Biology subjects

Rogalsky, C.

Publications and source records attributed to Rogalsky, C..

5 recordsLinked to original sources

bioRxiv2026

Aging Is Associated with Reduced Topographic Differentiation Between Speaking and Silent Reading

Aging affects how neural activity is organized and specialized, but its impact on neural differentiation across language tasks remains unclear. In this study, we investigated whether aging influences neural differentiation during speaking and silent reading. Fifteen young adults and 15 older adults completed speaking and silent-reading tasks in a delayed-response paradigm while we collected electroencephalography (EEG) data. We examined EEG signal strength using time-resolved global field power (GFP), spatial configuration using topographic analysis of variance (TANOVA), and task-specific neural differentiation using the global dissimilarity index (DISS). We also examined the relationship between neural and behavioral measures, including digit-span scores and speech onset time. We found that speaking was associated with higher GFP than silent reading in the 388-800 ms interval, with no significant effects of group or group x task interaction, indicating similar EEG strength across groups. TANOVA revealed age-related differences in scalp topography in the 229-334 ms and 377-538 ms intervals, a task effect in the 618-723 ms interval, and a group x task interaction in the 562-636 ms interval. Notably, young adults had greater DISS than older adults during the 508-629 ms and 660-800 ms intervals, reflecting more distinct neural configurations for speaking and reading. We did not find significant correlations between DISS or GFP and behavioral measures, and the two groups performed similarly on behavioral measures. Overall, aging was associated with reduced neural differentiation between speaking and silent reading, especially during later processing stages (e.g., motor command preparation), while preserving overall EEG activity and behavioral performance. These findings may suggest that aging reduces neural network specificity (as previously suggested) and alters spatial organization without necessarily impairing behavior.

neuroscience↗

bioRxiv2026

Larger Pre-Speech Auditory Modulation Is Associated With Smaller Corrective Responses To Auditory Errors

PurposeDuring speech planning, the brain predicts the auditory consequences of its movements and modulates the auditory system--a process called pre-speech auditory modulation (PSAM). We investigated the link between PSAM and behavioral error correction and determined how aging influences these mechanisms. MethodsSeventeen young adults (18-32 years) and 13 older adults (50-85 years) performed a speaking task involving auditory feedback perturbations and a silent reading control. We measured electrophysiological responses (N1/P2) to auditory probes during speech planning and correlated these modulations with the magnitude of participants subsequent behavioral corrective responses. ResultsBoth groups showed significant modulation of N1 and P2. However, N1 modulation correlated with corrective responses only in young adults. Older adults showed reduced behavioral corrections and smaller, delayed P2 components. Despite these age-related behavioral differences and the loss of the modulation-correction correlation, older adults maintained modulation magnitudes comparable to those of younger adults. ConclusionsN1 modulation serves as a neural index of the brains predictive processes during speech planning. Aging appears to selectively disrupt the integration of these signals into motor output rather than the internal generation of the predictions themselves.

neuroscience↗

bioRxiv2023

How can graph theory inform the dual-stream model of speech processing? a resting-state fMRI study of post-stroke aphasia

The dual-stream model of speech processing has been proposed to represent the cortical networks involved in speech comprehension and production. Although it is arguably the prominent neuroanatomical model of speech processing, it is not yet known if the dual-stream model represents actual intrinsic functional brain networks. Furthermore, it is unclear how disruptions after a stroke to the functional connectivity of the dual-stream models regions are related to specific types of speech production and comprehension impairments seen in aphasia. To address these questions, in the present study, we examined two independent resting-state fMRI datasets: (1) 28 neurotypical matched controls and (2) 28 chronic left-hemisphere stroke survivors with aphasia collected at another site. Structural MRI, as well as language and cognitive behavioral assessments, were collected. Using standard functional connectivity measures, we successfully identified an intrinsic resting-state network amongst the dual-stream models regions in the control group. We then used both standard functional connectivity analyses and graph theory approaches to determine how the functional connectivity of the dual-stream network differs in individuals with post-stroke aphasia, and how this connectivity may predict performance on clinical aphasia assessments. Our findings provide strong evidence that the dual-stream model is an intrinsic network as measured via resting-state MRI, and that weaker functional connectivity of the hub nodes of the dual-stream network defined by graph theory methods, but not overall average network connectivity, is weaker in the stroke group than in the control participants. Also, the functional connectivity of the hub nodes predicted specific types of impairments on clinical assessments. In particular, the relative strength of connectivity of the right hemispheres homologues of the left dorsal stream hubs to the left dorsal hubs versus right ventral stream hubs is a particularly strong predictor of post-stroke aphasia severity and symptomology.

neuroscience↗

bioRxiv2020

The Neuroanatomy of Speech Processing: A Large-Scale Lesion Study

The neural basis of language has been studied for centuries, yet the networks critically involved in simply identifying or understanding a spoken word remain elusive. Several functional-anatomical models of critical neural substrates of receptive speech have been proposed, including (1) auditory-related regions in the left mid-posterior superior temporal lobe, (2) motor-related regions in the left frontal lobe (in normal and/or noisy conditions), the left anterior superior temporal lobe, or (4) bilateral mid-posterior superior temporal areas. One difficulty in comparing these models is that they often focus on different aspects of the sound-to-meaning pathway and are supported by different types of stimuli and tasks. Two auditory tasks that are typically used in separate studies--syllable discrimination and word comprehension--often yield different conclusions. We assessed syllable discrimination (words and nonwords) and word comprehension (clear speech and with a noise masker) in 158 individuals with focal brain damage: left (n=113) or right (n=19) hemisphere stroke, left (n=18) or right (n=8) anterior temporal lobectomy, and 26 neurologically-intact controls. Discrimination and comprehension tasks are doubly dissociable both behaviorally and neurologically. In support of a bilateral model, clear speech comprehension was near ceiling in 95% of left stroke cases and right temporal damage impaired syllable discrimination. Lesion-symptom mapping analyses for the syllable discrimination and noisy word comprehension tasks each implicated most of the left superior temporal gyrus (STG). Comprehension but not discrimination tasks also implicated the left pMTG, while discrimination but not comprehension tasks also implicated more dorsal sensorimotor regions in posterior perisylvian cortex.

neuroscience↗

bioRxiv2017

The neurobiology of agrammatic sentence comprehension: a lesion study

Brocas area has long been implicated in sentence comprehension. Damage to this region is thought to be the central source of \"agrammatic comprehension\" in which performance is substantially worse (and near chance) on sentences with noncanonical word orders compared to canonical word order sentences (in English). This claim is supported by functional neuroimaging studies demonstrating greater activation in Brocas area for noncanonical versus canonical sentences. However, functional neuroimaging studies also have frequently implicated the anterior temporal lobe (ATL) in sentence processing more broadly, and recent lesion-symptom mapping studies have implicated the ATL and mid temporal regions in agrammatic comprehension. The present study investigates these seemingly conflicting findings in 66 left hemisphere patients with chronic focal cerebral damage. Patients completed two sentence comprehension measures, sentence-picture matching and plausibility judgments. Patients with damage including Brocas area (but excluding the temporal lobe; n=11) on average did not exhibit the expected agrammatic comprehension pattern, e.g. their performance was > 80% on noncanonical sentences in the sentence-picture matching task. Patients with ATL damage (n=18) also did not exhibit an agrammatic comprehension pattern. Across our entire patient sample, the lesions of patients with agrammatic comprehension patterns in either task had maximal overlap in posterior superior temporal and inferior parietal regions. Using voxel-based lesion symptom mapping (VLSM), we find that lower performances on canonical and noncanonical sentences in each task are both associated with damage to a large left superior temporal-inferior parietal network including portions of the ATL, but not Brocas area. Notably however, response bias in plausibility judgments was significantly associated with damage to inferior frontal cortex, including gray and white matter in Brocas area, suggesting that the contribution of Brocas area to sentence comprehension may be related to task-related cognitive demands.

neuroscience↗