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Matthew T Kaufman, Jeffrey S Seely, David Sussillo, Stephen I Ryu, Krishna V Shenoy, Mark M Churchland
Neural activity in monkey motor cortex (M1) and dorsal premotor cortex (PMd) can reflect a chosen movement well before that movement begins. The pattern of neural activity then changes profoundly just before movement onset. We considered the prediction, derived from formal considerations, that the transition from preparation to movement might be accompanied by a large overall change in the neural state that reflects when movement is made rather than which movement is made. Specifically, we examined "components" of the population response: time-varying patterns of activity from which each neuron's response is approximately composed...
July 2016: ENeuro
Kenny Skagerlund, Thomas Karlsson, Ulf Träff
Continuous dimensions, such as time, space, and numerosity, have been suggested to be subserved by common neurocognitive mechanisms. Neuroimaging studies that have investigated either one or two dimensions simultaneously have consistently identified neural correlates in the parietal cortex of the brain. However, studies investigating the degree of neural overlap across several dimensions are inconclusive, and it remains an open question whether a potential overlap can be conceptualized as a neurocognitive magnitude processing system...
2016: Frontiers in Human Neuroscience
Chien-Cheng Chen, Christopher J Bockisch, Dominik Straumann, Melody Ying-Yu Huang
Spontaneous eye movements of zebrafish larvae in the dark consist of centrifugal saccades that move the eyes from a central to an eccentric position and postsaccadic centripetal drifts. In a previous study, we showed that the fitted single-exponential time constants of the postsaccadic drifts are longer in the temporal-to-nasal (T->N) direction than in the nasal-to-temporal (N->T) direction. In the present study, we further report that saccadic peak velocities are higher and saccadic amplitudes are larger in the N->T direction than in the T->N direction...
2016: Frontiers in Systems Neuroscience
Ayako Yamaguchi, Jessica Cavin Barnes, Todd Appleby
Central pattern generators (CPG) in the brainstem are considered to underlie vocalizations in many vertebrate species, but the detailed mechanisms underlying how motor rhythms are generated, coordinated, and initiated remain unclear. We addressed these issues using isolated brain preparations of Xenopus laevis from which fictive vocalizations can be elicited. Advertisement calls of male X. laevis that consist of fast and slow trills are generated by vocal CPGs contained in the brainstem. Brainstem central vocal pathways consist of a premotor nucleus (DTAM) and a laryngeal motor nucleus (n...
October 19, 2016: Journal of Neurophysiology
E Mark Mahone, Deana Crocetti, Laura Tochen, Tina Kline, Stewart H Mostofsky, Harvey S Singer
BACKGROUND: Complex motor stereotypies in children are repetitive rhythmic movements that have a predictable pattern and location, seem purposeful, but serve no obvious function, tend to be prolonged, and stop with distraction, e.g., arm or hand flapping, waving. They occur in both "primary" (otherwise typically developing) and secondary conditions. These movements are best defined as habitual behaviors and therefore pathophysiologically hypothesized to reside in premotor to posterior putamen circuits...
September 8, 2016: Pediatric Neurology
Asanori Kiyuna, Norimoto Kise, Munehisa Hiratsuka, Shunsuke Kondo, Takayuki Uehara, Hiroyuki Maeda, Akira Ganaha, Mikio Suzuki
OBJECTIVES: Spasmodic dysphonia (SD) is considered a focal dystonia. However, the detailed pathophysiology of SD remains unclear, despite the detection of abnormal activity in several brain regions. The aim of this study was to clarify the pathophysiological background of SD. STUDY DESIGN: This is a case-control study. METHODS: Both task-related brain activity measured by functional magnetic resonance imaging by reading the five-digit numbers and resting-state functional connectivity (FC) measured by 150 T2-weighted echo planar images acquired without any task were investigated in 12 patients with adductor SD and in 16 healthy controls...
October 13, 2016: Journal of Voice: Official Journal of the Voice Foundation
Caroline C Meadows, Philip A Gable, Keith R Lohse, Matthew W Miller
The present study explored the relationship between motor-preparatory electroencephalographic (EEG) activity, motivation, and motor performance (specifically premotor reaction time [RT]). Participants performed a RT task by squeezing a hand dynamometer in response to an auditory "go" signal. We recorded EEG and electromyography to index beta-suppression and premotor RT, respectively. Participants' motivation on each trial was modulated by offering monetary incentives at different magnitudes. Mixed-effect linear regression models showed that monetary incentive predicted premotor RT when controlling for beta-suppression, and beta-suppression independently predicted premotor RT...
October 12, 2016: Neuroscience
M Beudel, K L Leenders, B M de Jong
The delay associated with cerebral processing time implies a lack of real-time representation of changes in the observed environment. To bridge this gap for motor actions in a dynamical environment, the brain uses predictions of the most plausible future reality based on previously provided information. To optimise these predictions, adjustments to actual experiences are necessary. This requires a perceptual memory buffer. In our study we gained more insight how the brain treats (real-time) information by comparing cerebral activations related to judging past-, present- and future locations of a moving ball, respectively...
October 11, 2016: Brain Research
Julio Plata-Bello, Cristián Modroño, Silvia Acosta-López, Yaiza Pérez-Martín, Francisco Marcano, Víctor García-Marín, José Luis González-Mora
Nearly 20 % of patients who suffer a subarachnoid hemorrhage (SAH) still display cognitive impairment even a year after follow-up. Visuospatial and visuoperceptive domains may be impaired in this cognitive impairment and may not have been fully studied in these patients. Furthermore, these cognitively impaired domains have been associated with activity in the so-called mirror neuron system (MNS). The aim of the study is to analyze the pattern of brain activity with an MNS task-based functional magnetic resonance imaging (fMRI) study in SAH patients...
October 12, 2016: Brain Imaging and Behavior
Raz Leib, Firas Mawase, Amir Karniel, Opher Donchin, John Rothwell, Ilana Nisky, Marco Davare
: How motion and sensory inputs are combined to assess an object's stiffness is still unknown. Here, we provide evidence for the existence of a stiffness estimator in the human posterior parietal cortex (PPC). We showed previously that delaying force feedback with respect to motion when interacting with an object caused participants to underestimate its stiffness. We found that applying theta-burst transcranial magnetic stimulation (TMS) over the PPC, but not the dorsal premotor cortex, enhances this effect without affecting movement control...
October 12, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Marco Lanzilotto, Alessandro Livi, Monica Maranesi, Marzio Gerbella, Falk Barz, Patrick Ruther, Leonardo Fogassi, Giacomo Rizzolatti, Luca Bonini
Grasping relies on a network of parieto-frontal areas lying on the dorsolateral and dorsomedial parts of the hemispheres. However, the initiation and sequencing of voluntary actions also requires the contribution of mesial premotor regions, particularly the pre-supplementary motor area F6. We recorded 233 F6 neurons from 2 monkeys with chronic linear multishank neural probes during reaching-grasping visuomotor tasks. We showed that F6 neurons play a role in the control of forelimb movements and some of them (26%) exhibit visual and/or motor specificity for the target object...
October 12, 2016: Cerebral Cortex
Hosung Kim, Ji-Hoon Kim, Katherine L Possin, Joseph Winer, Michael D Geschwind, Duan Xu, Christopher P Hess
In patients with premotor Huntington's disease (pmHD), literature has reported decreases in caudate volume. However, the regional vulnerability of the caudate nucleus to pmHD remains to be clarified. We aimed to determine whether regional structural damage of the caudate nucleus was present in pmHD and was correlated with clinical profile using a surface-based morphometric technique applied to T1-weighted MRI. The study cohort consisted of 14 volunteers with genetically confirmed pmHD (6 males; 41.8 ± 13...
October 11, 2016: Brain Imaging and Behavior
Sebastian Walther, Lea Schäppi, Andrea Federspiel, Stephan Bohlhalter, Roland Wiest, Werner Strik, Katharina Stegmayer
Catatonia is a psychomotor syndrome that not only frequently occurs in the context of schizophrenia but also in other conditions. The neural correlates of catatonia remain unclear due to small-sized studies. We therefore compared resting-state cerebral blood flow (rCBF) and gray matter (GM) density between schizophrenia patients with current catatonia and without catatonia and healthy controls. We included 42 schizophrenia patients and 41 controls. Catatonia was currently present in 15 patients (scoring >2 items on the Bush Francis Catatonia Rating Scale screening)...
October 11, 2016: Schizophrenia Bulletin
William A Liberti, Jeffrey E Markowitz, L Nathan Perkins, Derek C Liberti, Daniel P Leman, Grigori Guitchounts, Tarciso Velho, Darrell N Kotton, Carlos Lois, Timothy J Gardner
Motor skills can be maintained for decades, but the biological basis of this memory persistence remains largely unknown. The zebra finch, for example, sings a highly stereotyped song that is stable for years, but it is not known whether the precise neural patterns underlying song are stable or shift from day to day. Here we demonstrate that the population of projection neurons coding for song in the premotor nucleus, HVC, change from day to day. The most dramatic shifts occur over intervals of sleep. In contrast to the transient participation of excitatory neurons, ensemble measurements dominated by inhibition persist unchanged even after damage to downstream motor nerves...
October 10, 2016: Nature Neuroscience
Jost-Julian Rumpf, Mirko Wegscheider, Karen Hinselmann, Christopher Fricke, Bradley R King, David Weise, Juliane Klann, Ferdinand Binkofski, Giovanni Buccino, Avi Karni, Julien Doyon, Joseph Classen
Consolidation, by which performance increments after a training intervention are secured and sometimes generated, is reduced in elderly humans. The present study addressed the question whether transcranial direct current stimulation (tDCS) applied after motor training improves consolidation of explicit motor sequence learning in healthy older humans. In the first experiment, anodal or cathodal tDCS to the left primary motor cortex, anodal tDCS to premotor cortex, or sham tDCS was applied immediately after completion of a finger sequence learning task...
September 13, 2016: Neurobiology of Aging
M Hallett
Functional neurologic disorders are largely genuine and represent conversion disorders, where the dysfunction is unconscious, but there are some that are factitious, where the abnormality is feigned and conscious. Malingering, which can have the same manifestations, is similarly feigned, but not considered a genuine disease. There are no good methods for differentiating these three entities at the present time. Physiologic studies of functional weakness and sensory loss reveal normal functioning of primary motor and sensory cortex, but abnormalities of premotor cortex and association cortices...
2017: Handbook of Clinical Neurology
Nobuo Kunori, Ichiro Takashima
The motor cortex of rats contains two forelimb motor areas; the caudal forelimb area (CFA) and the rostral forelimb area (RFA). Although the RFA is thought to correspond to the premotor and/or supplementary motor cortices of primates, which are higher-order motor areas that receive somatosensory inputs, it is unknown whether the RFA of rats receives somatosensory inputs in the same manner. To investigate this issue, voltage-sensitive dye (VSD) imaging was used to assess the motor cortex in rats following a brief electrical stimulation of the forelimb...
October 7, 2016: European Journal of Neuroscience
Yosuke Saga, Yoshihisa Nakayama, Ken-Ichi Inoue, Tomoko Yamagata, Masashi Hashimoto, Léon Tremblay, Masahiko Takada, Eiji Hoshi
The thalamic reticular nucleus (TRN) collects inputs from the cerebral cortex and thalamus and, in turn, sends inhibitory outputs to the thalamic relay nuclei. This unique connectivity suggests that the TRN plays a pivotal role in regulating information flow through the thalamus. Here, we analyzed the roles of TRN neurons in visually guided reaching movements. We first used retrograde transneuronal labeling with rabies virus, and showed that the rostro-dorsal sector of the TRN (TRNrd) projected disynaptically to the ventral premotor cortex (PMv)...
October 5, 2016: European Journal of Neuroscience
Serena Bianchi, Laura D Reyes, William D Hopkins, Jared P Taglialatela, Chet C Sherwood
Vocal learning is a key property of spoken language, which might also be present in nonhuman primate species, such as chimpanzees (Pan troglodytes), to a limited degree. While understanding the origins of vocal learning in the primate brain may help shed light on the evolution of speech and language, little is still known regarding the neurobiological correlates of vocal flexibility in nonhuman primates. The current study used voxel-based morphometry (VBM) to assess whether the cerebral cortex of captive chimpanzees that learned to voluntarily produce sounds to attract the attention of a human experimenter (attention-getting sounds) differs in grey matter distribution compared to chimpanzees that do not exhibit this behavior...
October 5, 2016: Scientific Reports
Vincent Koppelmans, Yoo Young Hoogendam, Sarah Hirsiger, Susan Mérillat, Lutz Jäncke, Rachael D Seidler
Cerebellar volume declines with aging. Few studies have investigated age differences in regional cerebellar volume (RCV) and their association with motor and cognitive function. In 213 healthy older adults, we investigated the association of age with motor skills, cognition and RCV. Subsequently, we studied the association of RCV with motor skills and cognition. RCVs were derived from T1-weighted MRI scans using the automated SUIT segmentation method and clustered using principal component analysis (PCA). Motor skill (manual dexterity, tapping speed, bimanual visuomotor coordination, grip force) and cognition (mental rotation, verbal memory, inhibition, mental flexibility) were assessed...
October 3, 2016: Brain Structure & Function
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