scholarly journals Top-down influences of written text on perceived clarity of degraded speech.

2014 ◽  
Vol 40 (1) ◽  
pp. 186-199 ◽  
Author(s):  
Ediz Sohoglu ◽  
Jonathan E. Peelle ◽  
Robert P. Carlyon ◽  
Matthew H. Davis
Keyword(s):  
Top Down ◽  
Written Text ◽  
Degraded Speech

scholarly journals Event-related potentials reflect prediction errors and pop-out during comprehension of degraded speech

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Leah Banellis ◽  
Rodika Sokoliuk ◽  
Conor J Wild ◽  
Howard Bowman ◽  
Damian Cruse
Keyword(s):  
Prediction Error ◽  
Event Related Potentials ◽  
Event Related Potential ◽  
Prediction Errors ◽  
Top Down ◽  
Degraded Speech ◽  
Related Potentials ◽  
Task Goals ◽  
Post Hoc

Abstract Comprehension of degraded speech requires higher-order expectations informed by prior knowledge. Accurate top-down expectations of incoming degraded speech cause a subjective semantic ‘pop-out’ or conscious breakthrough experience. Indeed, the same stimulus can be perceived as meaningless when no expectations are made in advance. We investigated the event-related potential (ERP) correlates of these top-down expectations, their error signals and the subjective pop-out experience in healthy participants. We manipulated expectations in a word-pair priming degraded (noise-vocoded) speech task and investigated the role of top-down expectation with a between-groups attention manipulation. Consistent with the role of expectations in comprehension, repetition priming significantly enhanced perceptual intelligibility of the noise-vocoded degraded targets for attentive participants. An early ERP was larger for mismatched (i.e. unexpected) targets than matched targets, indicative of an initial error signal not reliant on top-down expectations. Subsequently, a P3a-like ERP was larger to matched targets than mismatched targets only for attending participants—i.e. a pop-out effect—while a later ERP was larger for mismatched targets and did not significantly interact with attention. Rather than relying on complex post hoc interactions between prediction error and precision to explain this apredictive pattern, we consider our data to be consistent with prediction error minimization accounts for early stages of processing followed by Global Neuronal Workspace-like breakthrough and processing in service of task goals.

scholarly journals Rapid computations of spectrotemporal prediction error support perception of degraded speech

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Ediz Sohoglu ◽  
Matthew H Davis
Keyword(s):  
Speech Perception ◽  
Prediction Error ◽  
Predictive Coding ◽  
Signal Quality ◽  
Neural Responses ◽  
Perceptual Inference ◽  
Written Text ◽  
Degraded Speech ◽  
Neural Representations ◽  
Brain Responses

Human speech perception can be described as Bayesian perceptual inference but how are these Bayesian computations instantiated neurally? We used magnetoencephalographic recordings of brain responses to degraded spoken words and experimentally manipulated signal quality and prior knowledge. We first demonstrate that spectrotemporal modulations in speech are more strongly represented in neural responses than alternative speech representations (e.g. spectrogram or articulatory features). Critically, we found an interaction between speech signal quality and expectations from prior written text on the quality of neural representations; increased signal quality enhanced neural representations of speech that mismatched with prior expectations, but led to greater suppression of speech that matched prior expectations. This interaction is a unique neural signature of prediction error computations and is apparent in neural responses within 100 ms of speech input. Our findings contribute to the detailed specification of a computational model of speech perception based on predictive coding frameworks.

scholarly journals Does Semantic Context Benefit Speech Understanding through “Top–Down” Processes? Evidence from Time-resolved Sparse fMRI

2011 ◽  
Vol 23 (12) ◽  
pp. 3914-3932 ◽  
Author(s):  
Matthew H. Davis ◽  
Michael A. Ford ◽  
Ferath Kherif ◽  
Ingrid S. Johnsrude
Keyword(s):  
Superior Temporal Gyrus ◽  
Hierarchical Organization ◽  
Top Down ◽  
Time Resolved ◽  
Degraded Speech ◽  
Neural Processes ◽  
Intelligible Speech ◽  
Speech Envelope ◽  
Envelope Spectrum ◽  
Rule Out

When speech is degraded, word report is higher for semantically coherent sentences (e.g., her new skirt was made of denim) than for anomalous sentences (e.g., her good slope was done in carrot). Such increased intelligibility is often described as resulting from “top–down” processes, reflecting an assumption that higher-level (semantic) neural processes support lower-level (perceptual) mechanisms. We used time-resolved sparse fMRI to test for top–down neural mechanisms, measuring activity while participants heard coherent and anomalous sentences presented in speech envelope/spectrum noise at varying signal-to-noise ratios (SNR). The timing of BOLD responses to more intelligible speech provides evidence of hierarchical organization, with earlier responses in peri-auditory regions of the posterior superior temporal gyrus than in more distant temporal and frontal regions. Despite Sentence content × SNR interactions in the superior temporal gyrus, prefrontal regions respond after auditory/perceptual regions. Although we cannot rule out top–down effects, this pattern is more compatible with a purely feedforward or bottom–up account, in which the results of lower-level perceptual processing are passed to inferior frontal regions. Behavioral and neural evidence that sentence content influences perception of degraded speech does not necessarily imply “top–down” neural processes.

Top-down knowledge supports the retrieval of lexical information from degraded speech

2007 ◽  
Vol 1153 ◽  
pp. 134-143 ◽  
Author(s):  
R. Hannemann ◽  
J. Obleser ◽  
C. Eulitz
Keyword(s):  
Top Down ◽  
Lexical Information ◽  
Degraded Speech

scholarly journals Event-related potentials reflect prediction errors and pop-out during comprehension of degraded speech

2020 ◽  
Author(s):  
Leah Banellis ◽  
Rodika Sokoliuk ◽  
Conor J Wild ◽  
Howard Bowman ◽  
Damian Cruse
Keyword(s):  
Prediction Error ◽  
Event Related Potentials ◽  
Prediction Errors ◽  
Top Down ◽  
Degraded Speech ◽  
Related Potentials ◽  
Task Goals ◽  
Post Hoc ◽  
Made In

AbstractComprehension of degraded speech requires higher-order expectations informed by prior-knowledge. Accurate top-down expectations of incoming degraded speech cause a subjective semantic “pop-out” or conscious breakthrough experience. Indeed, the same stimulus can be perceived as meaningless when no expectations are made in advance. We investigated the ERP correlates of these top-down expectations, their error signals, and the subjective pop-out experience in healthy participants. We manipulated expectations in a word-pair priming noise-vocoded speech task and investigated the role of top-down expectation with a between-groups attention manipulation. Consistent with the role of expectations in comprehension, repetition priming significantly enhanced perceptual intelligibility of the noise-vocoded degraded targets for attentive participants. An early ERP was larger for mismatched (i.e. unexpected) targets than matched targets, indicative of an initial error signal not reliant on top-down expectations. Subsequently, a P3a-like ERP was larger to matched targets than mismatched targets only for attending participants - i.e. a pop-out effect. Rather than relying on complex post hoc interactions between prediction error and precision to explain this apredictive pattern, we consider our data to be consistent with prediction error minimisation accounts for early stages of processing followed by Global Neuronal Workspace-like breakthrough and processing in service of task goals.

scholarly journals Rapid computations of spectrotemporal prediction error support perception of degraded speech

2020 ◽  
Author(s):  
Ediz Sohoglu ◽  
Matthew H. Davis
Keyword(s):  
Speech Perception ◽  
Prediction Error ◽  
Predictive Coding ◽  
Signal Quality ◽  
Neural Responses ◽  
Perceptual Inference ◽  
Written Text ◽  
Degraded Speech ◽  
Neural Representations ◽  
Brain Responses

AbstractHuman speech perception can be described as Bayesian perceptual inference but how are these Bayesian computations instantiated neurally? We use magnetoencephalographic recordings of brain responses to degraded spoken words as a function of signal quality and prior knowledge to demonstrate that spectrotemporal modulations in speech are more clearly represented in neural responses than alternative speech representations (e.g. spectrogram or articulatory features). We found an interaction between speech signal quality and expectations from prior written text on the quality of neural representations; increased signal quality enhanced neural representations of speech that mismatched with prior expectations, but led to greater suppression of speech that matched prior expectations. This interaction is a unique neural signature of prediction error computations and already apparent in neural responses within 250 ms of speech input. Our findings contribute towards the detailed specification of a computational model of speech perception based on predictive coding frameworks.

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

Functional Anatomy of Intensity Aspects of Attention

2003 ◽  
Vol 14 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Walter Sturm
Keyword(s):  
Right Hemisphere ◽  
Functional Anatomy ◽  
Fmri Data ◽  
Functional Networks ◽  
Top Down ◽  
Stimulus Modality ◽  
Spatial Orienting ◽  
Phasic Alertness ◽  
Co Activation ◽  
Attention System

Abstract: Behavioral and PET/fMRI-data are presented to delineate the functional networks subserving alertness, sustained attention, and vigilance as different aspects of attention intensity. The data suggest that a mostly right-hemisphere frontal, parietal, thalamic, and brainstem network plays an important role in the regulation of attention intensity, irrespective of stimulus modality. Under conditions of phasic alertness there is less right frontal activation reflecting a diminished need for top-down regulation with phasic extrinsic stimulation. Furthermore, a high overlap between the functional networks for alerting and spatial orienting of attention is demonstrated. These findings support the hypothesis of a co-activation of the posterior attention system involved in spatial orienting by the anterior alerting network. Possible implications of these findings for the therapy of neglect are proposed.

Auswirkungen eines Aufmerksamkeitstrainings auf die aphasische Symptomatik bei Schlaganfallpatienten

2011 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Julia Graf ◽  
Hartwig Kulke ◽  
Christa Sous-Kulke ◽  
Wilfried Schupp ◽  
Stefan Lautenbacher
Keyword(s):  
Top Down

Aufmerksamkeit kann als Kontrollsystem neuronaler Aktivität verstanden werden, welches Neuroplastizität top-down modulieren hilft. Bisher wurde selten versucht, durch deren gezielte Förderung Funktionswiederherstellungen nach Hirnschädigung zu begünstigen. In vorliegender Studie wurde dies am Beispiel der Aphasie erprobt. 15 Schlaganfallpatienten erhielten ein dreiwöchiges Training der selektiven Aufmerksamkeit mit den PC-Programmen CogniPlus und „Konzentration“ bei fünf Sitzungen pro Woche zusätzlich zur Standardtherapie, 13 weitere bildeten eine Kontrollgruppe ohne Aufmerksamkeitstraining. Zur Effektivitätskontrolle dienten zwei Versionen des Untertests Go/Nogo (Testbatterie zur Aufmerksamkeitsprüfung) und die Kurze Aphasieprüfung. Nach dem Training manifestierte sich zwischen den Untersuchungsgruppen kein Unterschied in Aufmerksamkeits- und Sprachfunktionen; das zusätzliche Aufmerksamkeitstraining war also wirkungslos. Allerdings zeigten Patienten mit deutlichen Aufmerksamkeitsverbesserungen tendenziell weniger Aphasie-Symptome, was die Hypothese aufmerksamkeitsvermittelter Plastizitätsmodulation nach Hirnschädigung partiell stützt.

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