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1.
Neuroimage Clin ; 24: 102057, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31715558

RESUMO

Beta oscillations within motor-cortical areas have been linked to sensorimotor function. In line with this, pathologically altered beta activity in cortico-basal ganglia pathways has been suggested to contribute to the pathophysiology of Parkinson's disease (PD), a neurodegenerative disorder primarily characterized by motor impairment. Although its precise function is still discussed, beta activity might subserve an anticipatory role in preparation of future actions. By reanalyzing previously published data, we aimed at investigating the role of pre-stimulus motor-cortical beta power modulation in motor sequence learning and its alteration in PD. 20 PD patients and 20 healthy controls (HC) performed a serial reaction time task (SRTT) in which reaction time gain presumably reflects the ability to anticipate subsequent sequence items. Randomly varying patterns served as control trials. Neuromagnetic activity was recorded using magnetoencephalography (MEG) and data was reanalyzed with respect to task stimuli onset. Assuming that pre-stimulus beta power modulation is functionally related to motor sequence learning, reaction time gain due to training on the SRTT should vary depending on the amount of beta power suppression prior to stimulus onset. We hypothesized to find less pre-stimulus beta power suppression in PD patients as compared to HC associated with reduced motor sequence learning in patients. Behavioral analyses revealed that PD patients exhibited smaller reaction time gain in sequence relative to random control trials than HC indicating reduced learning in PD. This finding was indeed paralleled by reduced pre-stimulus beta power suppression in PD patients. Further strengthening its functional relevance, the amount of pre-stimulus beta power suppression during sequence training significantly predicted subsequent reaction time advantage in sequence relative to random trials in patients. In conclusion, the present data provide first evidence for the contribution of pre-stimulus motor-cortical beta power suppression to motor sequence learning and support the hypothesis that beta oscillations may subserve an anticipatory, predictive function, possibly compromised in PD.

2.
Neuroimage Clin ; 20: 448-457, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30128283

RESUMO

Motor sequence learning plays a pivotal role in various everyday activities. Motor-cortical beta oscillations have been suggested to be involved in this type of learning. In Parkinson's disease (PD), oscillatory activity within cortico-basal-ganglia circuits is altered. Pathologically increased beta oscillations have received particular attention as they may be associated with motor symptoms such as akinesia. In the present magnetoencephalography (MEG) study, we investigated PD patients and healthy controls (HC) during implicit motor sequence learning with the aim to shed light on the relation between changes of cortical brain oscillations and motor learning in PD with a particular focus on beta power. To this end, 20 PD patients (ON medication) and 20 age- and sex-matched HC were trained on a serial reaction time task while neuromagnetic activity was recorded using a 306-channel whole-head MEG system. PD patients showed reduced motor sequence acquisition and were more susceptible to interference by random trials after training on the task as compared to HC. Behavioral differences were paralleled by changes at the neurophysiological level. Diminished sequence acquisition was paralleled by less training-related beta power suppression in motor-cortical areas in PD patients as compared to HC. In addition, PD patients exhibited reduced training-related theta activity in motor-cortical areas paralleling susceptibility to interference. The results support the hypothesis that the acquisition of a new motor sequence relies on suppression of motor-cortical beta oscillations, while motor-cortical theta activity might be related to stabilization of the learned sequence as indicated by reduced susceptibility to interference. Both processes appear to be impaired in PD.


Assuntos
Ritmo beta/fisiologia , Aprendizagem/fisiologia , Córtex Motor/fisiopatologia , Doença de Parkinson/fisiopatologia , Tempo de Reação/fisiologia , Ritmo Teta/fisiologia , Feminino , Humanos , Magnetoencefalografia/métodos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico , Estimulação Luminosa/métodos , Distribuição Aleatória
3.
Front Hum Neurosci ; 12: 289, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30072884

RESUMO

Motor sequence learning is associated with the activation of bilateral primary motor cortices (M1). While previous data support the hypothesis that the contralateral M1 is causally involved in the acquisition as well as early consolidation of a motor sequence, the functional significance of the ipsilateral M1 has yet to be solved. Transcranial direct current stimulation (tDCS) allows the non-invasive modulation of cortical excitability. Anodal tDCS applied to the left M1 has been shown to facilitate implicit motor sequence learning of the right hand most likely due to increased excitability. The present study aims at characterizing the functional contribution of the ipsilateral (right) M1 on implicit motor sequence learning of the right hand. To this end, 24 healthy, right-handed subjects received anodal and sham tDCS to the right M1 in a counterbalanced order. Stimulation started 8 min prior to training on a variant of the serial reaction time task (SRTT) with the right hand and persists over the entire training period. The SRTT comprised a fixed eight-digit sequence. A random pattern served as control condition. Reaction times were assessed before and at the end of the acquisition (EoA) immediately after training on the SRTT. The analysis revealed significantly faster reaction times of both hands independent of tDCS condition in sequential trials. However, the gain of reaction times was significantly smaller following anodal as compared to sham tDCS. The data suggest that anodal tDCS applied to the right M1 impairs implicit motor sequence learning of both hands. The underlying mechanism likely involves alterations of the interaction between bilateral M1.

4.
Neuropsychologia ; 117: 46-54, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29758227

RESUMO

Phasic dopamine (DA) signals conveyed from the substantia nigra to the striatum and the prefrontal cortex crucially affect learning from feedback, with DA bursts facilitating learning from positive feedback and DA dips facilitating learning from negative feedback. Consequently, diminished nigro-striatal dopamine levels as in unmedicated patients suffering from Parkinson's Disease (PD) have been shown to lead to a negative learning bias. Recent studies suggested a diminished striatal contribution to feedback processing when the outcome of an action is temporally delayed. This study investigated whether the bias towards negative feedback learning induced by a lack of DA in PD patients OFF medication is modulated by feedback delay. To this end, PD patients OFF medication and healthy controls completed a probabilistic selection task, in which feedback was given immediately (after 800 ms) or delayed (after 6800 ms). PD patients were impaired in immediate but not delayed feedback learning. However, differences in the preference for positive/negative learning between patients and controls were seen for both learning from immediate and delayed feedback, with evidence of stronger negative learning in patients than controls. A Bayesian analysis of the data supports the conclusion that feedback timing did not affect the learning bias in the patients. These results hint at reduced, but still relevant nigro-striatal contribution to feedback learning, when feedback is delayed.


Assuntos
Retroalimentação Psicológica , Deficiências da Aprendizagem/etiologia , Deficiências da Aprendizagem/terapia , Doença de Parkinson/complicações , Idoso , Análise de Variância , Aprendizagem por Associação , Teorema de Bayes , Comportamento de Escolha/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Reforço Psicológico , Fatores de Tempo
5.
Front Behav Neurosci ; 12: 63, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29670514

RESUMO

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that allows the modulation of cortical excitability as well as neuroplastic reorganization using a weak constant current applied through the skull on the cerebral cortex. TDCS has been found to improve motor performance in general and motor learning in particular. However, these effects have been reported almost exclusively for unimanual motor tasks such as serial reaction time tasks, adaptation tasks, or visuo-motor tracking. Despite the importance of bimanual actions in most activities of daily living, only few studies have investigated the effects of tDCS on bimanual motor skills. The objectives of this review article are: (i) to provide a concise overview of the few existing studies in this area; and (ii) to discuss the effects of tDCS on bimanual motor skills in healthy volunteers and patients suffering from neurological diseases. Despite considerable variations in stimulation protocols, the bimanual tasks employed, and study designs, the data suggest that tDCS has the potential to enhance bimanual motor skills. The findings imply that the effects of tDCS vary with task demands, such as complexity and the level of expertise of the participating volunteers. Nevertheless, optimized stimulation protocols tailored to bimanual tasks and individual performance considering the underlying neural substrates of task execution are required in order to probe the effectiveness of tDCS in greater detail, thus creating an opportunity to support motor recovery in neuro-rehabilitation.

6.
Front Neurosci ; 11: 677, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29270105

RESUMO

Pitch memory is a resource which is shared by music and language. Neuroimaging studies have shown that the right dorsolateral prefrontal cortex (DLPFC) is activated during pitch memory processes. The present study investigated the causal significance of this brain area for pitch memory in non-musicians by applying cathodal and sham transcranial direct current stimulation (tDCS) over the right DLPFC and examining the impact on offline pitch and visual memory span performances. On the overall sample (N = 22) no significant modulation effect of cathodal stimulation on the pitch span task was found. However, when dividing the sample by means of a median split of pre-test pitch memory abilities into a high and low performing group, a selective effect of significantly impaired pitch memory after cathodal tDCS in good performers was revealed. The visual control task was not affected by the stimulation in either group. The results support previous neuroimaging studies that the right DLPFC is involved in pitch memory processes in non-musicians and highlights the importance of baseline pitch memory abilities for the modulatory effect of tDCS.

7.
Front Hum Neurosci ; 11: 183, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28443012

RESUMO

The synchronization task is a well-established paradigm for the investigation of motor timing with respect to an external pacing signal. It requires subjects to synchronize their finger taps in synchrony with a regular metronome. A specific significance of the posterior parietal cortex (PPC) for superior synchronization in professional drummers has been suggested. In non-musicians, modulation of the excitability of the left PPC by means of transcranial direct current stimulation (tDCS) modulates synchronization performance of the right hand. In order to determine the significance of the left PPC for superior synchronization in drummers, we here investigate the effects of cathodal and anodal tDCS in 20 professional drummers on auditory-motor synchronization of the right hand. A continuation and a reaction time task served as control conditions. Moreover, the interaction between baseline performance and tDCS polarity was estimated in precise as compared to less precise synchronizers according to median split. Previously published data from 16 non-musicians were re-analyzed accordingly in order to highlight possible differences of tDCS effects in drummers and non-musicians. TDCS was applied for 10 min with an intensity of 0.25 mA over the left PPC. Behavioral measures were determined prior to and immediately after tDCS. In drummers the overall analysis of synchronization performance revealed significantly larger tap-to-tone asynchronies following anodal tDCS with the tap preceding the tone replicating findings in non-musicians. No significant effects were found on control tasks. The analysis for participants with large as compared to small baseline asynchronies revealed that only in drummers with small asynchronies tDCS interfered with synchronization performance. The re-analysis of the data from non-musicians indicated the reversed pattern. The data support the hypothesis that the PPC is involved in auditory-motor synchronization and extend previous findings by showing that its functional significance varies with musical expertise.

8.
Sci Rep ; 7: 42456, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28198386

RESUMO

Functional brain imaging studies and non-invasive brain stimulation methods have shown the importance of the left supramarginal gyrus (SMG) for pitch memory. The extent to which this brain region plays a crucial role in memory for other auditory material remains unclear. Here, we sought to investigate the role of the left and right SMG in pitch and rhythm memory in non-musicians. Anodal or sham transcranial direct current stimulation (tDCS) was applied over the left SMG (Experiment 1) and right SMG (Experiment 2) in two different sessions. In each session participants completed a pitch and rhythm recognition memory task immediately after tDCS. A significant facilitation of pitch memory was revealed when anodal stimulation was applied over the left SMG. No significant effects on pitch memory were found for anodal tDCS over the right SMG or sham condition. For rhythm memory the opposite pattern was found; anodal tDCS over the right SMG led to an improvement in performance, but anodal tDCS over the left SMG had no significant effect. These results highlight a different hemispheric involvement of the SMG in auditory memory processing depending on auditory material that is encoded.


Assuntos
Dominância Cerebral , Memória , Lobo Parietal/fisiologia , Nível de Percepção Sonora , Estimulação Acústica , Análise de Variância , Mapeamento Encefálico , Feminino , Humanos , Masculino
9.
Behav Brain Res ; 316: 87-93, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27542725

RESUMO

While the primary motor cortex (M1) is involved in the acquisition the premotor cortex (PMC) has been related to over-night consolidation of a newly learned motor skill. The present study aims at investigating the possible contribution of the left PMC for the stabilization of a motor sequence immediately after acquisition as determined by susceptibility to interference. Thirty six healthy volunteers received anodal, cathodal and sham transcranial direct current stimulation (tDCS) to the left PMC either immediately prior to or during training on a serial reaction time task (SRTT) with the right hand. TDCS was applied for 10min, respectively. Reaction times were measured prior to training (t1), at the end of training (t2), and after presentation of an interfering random pattern (t3). Beyond interference from learning, the random pattern served as control condition in order to estimate general effects of tDCS on reaction times. TDCS applied during SRTT training did not result in any significant effects neither on acquisition nor on susceptibility to interference. In contrast to this, tDCS prior to SRTT training yielded an unspecific facilitation of reaction times at t2 independent of tDCS polarity. At t3, reduced susceptibility to interference was found following cathodal stimulation. The results suggest the involvement of the PMC in early consolidation and reveal a piece of evidence for the hypothesis that behavioral tDCS effects vary with the activation state of the stimulated area.


Assuntos
Lateralidade Funcional/fisiologia , Aprendizagem/fisiologia , Córtex Pré-Frontal/fisiologia , Estimulação Transcraniana por Corrente Contínua/métodos , Adulto , Método Duplo-Cego , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Neuronavegação , Tempo de Reação/fisiologia , Fatores de Tempo , Adulto Jovem
10.
Behav Brain Res ; 313: 88-96, 2016 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-27374161

RESUMO

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) provides an effective treatment for Parkinson's disease (PD) motor symptoms. However, findings of effects on cognitive function such as feedback learning remain controversial and rare. The aim of the present study was to gain a better understanding of cognitive alterations associated with STN-DBS. Therefore, we investigated effects of STN-DBS on active and observational feedback learning in PD. 18 PD patients with STN-DBS and 18 matched healthy controls completed active and observational feedback learning tasks. Patients were investigated ON and OFF STN-DBS. Tasks consisted of learning (with feedback) and test phases (without feedback). STN-DBS improved active learning during feedback trials and PD patients ON (but not OFF) STN-DBS showed comparable performance patterns as healthy controls. No STN-DBS effect was found when assessing performance during active test trials without feedback. In this case, however, STN-DBS effects were found to depend on symptom severity. While more impaired patients benefited from STN-DBS, stimulation had no facilitating effect on patients with less severe symptoms. Along similar lines, the severity of motor symptoms tended to be significantly correlated with differences in active test performance due to STN-DBS. For observational feedback learning, there was a tendency for a positive STN-DBS effect with patients reaching the performance level of healthy controls only ON STN-DBS. The present data suggest that STN-DBS facilitates active feedback learning in PD patients. Furthermore, they provide first evidence that STN-DBS might not only affect learning from own but also from observed actions and outcomes.


Assuntos
Estimulação Encefálica Profunda , Feedback Formativo , Doença de Parkinson/psicologia , Doença de Parkinson/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Núcleo Subtalâmico/fisiopatologia
11.
Front Aging Neurosci ; 8: 89, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27199736

RESUMO

Although implicit motor sequence learning is rather well understood in young adults, effects of aging on this kind of learning are controversial. There is first evidence that working memory (WM) might play a role in implicit motor sequence learning in young adults as well as in adults above the age of 65. However, the knowledge about the development of these processes across the adult life span is rather limited. As the average age of our population continues to rise, a better understanding of age-related changes in motor sequence learning and potentially mediating cognitive processes takes on increasing significance. Therefore, we investigated aging effects on implicit motor sequence learning and WM. Sixty adults (18-71 years) completed verbal and visuospatial n-back tasks and were trained on a serial reaction time task (SRTT). Randomly varying trials served as control condition. To further assess consolidation indicated by off-line improvement and reduced susceptibility to interference, reaction times (RTs) were determined 1 h after initial learning. Young and older but not middle-aged adults showed motor sequence learning. Nine out of 20 older adults (compared to one young/one middle-aged) exhibited some evidence of sequence awareness. After 1 h, young and middle-aged adults showed off-line improvement. However, RT facilitation was not specific to sequence trials. Importantly, susceptibility to interference was reduced in young and older adults indicating the occurrence of consolidation. Although WM performance declined in older participants when load was high, it was not significantly related to sequence learning. The data reveal a decline in motor sequence learning in middle-aged but not in older adults. The use of explicit learning strategies in older adults might account for the latter result.

12.
Front Behav Neurosci ; 10: 4, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26834593

RESUMO

The primary motor cortex (M1) contributes to the acquisition and early consolidation of a motor sequence. Although the relevance of M1 excitability for motor learning has been supported, the significance of M1 oscillations remains an open issue. This study aims at investigating to what extent retrieval of a newly learned motor sequence can be differentially affected by motor-cortical transcranial alternating (tACS) and direct current stimulation (tDCS). Alpha (10 Hz), beta (20 Hz) or sham tACS was applied in 36 right-handers. Anodal or cathodal tDCS was applied in 30 right-handers. Participants learned an eight-digit serial reaction time task (SRTT; sequential vs. random) with the right hand. Stimulation was applied to the left M1 after SRTT acquisition at rest for 10 min. Reaction times were analyzed at baseline, end of acquisition, retrieval immediately after stimulation and reacquisition after eight further sequence repetitions. Reaction times during retrieval were significantly faster following 20 Hz tACS as compared to 10 Hz and sham tACS indicating a facilitation of early consolidation. tDCS yielded faster reaction times, too, independent of polarity. No significant differences between 20 Hz tACS and tDCS effects on retrieval were found suggesting that 20 Hz effects might be associated with altered motor-cortical excitability. Based on the behavioral modulation yielded by tACS and tDCS one might speculate that altered motor-cortical beta oscillations support early motor consolidation possibly associated with neuroplastic reorganization.

13.
Behav Brain Res ; 294: 141-8, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26254878

RESUMO

Brain imaging studies highlighted structural differences in congenital amusia, a life-long perceptual disorder that is associated with pitch perception and pitch memory deficits. A functional anomaly characterized by decreased low gamma oscillations (30-40 Hz range) in the right dorsolateral prefrontal cortex (DLPFC) during pitch memory has been revealed recently. Thus, the present study investigates whether applying transcranial alternating current stimulation (tACS) at 35 Hz to the right DLPFC would improve pitch memory. Nine amusics took part in two tACS sessions (either 35 Hz or 90 Hz) and completed a pitch and visual memory task before and during stimulation. 35 Hz stimulation facilitated pitch memory significantly. No modulation effects were found with 90 Hz stimulation or on the visual task. While amusics showed a selective impairment of pitch memory before stimulation, the performance during 35 Hz stimulation was not significantly different to healthy controls anymore. Taken together, the study shows that modulating the right DLPFC with 35 Hz tACS in congenital amusia selectively improves pitch memory performance supporting the hypothesis that decreased gamma oscillations within the DLPFC are causally involved in disturbed pitch memory and highlight the potential use of tACS to interact with cognitive processes.


Assuntos
Transtornos da Percepção Auditiva/fisiopatologia , Transtornos da Percepção Auditiva/terapia , Memória de Curto Prazo/fisiologia , Nível de Percepção Sonora/fisiologia , Córtex Pré-Frontal/fisiopatologia , Estimulação Transcraniana por Corrente Contínua/métodos , Estimulação Acústica , Transtornos da Percepção Auditiva/psicologia , Feminino , Humanos , Masculino , Música , Testes Neuropsicológicos , Índice de Gravidade de Doença , Detecção de Sinal Psicológico/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
14.
Behav Brain Res ; 293: 234-40, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26225845

RESUMO

At present it remains elusive to what extent motor-cortical alpha (8-12Hz) and beta (13-30Hz) oscillations are associated with motor sequence learning. In order to interact with motor-cortical oscillations, the present study applied transcranial alternating current stimulation (tACS) at 10Hz, 20Hz and sham stimulation over the left primary motor cortex (M1) during a serial reaction time task (SRTT) in 13 healthy volunteers. In a control experiment, tACS at 35Hz was applied in another sample of 13 volunteers. The participants performed the task with the right hand. A sequential pattern was interleaved by a randomly varying pattern serving as interference from sequence learning. Reaction times were determined as dependent variable. Both 10 and 20Hz tACS facilitated SRTT acquisition in contrast to sham and 35Hz tACS. After acquisition, the interfering condition led to increased reaction times comparable to baseline level during 10Hz, sham and 35Hz tACS. In contrast, during 20Hz tACS the initial learning success was retained despite interference. While motor-cortical tACS at 10 and 20Hz likewise facilitates the acquisition, tACS at 20Hz frequency additionally stabilizes the newly learned motor sequence indicated by less susceptibility to interference.


Assuntos
Potencial Evocado Motor/fisiologia , Aprendizagem/fisiologia , Córtex Motor/fisiologia , Movimento/fisiologia , Estimulação Transcraniana por Corrente Contínua , Análise de Variância , Biofísica , Método Duplo-Cego , Feminino , Mãos/inervação , Humanos , Masculino , Desempenho Psicomotor , Tempo de Reação/fisiologia , Fatores de Tempo , Adulto Jovem
15.
Eur J Neurosci ; 42(1): 1660-6, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25959620

RESUMO

Functional brain imaging studies have highlighted the significance of right-lateralized temporal, frontal and parietal brain areas for memory for melodies. The present study investigated the involvement of bilateral posterior parietal cortices (PPCs) for the recognition memory of melodies using transcranial direct current stimulation (tDCS). Participants performed a recognition task before and after tDCS. The task included an encoding phase (12 melodies), a retention period, as well as a recognition phase (24 melodies). Experiment 1 revealed that anodal tDCS over the right PPC led to a deterioration of overall memory performance compared with sham. Experiment 2 confirmed the results of Experiment 1 and further showed that anodal tDCS over the left PPC did not show a modulatory effect on memory task performance, indicating a right lateralization for musical memory. Furthermore, both experiments revealed that the decline in memory for melodies can be traced back to an interference of anodal stimulation on the recollection process (remember judgements) rather than to familiarity judgements. Taken together, this study revealed a causal involvement of the right PPC for memory for melodies and demonstrated a key role for this brain region in the recollection process of the memory task.


Assuntos
Lateralidade Funcional , Lobo Parietal/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto , Feminino , Humanos , Masculino , Música , Estimulação Transcraniana por Corrente Contínua , Adulto Jovem
16.
Cortex ; 64: 310-7, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25577719

RESUMO

Brain stimulation studies have previously demonstrated a causal link between general pitch memory processes and activity within the left supramarginal gyrus (SMG). Building on this evidence, the present study tested the impact of left SMG stimulation on two distinct pitch memory phases, retention and encoding. Repetitive transcranial magnetic stimulation (rTMS) was employed during the retention stage (Experiment 1) and the encoding phase (Experiment 2) of a pitch recognition task. Stimulation was applied on a trial-by-trial basis over the left SMG (target site) or the vertex (control site). A block without TMS was also completed. In Experiment 1, rTMS over the left SMG during pitch retention led to significantly increased reaction times compared to control conditions. In Experiment 2 no rTMS modulation effects were found during encoding. Experiment 3 was conducted as a control for non-specific stimulation effects; no effects were found when rTMS was applied over the left SMG at the two different time points during a perceptual task. Taken together, these findings highlight a phase-specific involvement of the left SMG in the retention phase of pitch memory, thereby indicating that the left SMG is involved in the maintenance of pitch information.


Assuntos
Lobo Parietal/fisiologia , Nível de Percepção Sonora/fisiologia , Retenção Psicológica/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Música , Tempo de Reação/fisiologia , Estimulação Magnética Transcraniana , Adulto Jovem
17.
Pediatr Diabetes ; 16(6): 454-61, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25040238

RESUMO

INTRODUCTION: The study aims to elucidate whether awareness of personal resources, such as positive attributions and beliefs or social support, affects metabolic control in children and adolescents with type 1 diabetes. In addition, it will be determined to what extent metabolic control is influenced by concordance between children and parents regarding awareness of resources and the parents' ability to adopt their children's perspective. Also, the children's wishes particularly in relation to their illness will be investigated, as well as the kind of advice they would offer to fellow patients. METHODS: Seventy-eight children/adolescents with type 1 diabetes completed the Essen Resource Inventory for Children and Adolescents including personal, social, structural, and migration-specific resources. In addition, children/adolescents and their parents completed a systemic-oriented, diabetes-specific resource questionnaire in order to explore the parents' ability to adopt their children's perspective. RESULTS: Resources such as body awareness and open-minded attitude to the disease were associated with metabolic control. Particularly, resources associated to a migration background were found to be inversely correlated with hemoglobin A1c (HbA1c) value. Moreover, it was shown that the parents' ability to adopt their children's perspective was associated with improved metabolic control. Children advising fellow patients to accept the disease showed the best HbA1c value. DISCUSSION: This data identified specific modifiable factors related to metabolic control that can be addressed during counseling of pediatric patients. Also the parents' ability for adopting their child's perspective was identified as a relevant factor which should be considered during clinical counseling of young type 1 diabetes patients.


Assuntos
Atitude Frente a Saúde , Educação Infantil , Diabetes Mellitus Tipo 1/terapia , Hiperglicemia/prevenção & controle , Hipoglicemia/prevenção & controle , Autoimagem , Apoio Social , Adolescente , Imagem Corporal , Criança , Terapia Combinada , Diabetes Mellitus Tipo 1/sangue , Feminino , Alemanha , Hemoglobina A Glicada/análise , Humanos , Masculino , Poder Familiar , Pais , Inquéritos e Questionários , Migrantes
18.
Brain Stimul ; 7(6): 800-6, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25216648

RESUMO

BACKGROUND: Flexible and precisely timed motor control is based on functional interaction within a cortico-subcortical network. The left posterior parietal cortex (PPC) is supposed to be crucial for anticipatory motor control by sensorimotor feedback matching. OBJECTIVE: Intention of the present study was to disentangle the specific relevance of the left PPC for anticipatory motor control using transcranial direct current stimulation (tDCS) since a causal link remains to be established. METHODS: Anodal vs. cathodal tDCS was applied for 10 min over the left PPC in 16 right-handed subjects in separate sessions. Left primary motor cortex (M1) tDCS served as control condition and was applied in additional 15 subjects. Prior to and immediately after tDCS, subjects performed three tasks demanding temporal motor precision with respect to an auditory stimulus: sensorimotor synchronization as measure of anticipatory motor control, interval reproduction and simple reaction. RESULTS: Left PPC tDCS affected right hand synchronization but not simple reaction times. Motor anticipation was deteriorated by anodal tDCS, while cathodal tDCS yielded the reverse effect. The variability of interval reproduction was increased by anodal left M1 tDCS, whereas it was reduced by cathodal tDCS. No significant effects on simple reaction times were found. CONCLUSION: The present data support the hypothesis that left PPC is causally involved in right hand anticipatory motor control exceeding pure motor implementation as processed by M1 and possibly indicating subjective timing. Since M1 tDCS particularly affects motor implementation, the observed PPC effects are not likely to be explained by alterations of motor-cortical excitability.


Assuntos
Antecipação Psicológica/fisiologia , Lateralidade Funcional/fisiologia , Lobo Parietal/fisiologia , Adulto , Método Duplo-Cego , Feminino , Mãos/fisiologia , Humanos , Masculino , Córtex Motor/fisiologia , Tempo de Reação/fisiologia , Estimulação Transcraniana por Corrente Contínua , Adulto Jovem
19.
Front Hum Neurosci ; 7: 511, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24009573

RESUMO

Synchronous oscillatory activity at alpha (8-12 Hz), beta (13-30 Hz), and gamma (30-90 Hz) frequencies is assumed to play a key role for motor control. Corticomuscular coherence (CMC) represents an established measure of the pyramidal system's integrity. Transcranial alternating current stimulation (tACS) offers the possibility to modulate ongoing oscillatory activity. Behaviorally, 20 Hz tACS in healthy subjects has been shown to result in movement slowing. However, the neurophysiological changes underlying these effects are not entirely understood yet. The present study aimed at ascertaining the effects of tACS at 10 and 20 Hz in healthy subjects on CMC and local power of the primary sensorimotor cortex. Neuromagnetic activity was recorded during isometric contraction before and at two time points (2-10 min and 30-38 min) after tACS of the left primary motor cortex (M1), using a 306 channel whole head magnetoencephalography (MEG) system. Additionally, electromyography (EMG) of the right extensor digitorum communis (EDC) muscle was measured. TACS was applied at 10 and 20 Hz, respectively, for 10 min at 1 mA. Sham stimulation served as control condition. The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction. This implies that tACS does not necessarily cause effects at stimulation frequency. Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle.

20.
Exp Neurol ; 247: 178-81, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23664959

RESUMO

Parkinson's disease (PD) is a common neurodegenerative disorder owing to loss of dopaminergic cells. Akinesia - one of the core symptoms of PD - is associated with exaggerated oscillations at beta frequency (13-30 Hz) within the subthalamic nucleus (STN). Thus, enhanced oscillations below 30 Hz are assumed to represent a pathophysiological marker of PD. However, recent data suggest that OFF medication exaggerated beta oscillations within basal ganglia (BG) cortical networks may serve for the compensation of BG dysfunctions. The STN is functionally connected to mesial prefrontal areas like the supplementary motor area (SMA). But, it is still not fully understood how enhanced beta oscillations within the BG exert dominance over the primary motor cortex (M1) thereby yielding motor impairment. The present study, therefore, investigates the effect of dopaminergic state on SMA-M1 functional connectivity using Magnetoencephalography (MEG). MEG data were recorded in 7 patients suffering from PD with preponderance of akinesia during isometric contraction of the right forearm and during rest. Coherence as a measure of functional connectivity between M1 and SMA was calculated OFF and ON medication and correlated with the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS III) and with disease duration. During rest a significant positive correlation between disease duration and SMA-M1 coherence was found ON but not OFF medication. Conversely, during isometric contraction SMA-M1 coherence and UPDRS III were inversely correlated OFF but not ON medication explaining more than 80% of variance. The results favor the hypothesis that OFF medication exaggerated cortical coherence at beta frequency represents a compensatory mechanism rather than a pathophysiological marker per se.


Assuntos
Ritmo beta/fisiologia , Córtex Motor/fisiopatologia , Doença de Parkinson/patologia , Doença de Parkinson/fisiopatologia , Núcleo Subtalâmico/fisiopatologia , Idoso , Gânglios da Base/fisiopatologia , Mapeamento Encefálico , Eletroencefalografia , Eletromiografia , Feminino , Humanos , Modelos Lineares , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença
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