismas neuronas en los diferentes niveles de la vía auditiva. Puesto que desconocemos en gran medida los detalles de este tipo de adaptación en el cuerpo geniculado medial y que los estudios existentes son en gran medida discutibles (Anderson et al., 2009; Ulanovsky et al., 2003; Yu et al., 2009), pensamos que es necesario un estudio detallado de caracterización fisiológica de la adaptación específica al estímulo en este centro talámico.
Download or read book Sensory Adaptation written by Mehdi Adibi and published by Frontiers Media SA. This book was released on 2022-01-27 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Inhibitory Synaptic Plasticity written by Melanie A. Woodin and published by Springer Science & Business Media. This book was released on 2010-11-02 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume will explore the most recent findings on cellular mechanisms of inhibitory plasticity and its functional role in shaping neuronal circuits, their rewiring in response to experience, drug addiction and in neuropathology. Inhibitory Synaptic Plasticity will be of particular interest to neuroscientists and neurophysiologists.
Download or read book The Book of GENESIS written by James M. Bower and published by Springer Verlag. This book was released on 1995 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title introduces and guides the reader through Genesis, a simulation and modeling software tool that is delivered on-line via the Internet from a California Institute of Technology file server. It contains a contribution of models and simulations, plus step-by-step tutorials. 50 illustrations. Approx.
Download or read book Auditory Efferent System New Insights from Cortex to Cochlea written by Paul H. Delano and published by Frontiers Media SA. This book was released on 2016-09-06 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main function of the sensory systems is the transducing of external stimuli into bioelectrical signals, which are conducted through afferent pathways from sensory epithelia to the brain. However, it is known that descending projections are ubiquitous in the different sensory modalities, and in the case of auditory efferents connect the cerebral cortex with sensory receptor cells. Several functions have been attributed to the efferent system, including protection to acoustic trauma, unmasking of auditory stimuli in background noise, balance of interaural sensitivity and some cognitive functions like modulation of cochlear sensitivity during selective attention to auditory or visual stimuli. In addition there is evidence of a possible involvement of the efferent system in the etiology or treatment of some clinical pathologies like tinnitus. In this e-book, entitled “Auditory Efferent System: New Insights from Cortex to Cochlea”, we aimed to give an overview of the advances concerning the descending projections from the auditory cortex to subcortical nuclei and the olivocochlear system. In addition, different theoretical proposals of efferent functions are presented. We think that this e-book is an important contribution to the understanding of the efferent system in mammals, merging auditory-cortex literature with studies performed in the olivocochlear system.
Download or read book Electrophysiology of Inhibition and Auditory Prediction Mechanisms in Human Cortex written by Yvonne Maria Fonken and published by . This book was released on 2017 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the core problems the brain has to solve is how to navigate and interact with the external world. This requires a complex analysis of sensory input, the translation of perceptual input to goal-directed behavior, followed by motor planning and execution. In this thesis we investigated two crucial aspects of this perception-action cycle. First, we examined the underlying neural mechanisms that support response inhibition. Here, novel sensory information is integrated on very short time-scales to cancel an already planned action. The frontal cortex is believed to play a crucial role in the temporal organization of goal-directed behavior and cognitive control and is implicated in stopping a motor response. Using the high spatiotemporal resolution of electrocorticography (ECoG), we found evidence for two distinct processes localized to the middle frontal gyrus (MFG). High-frequency band (HFB) power increased in stop-trials before the stop-signal reaction time (SSRT), showing no difference between successful and unsuccessful stops. We interpret this activation as contributing to the stopping process, either by signaling the stop-signal itself, or by implementing attentional control. A second HFB activation was observed after the go and stop processes have finished, and was larger for unsuccessful stops, and is likely related to behavioral monitoring. Our results support the notion that frontal cortex implements different functions related to stopping. Implementing the perception-action cycle not only involves re-acting to novel information from the senses in a bottom-up manner. It is believed that the brain also implements a strategy anticipating future events based on prior knowledge. Here we investigated how anticipation of sounds influences auditory processing. Using both EEG and ECoG, we employed a task with omissions of expected sounds, thereby isolating endogenous responses to expectations in auditory cortex. We found that a subset of auditory active electrodes in lateral superior temporal gyrus (STG) and superior temporal sulcus (STS) showing HFB power increases to omissions. We were able to successfully decode whether the subject heard the syllable ‘Ba’ or ‘Ga’. However, which sound was omitted could not be decoded from auditory active sites, nor from the omission HFB increase specifically. We also observed a negative ERP in posterior STG in the intracranial data, which may be related to an auditory cortical generator of the N2 component. In a separate EEG studies we also observed both an N2 negativity, as well as a negativity occurring before the intracranial negativity, the source of which may be in A1, a region which we could not access intracranially. Finally, a P3a ERP was observed in EEG, which points to both the HFB and ERP effects in posterior STG to be signatures of auditory-specific salience or mismatch detection.
Download or read book Cortical and Subcortical Mechanisms for Sound Processing written by Jennifer M. Blackwell and published by . This book was released on 2019 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: The auditory cortex is essential for encoding complex and behaviorally relevant sounds. Many questions remain concerning whether and how distinct cortical neuronal subtypes shape and encode both simple and complex sound properties. In chapter 2, we tested how neurons in the auditory cortex encode water-like sounds perceived as natural by human listeners, but that we could precisely parametrize. The stimuli exhibit scale-invariant statistics, specifically temporal modulation within spectral bands scaled with the center frequency of the band. We used chronically implanted tetrodes to record neuronal spiking in rat primary auditory cortex during exposure to our custom stimuli at different rates and cycle-decay constants. We found that, although neurons exhibited selectivity for subsets of stimuli with specific statistics, over the population responses were stable. These results contribute to our understanding of how auditory cortex processes natural sound statistics. In chapter 3, we review studies examining the role of different cortical inhibitory interneurons in shaping sound responses in auditory cortex. We identify the findings that support each other and the mechanisms that remain unexplored. In chapter 4, we tested how direct feedback from auditory cortex to the inferior colliculus modulated sound responses in the inferior colliculus. We optogenetically activated or suppressed cortico-collicular feedback while recording neuronal spiking in the mouse inferior colliculus in response to pure tones and dynamic random chords. We found that feedback modulated sound responses by reducing sound selectivity by decreasing responsiveness to preferred frequencies and increasing responsiveness to less preferred frequencies. Furthermore, we tested the effects of perturbing intra-cortical inhibitory-excitatory networks on sound responses in the inferior colliculus. We optogenetically activated or suppressed parvalbumin-positive (PV) and somatostatin-positive (SOM) interneurons while recording neuronal spiking in mouse auditory cortex and inferior colliculus. We found that modulation of neither PV- nor SOM-interneurons affected sound-evoked responses in the inferior colliculus, despite significant modulation of cortical responses. Our findings imply that cortico-collicular feedback can modulate responses to simple and complex auditory stimuli independently of cortical inhibitory interneurons. These experiments elucidate the role of descending auditory feedback in shaping sound responses. Together these results implicate the importance of the auditory cortex in sound processing.
Download or read book Audiovisual Speech Processing written by Gérard Bailly and published by Cambridge University Press. This book was released on 2012-04-26 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a complete overview of all aspects of audiovisual speech including perception, production, brain processing and technology.
Download or read book Auditory Spatial Adaptation written by I-Fan Lin and published by . This book was released on 2009 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Listeners can rapidly adjust how they localize auditory stimuli when consistently trained with spatially discrepant visual feedback. However, relatively little is known about what auditory processing stages are altered by adaptation or the mechanisms that cause the observed perceptual and behavioral changes. Experiments were conducted to test how spatial adaptation generalizes to novel frequencies and the degree to which perceptual recalibration and cognitive adjustment contribute to spatial adaptation. A neural network model was developed to help explain and predict behavioral results. Adaptation was found to generalize across frequency when both training and reference stimuli were dominated by interaural time differences (ITDs), but not when the training stimuli were dominated by interaural level difference (ILDs) and the reference stimuli were dominated by ITDs. These results suggest that spatial adaptation occurs after ITDs are integrated across frequency, but before ITDs and ILDs are integrated. Both perceptual and cognitive changes were found to contribute to short-term auditory adaptation. However, their relative contributions to adaptation depended on the form of the rearrangement of auditory space. For both a magnification and a rotation of auditory space, at least some of the adaptation comes from perceptual recalibration. However, for a magnification of auditory space, cognitive adjustment contributed less to the observed adaptation than for a rotation of auditory space. A hierarchical, supervised-learning model of short-term spatial perceptual, recalibration was developed. Discrepancies between the perceived and correct locations drive learning by adjusting how auditory inputs map to exocentric locations to reduce error. Learning affects locations near the input location through a spatial kernel with limited extent. Model results fit the observed evolution of localization errors and account for individual differences by adjusting only three model parameters: the internal sensory noise, the width of the spatial learning kernel, and the threshold for detecting an error. Results demonstrate how training helps listeners calibrate spatial auditory perception. This work can help inform the design of hearing aids and hearing-protection devices to ensure that listeners receive sufficient information to localize sounds accurately, despite distortions of auditory cues caused by these devices.
Download or read book Modeling Processing of Complex Sounds by Neurons at the Cortical Level written by Eric David Larson and published by . This book was released on 2011 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Cortical auditory processing is critical for speech perception, yet we understand little about how the neural representations available at the cortical level allow for sound recognition. In particular, the neural mechanisms for recognition of sounds via spiking patterns are currently unknown, and the characterization of auditory cortical neuron response properties using stimulus-response models remains incomplete. Previous work has shown that spike trains can be used to discriminate between sounds using analytical methods, but how biological circuits might perform such computations remains unclear. Therefore we devised a model for discrimination (inspired by a spike distance metric) that combines a network of integrate-and-fire model neurons with a decision network. We applied this model to the birdsong system, a powerful animal model for the study of audition. We then examined how stimuli could be recognized by sensory systems from spiking patterns by transforming spiking patterns into spatial representations. Previous "spike pattern recognition" models used artificially pre-processed and noiseless signals as input, despite the fact that neural spike trains show variability. Therefore, we used cortical-level neural recordings as input to a novel spike pattern recognition system designed to deal with the intrinsic variability and diverse response properties of cortical spike trains. We show that the model can learn to recognize neural responses to auditory stimuli using spike-timing dependent plasticity, and can play back learned spike patterns in reverse, not unlike the reverse spike train playback observed in hippocampus. A standard model for central auditory neurons is the spectro-temporal receptive field (STRF), which quantifies the spectral and temporal stimulus parameters that modulate neural activity. While the STRF has been used to predict neural responses, a causal connection between the STRF structure and neural responses is lacking. We used an adaptive stimulation paradigm to address this problem. Specifically, for each neuron, we filtered out stimulus frequencies predicted to be unimportant by the STRF (estimated using normalized reverse correlation), and measured responses to these stimuli. For some neurons, this filtering had little effect on neural firing, but adding a noise masker in the unimportant frequency regions adversely affected their responses, suggesting that frequency regions outside the STRF can play a role in determining neural responses.
