Background and Hypothesis Sequential saccade planning requires corollary discharge (CD) signals that provide information about the planned landing location of an eye movement. These CD signals may be altered among individuals with schizophrenia (SZ), providing a potential mechanism to explain passivity and anomalous self-experiences broadly. In healthy controls (HC), a key oculomotor CD network transmits CD signals from the thalamus to the frontal eye fields (FEF) and the intraparietal sulcus (IPS) and also remaps signals from FEF to IPS.Study Design Here, we modeled fMRI data using dynamic causal modeling (DCM) to examine patient-control differences in effective connectivity evoked by a double-step (DS) task (30 SZ, 29 HC). The interrogated network was formed from a combination of (1) functionally identified FEF and IPS regions that robustly responded on DS trials and (2) anatomically identified thalamic regions involved in CD transmission. We also examined the relationship between clinical symptoms and effective connectivity parameters associated with task modulation of network pathways.Study Results Network connectivity was indeed modulated by the DS task, which involves CD transmission. More importantly, we found reduced effective connectivity from thalamus to IPS in SZ, which was further correlated with passivity symptom severity.Conclusions These results reaffirm the importance of IPS and thalamocortical connections in oculomotor CD signaling and provide mechanistic insights into CD alterations and consequently agency disturbances in schizophrenia.

Background and Hypothesis:Unpacking the pathophysiological mechanisms of schizophrenia is necessary for advancing prediction, prevention, and treatment efforts. Mechanisms can be identified using easy-to-use and scalable clinical biomarkers, which reflect illness processes. Pupillometry is one such biomarker. Blunted dilation related to cognitive demand has been interpreted as a metric of diminished effort in schizophrenia, while blunted constriction to light has been interpreted as a metric of altered autonomic balance in schizophrenia. However, these 2 sets of findings may also reflect a common mechanism of schizophrenia. Therefore, this study aimed to explore the association between blunted cognitive dilation and blunted constriction to light to provide a parsimonious mechanism of autonomic and effort disturbances experienced by individuals with schizophrenia. Study Design:We assessed light-induced constriction and cognitive dilation during a double-step task in individuals with schizophrenia (n = 84) and demographically matched healthy controls (HC, n = 69), compared these metrics between groups, and computed their correlation within each group. Study Results:Replicating prior findings, dilation and constriction were blunted in schizophrenia relative to HC. Blunted constriction and dilation were positively correlated in schizophrenia but not HC (although the 2 correlations did not differ significantly). Conclusions:Findings provide, for the first time, preliminary support of a common mechanism linking blunted pupil constriction to light and dilation to cognitive demands in schizophrenia. We propose that individuals with schizophrenia may exhibit impaired top-down modulation of autonomic control. Future studies are needed to validate this proposed mechanism.

AbstractIntroductionPathophysiological theories of schizophrenia (SZ) symptoms posit an abnormality in using predictions to guide behavior. One such prediction is based on imminent movements, via corollary discharge signals (CD) that relay information about planned movement kinematics to sensory brain regions. Empirical evidence suggests a reduced influence of sensorimotor predictions in individuals with SZ within multiple sensory systems, including in the visual system. One function of CD in the visual system is to selectively enhance visual sensitivity at the location of planned eye movements (pre‐saccadic attention), thus enabling a prediction of the to‐be‐foveated stimulus. We expected pre‐saccadic attention shifts to be less pronounced in individuals with SZ than in healthy controls (HC), resulting in unexpected sensory consequences of eye movements, which may relate to symptoms than can be explained in the context of altered allocation of attention.MethodsWe examined this question by testing 30 SZ and 30 HC on a pre‐saccadic attention task. On each trial participants made a saccade to a cued location in an array of four stimuli. A discrimination target that was either congruent or incongruent with the cued location was briefly presented after the cue, during saccade preparation. Pre‐saccadic attention was quantified by comparing accuracy on congruent trials to incongruent trials within the interval preceding the saccade.ResultsAlthough SZs were less accurate overall, the magnitude of the pre‐saccadic attention effect generally did not differ across groups nor show a convincing relationship with symptom severity. We did, however, observe that SZ had reduced pre‐saccadic attention effects when the discrimination target (probe) was presented at early stages of saccade planning, when pre‐saccadic attention effects first emerged in HC.ConclusionThese findings suggest generally intact pre‐saccadic shifts of attention in SZ, albeit slightly delayed. Results contribute to our understanding of altered sensory predictions in people with schizophrenia.

Two largely separate lines of research have documented altered pupillary dynamics in individuals diagnosed with schizophrenia. An older set of studies has demonstrated reductions in the pupillary light reflex (PLR) in individuals with schizophrenia; however, clinical and cognitive correlates of this blunted PLR have been relatively unexplored. More recently, a large body of work has demonstrated reductions in pupillary dilation in response to cognitive demands in individuals with schizophrenia, and the degree of this blunted pupil dilation has been related to more severe cognitive deficits and motivational negative symptoms. These clinically relevant alterations in the cognitive modulation of pupil size have been interpreted as reflecting insufficient information processing resources or inappropriate effort allocation. To begin to bridge these two lines of work, we investigated the PLR in 34 individuals with schizophrenia and 30 healthy controls and related the amplitude of the PLR to motivational negative symptoms and cognitive performance. Consistent with prior work, we found that the PLR was reduced in individuals with schizophrenia, and furthermore, that these measurements were highly reliable across individuals. Blunted constriction was associated with more severe motivational negative symptoms and poorer working memory among individuals with schizophrenia. These observed correlates provide a bridge between older literature documenting an altered PLR and more recent work reporting associations between negative symptoms, cognition, and blunted pupillary dilation in response to cognitive demands in individuals with schizophrenia. We provide possible mechanistic interpretations of our data and consider a parsimonious explanation for reduced cognitive- and light-related modulation of pupil size.

Category learning is fundamental to cognition, but little is known about how it proceeds in real-world environments when learners do not have instructions to search for category-relevant information, do not make overt category decisions, and do not experience direct feedback. Prior research demonstrates that listeners can acquire task-irrelevant auditory categories incidentally as they engage in primarily visuomotor tasks. The current study examines the factors that support this incidental category learning. Three experiments systematically manipulated the relationship of four novel auditory categories with a consistent visual feature (color or location) that informed a simple behavioral keypress response regarding the visual feature. In both an in-person experiment and two online replications with extensions, incidental auditory category learning occurred reliably when category exemplars consistently aligned with visuomotor demands of the primary task, but not when they were misaligned. The presence of an additional irrelevant visual feature that was uncorrelated with the primary task demands neither enhanced nor harmed incidental learning. By contrast, incidental learning did not occur when auditory categories were aligned consistently with one visual feature, but the motor response in the primary task was aligned with another, category-unaligned visual feature. Moreover, category learning did not reliably occur across passive observation or when participants made a category-nonspecific, generic motor response. These findings show that incidental learning of categories is strongly mediated by the character of coincident behavior. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The ability to rapidly stop or change a planned action is a critical cognitive process that is impaired in schizophrenia. The current study aimed to examine whether this impairment reflects familial vulnerability to schizophrenia across two experiments comparing unaffected first-degree relatives to healthy controls. First, we examined performance on a saccadic stop-signal task that required rapid inhibition of an eye movement. Then, in a different sample, we investigated behavioral and neural responses (using fMRI) during a stop-signal task variant that required rapid modification of a prepared eye movement. Here, we examined differences between relatives and healthy controls in terms of activation and effective connectivity within an oculomotor control network during task performance. Like individuals with schizophrenia, the unaffected relatives showed behavioral evidence for more inefficient inhibitory processes. Unlike previous findings in individuals with schizophrenia, however, the relatives showed evidence for a compensatory waiting strategy. Behavioral differences were accompanied by more activation among the relatives in task-relevant regions across conditions and group differences in effective connectivity across the task that were modulated differently by the instruction to exert control over a planned saccade. Effective connectivity parameters were related to behavioral measures of inhibition efficiency. The results suggest that individuals at familial risk for schizophrenia were engaging an oculomotor control network differently than controls and in a way that compromises inhibition efficiency.

The ability to form associations between stimuli and commit those associations to memory is a cornerstone of human cognition. Dopamine and noradrenaline are neuromodulators that are critically implicated in a range of cognitive functions, including learning and memory. Eye blink rate (EBR) and pupil diameter have been shown to index dopaminergic and noradrenergic activity. Here, we examined how these ocular measures relate to accuracy during a paired-associate learning task where participants learned consistent object-location associations over eight trials. We recorded EBR, pupil diameter, and visual scanning behavior in a largely young adult sample (N=73). We examined these ocular metrics in terms of between and within participant mean centered effects using linear mixed effects modeling. In the encoding and delay epochs, we found that increased accuracy was related to increased EBR relative to the individual’s own average rate within the respective epoch across the eight trials. Additionally, increased between participant mean centered EBR showed decreased accuracy in pre-trial fixation, encoding, and retrieval epochs, indicating that blinking more relative to others during these epochs was related to poorer recall. These effects of EBR on accuracy were observed even after controlling for the extent of visual scanning, which, during the delay epoch, also conferred a beneficial effect on recall accuracy. Finally, we found no effect of pupil diameter on accuracy. These results provide novel evidence supporting the utility of ocular metrics in illuminating cognitive and neurobiological mechanisms of paired associate learning.

Purpose: Differences across language environments of prelingually deaf children who receive cochlear implants (CIs) may affect language acquisition; yet, whether mothers show individual differences in how they modify infant-directed (ID) compared with adult-directed (AD) speech has seldom been studied. This study assessed individual differences in how mothers realized speech modifications in ID register and whether these predicted differences in language outcomes for children with CIs.Method: Participants were 36 dyads of mothers and their children aged 0;8–2;5 (years;months) at the time of CI implantation. Mothers’ spontaneous speech was recorded in a lab setting in ID or AD conditions before ~15 months postimplantation. Mothers’ speech samples were characterized for acoustic–phonetic and lexical properties established as canonical indices of ID speech to typically hearing infants, such as vowel space area differences, fundamental frequency variability, and speech rate. Children with CIs completed longitudinal administrations of one or more standardized language assessment instruments at variable intervals from 6 months to 9.5 years postimplantation. Standardized scores on assessments administered longitudinally were used to calculate linear regressions, which gave rise to predicted language scores for children at 2 years postimplantation and language growth over 2-year intervals.Results: Mothers showed individual differences in how they modified speech in ID versus AD registers. Crucially, these individual differences significantly predicted differences in estimated language outcomes at 2 years postimplantation in children with CIs. Maternal speech variation in lexical quantity and vowel space area differences across ID and AD registers most frequently predicted estimates of language attainment in children with CIs, whereas prosodic differences played a minor role.Conclusion: Results support that caregiver language behaviors play a substantial role in explaining variability in language attainment in children receiving CIs.Supplemental Material S1. Additional participant enrollment; F0 measurement details; vowel measurement details; additional analyses.Dilley, L., Lehet, M., Wieland, E. A., Arjmandi, M. K., Kondaurova, M., Wang, Y., Reed, J., Svirsky, M., Houston, D., & Bergseen, T. (2020). Individual difference in mothers' spontaneous infant-directed speech predict language attainment in children with cochlear implants. Journal of Speech, Language, and Hearing Research. Advance online publication. https://doi.org/10.1044/2020_JSLHR-19-00229

Individuals with schizophrenia show reduced pupillary dilation during the performance of demanding cognitive tasks, which is related to anhedonia. These results have been interpreted as reflecting inappropriate effort allocation and reduced informational processing capabilities. Previous studies have also described abnormalities in the pupil light reflex in individuals with schizophrenia. It is unknown whether the dynamics of this reflex are also related to negative symptoms, and we sought to explore this in the current study.

This is a pre-print of the manuscript in press in the Journal of Experimental Psychology: Learning, Memory, and Cognition: Roark, C. L., Lehet, M. I., Dick, F., & Holt, L. L. (in press). Category learning is fundamental to cognition, but little is known about how it proceeds in real-world environments when learners do not have instructions to search for category-relevant information, do not make overt category decisions, and do not experience direct feedback. Prior research demonstrates that listeners can acquire task-irrelevant auditory categories incidentally as they engage in primarily visuomotor tasks. The current study examines the factors that support this incidental category learning. Three experiments systematically manipulated the relationship of four novel auditory categories with a consistent visual feature (color or location) that informed a simple behavioral keypress response regarding the visual feature. In both an in-person experiment and two online replications with extensions, incidental auditory category learning occurred reliably when category exemplars consistently aligned with visuomotor demands of the primary task, but not when they were misaligned. The presence of an additional irrelevant visual feature that was uncorrelated with the primary task demands neither enhanced nor harmed incidental learning. By contrast, incidental learning did not occur when auditory categories were aligned consistently with one visual feature, but the motor response in the primary task was aligned with another, category-unaligned visual feature. Moreover, category learning did not reliably occur across passive observation or when participants made a category-nonspecific, generic motor response. These findings show that incidental learning of categories is strongly mediated by the character of coincident behavior.

Speech is notoriously variable, with no simple mapping from acoustics to linguistically-meaningful units like words and phonemes. Empirical research on this theoretically central issue establishes at least two classes of perceptual phenomena that accommodate acoustic variability: normalization and perceptual learning. Intriguingly, perceptual learning is supported by learning across acoustic variability, but normalization is thought to counteract acoustic variability leaving open questions about how these two phenomena might interact. Here, we examine the joint impact of normalization and perceptual learning on how acoustic dimensions map to vowel categories. As listeners categorized nonwords as setch or satch, they experienced a shift in short-term distributional regularities across the vowels' acoustic dimensions. Introduction of this 'artificial accent' resulted in a shift in the contribution of vowel duration in categorization. Although this dimension-based statistical learning impacted the influence of vowel duration on vowel categorization, the duration of these very same vowels nonetheless maintained a consistent influence on categorization of a subsequent consonant via duration contrast, a form of normalization. Thus, vowel duration had a duplex role consistent with normalization and perceptual learning operating on distinct levels in the processing hierarchy. We posit that whereas normalization operates across auditory dimensions, dimension-based statistical learning impacts the connection weights among auditory dimensions and phonetic categories.

Individuals with schizophrenia (SZ) show impaired cognitive control of gaze, which is related to functional outcome. Neurophysiology studies revealed a network of cortical and sub-cortical regions that subserves eye movement control. The goal of the present study was to examine whether abnormal activity within and between these regions may underpin inhibitory control abnormalities in SZ.

Listeners exposed to accented speech must adjust how they map between acoustic features and lexical representations such as phonetic categories. A robust form of this adaptive perceptual learning is learning to perceive synthetic speech where the connections between acoustic features and phonetic categories must be updated. Both implicit learning through mere exposure and explicit learning through directed feedback have previously been shown to produce this type of adaptive learning. The present study crosses implicit exposure and explicit feedback with the presence or absence of a written identification task. We show that simple exposure produces some learning, but explicit feedback produces substantially stronger learning, whereas requiring written identification did not measurably affect learning. These results suggest that explicit feedback guides learning of new mappings between acoustic patterns and known phonetic categories. We discuss mechanisms that may support learning via implicit exposure.

Automatic speech processing devices have become popular for quantifying amounts of ambient language input to children in their home environments. We assessed error rates for language input estimates for the Language ENvironment Analysis (LENA) audio processing system, asking whether error rates differed as a function of adult talkers’ gender and whether they were speaking to children or adults. Audio was sampled from within LENA recordings from 23 families with children aged 4–34 months. Human coders identified vocalizations by adults and children, counted intelligible words, and determined whether adults’ speech was addressed to children or adults. LENA’s classification accuracy was assessed by parceling audio into 100-ms frames and comparing, for each frame, human and LENA classifications. LENA correctly classified adult speech 67% of the time across families (average false negative rate: 33%). LENA’s adult word count showed a mean +47% error relative to human counts. Classification and Adult Word Count error rates were significantly affected by talkers’ gender and whether speech was addressed to a child or an adult. The largest systematic errors occurred when adult females addressed children. Results show LENA’s classifications and Adult Word Count entailed random – and sometimes large – errors across recordings, as well as systematic errors as a function of talker gender and addressee. Due to systematic and sometimes high error in estimates of amount of adult language input, relying on this metric alone may lead to invalid clinical and/or research conclusions. Further validation studies and circumspect usage of LENA are warranted.

Purpose Differences across language environments of prelingually deaf children who receive cochlear implants (CIs) may affect language acquisition; yet, whether mothers show individual differences in how they modify infant-directed (ID) compared with adult-directed (AD) speech has seldom been studied. This study assessed individual differences in how mothers realized speech modifications in ID register and whether these predicted differences in language outcomes for children with CIs. Method Participants were 36 dyads of mothers and their children aged 0;8-2;5 (years;months) at the time of CI implantation. Mothers' spontaneous speech was recorded in a lab setting in ID or AD conditions before ~15 months postimplantation. Mothers' speech samples were characterized for acoustic-phonetic and lexical properties established as canonical indices of ID speech to typically hearing infants, such as vowel space area differences, fundamental frequency variability, and speech rate. Children with CIs completed longitudinal administrations of one or more standardized language assessment instruments at variable intervals from 6 months to 9.5 years postimplantation. Standardized scores on assessments administered longitudinally were used to calculate linear regressions, which gave rise to predicted language scores for children at 2 years postimplantation and language growth over 2-year intervals. Results Mothers showed individual differences in how they modified speech in ID versus AD registers. Crucially, these individual differences significantly predicted differences in estimated language outcomes at 2 years postimplantation in children with CIs. Maternal speech variation in lexical quantity and vowel space area differences across ID and AD registers most frequently predicted estimates of language attainment in children with CIs, whereas prosodic differences played a minor role. Conclusion Results support that caregiver language behaviors play a substantial role in explaining variability in language attainment in children receiving CIs. Supplemental Material https://doi.org/10.23641/asha.12560147.

Automated audio processing systems, such as the Language Environment Analysis (LENA) system, are useful tools for understanding developmental language behaviors for clinical and basic research purposes. However, it is still unclear how accurate they may be in comparison to the traditional gold standard of evaluation by trained human listeners. In our study, human coders identified starts and ends of communicative vocalizations of children and adults from sampled audio in day-long LENA recordings of 23 families with a child with variable hearing status; accuracy of LENA was then determined for each recording by comparing LENA and human-derived labels for 100-ms frames of sampled audio. Preliminary analysis suggests that LENA accurately identified communicative vocalizations of the target child wearing the device as being produced by that target child 65% of the time (35% error); accuracy ranged from 49%—79% across recordings. When any child vocalization was correctly identified, LENA accurately distinguished whether this belonged to the target child or another child 75% of the time (25% error); accuracy, however, ranged from 7%—96%. These accuracy levels suggest caution is needed in applying popular speech processing systems like LENA to clinical and scientific questions in absence of additional validation measures.

Many studies have demonstrated benefits of infant-directed speech (IDS) over adult-directed speech (ADS) for language development. For deaf children who use cochlear implants (CIs), a variety of factors might reduce the advantage of IDS in language development. We hypothesized that spectral degradation due to the number of channels in CI processing negatively affects acoustic separability of IDS and ADS, potentially reducing benefits for language development of IDS in early childhood. 493 sentences spoken in two speaking styles (IDS and ADS) were processed using 4, 8, 12, 16, 22, and 32 channels noise-vocoders to simulate the spectral degradation caused by CIs. The sentences were partitioned into frames of 30 ms and represented by Mel-frequency cepstral coefficients. The Mahalanobis distance was used to calculate the acoustic distance across speaking styles (ID versus AD) and processing condition (4, 8, 12, 16, 22, and 32 channels). The results show that spectral degradation imposed by CI processing has significant negative effects on separation of IDS from ADS. These findings suggest that the spectral information in speech received by infants with CIs is substantially degraded, which can weaken the facilitative link between IDS and language development in this at-risk population. [Work supported by NIH grant R01DC008581.]