Motor Adaptation Impairment in Chronic Cannabis Users Assessed by a Visuomotor Rotation Task

Background—The cerebellum has been recently suggested as an important player in the addiction brain circuit. Cannabis is one of the most used drugs worldwide, and its long-term effects on the central nervous system are not fully understood. No valid clinical evaluations of cannabis impact on the brain are available today. The cerebellum is expected to be one of the brain structures that are highly affected by prolonged exposure to cannabis, due to its high density in endocannabinoid receptors. We aim to use a motor adaptation paradigm to indirectly assess cerebellar function in chronic cannabis users (CCUs). Methods—We used a visuomotor rotation (VMR) task that probes a putatively-cerebellar implicit motor adaptation process together with the learning and execution of an explicit aiming rule. We conducted a case-control study, recruiting 18 CCUs and 18 age-matched healthy controls. Our main measure was the angular aiming error. Results—Our results show that CCUs have impaired implicit motor adaptation, as they showed a smaller rate of adaptation compared with healthy controls (drift rate: 19.3 +/− 6.8° vs. 27.4 +/− 11.6°; t(26) = −2.1, p = 0.048, Cohen’s d = −0.8, 95% CI = (−1.7, −0.15)). Conclusions—We suggest that a visuomotor rotation task might be the first step towards developing a useful tool for the detection of alterations in implicit learning among cannabis users.

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The Use of Botulinum Toxin for the Treatment of Chronic Joint Pain: Clinical and Experimental Evidence

Toxins ◽

10.3390/toxins12050314 ◽

2020 ◽

Vol 12 (5) ◽

pp. 314 ◽

Cited By ~ 2

Author(s):

Nicole Blanshan ◽

Hollis Krug

Keyword(s):

Pain Relief ◽

Joint Pain ◽

Peripheral Sensitization ◽

Long Term Effects ◽

Neuropeptide Release ◽

Osteoarthritis Pain ◽

Catalytically Active ◽

The Central Nervous System ◽

The Brain

Chronic osteoarthritis pain is an increasing worldwide problem. Treatment for osteoarthritis pain is generally inadequate or fraught with potential toxicities. Botulinum toxins (BoNTs) are potent inhibitors of neuropeptide release. Paralytic toxicity is due to inhibition at the neuromuscular junction, and this effect has been utilized for treatments of painful dystonias. Pain relief following BoNT muscle injection has been noted to be more significant than muscle weakness and hypothesized to occur because of the inhibition of peripheral neuropeptide release and reduction of peripheral sensitization. Because of this observation, BoNT has been studied as an intra-articular (IA) analgesic for chronic joint pain. In clinical trials, BoNT appears to be effective for nociceptive joint pain. No toxicity has been reported. In preclinical models of joint pain, BoNT is similarly effective. Examination of the dorsal root ganglion (DRG) and the central nervous system has shown that catalytically active BoNT is retrogradely transported by neurons and then transcytosed to afferent synapses in the brain. This suggests that pain relief may also be due to the central effects of the drug. In summary, BoNT appears to be safe and effective for the treatment of chronic joint pain. The long-term effects of IA BoNT are still being determined.

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Evidence in cortical folding patterns for prenatal predispositions to hallucinations in schizophrenia

Translational Psychiatry ◽

10.1038/s41398-020-01075-y ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Colleen P. E. Rollins ◽

Jane R. Garrison ◽

Maite Arribas ◽

Aida Seyedsalehi ◽

Zhi Li ◽

...

Keyword(s):

Brain Development ◽

Large Scale ◽

Fetal Brain ◽

Brain Structures ◽

Physical Reality ◽

Healthy Controls ◽

Cortical Folding ◽

Diverse World ◽

Fetal Brain Development ◽

The Brain

Abstract All perception is a construction of the brain from sensory input. Our first perceptions begin during gestation, making fetal brain development fundamental to how we experience a diverse world. Hallucinations are percepts without origin in physical reality that occur in health and disease. Despite longstanding research on the brain structures supporting hallucinations and on perinatal contributions to the pathophysiology of schizophrenia, what links these two distinct lines of research remains unclear. Sulcal patterns derived from structural magnetic resonance (MR) images can provide a proxy in adulthood for early brain development. We studied two independent datasets of patients with schizophrenia who underwent clinical assessment and 3T MR imaging from the United Kingdom and Shanghai, China (n = 181 combined) and 63 healthy controls from Shanghai. Participants were stratified into those with (n = 79 UK; n = 22 Shanghai) and without (n = 43 UK; n = 37 Shanghai) hallucinations from the PANSS P3 scores for hallucinatory behaviour. We quantified the length, depth, and asymmetry indices of the paracingulate and superior temporal sulci (PCS, STS), which have previously been associated with hallucinations in schizophrenia, and constructed cortical folding covariance matrices organized by large-scale functional networks. In both ethnic groups, we demonstrated a significantly shorter left PCS in patients with hallucinations compared to those without, and to healthy controls. Reduced PCS length and STS depth corresponded to focal deviations in their geometry and to significantly increased covariance within and between areas of the salience and auditory networks. The discovery of neurodevelopmental alterations contributing to hallucinations establishes testable models for these enigmatic, sometimes highly distressing, perceptions and provides mechanistic insight into the pathological consequences of prenatal origins.

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Relative sensitivity of explicit reaiming and implicit motor adaptation

Journal of Neurophysiology ◽

10.1152/jn.00283.2018 ◽

2018 ◽

Vol 120 (5) ◽

pp. 2640-2648 ◽

Cited By ~ 4

Author(s):

Sarah A. Hutter ◽

Jordan A. Taylor

Keyword(s):

Motor Adaptation ◽

Relative Sensitivity ◽

Sensitivity Function ◽

Prior Work ◽

Visuomotor Rotation ◽

Small Perturbations ◽

Task Relevance ◽

Error Magnitude ◽

Implicit Motor ◽

Visual Error

It has become increasingly clear that learning in visuomotor rotation tasks, which induce an angular mismatch between movements of the hand and visual feedback, largely results from the combined effort of two distinct processes: implicit motor adaptation and explicit reaiming. However, it remains unclear how these two processes work together to produce trial-by-trial learning. Previous work has found that implicit motor adaptation operates automatically, regardless of task relevance, and saturates for large errors. In contrast, little is known about the automaticity of explicit reaiming and its sensitivity to error magnitude. Here we sought to characterize the automaticity and sensitivity function of these two processes to determine how they work together to facilitate performance in a visuomotor rotation task. We found that implicit adaptation scales relative to the visual error but only for small perturbations—replicating prior work. In contrast, explicit reaiming scales linearly for all tested perturbation sizes. Furthermore, the consistency of the perturbation appears to diminish both implicit adaptation and explicit reaiming, but to different degrees. Whereas implicit adaptation always displayed a response to the error, explicit reaiming was only engaged when errors displayed a minimal degree of consistency. This comports with the idea that implicit adaptation is obligatory and less flexible, whereas explicit reaiming is volitional and flexible. NEW & NOTEWORTHY This paper provides the first psychometric sensitivity function for explicit reaiming. Additionally, we show that the sensitivities of both implicit adaptation and explicit reaiming are influenced by consistency of errors. The pattern of results across two experiments further supports the idea that implicit adaptation is largely inflexible, whereas explicit reaiming is flexible and can be suppressed when unnecessary.

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Relative sensitivity of explicit re-aiming and implicit motor adaptation

10.1101/308510 ◽

2018 ◽

Cited By ~ 2

Author(s):

Sarah A. Hutter ◽

Jordan A. Taylor

Keyword(s):

Motor Adaptation ◽

Relative Sensitivity ◽

Sensitivity Function ◽

Prior Work ◽

Visuomotor Rotation ◽

Small Perturbations ◽

Error Magnitude ◽

Implicit Motor ◽

Task Relevancy ◽

Visual Error

AbstractIt has become increasingly clear that learning in visuomotor rotation tasks, which induce an angular mismatch between movements of the hand and visual feedback, largely results from the combined effort of two distinct processes: implicit motor adaptation and explicit re-aiming. However, it remains unclear how these two processes work together to produce trial-by-trial learning. Previous work has found that implicit motor adaptation operates automatically, regardless of task relevancy, and saturates for large errors. In contrast, little is known about the automaticity of explicit re-aiming and its sensitivity to error magnitude. Here we sought to characterize the automaticity and sensitivity function of these two processes to determine how they work together to facilitate performance in a visuomotor rotation task. We found that implicit adaptation scales relative to the visual error, but only for small perturbations – replicating prior work. In contrast, explicit re-aiming scales linearly for all tested perturbation sizes. Furthermore, the consistency of the perturbation appears to diminish both implicit adaptation and explicit re-aiming, but to different degrees. Whereas implicit adaptation always displayed a response to the error, explicit re-aiming was only engaged when errors displayed a minimal degree of consistency. This comports with the idea that implicit adaptation is obligatory and less flexible, while explicit re-aiming is volitional and flexible.

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Increased serum levels of the brain damage marker S100B after apnea in trained breath-hold divers: a study including respiratory and cardiovascular observations

Journal of Applied Physiology ◽

10.1152/japplphysiol.91434.2008 ◽

2009 ◽

Vol 107 (3) ◽

pp. 809-815 ◽

Cited By ~ 22

Author(s):

Johan P. A. Andersson ◽

Mats H. Linér ◽

Henrik Jönsson

Keyword(s):

Brain Damage ◽

Serum Levels ◽

Breath Hold ◽

Long Term Effects ◽

Arterial Blood ◽

The Central Nervous System ◽

Serious Injury ◽

Protein S100b ◽

The Brain ◽

Damage Marker

The concentration of the protein S100B in serum is used as a brain damage marker in various conditions. We wanted to investigate whether a voluntary, prolonged apnea in trained breath-hold divers resulted in an increase of S100B in serum. Nine trained breath-hold divers performed a protocol mimicking the procedures they use during breath-hold training and competition, including extensive preapneic hyperventilation and glossopharyngeal insufflation, in order to perform a maximum-duration apnea, i.e., “static apnea” (average: 335 s, range: 281–403 s). Arterial blood samples were collected and cardiovascular variables recorded. Arterial partial pressures of O2 and CO2 (PaO2 and PaCO2) were 128 Torr and 20 Torr, respectively, at the start of apnea. The degree of asphyxia at the end of apnea was considerable, with PaO2 and PaCO2 reaching 28 Torr and 45 Torr, respectively. The concentration of S100B in serum transiently increased from 0.066 μg/l at the start of apnea to 0.083 μg/l after the apnea ( P < 0.05). The increase in S100B is attributed to the asphyxia or to other physiological responses to apnea, for example, increased blood pressure, and probably indicates a temporary opening of the blood-brain barrier. It is not possible to conclude that the observed increase in S100B levels in serum after a maximal-duration apnea reflects a serious injury to the brain, although the results raise concerns considering negative long-term effects. At the least, the results indicate that prolonged, voluntary apnea affects the integrity of the central nervous system and do not preclude cumulative effects.

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The microanatomy of the central nervous system and brain of the Indo-Pacific seahorse, Hippocampus barbouri, during development

Zoologia (Curitiba) ◽

10.3897/zoologia.37.e53734 ◽

2020 ◽

Vol 37 ◽

pp. 1-11

Author(s):

Sinlapachai Senarat ◽

Jes Kettratad ◽

Gen Kaneko ◽

Thatpon Kamnurdnin ◽

Chanyut Sudtongkong

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Purkinje Cells ◽

Optic Tectum ◽

Brain Structures ◽

Brain Morphology ◽

Medium Size ◽

Reproductive Behaviors ◽

The Central Nervous System ◽

The Brain

The central nervous system (CNS) of Teleostei is a complex system of self-governance and its morphology is reflected in the physiological and reproductive behaviors. The Indo-Pacific seahorse, Hippocampus barbouri Jordan & Richardson, 1908, is a new candidate species for aquaculture in Thailand. In this study, we investigated the brain morphology of H. barbouri across various developmental windows. Light microscopic observations of adult brains revealed a large optic tectum in the mesencephalon, whereas the cerebral hemispheres and the cerebellum are of medium size. The detailed brain structures were generally similar to those of other teleosts; however, only five distinct layers were present in the optic tectum, including the stratum marginale, stratum opticum, stratum album central, stratum griseum central, and stratum periventriculae, versus six layers observed in other fish. One day after birth (1 DAB) the brain was a packed structure without any clear sub-structures. The number of capillaries in the optic tectum began to increase at 6 DAB, and at 14 DAB several features, including small blood vessels in the optic tectum and Purkinje cells, became noticeable. By 35 DAB, the optic tectum became highly vascularized and included five layers. Additionally, large Purkinje cells were developed in the cerebellum. Based on the brain development pattern, we speculate that the predatory ability of this fish starts to develop from 6 to 14 days after birth.

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Advances in Fetal Neurophysiology

Donald School Journal of Ultrasound in Obstetrics & Gynecology ◽

10.5005/jp-journals-10009-1063 ◽

2008 ◽

Vol 2 (3) ◽

pp. 19-34 ◽

Cited By ~ 1

Author(s):

Maja Predojevic ◽

Aida Salihagic Kadic

Keyword(s):

Brain Function ◽

State Of The Art ◽

Sensory System ◽

Nerve Cells ◽

Long Term Effects ◽

Intrauterine Life ◽

Period 2 ◽

The Central Nervous System ◽

The Brain

Abstract The human brain function is certainly one of the most amazing phenomena known. All behavior is the result of the brain function. The 100 billion nerve cells are the home to our centers of feelings and senses, pleasure and satisfaction; it is where the centers for learning, memory and creative work are located; where laughing and crying areas and the centers of our mind are. Our cognitive functions, such as thinking, speaking or creating works of art and science, all reside within the cerebral cortex. One of the tasks of the neural science is to explain how the brain marshals its millions of individual nerve cells to produce behavior and how these cells are affected by the environment.1 The brain function still remains shrouded in a veil of mystery. But what is known is that over 99 percent of the human neocortex is produced during the fetal period.2 Owing to the employment of state-of-the-art methods and techniques in prenatal investigations, a growing pool of information on the development of the central nervous system (CNS) and behavioral patterns during intrauterine life has been made available. This review outlines these events, along with the development of the fetal sensory system and circadian rhythms, the senses of vision and hearing, fetal learning and memory, and long-term effects of fetal stress on behavior. In brief, this review offers a glimpse of the fascinating world of the intrauterine life.

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Assessment of brain cholesterol metabolism biomarker 24S-hydroxycholesterol in schizophrenia

npj Schizophrenia ◽

10.1038/s41537-020-00121-4 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Joshua Chiappelli ◽

Maria S. Quinton ◽

Dmitri Volfson ◽

Michael Cwik ◽

Wyatt Marshall ◽

...

Keyword(s):

White Matter ◽

No Value ◽

Cognitive Deficits ◽

Plasma Levels ◽

Cholesterol Metabolism ◽

Brain Structures ◽

Healthy Controls ◽

Neurologic Disorders ◽

Brain Metabolite ◽

The Central Nervous System

AbstractPlasma 24S-hydroxycholesterol mostly originates in brain tissue and likely reflects the turnover of cholesterol in the central nervous system. As cholesterol is disproportionally enriched in many key brain structures, 24S-hydroxycholesterol is a promising biomarker for psychiatric and neurologic disorders that impact brain structure. We hypothesized that, as schizophrenia patients have widely reported gray and white matter deficits, they would have abnormal levels of plasma 24S-hydroxycholesterol, and that plasma levels of 24S-hydroxycholesterol would be associated with brain structural and functional biomarkers for schizophrenia. Plasma levels of 24S-hydroxycholesterol were measured in 226 individuals with schizophrenia and 204 healthy controls. The results showed that levels of 24S-hydroxycholesterol were not significantly different between patients and controls. Age was significantly and negatively correlated with 24S-hydroxycholesterol in both groups, and in both groups, females had significantly higher levels of 24S-hydroxycholesterol compared to males. Levels of 24S-hydroxycholesterol were not related to average fractional anisotropy of white matter or cortical thickness, or to cognitive deficits in schizophrenia. Based on these results from a large sample and using multiple brain biomarkers, we conclude there is little to no value of plasma 24S-hydroxycholesterol as a brain metabolite biomarker for schizophrenia.

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Generalization via superposition: combined effects of mixed reference frame representations for explicit and implicit learning in a visuomotor adaptation task

Journal of Neurophysiology ◽

10.1152/jn.00624.2018 ◽

2019 ◽

Vol 121 (5) ◽

pp. 1953-1966 ◽

Cited By ~ 1

Author(s):

Eugene Poh ◽

Jordan A. Taylor

Keyword(s):

Implicit Learning ◽

Reference Frame ◽

Reference Frames ◽

Visuomotor Adaptation ◽

Visuomotor Rotation ◽

Mixed Representation ◽

Multiple Processes ◽

Implicit Motor ◽

The Individual ◽

The Brain

Studies on generalization of learned visuomotor perturbations have generally focused on whether learning is coded in extrinsic or intrinsic reference frames. This dichotomy, however, is challenged by recent findings showing that learning is represented in a mixed reference frame. Overlooked in this framework is how learning appears to consist of multiple processes, such as explicit reaiming and implicit motor adaptation. Therefore, the proposed mixed representation may simply reflect the superposition of explicit and implicit generalization functions, each represented in different reference frames. Here we characterized the individual generalization functions of explicit and implicit learning in relative isolation to determine whether their combination could predict the overall generalization function when both processes are in operation. We modified the form of feedback in a visuomotor rotation task in an attempt to isolate explicit and implicit learning and tested generalization across new limb postures to dissociate the extrinsic/intrinsic representations. We found that the amplitude of explicit generalization was reduced with postural change and was only marginally shifted, resembling an extrinsic representation. In contrast, implicit generalization maintained its amplitude but was significantly shifted, resembling a mixed representation. A linear combination of individual explicit and implicit generalization functions accounted for nearly 85% of the variance associated with the generalization function in a typical visuomotor rotation task, where both processes are in operation. This suggests that each form of learning results from a mixed representation with distinct extrinsic and intrinsic contributions and the combination of these features shapes the generalization pattern observed at novel limb postures. NEW & NOTEWORTHY Generalization following learning in visuomotor adaptation tasks can reflect how the brain represents what it learns. In this study, we isolated explicit and implicit forms of learning and showed that they are derived from a mixed reference frame representation with distinct extrinsic and intrinsic contributions. Furthermore, we showed that the overall generalization pattern at novel workspaces is due to the superposition of independent generalization effects developed by explicit and implicit learning processes.

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The Brain-Gut Team

Digestive Diseases ◽

10.1159/000505810 ◽

2020 ◽

Vol 38 (4) ◽

pp. 293-298 ◽

Cited By ~ 2

Author(s):

Juan R. Malagelada

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Brain Structures ◽

Normal Function ◽

Simple Concept ◽

The Central Nervous System ◽

The Brain

Background: Interactions between brain and gut have been suspected for centuries but our understanding of the neural centers and neurohormonal links that establish bidirectional regulatory communication between these 2 body systems has advanced significantly in the last decades. The label “brain-gut axis” designates a useful but deceivingly simple concept, since the mechanistic complexity of brain-gut interaction is enormous. Summary: The significance of the brain-gut axis is perhaps best conceived as “a team” since both systems are physiologically coordinated to ensure a healthy status. However, under pathophysiological conditions, the axis also contributes substantially to distort homeostasis. For instance, normal signals emanating from the gut may be inappropriately received and interpreted by the central nervous system that responds by inadequately recruiting other brain structures and generate both symptoms and commands that disturb normal gut activity. Key Messages: Thus, at each end and in the brain-gut connecting routes, there is the potential for altering perceived and unperceived sensations and further impinging on normal function.

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