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Edward F. Chang - One of the best experts on this subject based on the ideXlab platform.
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A speech envelope landmark for syllable encoding in human Superior Temporal Gyrus
Science Advances, 2019Co-Authors: Yulia Oganian, Edward F. ChangAbstract:The most salient acoustic features in speech are the modulations in its intensity, captured by the amplitude envelope. Perceptually, the envelope is necessary for speech comprehension. Yet, the neural computations that represent the envelope and their linguistic implications are heavily debated. We used high-density intracranial recordings, while participants listened to speech, to determine how the envelope is represented in human speech cortical areas on the Superior Temporal Gyrus (STG). We found that a well-defined zone in middle STG detects acoustic onset edges (local maxima in the envelope rate of change). Acoustic analyses demonstrated that timing of acoustic onset edges cues syllabic nucleus onsets, while their slope cues syllabic stress. Synthesized amplitude-modulated tone stimuli showed that steeper slopes elicited greater responses, confirming cortical encoding of amplitude change, not absolute amplitude. Overall, STG encoding of the timing and magnitude of acoustic onset edges underlies the perception of speech Temporal structure.
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The Encoding of Speech Sounds in the Superior Temporal Gyrus
Neuron, 2019Co-Authors: Matthew K. Leonard, Edward F. ChangAbstract:Summary The human Superior Temporal Gyrus (STG) is critical for extracting meaningful linguistic features from speech input. Local neural populations are tuned to acoustic-phonetic features of all consonants and vowels and to dynamic cues for intonational pitch. These populations are embedded throughout broader functional zones that are sensitive to amplitude-based Temporal cues. Beyond speech features, STG representations are strongly modulated by learned knowledge and perceptual goals. Currently, a major challenge is to understand how these features are integrated across space and time in the brain during natural speech comprehension. We present a theory that Temporally recurrent connections within STG generate context-dependent phonological representations, spanning longer Temporal sequences relevant for coherent percepts of syllables, words, and phrases.
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Spontaneous Neural Activity in the Superior Temporal Gyrus Recapitulates Tuning for Speech Features
Frontiers in Human Neuroscience, 2018Co-Authors: Jonathan D. Breshears, Liberty S. Hamilton, Edward F. ChangAbstract:Background: Numerous studies have demonstrated that individuals exhibit structured neural activity in many brain regions during rest that is also observed during different tasks, however it is still not clear whether and how resting state activity patterns may relate to underlying tuning for specific stimuli. In the posterior Superior Temporal Gyrus (STG), distinct neural activity patterns are observed during the perception of specific linguistic speech features. We hypothesized that spontaneous resting-state neural dynamics of the STG would be structured to reflect its role in speech perception, exhibiting an organization along speech features as seen during speech perception. Methods: Human cortical local field potentials were recorded from the Superior Temporal Gyrus (STG) in 8 patients undergoing surgical treatment of epilepsy. Signals were recorded during speech perception and rest. Patterns of neural activity (high gamma power: 70-150 Hz) during rest, extracted with spatioTemporal principal component analysis, were compared to spatioTemporal neural responses to speech features during perception. Hierarchical clustering was applied to look for patterns in rest that corresponded to speech feature tuning. Results: Significant correlations were found between neural responses to speech features (sentence onsets, consonants, and vowels) and the spontaneous neural activity in the STG. Across subjects, these correlations clustered into five groups, demonstrating tuning for speech features-most robustly for acoustic onsets. These correlations were not seen in other brain areas, or during motor and spectrally-rotated speech control tasks. Conclusions: In this study, we present evidence that the RS structure of STG activity robustly recapitulates its stimulus-evoked response to acoustic onsets. Further, secondary patterns in RS activity appear to correlate with stimulus-evoked responses to speech features. The role of these spontaneous spatioTemporal activity patterns remains to be elucidated.
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A speech envelope landmark for syllable encoding in human Superior Temporal Gyrus
bioRxiv, 2018Co-Authors: Yulia Oganian, Edward F. ChangAbstract:Listeners use the slow amplitude modulations of speech, known as the envelope, to segment continuous speech into syllables. However, the underlying neural computations are heavily debated. We used high-density intracranial cortical recordings while participants listened to natural and synthesized control speech stimuli to determine how the envelope is represented in the human Superior Temporal Gyrus (STG), a critical auditory brain area for speech processing. We found that the STG does not encode the instantaneous, moment-by-moment amplitude envelope of speech. Rather, a zone of the middle STG detects discrete acoustic onset edges, defined by local maxima in the rate-of-change of the envelope. Acoustic analysis demonstrated that acoustic onset edges reliably cue the information-rich transition between the consonant-onset and vowel-nucleus of syllables. Furthermore, the steepness of the acoustic edge cued whether a syllable was stressed. Synthesized amplitude-modulated tone stimuli showed that steeper edges elicited monotonically greater cortical responses, confirming the encoding of relative but not absolute amplitude. Overall, encoding of the timing and magnitude of acoustic onset edges in STG underlies our perception of the syllabic rhythm of speech.
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Human Superior Temporal Gyrus Organization of SpectroTemporal Modulation Tuning Derived from Speech Stimuli
The Journal of Neuroscience, 2016Co-Authors: Patrick W. Hullett, Nima Mesgarani, Liberty S. Hamilton, Christoph E. Schreiner, Edward F. ChangAbstract:The human Superior Temporal Gyrus (STG) is critical for speech perception, yet the organization of spectroTemporal processing of speech within the STG is not well understood. Here, to characterize the spatial organization of spectroTemporal processing of speech across human STG, we use high-density cortical surface field potential recordings while participants listened to natural continuous speech. While synthetic broad-band stimuli did not yield sustained activation of the STG, spectroTemporal receptive fields could be reconstructed from vigorous responses to speech stimuli. We find that the human STG displays a robust anterior–posterior spatial distribution of spectroTemporal tuning in which the posterior STG is tuned for Temporally fast varying speech sounds that have relatively constant energy across the frequency axis (low spectral modulation) while the anterior STG is tuned for Temporally slow varying speech sounds that have a high degree of spectral variation across the frequency axis (high spectral modulation). This work illustrates organization of spectroTemporal processing in the human STG, and illuminates processing of ethologically relevant speech signals in a region of the brain specialized for speech perception. SIGNIFICANCE STATEMENT Considerable evidence has implicated the human Superior Temporal Gyrus (STG) in speech processing. However, the gross organization of spectroTemporal processing of speech within the STG is not well characterized. Here we use natural speech stimuli and advanced receptive field characterization methods to show that spectroTemporal features within speech are well organized along the posterior-to-anterior axis of the human STG. These findings demonstrate robust functional organization based on spectroTemporal modulation content, and illustrate that much of the encoded information in the STG represents the physical acoustic properties of speech stimuli.
Martha E. Shenton - One of the best experts on this subject based on the ideXlab platform.
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An MRI Study of Superior Temporal Gyrus Volume in Women With Schizotypal Personality Disorder
American Journal of Psychiatry, 2003Co-Authors: Chandlee C Dickey, Margaret A Niznikiewicz, Martina M Voglmaier, Robert W. Mccarley, Larry J Seidman, Susan Demeo, Melissa Frumin, Martha E. ShentonAbstract:Objective: An abnormal Superior Temporal Gyrus has figured prominently in schizophrenia research, and left Superior Temporal Gyrus volume has been shown to be smaller in male subjects with schizotypal personality disorder. This is the first structural magnetic resonance imaging study to examine a group of female subjects with schizotypal personality disorder. Method: The Superior Temporal Gyrus was drawn on coronal images acquired from female subjects recruited from the community (schizotypal personality disorder group: N=21, comparison group: N=29). Results: There were no gray matter volume differences in the left or right Superior Temporal Gyrus between the subjects with schizotypal personality disorder and the comparison subjects. Within the schizotypal personality disorder group, however, there was an interaction between hemisphere and family history of mental illness. Moreover, subjects with schizotypal personality disorder did demonstrate formal thought disorder and a negative correlation between left Superior Temporal Gyrus volume and odd speech. Conclusions: This study of female subjects with schizotypal personality disorder showed no Superior Temporal Gyrus volume differences, but preliminary findings indicate that among female subjects with schizotypal personality disorder, there is a left–right difference in those who have a family history of mental illness relative to those who do not. These data also suggest an association between abnormal speech and left Superior Temporal Gyrus volume, a finding similar to that found in schizophrenia. Results from this study thus clearly reinforce the importance of studying female subjects separately.
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Progressive Decrease of Left Superior Temporal Gyrus Gray Matter Volume in Patients With First-Episode Schizophrenia
American Journal of Psychiatry, 2003Co-Authors: Kiyoto Kasai, Martha E. Shenton, Ron Kikinis, Dean F. Salisbury, Yoshio Hirayasu, Chang-uk Lee, Aleksandra A. Ciszewski, Deborah A. Yurgelun-todd, Ferenc A. JoleszAbstract:Objective: Smaller Temporal lobe cortical gray matter volumes, including the left Superior Temporal Gyrus, have been reported in magnetic resonance imaging (MRI) studies of patients with chronic schizophrenia and, more recently, in patients with first-episode schizophrenia. However, it remains unknown whether there are progressive decreases in Temporal lobe cortical gray matter volumes in patients with first-episode schizophrenia and whether similarly progressive volume decreases are present in patients with affective psychosis. Method: High-spatial-resolution MRI scans at initial hospitalization and 1.5 years later were obtained from 13 patients with first-episode schizophrenia, 15 patients with first-episode affective psychosis (mainly manic), and 14 healthy comparison subjects. MRI volumes were calculated for gray matter of Superior Temporal Gyrus and for the amygdala-hippocampal complex. Results: Patients with first-episode schizophrenia showed significant decreases in gray matter volume over time in the left Superior Temporal Gyrus compared with patients with first-episode affective psychosis or healthy comparison subjects. This progressive decrease was more pronounced in the posterior portion of the left Superior Temporal Gyrus (mean=9.6%) than in the anterior portions (mean= 8.4%). No group differences in the rate of change over time were present in other regions. Conclusions: These findings demonstrate a progressive volume reduction of the left posterior Superior Temporal Gyrus gray matter in patients with first-episode schizophrenia but not in patients with first-episode affective psychosis.
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Superior Temporal Gyrus Volume Abnormalities and Thought Disorder in Left-Handed Schizophrenic Men
American Journal of Psychiatry, 1999Co-Authors: Dorothy P. Holinger, Martha E. Shenton, Cynthia G. Wible, Robert Donnino, Ron Kikinis, Ferenc A. JoleszAbstract:Objective: Studies of schizophrenia have not clearly defined handedness as a differentiating variable. Moreover, the relationship between thought disorder and anatomical anomalies has not been studied extensively in left-handed schizophrenic men. The twofold purpose of this study was to investigate gray matter volumes in the Superior Temporal Gyrus of the Temporal lobe (left and right hemispheres) in left-handed schizophrenic men and lefthanded comparison men, in order to determine whether thought disorder in the left-handed schizophrenic men correlated with tissue volume abnormalities. Method: Left-handed male patients (N=8) with DSM-III-R diagnoses of schizophrenia were compared with left-handed comparison men (N=10) matched for age, socioeconomic status, and IQ. Magnetic resonance imaging (MRI) with a 1.5-T magnet was used to obtain scans, which consisted of contiguous 1.5-mm slices of the whole brain. MRI analyses (as previously defined by the authors) included the anterior, posterior, and total Superior Temporal Gyrus in both the left and right hemispheres. Results: There were three significant findings regarding the left-handed schizophrenic men: 1) bilaterally smaller gray matter volumes in the posterior Superior Temporal Gyrus (16% smaller on the right, 15% smaller on the left); 2) a smaller volume on the right side of the total Superior Temporal Gyrus; and 3) a positive correlation between thought disorder and tissue volume in the right anterior Superior Temporal Gyrus. Conclusions: These results suggest that expression of brain pathology differs between left-handed and right-handed schizophrenic men and that the pathology is related to cognitive disturbance. (Am J Psychiatry 1999; 156:1730‐1735)
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Auditory P300 Abnormalities and Left Posterior Superior Temporal Gyrus Volume Reduction in Schizophrenia
Archives of General Psychiatry, 1993Co-Authors: Martha E. Shenton, Ron Kikinis, Brian F. O'donnell, Stephen F. Faux, Paul G. Nestor, Ferenc A. JoleszAbstract:• Abnormalities in the auditory P300 event-related potential are one of the most robust findings in schizophrenia. To investigate the brain source(s) of this major functional abnormality, we combined P300 recordings with the use of a new generation of magnetic resonance imaging (MRI) technology to examine specific Temporal lobe gray matter regions of interest in schizophrenics and normal controls. In schizophrenics, gray matter volume reductions in the left posterior Superior Temporal Gyrus (STG), which includes Heschl's Gyrus and the planum Temporale, were highly and specifically associated with both P300 amplitude reduction and left
Peter Falkai - One of the best experts on this subject based on the ideXlab platform.
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The cytoarchitecture of the Superior Temporal Gyrus in bipolar disorder using GLI-methodology
Bipolar Disorders, 2002Co-Authors: Kai Vogeley, Ralf Tepest, Thomas Schneider-axmann, William G. Honer, Peter FalkaiAbstract:Vogeley K, Tepest R, Schneider-Axmann T, Honer WG, Falkai P. Thecytoarchitecture of the Superior Temporal Gyrus in bipolar disorder using GLI-methodology. Bipolar Disord 2002: 4(Suppl. 1): . © Blackwell Munksgaard, 2002
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Compartmental volumetry of the Superior Temporal Gyrus reveals sex differences in schizophrenia--a post-mortem study.
Schizophrenia research, 1998Co-Authors: Kai Vogeley, Thomas Schneider-axmann, William G. Honer, T Hobson, B Bogerts, Peter FalkaiAbstract:Brain imaging studies have shown Superior Temporal Gyrus (STG) volume loss and abnormal patterns of asymmetry in schizophrenia; however, these are not consistent findings. Post-mortem volumetry of three different STG regions (defined by external landmarks) was used to compare 17 schizophrenics to 20 age- and sex-matched controls. Total STG volumes did not differ. A significant gray-matter volume reduction in schizophrenics was observed in the middle compartment (reaching from the mamillary body to the lateral geniculate body). This may have been related to reduced length of this region, particularly in schizophrenic females. These results reflect the problematic issue of defining boundaries of macroscopic brain structures.
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Compartmental volumetry of the Superior Temporal Gyrus reveals sex differences in schizophrenia—a post-mortem study
Schizophrenia Research, 1998Co-Authors: Kai Vogeley, Thomas Schneider-axmann, William G. Honer, T Hobson, B Bogerts, Peter FalkaiAbstract:Brain imaging studies have shown Superior Temporal Gyrus (STG) volume loss and abnormal patterns of asymmetry in schizophrenia; however, these are not consistent findings. Post-mortem volumetry of three different STG regions (defined by external landmarks) was used to compare 17 schizophrenics to 20 age- and sex-matched controls. Total STG volumes did not differ. A significant gray-matter volume reduction in schizophrenics was observed in the middle compartment (reaching from the mamillary body to the lateral geniculate body). This may have been related to reduced length of this region, particularly in schizophrenic females. These results reflect the problematic issue of defining boundaries of macroscopic brain structures.
Andrea Kwakowsky - One of the best experts on this subject based on the ideXlab platform.
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GABAA receptor subunit expression changes in the human Alzheimer's disease hippocampus, subiculum, entorhinal cortex and Superior Temporal Gyrus.
Journal of Neurochemistry, 2018Co-Authors: Andrea Kwakowsky, Henry J. Waldvogel, Clinton Turner, Beatriz Calvo-flores Guzmán, Madhavi Pandya, Richard L.m. FaullAbstract:Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. GABA type A receptors (GABAA Rs) are severely affected in Alzheimer's disease (AD). However, the distribution and subunit composition of GABAA Rs in the AD brain are not well understood. This is the first comprehensive study to show brain region- and cell layer-specific alterations in the expression of the GABAA R subunits α1-3, α5, β1-3 and γ2 in the human AD hippocampus, entorhinal cortex and Superior Temporal Gyrus. In late-stage AD tissue samples using immunohistochemistry we found significant alteration of all investigated GABAA Rs subunits except for α3 and β1 that were well preserved. The most prominent changes include an increase in GABAA R α1 expression associated with AD in all layers of the CA3 region, in the stratum (str.) granulare and hilus of the dentate Gyrus. We found a significant increase in GABAA R α2 expression in the str. oriens of the CA1-3, str. radiatum of the CA2,3 and decrease in the str. pyramidale of the CA1 region in AD cases. In AD there was a significant increase in GABAA R α5 subunit expression in str. pyramidale, str. oriens of the CA1 region and decrease in the Superior Temporal Gyrus. We also found a significant decrease in the GABAA R β3 subunit immunoreactivity in the str. oriens of the CA2, str. granulare and str. moleculare of the dentate Gyrus. In conclusion, these findings indicate that the expression of the GABAA R subunits shows brain region- and layer-specific alterations in AD, and these changes could significantly influence and alter GABAA R function in the disease. Cover Image for this issue: doi: 10.1111/jnc.14179.
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Impaired expression of GABA transporters in the human Alzheimer's disease hippocampus, subiculum, entorhinal cortex and Superior Temporal Gyrus.
Neuroscience, 2017Co-Authors: Tessa E. Fuhrer, Thulani H. Palpagama, Henry J. Waldvogel, Beth J. Synek, Clinton Turner, Richard L.m. Faull, Andrea KwakowskyAbstract:Abstract Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain and plays an important role in regulating neuronal excitability. GABA reuptake from the synapse is dependent on specific transporters – mainly GAT-1, GAT-3 and BGT-1 (GATs). This study is the first to show alterations in the expression of the GATs in the Alzheimer’s disease (AD) hippocampus, entorhinal cortex and Superior Temporal Gyrus. We found a significant increase in BGT-1 expression associated with AD in all layers of the dentate Gyrus, in the stratum oriens of the CA2 and CA3 and the Superior Temporal Gyrus. In AD there was a significant decrease in GAT-1 expression in the entorhinal cortex and Superior Temporal Gyrus. We also found a significant decrease in GAT-3 immunoreactivity in the stratum pyramidale of the CA1 and CA3, the subiculum and entorhinal cortex. These observations indicate that the expression of the GATs shows brain-region- and layer-specific alterations in AD, suggesting a complex activation pattern of different GATs during the course of the disease.
Matthew K. Leonard - One of the best experts on this subject based on the ideXlab platform.
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The Encoding of Speech Sounds in the Superior Temporal Gyrus
Neuron, 2019Co-Authors: Matthew K. Leonard, Edward F. ChangAbstract:Summary The human Superior Temporal Gyrus (STG) is critical for extracting meaningful linguistic features from speech input. Local neural populations are tuned to acoustic-phonetic features of all consonants and vowels and to dynamic cues for intonational pitch. These populations are embedded throughout broader functional zones that are sensitive to amplitude-based Temporal cues. Beyond speech features, STG representations are strongly modulated by learned knowledge and perceptual goals. Currently, a major challenge is to understand how these features are integrated across space and time in the brain during natural speech comprehension. We present a theory that Temporally recurrent connections within STG generate context-dependent phonological representations, spanning longer Temporal sequences relevant for coherent percepts of syllables, words, and phrases.
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Human Superior Temporal Gyrus encoding of speech sequence probabilities
Journal of the Acoustical Society of America, 2013Co-Authors: Matthew K. Leonard, Kristofer E. Bouchard, Edward F. ChangAbstract:Spoken word representations are hypothesized to be built from smaller segments of the speech signal, including phonemes and acoustic features. The language-level statistics of sound sequences (“phonotactics”) are speculated to play a role in integrating sub-lexical representations into words in the human brain. In four neurosurgical patients, we recorded electrocorticographic (ECoG) neural activity directly from the brain surface while they listened to spoken real and pseudo words with varying transition probabilities (TPs) between the consonants and vowels (Cs and Vs) in a set of CVC stimuli. Electrodes over left Superior Temporal Gyrus (STG) were sensitive to TPs in a way that suggested dynamic, near real-time tracking of the speech input. TP effects were seen independently from activity explained by acoustic variability as measured by each electrode’s spectroTemporal receptive field (STRF). Furthermore, population-level analyses of STG electrodes demonstrated that TP effects were different for real vs ...
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Speech-Specific Tuning of Neurons in Human Superior Temporal Gyrus
Cerebral Cortex, 2013Co-Authors: Alexander Chan, Andrew R. Dykstra, Vinay Jayaram, Matthew K. Leonard, Katherine E. Travis, Brian Gygi, Janet M. Baker, Emad N. Eskandar, Leigh R. Hochberg, Eric HalgrenAbstract:How the brain extracts words from auditory signals is an unanswered question. We recorded approximately 150 single and multi-units from the left anterior Superior Temporal Gyrus of a patient during multiple auditory experiments. Against low background activity, 45% of units robustly fired to particular spoken words with little or no response to pure tones, noise-vocoded speech, or environmental sounds. Many units were tuned to complex but specific sets of phonemes, which were influenced by local context but invariant to speaker, and suppressed during self-produced speech. The firing of several units to specific visual letters was correlated with their response to the corresponding auditory phonemes, providing the first direct neural evidence for phonological recoding during reading. Maximal decoding of individual phonemes and words identities was attained using firing rates from approximately 5 neurons within 200 ms after word onset. Thus, neurons in human Superior Temporal Gyrus use sparse spatially organized population encoding of complex acoustic–phonetic features to help recognize auditory and visual words.