Neurosciences Commons^™

Agrammatism And Paragrammatism: A Cortical Double Dissociation Revealed By Lesion-Symptom Mapping, William Matchin, Alexandra Basilakos, Brielle C. Stark, Dirk B. Den Ouden, Fridolin Gross, Gregory Hickok

Communication Sciences and Disorders Faculty Articles and Research

The fundamental distinction of grammatical deficits in aphasia, agrammatism and paragrammatism, was made over a century ago. However, the extent to which the agrammatism/paragrammatism distinction exists independently of differences in speech fluency has not clearly been investigated. Despite much research on agrammatism, the lesion correlates of paragrammatism are essentially unknown. Lesion-symptom mapping was used to investigate the degree to which the lesion correlates of agrammatism and paragrammatism overlap or dissociate. Four expert raters assessed videos of 53 right-handed patients with aphasia following chronic left-hemisphere stroke retelling the Cinderella story. Consensus discussion determined each subject’s classification with respect to grammatical deficits …

Learning In The Machine: To Share Or Not To Share?, Jordan Ott, Erik Linstead, Nicholas Lahaye, Pierre Baldi

Engineering Faculty Articles and Research

Weight-sharing is one of the pillars behind Convolutional Neural Networks and their successes. However, in physical neural systems such as the brain, weight-sharing is implausible. This discrepancy raises the fundamental question of whether weight-sharing is necessary. If so, to which degree of precision? If not, what are the alternatives? The goal of this study is to investigate these questions, primarily through simulations where the weight-sharing assumption is relaxed. Taking inspiration from neural circuitry, we explore the use of Free Convolutional Networks and neurons with variable connection patterns. Using Free Convolutional Networks, we show that while weight-sharing is a pragmatic optimization …

A Nwb-Based Dataset And Processing Pipeline Of Human Single-Neuron Activity During A Declarative Memory Task, N. Chandravadia, D. Liang, A. G. P. Schjetnan, A. Carlson, M. Faraut, J. M. Chung, C. M. Reed, B. Dichter, Uri Maoz, S. K. Kalia, T. A. Valiante, A. N. Mamelak, U. Rutishauser

Psychology Faculty Articles and Research

A challenge for data sharing in systems neuroscience is the multitude of different data formats used. Neurodata Without Borders: Neurophysiology 2.0 (NWB:N) has emerged as a standardized data format for the storage of cellular-level data together with meta-data, stimulus information, and behavior. A key next step to facilitate NWB:N adoption is to provide easy to use processing pipelines to import/export data from/to NWB:N. Here, we present a NWB-formatted dataset of 1863 single neurons recorded from the medial temporal lobes of 59 human subjects undergoing intracranial monitoring while they performed a recognition memory task. We provide code to analyze and export/import …

A Native Function For Ran Translation And Cgg Repeats In Regulating Fragile X Protein Synthesis, Caitlin M. Rodriguez, Shannon E. Wright, Michael G. Kearse, Jill M. Haenfler, Brittany N. Flores, Yu Liu, Marius F. Ifrim, M. Rebecca Glineburg, Amy Krans, Paymaan Jafar-Nejad, Michael A. Sutton, Gary J. Bassell, Jack M. Parent, Frank Rigo, Sami J. Barmada, Peter K. Todd

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Repeat-associated non-AUG-initiated translation of expanded CGG repeats (CGG RAN) from the FMR1 5′-leader produces toxic proteins that contribute to neurodegeneration in fragile X-associated tremor/ataxia syndrome. Here we describe how unexpanded CGG repeats and their translation play conserved roles in regulating fragile X protein (FMRP) synthesis. In neurons, CGG RAN acts as an inhibitory upstream open reading frame to suppress basal FMRP production. Activation of mGluR5 receptors enhances FMRP synthesis. This enhancement requires both the CGG repeat and CGG RAN initiation sites. Using non-cleaving antisense oligonucleotides (ASOs), we selectively blocked CGG RAN. This ASO blockade enhanced endogenous FMRP expression in human …

Immune-Endocrine Links To Gregariousness In Wild House Mice, Patricia C. Lopes, Esther H. D. Carlitz, Morgan Kindel, Barbara König

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Social interactions are critically important for survival and impact overall-health, but also impose costs on animals, such as exposure to contagious agents. The immune system can play a critical role in modulating social behavior when animals are sick, as has been demonstrated within the context of “sickness behaviors.” Can immune molecules affect or be affected by social interactions even when animals are not sick, therefore serving a role in mediating pathogen exposure? We tested whether markers of immune function in both the blood and the brain are associated with gregariousness, quantified as number of animals interacted with per day. To …

Brain Damage Associated With Impaired Sentence Processing In Acute Aphasia, Sigfus Kristinsson, Helga Thors, Grigori Yourganov, Sigridur Magnusdottir, Haukur Hjaltason, Brielle C. Stark, Alexandra Basilakos, Dirk B. Den Ouden, Leo Bonilha, Chris Rorden, Gregory Hickok, Argye E. Hillis, Julius Fridriksson

Communication Sciences and Disorders Faculty Articles and Research

Left-hemisphere brain damage commonly affects patients' abilities to produce and comprehend syntactic structures, a condition typically referred to as “agrammatism.” The neural correlates of agrammatism remain disputed in the literature, and distributed areas have been implicated as important predictors of performance, for example, Broca's area, anterior temporal areas, and temporo-parietal areas. We examined the association between damage to specific language-related ROIs and impaired syntactic processing in acute aphasia. We hypothesized that damage to the posterior middle temporal gyrus, and not Broca's area, would predict syntactic processing abilities. One hundred four individuals with acute aphasia (< 20 days poststroke) were included in the study. Structural MRI scans were obtained, and all participants completed a 45-item sentence–picture matching task. We performed an ROI-based stepwise regression analyses to examine the relation between cortical brain damage and impaired comprehension of canonical and noncanonical sentences. Damage to the posterior middle temporal gyrus was the strongest predictor for overall task performance and performance on noncanonical sentences. Damage to the angular gyrus was the strongest predictor for performance on canonical sentences, and damage to the posterior superior temporal gyrus predicted noncanonical scores when performance on canonical sentences was included as a cofactor. Overall, our models showed that damage to temporo-parietal and posterior temporal areas was associated with impaired syntactic comprehension. Our results indicate that the temporo-parietal area is crucially implicated in complex syntactic processing, whereas the role of Broca's area may be complementary.

Short Amylin Receptor Antagonist Peptides Improve Memory Deficits In Alzheimer’S Disease Mouse Model, Rania Soudy, Ryoichi Kimura, Aarti Patel, Wen Fu, Kamaljit Kaur, David Westaway, Jing Yang, Jack Jhamandas

Pharmacy Faculty Articles and Research

Recent evidence supports involvement of amylin and the amylin receptor in the pathogenesis of Alzheimer’s disease (AD). We have previously shown that amylin receptor antagonist, AC253, improves spatial memory in AD mouse models. Herein, we generated and screened a peptide library and identified two short sequence amylin peptides (12–14 aa) that are proteolytically stable, brain penetrant when administered intraperitoneally, neuroprotective against Aβ toxicity and restore diminished levels of hippocampal long term potentiation in AD mice. Systemic administration of the peptides for five weeks in aged 5XFAD mice improved spatial memory, reduced amyloid plaque burden, and neuroinflammation. The common residue SQELHRLQTY …

An Integration-To-Bound Model Of Decision-Making That Accounts For The Spectral Properties Of Neural Data, Ramón Guevara Erra, Marco Arbotto, Aaron Schurger

Psychology Faculty Articles and Research

Integration-to-bound models are among the most widely used models of perceptual decision-making due to their simplicity and power in accounting for behavioral and neurophysiological data. They involve temporal integration over an input signal (“evidence”) plus Gaussian white noise. However, brain data shows that noise in the brain is long-term correlated, with a spectral density of the form 1/fα (with typically 1 < α < 2), also known as pink noise or ‘1/f’ noise. Surprisingly, the adequacy of the spectral properties of drift-diffusion models to electrophysiological data has received little attention in the literature. Here we propose a model of accumulation of evidence for decision-making that takes into consideration the spectral properties of brain signals. We develop a generalization of the leaky stochastic accumulator model using a Langevin equation whose non-linear noise term allows for varying levels of autocorrelation in the time course of the decision variable. We derive this equation directly from magnetoencephalographic data recorded while subjects performed a spontaneous movement initiation task. We then propose a nonlinear model of accumulation of evidence that accounts for the ‘1/f’ spectral properties of brain signals, and the observed variability in the power spectral properties of brain signals. Furthermore, our model outperforms the standard drift-diffusion model at approximating the empirical waiting time distribution.

Measuring Neural Time Series Data In A Sensory Deprivation Tank, Jackson Gregory, Tian Lan, Uri Maoz, Amir Raz

Student Scholar Symposium Abstracts and Posters

We are interested in studying the neurological and physiological effects of the float pod, also known as REST therapy, or sensory deprivation tank. Float pods rely on the concept of depriving most senses (from sound and light to temperature and proprioception) in a pool filled with buoyant salt water at body temperature. While float pods are most commonly used in spa environments, we intend to look at the potential benefits of floating under the empirical lens. In this study, we aim to measure neural activity using electroencephalography (EEG). We intend to look at the different levels of relaxation and the …

Does It Matter Whether You Or Your Brain Did It? An Empirical Investigation Of The Influence Of The Double Subject Fallacy On Moral Responsibility Judgments, Uri Maoz, Kellienne R. Sita, Jeroen J. A. Van Boxtel, Liad Mudrik

Psychology Faculty Articles and Research

Despite progress in cognitive neuroscience, we are still far from understanding the relations between the brain and the conscious self. We previously suggested that some neuroscientific texts that attempt to clarify these relations may in fact make them more difficult to understand. Such texts—ranging from popular science to high-impact scientific publications—position the brain and the conscious self as two independent, interacting subjects, capable of possessing opposite psychological states. We termed such writing ‘Double Subject Fallacy’ (DSF). We further suggested that such DSF language, besides being conceptually confusing and reflecting dualistic intuitions, might affect people’s conceptions of moral responsibility, lessening the …

Behavioral And Neural Correlates Of Normal Aging Effects On Motor Preparatory Mechanisms Of Speech Production And Limb Movement, Karim Johari, Dirk B. Den Ouden, Roozbeh Behroozmand

Communication Sciences and Disorders Faculty Articles and Research

Normal aging is associated with decline of the sensorimotor mechanisms that support movement function in the human brain. In this study, we used behavioral and event-related potential (ERP) recordings to investigate the effects of normal aging on the motor preparatory mechanisms of speech production and limb movement. The experiment involved two groups of older and younger adults who performed randomized speech vowel vocalization and button press motor reaction time tasks in response to temporally predictable and unpredictable visual stimuli. Behavioral results revealed age-related slowness of motor reaction time only during speech production in response to temporally unpredictable stimuli, and this …

Systematic Literature Review Of Quetiapine For The Treatment Of Psychosis In Patients With Parkinsonism, Jack J. Chen, Henry Hua, Lilian Massihi, Ivan Portillo, Azita Alipour, William Ondo, Khashayar Dashtipour

Library Articles and Research

Objective:

The purpose of this article was to determine the efficacy and tolerability of quetiapine compared with placebo or other interventions for psychosis in parkinsonism.

Methods:

Participants with a diagnosis of parkinsonism participated in randomized controlled trials (RCTs) investigating the efficacy and tolerability of quetiapine for psychotic symptoms within a defined follow-up period. The authors conducted searches on PubMed, Cochrane Controlled Register of Trials, and EMBASE for articles published from January 1991 to October 2017. Study methodology and patient- and treatment-level data were independently extracted and summarized by using descriptive statistics. Studies underwent quality assessment for risk of bias.

Results: …

Leveling The Playing Field: Supporting Neurodiversity Via Virtual Realities, Louanne E. Boyd, Kendra Day, Natalia Stewart, Kaitlyn Abdo, Kathleen Lamkin, Erik J. Linstead

Mathematics, Physics, and Computer Science Faculty Articles and Research

Neurodiversity is a term that encapsulates the diverse expression of human neurology. By thinking in broad terms about neurological development, we can become focused on delivering a diverse set of design features to meet the needs of the human condition. In this work, we move toward developing virtual environments that support variations in sensory processing. If we understand that people have differences in sensory perception that result in their own unique sensory traits, many of which are clustered by diagnostic labels such as Autism Spectrum Disorder (ASD), Sensory Processing Disorder, Attention-Deficit/Hyperactivity Disorder, Rett syndrome, dyslexia, and so on, then we …

The Effect Of Energy-Matched Exercise Intensity On Brain-Derived Neurotrophic Factor And Motor Learning, Jessica F. Baird, Mary E. Gaughan, Heath M. Saffer, Mark A. Sarzynski, Troy M. Herter, Stacy L. Fritz, Dirk B. Den Ouden, Jill Campbell Stewart

Communication Sciences and Disorders Faculty Articles and Research

Background

Methods

Neural Constraints Affect The Ability To Generate Hip Abduction Torques When Combined With Hip Extension Or Ankle Plantarflexion In Chronic Hemiparetic Stroke, Natalia Sánchez, Ana M. Acosta, Roberto López-Rosado, Julius P. A. Dewald

Physical Therapy Faculty Articles and Research

Stroke lesions interrupt descending corticofugal fibers that provide the volitional control of the upper and lower extremities. Despite the evident manifestation of movement impairments post-stroke during standing and gait, neural constraints in the ability to generate joint torque combinations in the lower extremities are not yet well determined. Twelve chronic hemiparetic participants and 8 age-matched control individuals participated in the present study. In an isometric setup, participants were instructed to combine submaximal hip extension or ankle plantarflexion torques with maximal hip abduction torques. Statistical analyses were run using linear mixed effects models. Results for the protocol combining hip extension and …

Mooney Face Stimuli For Visual Perception Research, Caspar M. Schwiedrzik, Lucia Melloni, Aaron Schurger

Psychology Faculty Articles and Research

In 1957, Craig Mooney published a set of human face stimuli to study perceptual closure: the formation of a coherent percept on the basis of minimal visual information. Images of this type, now known as "Mooney faces", are widely used in cognitive psychology and neuroscience because they offer a means of inducing variable perception with constant visuospatial characteristics (they are often not perceived as faces if viewed upside down). Mooney's original set of 40 stimuli has been employed in several studies. However, it is often necessary to use a much larger stimulus set. We created a new set of over …

Treating Adhd With Suggestion: Neurofeedback And Placebo Therapeutics, Robert T. Thibault, Samuel Vassière, Jay A. Olson, Amir Raz

Psychology Faculty Articles and Research

Objective: We propose that clinicians can use suggestion to help treat conditions such as ADHD. Methods: We use EEG neurofeedback as a case study, alongside evidence from a recent pilot experiment utilizing a sham MRI scanner to highlight the therapeutic potential of suggestion-based treatments. Results: The medical literature demonstrates that many practitioners already prescribe treatments that hardly outperform placebo comparators. Moreover, the sham MRI experiment showed that, even with full disclosure of the procedure, suggestion alone can reduce the symptomatology of ADHD. Conclusion: Non-deceptive suggestion-based treatments, especially those drawing on accessories from neuroscience, may offer a safe complement and potential …

Network Specialization During Adolescence: Hippocampal Effective Connectivity In Boys And Girls, Jeffrey D. Riley, E. Elinor Chen, Jessica Winsell, Elyssia Poggi Davis, Laura M. Glynn, Tallie Z. Baram, Curt A. Sandman, Steven L. Small, Ana Solodkin

Psychology Faculty Articles and Research

Adolescence is a complex period of concurrent mental and physical development that facilitates adult functioning at multiple levels. Despite the growing number of neuroimaging studies of cognitive development in adolescence focusing on regional activation patterns, there remains a paucity of information about the functional interactions across these participating regions that are critical for cognitive functioning, including memory. The current study used structural equation modeling (SEM) to determine how interactions among brain regions critical for memory change over the course of adolescence. We obtained functional MRI in 77 individuals aged 8–16 years old, divided into younger (ages 8–10) and older (ages …

Variant Intestinal-Cell Kinase In Juvenile Myoclonic Epilepsy, J. N. Bailey, L. De Nijs, D. Bai, T. Suzuki, H. Miyamoto, M. Tanaka, C. Patterson, Y.-C. Lin, M. T. Medina, M. E. Alonso, J. M. Serratosa, R. M. Durón, Viet-Hong Nguyen, J. E. Wight, I. E. Martínez‑Juárez, A. Ochoa, A. Jara-Prado, L. Guilhoto, Y. Molina, E. M. Yacubian, M. López‑Ruiz, Y. Inoue, S. Kaneko, S. Hirose, M. Osawa, H. Oguni, S. Fujimoto, T. M. Grisar, J. M. Stern, K. Yamakawa, B. Lakaye, A. V. Delgado-Escueta

Pharmacy Faculty Articles and Research

BACKGROUND

In juvenile myoclonic epilepsy, data are limited on the genetic basis of networks promoting convulsions with diffuse polyspikes on electroencephalography (EEG) and the subtle microscopic brain dysplasia called microdysgenesis.

METHODS

Using Sanger sequencing, we sequenced the exomes of six members of a large family affected with juvenile myoclonic epilepsy and confirmed cosegregation in all 37 family members. We screened an additional 310 patients with this disorder for variants on DNA melting-curve analysis and targeted real-time DNA sequencing of the gene encoding intestinal-cell kinase (ICK). We calculated Bayesian logarithm of the odds (LOD) scores for cosegregating variants, odds …

Cortical Thinning And Neuropsychiatric Outcomes In Children Exposed To Prenatal Adversity: A Role For Placental Crh?, Curt A. Sandman, Megan M. Curran, Elyssia Poggi Davis, Laura M. Glynn, Kevin Head, Tallie Z. Baram

Psychology Faculty Articles and Research

Exposure to early life adversity may disrupt the development and maturation of neurons and brain circuits, which, in turn, underlie neurodevelopment and mental illnesses. During fetal life, maternal adversity is conveyed to the developing brain via several molecular signals, including the stress hormone corticotropin releasing hormone (CRH). Employing a large well characterized prospective cohort, we find that fetal exposure to placental-origin CRH levels predicts structural and functional brain outcomes in children. Specifically, elevated placental CRH levels portend thinning of selective cortical regions of exposed individuals, with commensurate cognitive and emotional deficits. Notably, the relations of placental-origin CRH to cortical thinning …

Repeat-Associated Non-Aug (Ran) Translation And Other Molecular Mechanisms In Fragile X Tremor Ataxia Syndrome, M. Rebecca Glineburg, Peter K. Todd, Nicolas Charlet-Berguerand, Chantal Sellier

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset inherited neurodegenerative disorder characterized by progressive intention tremor, gait ataxia and dementia associated with mild brain atrophy. The cause of FXTAS is a premutation expansion, of 55 to 200 CGG repeats localized within the 5′UTR of FMR1. These repeats are transcribed in the sense and antisense directions into mutants RNAs, which have increased expression in FXTAS. Furthermore, CGG sense and CCG antisense expanded repeats are translated into novel proteins despite their localization in putatively non-coding regions of the transcript. Here we focus on two proposed disease mechanisms for FXTAS: 1) RNA …

Specific Relationship Between The Shape Of The Readiness Potential, Subjective Decision Time, And Waiting Time Predicted By An Accumulator Model With Temporally Autocorrelated Input Noise, Aaron Schurger

Psychology Faculty Articles and Research

Self-initiated movements are reliably preceded by a gradual buildup of neuronal activity known as the readiness potential (RP). Recent evidence suggests that the RP may reflect subthreshold stochastic fluctuations in neural activity that can be modeled as a process of accumulation to bound. One element of accumulator models that has been largely overlooked in the literature is the stochastic term, which is traditionally modeled as Gaussian white noise. While there may be practical reasons for this choice, we have long known that noise in neural systems is not white – it is long-term correlated with spectral density of the form …

Geometroneurodynamics And Neuroscience, Keun-Hang Susan Yang, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The Orthodox Interpretation of quantum mechanics, as developed by many physicists, particularly John von Neumann, addresses the role of measurement, available choices and response of the quantum system to questions posed by an observer in specific quantum laboratory experiments. As such, it is, more consistent and clearer than other interpretations of quantum mechanics and it provides an account of the interactions of observers with the external world. However, in order to explore whether quantum mechanics plays a role in the brain, which is the primary issue, one has to examine the applicability of Hilbert space structure as a valid geometric …

Virtual Reality As A Training Tool To Treat Physical Inactivity In Children, Adam W. Kiefer, David Pincus, Michael J. Richardson, Gregory D. Myer

Psychology Faculty Articles and Research

Lack of adequate physical activity in children is an epidemic that can result in obesity and other poor health outcomes across the lifespan. Physical activity interventions focused on motor skill competence continue to be developed, but some interventions, such as neuromuscular training (NMT), may be limited in how early they can be implemented due to dependence on the child’s level of cognitive and perceptual-motor development. Early implementation of motor-rich activities that support motor skill development in children is critical for the development of healthy levels of physical activity that carry through into adulthood. Virtual reality (VR) training may be beneficial …

Ran Translation At C9orf72-Associated Repeat Expansions Is Selectively Enhanced By The Integrated Stress Response, Katelyn M. Green, M. Rebecca Glineburg, Michael G. Kearse, Brittany N. Flores, Alexander E. Linsalata, Stephen J. Fedak, Aaron C. Goldstrohm, Sami J. Barmada, Peter K. Todd

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Repeat-associated non-AUG (RAN) translation allows for unconventional initiation at disease-causing repeat expansions. As RAN translation contributes to pathogenesis in multiple neurodegenerative disorders, determining its mechanistic underpinnings may inform therapeutic development. Here we analyze RAN translation at G₄C₂ repeat expansions that cause C9orf72-associated amyotrophic lateral sclerosis and frontotemporal dementia (C9RAN) and at CGG repeats that cause fragile X-associated tremor/ataxia syndrome. We find that C9RAN translation initiates through a cap- and eIF4A-dependent mechanism that utilizes a CUG start codon. C9RAN and CGG RAN are both selectively enhanced by integrated stress response (ISR) activation. ISR-enhanced RAN translation requires an …

Structural Insights Into The Potency Of Sk Channel Positive Modulators, Young-Woo Nam, Razan Orfali, Tingting Liu, Kunqian Yu, Meng Cui, Heike Wulff, Miao Zhang

Pharmacy Faculty Articles and Research

Small-conductance Ca2+-activated K+ (SK) channels play essential roles in the regulation of cellular excitability and have been implicated in neurological and cardiovascular diseases through both animal model studies and human genetic association studies. Over the past two decades, positive modulators of SK channels such as NS309 and 1-EBIO have been developed. Our previous structural studies have identified the binding pocket of 1-EBIO and NS309 that is located at the interface between the channel and calmodulin. In this study, we took advantage of four compounds with potencies varying over three orders of magnitude, including 1-EBIO, NS309, SKS-11 (6-bromo-5-methyl-1H-indole-2,3-dione-3-oxime) and …

Validation Of Minimally-Invasive Sample Collection Methods For Measurement Of Telomere Length, Stephanie A. Stout, Jue Lin, Natalie Hernandez, Elyssia Poggi Davis, Judith E. Carroll, Laura M. Glynn

Psychology Faculty Articles and Research

Objective: The discovery of telomere length (TL) as a biomarker of cellular aging and correlate of age-related disease has generated a new field of research in the biology of healthy aging. Although the most common method of sample collection for TL is venous blood draw, less-invasive DNA collection methods are becoming more widely used. However, how TL relates across tissues derived from these sample collection methods is poorly understood. The current study is the first to characterize the associations in TL across three sample collection methods: venous whole blood, finger prick dried blood spot and saliva.

Methods: TL …

The Climate Of Neurofeedback: Scientific Rigour And The Perils Of Ideology, Robert T. Thibault, Michael Lifshitz, Amir Raz

Psychology Faculty Articles and Research

Over the last six decades, an in-group with ideological and financial stakes has been conducting sub-par research to develop an ostensibly effective clinical intervention: EEG-neurofeedback. More recently, however, a string of independent studies featuring increased scientific rigour and tighter experimental controls has challenged the foundation on which EEG-neurofeedback stands. Earlier this year, Brain published one of the most robust EEG-neurofeedback experiments to date (Schabus et al., 2017), which sparked a flurry of correspondence concerning the therapeutic value of neurofeedback (Fovet et al., 2017; Schabus, 2017); notably, a parallel discussion continues in Lancet Psychiatry …

Non-Fluent Speech Following Stroke Is Caused By Impaired Efference Copy, Lynda Feenaughty, Alexandra Basilakos, Leonardo Bonilha, Dirk B. Den Ouden, Chris Rorden, Brielle C. Stark, Julius Fridriksson

Communication Sciences and Disorders Faculty Articles and Research

Efference copy is a cognitive mechanism argued to be critical for initiating and monitoring speech: however, the extent to which breakdown of efference copy mechanisms impact speech production is unclear. This study examined the best mechanistic predictors of non-fluent speech among 88 stroke survivors. Objective speech fluency measures were subjected to a principal component analysis (PCA). The primary PCA factor was then entered into a multiple stepwise linear regression analysis as the dependent variable, with a set of independent mechanistic variables. Participants’ ability to mimic audio-visual speech (“speech entrainment response”) was the best independent predictor of non-fluent speech. We suggest …

Cortical Contribution To Linear, Non-Linear And Frequency Components Of Motor Variability Control During Standing, Niklas König Ignasiak

Physical Therapy Faculty Articles and Research

Motor variability is an inherent feature of all human movements and reflects the quality of functional task performance. Depending on the requirements of the motor task, the human sensory-motor system is thought to be able to flexibly govern the appropriate level of variability. However, it remains unclear which neurophysiological structures are responsible for the control of motor variability. In this study, we tested the contribution of cortical cognitive resources on the control of motor variability (in this case postural sway) using a dual-task paradigm and furthermore observed potential changes in control strategy by evaluating Ia-afferent integration (H-reflex). Twenty healthy subjects …