Dissociation Patterns Research Articles

Default mode network dissociation linking cerebral beta amyloid retention and depression in cognitively normal older adults

AbstractBackgroundTo date, cerebral beta amyloid (Aß) deposition and late‐life depression (LLD) are known to be associated with trajectory of Alzheimer’s disease (AD). However, their neurobiological link is not clear. Although previous studies showed aberrant functional connectivity (FC) change of default mode network (DMN) in early Aß deposition and LLD respectively, its mediating role is not elucidated. The aim of this study is to investigate distinctive association pattern of DMN FC linking LLD and Aß retention in the cognitively normal older adults.MethodTwo hundred thirty‐five cognitively normal older adults with (N=118) and without depression (N=117) underwent resting state functional magnetic resonance image and 18F‐Flutemetamol positron emission tomography. We investigated associations among Aß burden, depression, and DMN FC.ResultIndependent component analysis showed increased anterior DMN FC and decreased posterior DMN FC in depression group compared with no depression group. Global cerebral Aß retention correlated positively with anterior and negatively with posterior DMN FC. Anterior DMN FCs were positively correlated with depression severity whereas posterior DMN FCs were negatively correlated with cognitive function. In addition, effect of global cerebral Aß retention on depression severity was mediated by subgenual anterior cingulate FC.ConclusionOur results of anterior and posterior DMN FC dissociation pattern might play pivotal role in linking cerebral Aß pathology and LLD in the course of AD progression. Further longitudinal studies would be needed to confirm causal relationships between cerebral Aß retention and LLD.

Diskriminasi Terhadap Penyandang Disabilitas Pada Novel Invalidite Karya Faradita

This writing is a proof of acts of discrimination against persons with disabilities in Faradita's third edition of Invalidite novel which was published in 2019. This writing uses Blank and Dabady's discrimination theory, social interaction, and the impact of acts of discrimination against persons with disabilities in the umbrella of literary sociology. The method used in this study is a qualitative method where this method is used in translating data relating to acts of discrimination, social interactions and impacts with the environment. At this writing, 23 data were found on acts of discrimination against persons with disabilities, social interactions and social impacts. These actions are in the form of deliberate and obvious discrimination, subtle discrimination, unconsciously and automatically, discrimination based on data and profiles, discrimination in organizational processes. In addition, there are dissociative interaction pat-terns of competition, contravention, and conflict. Keywords: literary sociology, discrimination, patterns of social interaction

Unimolecular Double Photoionization-Induced Processes in Iron Pentacarbonyl.

The dissociations of nascent Fe(CO)5++ ions created by 40.81 eV photoionization of iron pentacarbonyl have been examined using threefold and fourfold electron–ion coincidence measurements. The energies and forms of the ions have been explored by high-level calculations, revealing several new structures. The most stable form of Fe(CO)5++ has a quite different geometry from that of the neutral molecule. The dissociation pattern can be modeled as a sequence of CO evaporations followed by two-body charge separations. Each Fe(CO)n++ (n = 1–4) dication is stable in a restricted energy range; as its internal energy increases, it first ejects a neutral CO, then loses CO+ by charge separation at higher energy. In the initial stages, charge-retaining CO evaporations dominate over charge separation, but the latter become more competitive as the number of residual CO ligands decreases. At energies where ionization is mainly from the CO ligands, new Fe–C and C–C bonds are created by a mechanism which might be relevant to catalysis by Fe.

Tuning the selectivity of catalytic nitriles hydrogenation by structure regulation in atomically dispersed Pd catalysts

The product selectivity in catalytic hydrogenation of nitriles is strongly correlated with the structure of the catalyst. In this work, two types of atomically dispersed Pd species stabilized on the defect-rich nanodiamond-graphene (ND@G) hybrid support: single Pd atoms (Pd1/ND@G) and fully exposed Pd clusters with average three Pd atoms (Pdn/ND@G), were fabricated. The two catalysts show distinct difference in the catalytic transfer hydrogenation of nitriles. The Pd1/ND@G catalyst preferentially generates secondary amines (Turnover frequency (TOF@333 K 709 h−1, selectivity >98%), while the Pdn/ND@G catalyst exhibits high selectivity towards primary amines (TOF@313 K 543 h−1, selectivity >98%) under mild reaction conditions. Detailed characterizations and density functional theory (DFT) calculations show that the structure of atomically dispersed Pd catalysts governs the dissociative adsorption pattern of H2 and also the hydrogenation pathway of the benzylideneimine (BI) intermediate, resulting in different product selectivity over Pd1/ND@G and Pdn/ND@G, respectively. The structure-performance relationship established over atomically dispersed Pd catalysts provides valuable insights for designing catalysts with tunable selectivity.

Tunable CO Dissociation Assisted by H2 over Cobalt Species: A Mechanistic Study by In‐situ DRIFTS

AbstractFischer‐Tropsch synthesis (FTS) is an important heterogeneous catalytic process that can effectively reduce human dependence on the non‐renewable petroleum resources. Cobalt is a crucial active metal center in most catalysts, which effectively catalyzes syngas into valuable products such as liquid fuels. On this basis, we systematically investigated the adsorption of CO on the surface of different cobalt species and its dissociation characteristics assisted by H2 are studied by the in‐situ DRIFTS. For the metallic cobalt phase, H2‐assisted CO dissociation not only possessed the FTS activity, but also inhibited the CO disproportionation reaction. However, for the CoO phase, the bidentate carbonate species were decomposed into CO2. In addition, CoO presented a high‐chain propagation ability than that of Co under the same operation conditions. Co2O3 and Co3O4 also exhibited similar CO dissociation patterns with the assistance of H2. However, different from CoO phase, formate species also formed under the H2 atmosphere over these two Co species. In summary, CO dissociation would be well tuned via the assistance of H2 as demonstrated by the in‐situ DRIFTS. This work provides a new sight on the rational design of efficient cobalt catalysts toward the FTS processes.

Pore-scale study of the multiphase methane hydrate dissociation dynamics and mechanisms in the sediment

Methane hydrate is a promising energy resource, but the hydrate development still faces technical difficulties due to the complicated multiple physicochemical and thermal processes during the multiphase hydrate dissociation in the sediment. In this study, a pore-scale numerical model based on the lattice Boltzmann method was proposed to simulate methane hydrate dissociation considering multiphase flow, heat and species transport, heterogeneous reaction and hydrate structure evolution. The single-phase hydrate dissociation was firstly simulated to identify the convection and diffusion transport-limited regimes according to the Péclet number. Effects of the connate water saturation and the Péclet number on the multiphase hydrate dissociation were then investigated to understand the varying dissociation dynamics and dissociation mechanisms. The competitive mass-transfer-limitation and heat-transfer-limitation were quantified to elucidate the interplay between multiphase mass transport and heat transport on the hydrate recovery efficiency. The regime diagram of the methane hydrate dissociation was mapped to exhibit five dissociation regimes according to the connate water saturation and the Péclet number. Empirical correction of the permeability and the specific surface area was obtained to improve the REV (Representative Element Volume)-scaled modeling accuracy of the volume-averaged transport and geometric properties with three typical dissociation patterns. The insights from the pore-scale multiphase dissociation studies can enlighten the accurate REV-scaled simulation with the addressed non-negligible physics.

Photodissociation and Infrared Spectroscopy of Uranium-Nitrogen Cation Complexes.

Laser vaporization of uranium in a pulsed supersonic expansion of nitrogen is used to produce complexes of the form U+(N2)n (n = 1-8). These ions are mass selected in a reflectron time-of-flight spectrometer and studied with visible and UV laser fixed-frequency photodissociation and with tunable infrared laser photodissociation spectroscopy. The dissociation patterns and spectroscopy of U+(N2)n indicate that N2 ligands are intact molecules and that there is no insertion chemistry resulting in UN+ or NUN+. Fixed frequency photodissociation at 532 and 355 nm indicate that the U+-N2 bond dissociation energy varies little with changing coordination. The photon energy and the number of ligands eliminated allow an estimate of the average U+-N2 dissociation energy of 12 kcal/mol. Infrared bands are observed for these complexes near the N-N stretch vibration via elimination of N2 molecules. These resonances are observed to be shifted about 130 cm-1 to the red from the free-N2 frequency for complexes with n = 3-8. Density functional theory indicates that U+ is most stable in the sextet state in these complexes and that N2 molecules bind in end-on configurations. The fully coordinated complex is predicted to be U+(N2)8, which has a cubic structure. The vibrational frequencies predicted by theory are consistently lower than those in the experiment, independent of the isomeric structure or spin state of the complexes. Despite its failure to reproduce the infrared spectra, theory provides an average U+-N2 dissociation energy of 11.8 ± 0.5 kcal/mol, in good agreement with the value from the experiments.

Mental individuation of imagined finger movements can be achieved using TMS-based neurofeedback

Neurofeedback (NF) in combination with motor imagery (MI) can be used for training individuals to volitionally modulate sensorimotor activity without producing overt movements. However, until now, NF methods were of limited utility for mentally training specific hand and finger actions. Here we employed a novel transcranial magnetic stimulation (TMS) based protocol to probe and detect MI-induced motor activity patterns in the primary motor cortex (M1) with the aim to reinforce selective facilitation of single finger representations. We showed that TMS-NF training but not MI training with uninformative feedback enabled participants to selectively upregulate corticomotor excitability of one finger, while simultaneously downregulating excitability of other finger representations within the same hand. Successful finger individuation during MI was accompanied by strong desynchronization of sensorimotor brain rhythms, particularly in the beta band, as measured by electroencephalography. Additionally, informative TMS-NF promoted more dissociable EEG activation patterns underlying single finger MI, when compared to MI of the control group where no such feedback was provided. Our findings suggest that selective TMS-NF is a new approach for acquiring the ability of finger individuation even if no overt movements are performed. This might offer new treatment modality for rehabilitation after stroke or spinal cord injury.

How task-unrelated and freely moving thought relate to affect: Evidence for dissociable patterns in everyday life.

Much of our knowledge about the correlates of mind-wandering comes from assessing task-unrelated thought. Less is known about the correlates of freely moving thought, a dimension that assesses the degree to which thoughts arise and unfold with low levels of guidance or constraints. Task-unrelated thought is consistently associated with more negative affective valence compared with being on task; however, it is unclear whether freely moving thought shares the same relationship with affect. We conducted two ecological momentary assessment studies in the context of everyday life and found that the two dimensions have different affective correlates. In Study 1, task-unrelated thought was associated with less positive concurrent valence than being on-task. However, freely moving thought was associated with more positive concurrent valence and was predictive of more positive valence at a subsequent timepoint. Freely moving thought, but not task-unrelated thought, also positively predicted concurrent arousal. Computational sentiment analyses of participants' thought descriptions offered convergent evidence of differential relationships between the two thought dimensions and affect. Study 2 used different measurement scales to assess whether (a) the pattern of findings replicated and (b) if the effects were robust to changes in measurement. The main findings were replicated: task-unrelated thought was negatively associated with concurrent valence, whereas freely moving thought was positively associated with concurrent valence. However, freely moving thought did not predict subsequent valence and was not related to concurrent arousal. The most robust findings related to concurrent valence. Although mind-wandering has acquired a relatively negative reputation to date, our findings suggest that there might be positive aspects that remain unexplored. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Default mode network dissociation linking cerebral beta amyloid retention and depression in cognitively normal older adults.

Cerebral beta amyloid (Aβ) deposition and late-life depression (LLD) are known to be associated with the trajectory of Alzheimer's disease (AD). However, their neurobiological link is not clear. Previous studies showed aberrant functional connectivity (FC) changes in the default mode network (DMN) in early Aβ deposition and LLD, but its mediating role has not been elucidated. This study was performed to investigate the distinctive association pattern of DMN FC linking LLD and Aβ retention in cognitively normal older adults. A total of 235 cognitively normal older adults with (n = 118) and without depression (n = 117) underwent resting-state functional magnetic resonance imaging and 18F-flutemetamol positron emission tomography to investigate the associations between Aβ burden, depression, and DMN FC. Independent component analysis showed increased anterior DMN FC and decreased posterior DMN FC in the depression group compared with the no depression group. Global cerebral Aβ retention was positively correlated with anterior and negatively correlated with posterior DMN FC. Anterior DMN FC was positively correlated with severity of depression, whereas posterior DMN FC was negatively correlated with cognitive function. In addition, the effects of global cerebral Aβ retention on severity of depression were mediated by subgenual anterior cingulate FC. Our results of anterior and posterior DMN FC dissociation pattern may be pivotal in linking cerebral Aβ pathology and LLD in the course of AD progression. Further longitudinal studies are needed to confirm the causal relationships between cerebral Aβ retention and LLD.

OBJECTIVE MEASUREMENT OF TUMOR FRONTS IN EARLY ORAL CANCER

<h3>Introduction</h3> Oral cancer, one of the 10 most common cancers worldwide, has a high mortality rate, and the level of disfigurement that survivors experience gives rise to a considerable global public health burden. Some early-stage oral tongue squamous cell carcinomas (OTSCCs) show aggressive behavior and poor prognosis even in cN0 patients. This motivates the search for prognostically relevant features to tailor individual management. Histopathologic reporting of oral cancer is limited by some elements of subjectivity. This study aimed to identify quantitative histologic features that allow objective stratification of patients into treatment categories and improve overall patient outcome. <h3>Methods</h3> We conducted a retrospective study of 50 cases of early stage T1/T2 OTSCC. Sections immunostained with anti–pan-cytokeratin antibodies were scanned into digital images to assess the global complexity (fractal dimension) of the tumor epithelial–connective tissue interface (ECTI). The results were related to information from the Royal College of Pathology Dataset for mucosal malignancies of the oral cavity. <h3>Results</h3> At tumor depths over 5.5 mm, there was a positive correlation between tumor invasion depth and ECTI complexity. There were also significant differences in ECTI complexity between tumors graded as well, moderately, and poorly differentiated (1.24 ± 0.10, 1.32 ± 0.06, and 1.39 ± 0.07, respectively). The ECTI complexity in poorly differentiated tumors was significantly lower in the patients with a positive 5-year survival status. <h3>Conclusions</h3> Fractal analysis of the ECTI provided an unbiased descriptor of neoplasm dissociation and invasion pattern modality with potentially useful prognostic value.

Leprous Neuropathy: Observational Study Highlighting the Role of Electrophysiology in Early Diagnosis.

Background Worldwide leprosy is a common cause of peripheral neuropathy. Electrophysiology is underutilized in its diagnosis. Objective This study aims to evaluate the usefulness of electrophysiological study in the diagnosis of leprous neuropathy. Materials and Methods Clinical and electrophysiological abnormalities of 36 histopathology proven leprosy patients from January 2015 to January 2017 were studied. Statistical Analysis Proportions were compared by Chi-square test. Results Total patients were 36. Thirty-four patients had abnormal electrophysiology and 34 had neurological deficits like weakness, sensory changes, and thickening. By clinical examination, multiple nerve involvement (motor weakness, sensory changes, and nerve thickening) occurred in 29, single nerve in 5, and no nerve involvement in 2. With electrophysiology, multiple nerve involvement (mononeuritis multiplex) was present in 32, single nerve in 2, and normal conduction parameters in 2. From the 36 patients, a total of 1,008 nerves were subjected to clinical examination and 132 were picked up clinically as affected, (13.1%). Electrophysiological study was done in 504 nerves, and 215 were found to be involved, (43%). Nerve abnormality detected by electrophysiology is significantly higher than clinical detection. (Chi-square =164.4054; p = 0.0000). Clinically, the most commonly affected nerve was unar (27) and the least affected was median (2) nerve. Electrophysiology detected 69% of nerves with demyelination and 35% of nerves with axonal features (mosaic pattern). Discussion There was subclinical neuropathy with electroclinical dissociation, as evidenced by more abnormality in electrophysiology than clinical examination. The nerve involvement was mononeuritis or mononeuritis multiplex pattern, both clinically and electrophysiologically. Electrophysiology showed both axonal and demyelinating nerve involvement (mosaic pattern). All the three features are present in leprous neuropathy. In corollary, if a patient has these electrophysiological features, he should be thoroughly investigated for leprosy. Conclusion Triple findings, such as subclinical neuropathy with electroclinical dissociation, mononeuritis multiplex, and mosaic pattern of demyelination and axonopathy, suggest leprous neuropathy

Dynamic integration and segregation of amygdala subregional functional circuits linking to physiological arousal

The dynamical organization of brain networks is essential to support human cognition and emotion for rapid adaption to ever-changing environment. As the core nodes of emotion-related brain circuitry, the basolateral amygdala (BLA) and centromedial amygdala (CMA) as two major amygdalar nuclei, are recognized to play distinct roles in affective functions and internal states, via their unique connections with cortical and subcortical structures in rodents. However, little is known how the dynamical organization of emotion-related brain circuitry reflects internal autonomic responses in humans. Using resting-state functional magnetic resonance imaging (fMRI) with K-means clustering approach in a total of 79 young healthy individuals (cohort 1: 42; cohort 2: 37), we identified two distinct states of BLA- and CMA-based intrinsic connectivity patterns, with one state (integration) showing generally stronger BLA- and CMA-based intrinsic connectivity with multiple brain networks, while the other (segregation) exhibiting weaker yet dissociable connectivity patterns. In an independent cohort 2 of fMRI data with concurrent recording of skin conductance, we replicated two similar dynamic states and further found higher skin conductance level in the integration than segregation state. Moreover, machine learning-based Elastic-net regression analyses revealed that time-varying BLA and CMA intrinsic connectivity with distinct network configurations yield higher predictive values for spontaneous fluctuations of skin conductance level in the integration than segregation state. Our findings highlight dynamic functional organization of emotion-related amygdala nuclei circuits and networks and its links to spontaneous autonomic arousal in humans.

Motility disorders and disintegration into separate cells of Trichoplax sp. H2 in the presence of Zn2+ ions and L-cysteine molecules: A systems approach

Placozoa remain an ancient multicellular system with a dynamic body structure where calcium ions carry out a primary role in maintaining the integrity of the entire animal. Zinc ions can compete with calcium ions adsorption. We studied the effect of zinc ions and l-cysteine molecules on the interaction of Trichoplax sp. H2 cells. The regularity of formless motion was diminished in the presence of 20–25 μM of Zn2+ ions leading to the formation of branching animal forms. Locomotor ciliated cells moved chaotically and independently of each other leaving the Trichoplax body and opening a network of fiber cells. Application of 100 μM cysteine resulted in dissociation of the plate into separate cells. The combined chemical treatment shifted the effect in a random sample of animals toward disintegration, i.e. initially leading to disorder of collective cell movement and then to total body fragmentation. Two dissociation patterns of Trichoplax plate as “expanding ring” and “bicycle wheel” were revealed. Analysis of the interaction of Ca2+ and Zn2+ ions with cadherin showed that more than half (54%) of the amino acid residues with which Ca2+ and Zn2+ ions bind are common. The contact interaction of cells covered by the cadherin molecules is important for the coordinated movements of Trichoplax organism, while zinc ions are capable to break junctions between the cells. The involvement of other players, for example, l-cysteine in the regulation of Ca2+-dependent adhesion may be critical leading to the typical dissociation of Trichoplax body like in a calcium-free environment. A hypothesis about the essential role of calcium ions in the emergence of Metazoa ancestor is proposed.

Semantic and phonological false memory: A review of theory and data

• False memory share surface or semantic resemblance or both with actual experience. • Semantic and phonological DRM illusions mostly display dissociative patterns. • Fuzzy trace theory and activation monitoring framework explain the two illusions differently. • Both theories can offer a fairly good account of the reviewed data. False memories typically share semantic or surface features with actual experiences, sometimes both. However, it is unclear whether false memories that are rooted in semantic versus surface resemblance obey the same laws. The Deese/Roediger/McDermott (DRM) illusion offers an attractive testbed for comparing semantic and surface false memories under closely matched conditions, owing to parallel semantic and phonological versions of the illusion. We review three lines of evidence in which semantic and phonological DRM illusions have been compared: (a) studies in which the two illusions were tracked in populations with different semantic or surface memory abilities; (b) studies that investigated the effects of manipulations that target semantic content or surface content or both; and (c) studies that examined hybrid forms of the illusion in which there was both semantic and surface resemblance between false memories and actual experiences. The three lines of evidence showed that semantic and phonological DRM illusions display dissociative patterns in most instances, indicating that they are two distinct types of false memories. The two major theories of the DRM illusion, fuzzy-trace theory and the activation/monitoring framework, have different views of the underlying mechanisms for the semantic and phonological illusions. We discuss the implications of this literature for the two theories.

The electric conductance of dilute sulfuric acid in water: a new theoretical interpretation

The variation of the activity coefficient of aqueous sulfuric acid with acid concentration, solution's temperature, and solvent's (water) dielectric constant, clearly fits a typical strong 1–3 electrolyte behaviour [Fraenkel, J. Phys. Chem. B. 116, 11662 (2012)]. Therefore, the aqueous acid was proposed to have the molecular formula H4SO5, and to dissociate to 3H+ (3H3O+) and 1HSO5 3−. When the above study was reported, electric conductivity data of the aqueous acid could not be theoretically interpreted to prove or disprove the 1–3 electrolyte behaviour, due to the lack of an appropriate conductance theory. The improved Debye–Hückel–Onsager (DHO) theory, DHO–SiS, recently reported [Fraenkel, Phys. Chem. Chem. Phys. 20, 29896 (2018)], allows, unlike its parent theory, a quantitative analysis of strong 1–1, 1–2 and 1–3 electrolytes. A good-to-excellent theory–experiment agreement is achieved for dilute aqueous H2SO4 at 0–50°C, but only if the acid is considered, as before, as a strong 1–3 electrolyte; the new analysis thus corroborates the previous activity-based findings. In contrast, the conductance of dilute sulfuric acid in pure methanol follows the conventional H2SO4 dissociation pattern, exhibiting a ‘mixed 1–1/1–2’ electrolyte behaviour.

Direct Visualization of CH4/CO2 Hydrate Phase Transitions in Sandstone Pores

This paper reports the formation and dissociation pattern of hydrate crystals with varying compositions of CH4 and CO2 in porous media. Direct visualization was carried out using a high-pressure, w...

A detailed morphology investigation on the effects of mixed anionic and nonionic surfactants on methane hydrate formation and dissociation

Foam generation from the presence of sodium dodecyl sulfate (SDS) as a kinetic promoter in methane hydrate formation can be potentially reduced by using mixed surfactants. Mixtures of SDS with nonionic surfactants were proposed to solve this problem. Polyoxyethylene (n) lauryl ether (EO3 and EO5) and alkyl poly glycol ether (APG) were chosen to mix with SDS in different concentrations at 8 MPa and 4 °C in the quiescent system for both kinetics and morphology studies. The result showed that the addition of EO3 resulted in the slight increase for the induction time but no change in the formation rate. Adding EO5 showed the stochastic phenomenon on hydrate formation kinetics. In the presence of APG, the induction time increased up to ten times and lowered the hydrate formation rate compared to only 0.25 wt% SDS. The methane uptakes were about the same with all conditions. The morphology showed similar hydrate formation and dissociation patterns with all investigated solutions. Interestingly, the mixture of nonionic surfactants with SDS decreased the foam formation compared with the system with only SDS. The addition EO3 showed the gradual decrease in the foam height with the higher concentration of EO3. Adding the highest EO5 concentration showed the optimum foam reduction compared with all conditions. Moreover, the presence of APG showed the similar effects of foam reduction with EO5.

Equilibrium Conditions of Methane Hydrates in Seawater From Krishna-Godavari Basin, India

Abstract Immense gas hydrate reservoirs have been reported in the Krishna-Godavari Basin, India. They mostly constitute methane gas and could serve as an alternative energy source. For efficient exploitation of methane from hydrates, it is crucial to know the region's stability conditions. The present study reports the stability and equilibrium conditions of methane hydrates, synthesized with seawater obtained from the Krishna-Godavari Basin. At Station MD161/02/GH, the water samples are collected at depths ranging from 500 to 1,500 m. The influence of salinity on methane hydrate formation and dissociation in the presence of seawater is established. The hydrate dissociation patterns in seawater and saline water (4 wt% NaCl) are similar and follow the phase equilibrium around 6 wt% NaCl. The identical dissociation behavior of the two systems ascertains seawater to have ~4 wt% salinity. The salinity concentration varies little with depth because the hydrate dissociation temperatures are the same for all the samples collected at the three depths. Using the Clausius-Clapeyron equation, dissociation enthalpies are calculated. The dissociation enthalpy in saline systems is about 6% higher. The hydrate growth kinetics is marginally faster in the saline system.

Dr. Strangelove demystified: Disconnection of hand and language dominance explains alien-hand syndrome after corpus callosotomy

BackgroundAlien hand syndrome (AHS) is a disabling condition in which one hand behaves in a way that the person finds "alien". This feeling of alienation is related to the occurrence of movements of the respective hand performed without or against conscious intention. Most information on AHS stems from single case observations in patients with frontal, callosal, or parietal brain damage. MethodsRetrospective analysis of distinctive clinical features of three out of 18 epilepsy patients who developed AHS with antagonistic movements of the left hand after corpus callosotomy (CC) (one anterior, two complete) for the control of epileptic seizures, particularly epileptic drop attacks (EDA). ResultsRemarkably, these three patients, two men and one woman, displayed atypical language dominance with a bilateral, left more than right hemisphere language representation in intracarotidal amobarbital testing before surgery. The overall additional distinctive feature of the target patients was genuine left-handedness, with writing retrained to right-handedness in two patients. After surgery the left hands became alien. The problem was permanent, despite strategies for compensation. ConclusionFrom this observation we suggest that under the conditions of dissociation of language and motor dominance, loss of both intentional control of contralateral action and physiological inhibition of antagonistic movements lead to post-callosotomy alien-hand-like motor phenomena. The dissociation pattern posing this risk seems rare but needs to be considered when evaluating candidates for callosotomy.