scholarly journals Principles of auditory processing differ between sensory and premotor structures of the songbird forebrain

2017 ◽  
Vol 117 (3) ◽  
pp. 1266-1280 ◽  
Author(s):  
Efe Soyman ◽  
David S. Vicario

Sensory and motor brain structures work in collaboration during perception. To evaluate their respective contributions, the present study recorded neural responses to auditory stimulation at multiple sites simultaneously in both the higher-order auditory area NCM and the premotor area HVC of the songbird brain in awake zebra finches ( Taeniopygia guttata). Bird’s own song (BOS) and various conspecific songs (CON) were presented in both blocked and shuffled sequences. Neural responses showed plasticity in the form of stimulus-specific adaptation, with markedly different dynamics between the two structures. In NCM, the response decrease with repetition of each stimulus was gradual and long-lasting and did not differ between the stimuli or the stimulus presentation sequences. In contrast, HVC responses to CON stimuli decreased much more rapidly in the blocked than in the shuffled sequence. Furthermore, this decrease was more transient in HVC than in NCM, as shown by differential dynamics in the shuffled sequence. Responses to BOS in HVC decreased more gradually than to CON stimuli. The quality of neural representations, computed as the mutual information between stimuli and neural activity, was higher in NCM than in HVC. Conversely, internal functional correlations, estimated as the coherence between recording sites, were greater in HVC than in NCM. The cross-coherence between the two structures was weak and limited to low frequencies. These findings suggest that auditory communication signals are processed according to very different but complementary principles in NCM and HVC, a contrast that may inform study of the auditory and motor pathways for human speech processing. NEW & NOTEWORTHY Neural responses to auditory stimulation in sensory area NCM and premotor area HVC of the songbird forebrain show plasticity in the form of stimulus-specific adaptation with markedly different dynamics. These two structures also differ in stimulus representations and internal functional correlations. Accordingly, NCM seems to process the individually specific complex vocalizations of others based on prior familiarity, while HVC responses appear to be modulated by transitions and/or timing in the ongoing sequence of sounds.

2015 ◽  
Vol 113 (5) ◽  
pp. 1480-1492 ◽  
Author(s):  
Brittany A. Bell ◽  
Mimi L. Phan ◽  
David S. Vicario

How do social interactions form and modulate the neural representations of specific complex signals? This question can be addressed in the songbird auditory system. Like humans, songbirds learn to vocalize by imitating tutors heard during development. These learned vocalizations are important in reproductive and social interactions and in individual recognition. As a model for the social reinforcement of particular songs, male zebra finches were trained to peck for a food reward in response to one song stimulus (GO) and to withhold responding for another (NoGO). After performance reached criterion, single and multiunit neural responses to both trained and novel stimuli were obtained from multiple electrodes inserted bilaterally into two songbird auditory processing areas [caudomedial mesopallium (CMM) and caudomedial nidopallium (NCM)] of awake, restrained birds. Neurons in these areas undergo stimulus-specific adaptation to repeated song stimuli, and responses to familiar stimuli adapt more slowly than to novel stimuli. The results show that auditory responses differed in NCM and CMM for trained (GO and NoGO) stimuli vs. novel song stimuli. When subjects were grouped by the number of training days required to reach criterion, fast learners showed larger neural responses and faster stimulus-specific adaptation to all stimuli than slow learners in both areas. Furthermore, responses in NCM of fast learners were more strongly left-lateralized than in slow learners. Thus auditory responses in these sensory areas not only encode stimulus familiarity, but also reflect behavioral reinforcement in our paradigm, and can potentially be modulated by social interactions.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Joseph P. Pillion

Deficits in central auditory processing may occur in a variety of clinical conditions including traumatic brain injury, neurodegenerative disease, auditory neuropathy/dyssynchrony syndrome, neurological disorders associated with aging, and aphasia. Deficits in central auditory processing of a more subtle nature have also been studied extensively in neurodevelopmental disorders in children with learning disabilities, ADD, and developmental language disorders. Illustrative cases are reviewed demonstrating the use of an audiological test battery in patients with auditory neuropathy/dyssynchrony syndrome, bilateral lesions to the inferior colliculi, and bilateral lesions to the temporal lobes. Electrophysiological tests of auditory function were utilized to define the locus of dysfunction at neural levels ranging from the auditory nerve, midbrain, and cortical levels.


2019 ◽  
Author(s):  
Jérémy Giroud ◽  
Agnès Trébuchon ◽  
Daniele Schön ◽  
Patrick Marquis ◽  
Catherine Liegeois-Chauvel ◽  
...  

AbstractSpeech perception is mediated by both left and right auditory cortices, but with differential sensitivity to specific acoustic information contained in the speech signal. A detailed description of this functional asymmetry is missing, and the underlying models are widely debated. We analyzed cortical responses from 96 epilepsy patients with electrode implantation in left or right primary, secondary, and/or association auditory cortex. We presented short acoustic transients to reveal the stereotyped spectro-spatial oscillatory response profile of the auditory cortical hierarchy. We show remarkably similar bimodal spectral response profiles in left and right primary and secondary regions, with preferred processing modes in the theta (∼4-8 Hz) and low gamma (∼25-50 Hz) ranges. These results highlight that the human auditory system employs a two-timescale processing mode. Beyond these first cortical levels of auditory processing, a hemispheric asymmetry emerged, with delta and beta band (∼3/15 Hz) responsivity prevailing in the right hemisphere and theta and gamma band (∼6/40 Hz) activity in the left. These intracranial data provide a more fine-grained and nuanced characterization of cortical auditory processing in the two hemispheres, shedding light on the neural dynamics that potentially shape auditory and speech processing at different levels of the cortical hierarchy.Author summarySpeech processing is now known to be distributed across the two hemispheres, but the origin and function of lateralization continues to be vigorously debated. The asymmetric sampling in time (AST) hypothesis predicts that (1) the auditory system employs a two-timescales processing mode, (2) present in both hemispheres but with a different ratio of fast and slow timescales, (3) that emerges outside of primary cortical regions. Capitalizing on intracranial data from 96 epileptic patients we sensitively validated each of these predictions and provide a precise estimate of the processing timescales. In particular, we reveal that asymmetric sampling in associative areas is subtended by distinct two-timescales processing modes. Overall, our results shed light on the neurofunctional architecture of cortical auditory processing.


2019 ◽  
Author(s):  
Shyanthony R. Synigal ◽  
Emily S. Teoh ◽  
Edmund C. Lalor

ABSTRACTThe human auditory system is adept at extracting information from speech in both single-speaker and multi-speaker situations. This involves neural processing at the rapid temporal scales seen in natural speech. Non-invasive brain imaging (electro-/magnetoencephalography [EEG/MEG]) signatures of such processing have shown that the phase of neural activity below 16 Hz tracks the dynamics of speech, whereas invasive brain imaging (electrocorticography [ECoG]) has shown that such rapid processing is even more strongly reflected in the power of neural activity at high frequencies (around 70-150 Hz; known as high gamma). The aim of this study was to determine if high gamma power in scalp recorded EEG carries useful stimulus-related information, despite its reputation for having a poor signal to noise ratio. Furthermore, we aimed to assess whether any such information might be complementary to that reflected in well-established low frequency EEG indices of speech processing. We used linear regression to investigate speech envelope and attention decoding in EEG at low frequencies, in high gamma power, and in both signals combined. While low frequency speech tracking was evident for almost all subjects as expected, high gamma power also showed robust speech tracking in a minority of subjects. This same pattern was true for attention decoding using a separate group of subjects who undertook a cocktail party attention experiment. For the subjects who showed speech tracking in high gamma power, the spatiotemporal characteristics of that high gamma tracking differed from that of low-frequency EEG. Furthermore, combining the two neural measures led to improved measures of speech tracking for several subjects. Overall, this indicates that high gamma power EEG can carry useful information regarding speech processing and attentional selection in some subjects and combining it with low frequency EEG can improve the mapping between natural speech and the resulting neural responses.


2021 ◽  
Author(s):  
Shannon L.M. Heald ◽  
Stephen C. Van Hedger ◽  
John Veillette ◽  
Katherine Reis ◽  
Joel S. Snyder ◽  
...  

AbstractThe ability to generalize rapidly across specific experiences is vital for robust recognition of new patterns, especially in speech perception considering acoustic-phonetic pattern variability. Behavioral research has demonstrated that listeners are rapidly able to generalize their experience with a talker’s speech and quickly improve understanding of a difficult-to-understand talker without prolonged practice, e.g., even after a single training session. Here, we examine the differences in neural responses to generalized versus rote learning in auditory cortical processing by training listeners to understand a novel synthetic talker using a Pretest-Posttest design with electroencephalography (EEG). Participants were trained using either (1) a large inventory of words where no words repeated across the experiment (generalized learning) or (2) a small inventory of words where words repeated (rote learning). Analysis of long-latency auditory evoked potentials at Pretest and Posttest revealed that while rote and generalized learning both produce rapid changes in auditory processing, the nature of these changes differed. In the context of adapting to a talker, generalized learning is marked by an amplitude reduction in the N1-P2 complex and by the presence of a late-negative (LN) wave in the auditory evoked potential following training. Rote learning, however, is marked only by temporally later source configuration changes. The early N1-P2 change, found only for generalized learning, suggests that generalized learning relies on the attentional system to reorganize the way acoustic features are selectively processed. This change in relatively early sensory processing (i.e. during the first 250ms) is consistent with an active processing account of speech perception, which proposes that the ability to rapidly adjust to the specific vocal characteristics of a new talker (for which rote learning is rare) relies on attentional mechanisms to adaptively tune early auditory processing sensitivity.Statement of SignificancePrevious research on perceptual learning has typically examined neural responses during rote learning: training and testing is carried out with the same stimuli. As a result, it is not clear that findings from these studies can explain learning that generalizes to novel patterns, which is critical in speech perception. Are neural responses to generalized learning in auditory processing different from neural responses to rote learning? Results indicate rote learning of a particular talker’s speech involves brain regions focused on the memory encoding and retrieving of specific learned patterns, whereas generalized learning involves brain regions involved in reorganizing attention during early sensory processing. In learning speech from a novel talker, only generalized learning is marked by changes in the N1-P2 complex (reflective of secondary auditory cortical processing). The results are consistent with the view that robust speech perception relies on the fast adjustment of attention mechanisms to adaptively tune auditory sensitivity to cope with acoustic variability.


2020 ◽  
Vol 149 ◽  
pp. 107807
Author(s):  
Marta Font-Alaminos ◽  
Miriam Cornella ◽  
Jordi Costa-Faidella ◽  
Amaia Hervás ◽  
Sumie Leung ◽  
...  

2019 ◽  
Vol 30 (3) ◽  
pp. 942-951 ◽  
Author(s):  
Lanfang Liu ◽  
Yuxuan Zhang ◽  
Qi Zhou ◽  
Douglas D Garrett ◽  
Chunming Lu ◽  
...  

Abstract Whether auditory processing of speech relies on reference to the articulatory motor information of speaker remains elusive. Here, we addressed this issue under a two-brain framework. Functional magnetic resonance imaging was applied to record the brain activities of speakers when telling real-life stories and later of listeners when listening to the audio recordings of these stories. Based on between-brain seed-to-voxel correlation analyses, we revealed that neural dynamics in listeners’ auditory temporal cortex are temporally coupled with the dynamics in the speaker’s larynx/phonation area. Moreover, the coupling response in listener’s left auditory temporal cortex follows the hierarchical organization for speech processing, with response lags in A1+, STG/STS, and MTG increasing linearly. Further, listeners showing greater coupling responses understand the speech better. When comprehension fails, such interbrain auditory-articulation coupling vanishes substantially. These findings suggest that a listener’s auditory system and a speaker’s articulatory system are inherently aligned during naturalistic verbal interaction, and such alignment is associated with high-level information transfer from the speaker to the listener. Our study provides reliable evidence supporting that references to the articulatory motor information of speaker facilitate speech comprehension under a naturalistic scene.


1998 ◽  
Vol 21 (2) ◽  
pp. 282-283
Author(s):  
Michael J. Ryan ◽  
Nicole M. Kime ◽  
Gil G. Rosenthal

We consider Sussman et al.'s suggestion that auditory biases for processing low-noise relationships among pairs of acoustic variables is a preadaptation for human speech processing. Data from other animal communication systems, especially those involving sexual selection, also suggest that neural biases in the receiver system can generate strong selection on the form of communication signals.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maya Inbar ◽  
Eitan Grossman ◽  
Ayelet N. Landau

Abstract Studies of speech processing investigate the relationship between temporal structure in speech stimuli and neural activity. Despite clear evidence that the brain tracks speech at low frequencies (~ 1 Hz), it is not well understood what linguistic information gives rise to this rhythm. In this study, we harness linguistic theory to draw attention to Intonation Units (IUs), a fundamental prosodic unit of human language, and characterize their temporal structure as captured in the speech envelope, an acoustic representation relevant to the neural processing of speech. IUs are defined by a specific pattern of syllable delivery, together with resets in pitch and articulatory force. Linguistic studies of spontaneous speech indicate that this prosodic segmentation paces new information in language use across diverse languages. Therefore, IUs provide a universal structural cue for the cognitive dynamics of speech production and comprehension. We study the relation between IUs and periodicities in the speech envelope, applying methods from investigations of neural synchronization. Our sample includes recordings from every-day speech contexts of over 100 speakers and six languages. We find that sequences of IUs form a consistent low-frequency rhythm and constitute a significant periodic cue within the speech envelope. Our findings allow to predict that IUs are utilized by the neural system when tracking speech. The methods we introduce here facilitate testing this prediction in the future (i.e., with physiological data).


2011 ◽  
Vol 23 (12) ◽  
pp. 4008-4021 ◽  
Author(s):  
Tullia Padovani ◽  
Thomas Koenig ◽  
Daniel Brandeis ◽  
Walter J. Perrig

There is an increasing line of evidence supporting the idea that the formation of lasting memories involves neural activity preceding stimulus presentation. Following this line, we presented words in an incidental learning setting and manipulated the prestimulus state by asking the participants to perform either an emotional (neutral or emotional) or a semantic (animate or inanimate) decision task. Later, we tested the retrieval of each previously presented word with a recognition memory test. For both conditions, the subsequent memory effect (SME) was defined as ERP difference between subsequently remembered and forgotten words. Comparing the prestimulus SME between and within the two conditions yielded topographic differences in the time interval from −1300 to −700 msec before stimulus onset. This indicates that the activity of brain areas involved in incidental encoding of semantic information varied in the spatial distribution of ERPs, depending on the emotional and semantic requirements of the task. These findings provide evidence that there is a difference in semantic and emotional preparatory processes, which modulates successful encoding into episodic memory. This difference suggests that there are multiple task-specific functional neural systems that support memory formation. These systems differ in location and/or relative contribution of some of the brain structures that generate the measured scalp electric fields. Consequently, the cognitive processes that enable memory formation depend on the differential semantic nature of the study task and reflect differences in the preparatory processing of the multiple semantic components of a word's meaning.


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