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1.
JMIR Med Educ ; 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38712378

RESUMEN

BACKGROUND: Multiple-choice examinations are frequently employed among German dental schools. However, details regarding the used item types and applied scoring methods are lacking. OBJECTIVE: We aimed to gain an insight into the current usage of multiple-choice items (ie, questions) in summative examinations in German undergraduate dental training programmes. METHODS: A paper-based 10-item questionnaire regarding the employed assessment methods, multiple-choice item types, and applied scoring methods was designed. The pilot-tested questionnaire was mailed to the Deans of Studies and to the Heads of Department of Operative/Restorative Dentistry at all 30 dental schools in Germany in February 2023. Statistical analysis was performed using Fisher's exact test (P<.05). RESULTS: The response rate amounted to 90.0% (27/30 dental schools). All respondent dental schools employed multiple-choice examinations for summative assessments. Examinations were delivered electronically by 70.4% (19/27) of the dental schools. Almost all dental schools used single-choice Type A items (88.9%) which accounted for the largest number of items in about half of the dental schools. Further item types (eg, conventional multiple-select items, Multiple-True-False, Pick-N) were only used by fewer dental schools (≤66.7%, up to 18 out of 27 dental schools). For the multiple-select item types, the applied scoring methods varied considerably (ie, awarding [intermediate] partial credit, requirements for partial credit). Dental schools with the possibility of electronic examinations used multiple-select items slightly more often (73.7%, 14/19 vs. 50.0%, 4/8). However, this difference was statistically not significant (P=.375). Dental schools used items either individually or as key feature problems consisting of a clinical case scenario followed by a number of items focusing on critical treatment steps (55.6%, 15/27). Not a single school employed alternative testing methods (eg, answer-until-correct). A formal item review process was established at about half of the dental schools (55.6%, 15/27). CONCLUSIONS: Summative assessment methods among German dental schools vary widely. Especially, a large variability regarding the use and scoring of multiple-select multiple-choice items was found.

2.
JMIR Med Educ ; 9: e43792, 2023 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-36841970

RESUMEN

BACKGROUND: Scoring and awarding credit are more complex for multiple-select items than for single-choice items. Forty-one different scoring methods were retrospectively applied to 2 multiple-select multiple-choice item types (Pick-N and Multiple-True-False [MTF]) from existing examination data. OBJECTIVE: This study aimed to calculate and compare the mean scores for both item types by applying different scoring methods, and to investigate the effect of item quality on mean raw scores and the likelihood of resulting scores at or above the pass level (≥0.6). METHODS: Items and responses from examinees (ie, marking events) were retrieved from previous examinations. Different scoring methods were retrospectively applied to the existing examination data to calculate corresponding examination scores. In addition, item quality was assessed using a validated checklist. Statistical analysis was performed using the Kruskal-Wallis test, Wilcoxon rank-sum test, and multiple logistic regression analysis (P<.05). RESULTS: We analyzed 1931 marking events of 48 Pick-N items and 828 marking events of 18 MTF items. For both item types, scoring results widely differed between scoring methods (minimum: 0.02, maximum: 0.98; P<.001). Both the use of an inappropriate item type (34 items) and the presence of cues (30 items) impacted the scoring results. Inappropriately used Pick-N items resulted in lower mean raw scores (0.88 vs 0.93; P<.001), while inappropriately used MTF items resulted in higher mean raw scores (0.88 vs 0.85; P=.001). Mean raw scores were higher for MTF items with cues than for those without cues (0.91 vs 0.8; P<.001), while mean raw scores for Pick-N items with and without cues did not differ (0.89 vs 0.90; P=.09). Item quality also impacted the likelihood of resulting scores at or above the pass level (odds ratio ≤6.977). CONCLUSIONS: Educators should pay attention when using multiple-select multiple-choice items and select the most appropriate item type. Different item types, different scoring methods, and presence of cues are likely to impact examinees' scores and overall examination results.

3.
Nervenarzt ; 91(7): 635-641, 2020 Jul.
Artículo en Alemán | MEDLINE | ID: mdl-31468093

RESUMEN

BACKGROUND: The master plan for medical studies 2020 (MM2020) aims at a restructuring of medical education. The examinations should represent the key element of the evaluation and electronically supported examination methods will be expanded. OBJECTIVE: Videos of actors displaying psychopathological phenomena were implemented into examination questions for the first time through the use of an electronically supported examination (e-examination) and therefore in accordance with the aims of MM2020. METHODS: A total of four multiple choice (MC) questions referencing short video representations of different psychopathological phenomena were formulated and shown to medical students within an e­examination. The MC questions were evaluated with respect to scientific quality criteria and the medical students were asked to fill in a questionnaire regarding their evaluation of the content and format of the MC questions after participating in the examination. RESULTS: The MC video questions were presented to the students directly following the regular e­examination of the teaching module in psychiatry. Out of 69 students 60 participated in the study. The MC video questions had a high level of acceptance and positive evaluation by the students. With respect to the scientific quality criteria, the MC questions showed heterogeneous results. CONCLUSION: Due to the versatile applicability and high efficiency, MC questions will continue to play an important role in medical examinations. In accordance with the aims of MM2020, it could be shown that psychiatric knowledge can be examined in a competence-oriented manner and with a practical orientation by means of video presentations in an e­examination. A broader application of video presentations could complement electronically supported examinations in the discipline of psychiatry.


Asunto(s)
Educación de Pregrado en Medicina , Educación Médica , Psiquiatría , Estudiantes de Medicina , Evaluación Educacional , Humanos , Examen Físico , Proyectos Piloto , Psiquiatría/educación , Grabación en Video
4.
BMC Neurol ; 19(1): 312, 2019 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-31801464

RESUMEN

BACKGROUND: Vertebral artery dissection (VAD) may cause cerebral ischemia and impair quality of life (QOL) despite of good functional outcome. The aim of this study was the multimodal analysis of patient characteristics after VAD to identify contributing factors. METHODS: In an exploratory study, 34 consecutive patients with first-ever spontaneous VAD were prospectively examined in comparison to 38 patients with cerebral ischemia without dissection and 25 stroke mimics as control groups. Multimodal assessment was performed for clinical, neurological, cognitive, psychological and radiological data at baseline and for QOL, functional outcome, and stress symptoms by questionnaire at six months follow-up. Subgroup analysis stratified for QOL by Stroke Specific Quality of Life Scale (SS-QOL) were done for patients with good functional outcome (modified Ranking Scale (mRS) scoring 0-2). Predictors for QOL at follow-up were analyzed by regression model. RESULTS: 88.2% of patients with VAD suffered from acute cerebral ischemia. Thirteen of 32 VAD patients (40.6%) rated QOL at follow-up as bad (SS-QOL score ≤ 3.9) despite of good functional outcome (mRS score 0-2). Subgroup analysis yielded significantly higher scores for posttraumatic stress symptoms (p = 0.002) in this subgroup. Posttraumatic stress symptoms, severity of neurological disorders, and impaired neuropsychological baseline performance proved to be independent predictors for reduced QOL at follow-up according to regression analysis. CONCLUSION: VAD leads to impaired QOL at 6 months follow-up due to multiple factors. The data suggest that posttraumatic stress symptoms are of significant importance for the QOL after VAD. Clinical monitoring should address this topic to make timely treatment possible.


Asunto(s)
Isquemia Encefálica/etiología , Calidad de Vida , Accidente Cerebrovascular/etiología , Disección de la Arteria Vertebral/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Infarto Cerebral/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Radiografía , Encuestas y Cuestionarios
5.
Neuroimage ; 201: 116016, 2019 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-31310861

RESUMEN

Childhood obesity is a rising problem caused in part by unhealthy food choices. Food choices are based on a neural value signal encoded in the ventromedial prefrontal cortex, and self-control involves modulation of this signal by the dorsolateral prefrontal cortex (dlPFC). We determined the effects of development, body mass (BMI Cole score) and body mass history on the neural correlates of healthy food choice in children. 141 children (aged 10-17y) from Germany, Hungary and Sweden were scanned with fMRI while performing a food choice task. Afterwards health and taste ratings of the foods were collected. In the food choice task children were asked to consider the healthiness or tastiness of the food or to choose naturally. Overall, children made healthier choices when asked to consider healthiness. However, children who had a higher weight gain per year chose less healthy foods when considering healthiness but not when choosing naturally. Pubertal development stage correlated positively while current body mass correlated negatively with dlPFC activation when accepting foods. Pubertal development negatively and current body mass positively influenced the effect of considering healthiness on activation of brain areas involved in salience and motivation. In conclusion, children in earlier stages of pubertal development and children with a higher body weight exhibited less activation in the dlPFC, which has been implicated in self-control during food choice. Furthermore, pubertal development and body mass influenced neural responses to a health cue in areas involved in salience and motivation. Thus, these findings suggest that children in earlier stages of pubertal development, children with a higher body mass gain and children with overweight may possibly be less susceptible to healthy eating interventions that rely on self-control or that highlight health aspects of food.


Asunto(s)
Índice de Masa Corporal , Conducta de Elección/fisiología , Preferencias Alimentarias/fisiología , Corteza Prefrontal/fisiología , Autocontrol , Adolescente , Niño , Dieta Saludable , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Sobrepeso
6.
PLoS One ; 13(10): e0205331, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30335775

RESUMEN

OBJECTIVES: Neuroimaging data suggest that pediatric overweight and obesity are associated with morphological alterations in gray matter (GM) brain structures, but previous studies using mainly voxel-based morphometry (VBM) showed inconsistent results. Here, we aimed to examine the relationship between youth obesity and the volume of predefined reward system structures using magnetic resonance (MR) volumetry. We also aimed to complement volumetry with VBM-style analysis. METHODS: Fifty-one Caucasian young subjects (32 females; mean age: 13.8±1.9, range: 10.2-16.5 years) were included. Subjects were selected from a subsample of the I.Family study examined in the Hungarian center. A T1-weighted 1 mm3 isotropic resolution image was acquired. Age- and sex-standardized body mass index (zBMI) was assessed at the day of MRI and ~1.89 years (mean±SD: 689±188 days) before the examination. Obesity related GM alterations were investigated using MR volumetry in five predefined brain structures presumed to play crucial roles in body weight regulation (hippocampus, amygdala, accumbens, caudate, putamen), as well as whole-brain and regional VBM. RESULTS: The volumes of accumbens and amygdala showed significant positive correlations with zBMI, while their GM densities were inversely related to zBMI. Voxel-based GM mass also showed significant negative correlation with zBMI when investigated in the predefined amygdala region, but this relationship was mediated by GM density. CONCLUSIONS: Overweight/obesity related morphometric brain differences already seem to be present in children/adolescents. Our work highlights the disparity between volume and VBM-derived measures and that GM mass (combination of volume and density) is not informative in the context of obesity related volumetric changes. To better characterize the association between childhood obesity and GM morphometry, a combination of volumetric segmentation and VBM methods, as well as future longitudinal studies are necessary. Our results suggest that childhood obesity is associated with enlarged structural volumes, but decreased GM density in the reward system.


Asunto(s)
Amígdala del Cerebelo/anatomía & histología , Sustancia Gris/anatomía & histología , Sobrepeso/diagnóstico por imagen , Obesidad Infantil/diagnóstico por imagen , Adolescente , Amígdala del Cerebelo/diagnóstico por imagen , Índice de Masa Corporal , Niño , Tomografía Computarizada de Haz Cónico , Femenino , Sustancia Gris/diagnóstico por imagen , Hipocampo/anatomía & histología , Hipocampo/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Sobrepeso/fisiopatología , Obesidad Infantil/fisiopatología , Putamen/anatomía & histología , Putamen/diagnóstico por imagen
7.
J Dent Educ ; 82(9): 943-948, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30173190

RESUMEN

The aim of this study was to evaluate dental students' retention of factual and procedural knowledge gained in a preclinical course in operative dentistry during a clinical dental curriculum. In 2017, all 157 seventh- to tenth-semester dental students at a dental school in Germany were asked to repeat the same written examination performed at the end of the preclinical course in the sixth semester. The examinations consisted of 30 multiple-choice questions covering factual and procedural knowledge. The percentage of correctly answered questions per exam and differences in correct answers between the original examination and the re-examination (per question) were analyzed. Students were also asked to self-rate their percentage of correctly answered questions and their knowledge in various disciplines of operative dentistry at the times of the original examination and the re-examination. After exclusions, data were analyzed for 129 students, for a participation rate of 82%. For the seventh- and tenth-semester students, the results on the original examination and the re-examination were not significantly different, while the eighth- and ninth-semester students performed significantly better on the original examination than the re-examination. In all semesters, procedural knowledge remained stable between the original examination and the re-examination, while factual knowledge decreased slightly. Their performance on the original examination was underestimated by the eighth- and ninth-semester students. All the students underestimated their performance on the re-examination. Students mostly rated their knowledge level significantly higher on the original examination than on the re-examination. Overall, this study found that factual and procedural knowledge gained in a preclinical course in operative dentistry was not increased during the clinical dental curriculum.


Asunto(s)
Operatoria Dental/educación , Retención en Psicología , Estudiantes de Odontología/psicología , Curriculum , Operatoria Dental/métodos , Evaluación Educacional , Femenino , Humanos , Masculino , Factores Sexuales , Estudiantes de Odontología/estadística & datos numéricos
8.
BMC Neurosci ; 19(1): 35, 2018 06 19.
Artículo en Inglés | MEDLINE | ID: mdl-29914377

RESUMEN

BACKGROUND: Memory performance of an individual (within the age range: 50-55 years old) showing superior memory abilities (protagonist PR) was compared to an age- and education-matched reference group in a historical facts ("famous events") retrieval task. RESULTS: Contrasting task versus baseline performance both PR and the reference group showed fMRI activation patterns in parietal and occipital brain regions. The reference group additionally demonstrated activation patterns in cingulate gyrus, whereas PR showed additional widespread activation patterns comprising frontal and cerebellar brain regions. The direct comparison between PR and the reference group revealed larger fMRI contrasts for PR in right frontal, superior temporal and cerebellar brain regions. CONCLUSIONS: It was concluded that PR generally recruits brain regions as normal memory performers do, but in a more elaborate way, and furthermore, that he applied a memory-strategy that potentially includes executively driven multi-modal transcoding of information and recruitment of implicit memory resources.


Asunto(s)
Factores de Edad , Encéfalo/fisiología , Procesamiento de Imagen Asistido por Computador , Memoria/fisiología , Recuerdo Mental/fisiología , Encéfalo/patología , Mapeo Encefálico , Educación , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad
9.
Sci Rep ; 8(1): 1580, 2018 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-29371681

RESUMEN

The present study examined whether feature-based cueing affects early or late stages of flanker conflict processing using EEG and fMRI. Feature cues either directed participants' attention to the upcoming colour of the target or were neutral. Validity-specific modulations during interference processing were investigated using the N200 event-related potential (ERP) component and BOLD signal differences. Additionally, both data sets were integrated using an fMRI-constrained source analysis. Finally, the results were compared with a previous study in which spatial instead of feature-based cueing was applied to an otherwise identical flanker task. Feature-based and spatial attention recruited a common fronto-parietal network during conflict processing. Irrespective of attention type (feature-based; spatial), this network responded to focussed attention (valid cueing) as well as context updating (invalid cueing), hinting at domain-general mechanisms. However, spatially and non-spatially directed attention also demonstrated domain-specific activation patterns for conflict processing that were observable in distinct EEG and fMRI data patterns as well as in the respective source analyses. Conflict-specific activity in visual brain regions was comparable between both attention types. We assume that the distinction between spatially and non-spatially directed attention types primarily applies to temporal differences (domain-specific dynamics) between signals originating in the same brain regions (domain-general localization).


Asunto(s)
Atención , Lóbulo Frontal/fisiología , Vías Nerviosas/fisiología , Lóbulo Parietal/fisiología , Corteza Visual/fisiología , Adulto , Señales (Psicología) , Electroencefalografía , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Adulto Joven
10.
Sci Rep ; 6: 38700, 2016 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-27958301

RESUMEN

We investigated if single and double conflicts are processed separately in different brain regions and if they are differentially vulnerable to TMS perturbation. Fifteen human volunteers performed a single (Flanker or Simon) conflict task or a double (Flanker and Simon) conflict task in a combined functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS) study. The fMRI approach aimed at localizing brain regions involved in interference resolution induced by single Flanker (stimulus-stimulus, S-S) and Simon (stimulus-response, S-R) conflicts as well as regions involved in the double conflict condition. The data revealed a distinct activation in the right intraparietal sulcus (IPS) for Flanker interference and in the right middle frontal gyrus (MFG) for the double interference condition. The causal functional role of these brain regions was then examined in the same volunteers by using offline TMS over right IPS and right MFG. TMS perturbation of the right IPS increased the Flanker effect, but had no effect in the Simon or double conflict condition. In contrast, perturbation of the right MFG had no effect on any of the conflict types. These findings suggest a causal role of the right IPS in the processing of the single conflict of Flanker (stimulus-stimulus) interference.


Asunto(s)
Cognición/fisiología , Lóbulo Frontal , Imagen por Resonancia Magnética , Lóbulo Parietal , Estimulación Magnética Transcraneal , Adulto , Femenino , Lóbulo Frontal/diagnóstico por imagen , Lóbulo Frontal/fisiología , Humanos , Masculino , Lóbulo Parietal/diagnóstico por imagen , Lóbulo Parietal/fisiología
11.
Neuroimage ; 136: 45-56, 2016 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-27181762

RESUMEN

Usually, incongruent flanker stimuli provoke conflict processing whereas congruent flankers should facilitate task performance. Various behavioral studies reported improved or even absent conflict processing with correctly oriented selective attention. In the present study we attempted to reinvestigate these behavioral effects and to disentangle neuronal activity patterns underlying the attentional cueing effect taking advantage of a combination of the high temporal resolution of Electroencephalographic (EEG) and the spatial resolution of functional magnetic resonance imaging (fMRI). Data from 20 participants were acquired in different sessions per method. We expected the conflict-related N200 event-related potential (ERP) component and areas associated with flanker processing to show validity-specific modulations. Additionally, the spatio-temporal dynamics during cued flanker processing were examined using an fMRI-constrained source analysis approach. In the ERP data we found early differences in flanker processing between validity levels. An early centro-parietal relative positivity for incongruent stimuli occurred only with valid cueing during the N200 time window, while a subsequent fronto-central negativity was specific to invalidly cued interference processing. The source analysis additionally pointed to separate neural generators of these effects. Regional sources in visual areas were involved in conflict processing with valid cueing, while a regional source in the anterior cingulate cortex (ACC) seemed to contribute to the ERP differences with invalid cueing. Moreover, the ACC and precentral gyrus demonstrated an early and a late phase of congruency-related activity differences with invalid cueing. We discuss the first effect to reflect conflict detection and response activation while the latter more likely originated from conflict monitoring and control processes during response competition.


Asunto(s)
Atención/fisiología , Mapeo Encefálico/métodos , Corteza Cerebral/fisiología , Conflicto Psicológico , Inhibición Psicológica , Red Nerviosa/fisiología , Reconocimiento Visual de Modelos/fisiología , Adulto , Señales (Psicología) , Electroencefalografía/métodos , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Análisis Espacio-Temporal
12.
Front Aging Neurosci ; 8: 53, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27014059

RESUMEN

Aging is usually accompanied by alterations of cognitive control functions such as conflict processing. Recent research suggests that aging effects on cognitive control seem to vary with degree and source of conflict, and conflict specific aging effects on performance measures as well as neural activation patterns have been shown. However, there is sparse information whether and how aging affects different stages of conflict processing as indicated by event related potentials (ERPs) such as the P2, N2 and P3 components. In the present study, 19 young and 23 elderly adults performed a combined Flanker conflict and stimulus-response-conflict (SRC) task. Analysis of the reaction times (RTs) revealed an increased SRC related conflict effect in elderly. ERP analysis furthermore demonstrated an age-related increase of the P2 amplitude in response to the SRC task. In addition, elderly adults exhibited an increased P3 amplitude modulation induced by incongruent SRC and Flanker conflict trials.

13.
Brain Struct Funct ; 221(6): 3157-70, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-26239549

RESUMEN

The steepness of the delay discounting function shows considerable interindividual differences. Moreover, faster devaluation of future rewards has been consistently observed in pathological gamblers (PGs). Here, we asked whether variability in delay discounting is at least partially driven by differences in the anatomy of gray and white matter. For 40 healthy young subjects (study 1) as well as 15 PG and 15 age-matched healthy controls (HCs, study 2), the individual discounting parameter k was obtained. Based on 3D T1-weighted high-resolution magnetic resonance scans and diffusion tensor imaging, we performed voxel-based morphometry and tract-based spatial statistics, respectively, to examine the relation of gray matter volume (GMV) and white matter properties (as indicated by fractional anisotropy, FA) to k. Healthy groups from both studies showed a negative correlation between k and FA for the superior longitudinal fascicle and inferior longitudinal fascicle, whereas a positive correlation was found in the PG group for the inferior longitudinal fascicle and left inferior fronto-occipital fascicle. The latter also was significantly different between HC and PG in the group statistics (albeit on the right side), thus suggesting that this is a significant structure for the development of pathological gambling. GMV of the right frontal orbital cortex, left insular cortex and right lateral occipital cortex showed a positive correlation to k HC (studies 1 and 2) and PG, whereas a negative correlation was found for the left frontal pole in all three groups. Group comparison of GMV (study 2) revealed a decrease in PG for several cortical and subcortical areas.


Asunto(s)
Encéfalo/fisiología , Encéfalo/fisiopatología , Descuento por Demora/fisiología , Juego de Azar/fisiopatología , Adolescente , Adulto , Encéfalo/patología , Imagen de Difusión por Resonancia Magnética , Imagen de Difusión Tensora , Femenino , Juego de Azar/patología , Sustancia Gris/patología , Sustancia Gris/fisiología , Sustancia Gris/fisiopatología , Humanos , Masculino , Recompensa , Sustancia Blanca/patología , Sustancia Blanca/fisiología , Sustancia Blanca/fisiopatología , Adulto Joven
16.
Neuroimage ; 111: 289-99, 2015 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-25731996

RESUMEN

Previous studies reported heterogeneous findings in working memory tasks when examining differences between correct recognition (targets) and correct rejection (non-targets). In the present study, twenty human participants completed a delayed match-to-sample task in two separate functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) sessions. Targets and non-target items were presented at different within-trial positions. We used fMRI-constrained source analysis to investigate the spatio-temporal neuronal dynamics of probe processing. Probe type-related differences were modulated by position in the trial or by the ratio of target stimuli to non-target stimuli at different trial positions. fMRI-constrained source analysis revealed a temporal pattern of source activities starting in occipital and temporal brain regions, followed by a simultaneous engagement of parietal and frontal brain regions and a later activity of a source in pre-SMA (supplementary motor area). Source activities demonstrated a specific involvement of left fusiform gyrus in the non-target condition compared to the target condition that might be associated with mental imagination of the target stimulus during non-target probe processing. Source activities, furthermore, showed the anterior cingulate to be particularly involved in target processing compared to non-target processing before response execution and the pre-SMA before and during response execution. These brain areas appear to be activated in different stages of conflict managing operations due to a lower stimulus frequency of target trials compared to non-target trials at different target positions in the present design.


Asunto(s)
Corteza Cerebral/fisiología , Potenciales Evocados/fisiología , Función Ejecutiva/fisiología , Neuroimagen Funcional/métodos , Memoria a Corto Plazo/fisiología , Desempeño Psicomotor/fisiología , Adulto , Electroencefalografía , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Adulto Joven
17.
PLoS One ; 10(3): e0120582, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25790026

RESUMEN

Several studies demonstrated that visual filtering mechanisms might underlie both conflict resolution of the Flanker conflict and the control of the Garner effect. However, it remains unclear whether the mechanisms involved in the processing of both effects depend on similar filter mechanisms, such that especially the Garner effect is able to modulate filtering needs in the Flanker conflict. In the present experiment twenty-four subjects participated in a combined Garner and Flanker task during two runs of functional magnetic resonance imaging (fMRI) recordings. Behavioral data showed a significant Flanker but no Garner effect. A run-wise analysis, however, revealed a Flanker effect in the Garner filtering condition in the first experimental run, while we found a Flanker effect in the Garner baseline condition in the second experimental run. The fMRI data revealed a fronto-parietal network involved in the processing of both types of effects. Flanker interference was associated with activity in the inferior frontal gyrus, the anterior cingulate cortex, the precuneus as well as the inferior (IPL) and superior parietal lobule (SPL). Garner interference was associated with activation in middle frontal and middle temporal gyrus, the lingual gyrus as well as the IPL and SPL. Interaction analyses between the Garner and the Flanker effect additionally revealed differences between the two experimental runs. In the first experimental run, activity specifically related to the interaction of effects was found in frontal and parietal regions, while in the second run we found activity in the hippocampus, the parahippocampal cortex and the basal ganglia. This shift in activity for the interaction effects might be associated with a task-related learning process to control filtering demands. Especially perceptual learning mechanisms might play a crucial role in the present Flanker and Garner task design and, therefore, increased performance in the second experimental run could be the reason for the lack of behavioral Garner interference on the level of the whole experiment.


Asunto(s)
Encéfalo/diagnóstico por imagen , Neuronas/fisiología , Adulto , Mapeo Encefálico , Conflicto Psicológico , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Estimulación Luminosa , Radiografía , Percepción Visual/fisiología
18.
Brain Imaging Behav ; 9(4): 887-98, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25644499

RESUMEN

Pathological gambling is thought to result from a shift of balance between two competing neurobiological mechanisms: on the one hand the reward system involved in the regulation of the urge to get rewards and on the other hand the top-down control system. Fifteen pathological gamblers (PG) and fifteen healthy controls (HC) were studied in an event-related functional magnetic resonance imaging experiment where participants had to choose either a smaller, but immediately available monetary reward (SIR) or a larger delayed reward (LDR). We examined contrasts between LDR and SIR decisions. Additionally, we contrasted choices near the individual indifference point (indifferent decisions) and clear SIR or LDR choices (sure decisions). Behavioral data confirmed former results of steeper discount rates in PG. Contrasting choices of LDR vs. SIR showed widespread bilateral activations in PG, including postcentral gyrus, thalamus, superior/medial frontal gyrus and cingulate gyrus, whereas HC demonstrated only focal left-sided pre/postcentral activity. Forgoing an immediate reward thus recruits a widespread brain network including typical control areas. Indifferent vs. sure decisions were associated with widespread activation in PG, including the bilateral fronto-parietal cortex, insula, anterior cingulate gyrus, and striatum, whereas in HC, only bilateral frontal cortex and insula were activated. The reverse contrast demonstrated more activity for sure decisions in the cingulate gyrus, insula, and medial frontal gyrus in HC, whereas PG showed inferior parietal and superior temporal activity. The present study demonstrates that pathological gambling is associated with a shift in the interplay between a prefrontal-parietal control network and a brain network involved in immediate reward consumption.


Asunto(s)
Encéfalo/fisiopatología , Descuento por Demora/fisiología , Juego de Azar/fisiopatología , Conducta Impulsiva/fisiología , Recompensa , Adulto , Mapeo Encefálico , Conflicto Psicológico , Juego de Azar/psicología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas/fisiopatología , Pruebas Neuropsicológicas
19.
BMC Psychiatry ; 14: 229, 2014 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-25108447

RESUMEN

BACKGROUND: The temporo-spatial dynamics of risk assessment and reward processing in problem gamblers with a focus on an ecologically valid design has not been examined previously. METHODS: We investigated risk assessment and reward processing in 12 healthy male occasional gamblers (OG) and in 12 male problem gamblers (PG) with a combined EEG and fMRI approach to identify group-differences in successively activated brain regions during two stages within a quasi-realistic blackjack game. RESULTS: Both groups did not differ in reaction times but event-related potentials in PG and OG produced significantly different amplitudes in middle and late time-windows during high-risk vs. low-risk decisions. Applying an fMRI-constrained regional source model during risk assessment resulted in larger source moments in PG in the high-risk vs. low-risk comparison in thalamic, orbitofrontal and superior frontal activations within the 600-800 ms time window. During reward processing, PG showed a trend to enhanced negativity in an early time window (100-150 ms) potentially related to higher rostral anterior cingulate activity and a trend to centro-parietal group-differences in a later time window (390-440 ms) accompanied by increased superior-frontal (i.e., premotor-related) source moments in PG vs. OG. CONCLUSIONS: We suggest that problem gambling is characterized by stronger cue-related craving during risk assessment. Reward processing is associated with early affective modulation followed by increased action preparation for ongoing gambling in PG.


Asunto(s)
Potenciales Evocados , Juego de Azar/fisiopatología , Juego de Azar/psicología , Recompensa , Adulto , Encéfalo/fisiopatología , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Tiempo de Reacción , Medición de Riesgo
20.
BMC Neurosci ; 15: 85, 2014 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-25015103

RESUMEN

BACKGROUND: Initially, human area MT+ was considered a visual area solely processing motion information but further research has shown that it is also involved in various different cognitive operations, such as working memory tasks requiring motion-related information to be maintained or cognitive tasks with implied or expected motion.In the present fMRI study in humans, we focused on MT+ modulation during working memory maintenance using a dynamic shape-tracking working memory task with no motion-related working memory content. Working memory load was systematically varied using complex and simple stimulus material and parametrically increasing retention periods. Activation patterns for the difference between retention of complex and simple memorized stimuli were examined in order to preclude that the reported effects are caused by differences in retrieval. RESULTS: Conjunction analysis over all delay durations for the maintenance of complex versus simple stimuli demonstrated a wide-spread activation pattern. Percent signal change (PSC) in area MT+ revealed a pattern with higher values for the maintenance of complex shapes compared to the retention of a simple circle and with higher values for increasing delay durations. CONCLUSIONS: The present data extend previous knowledge by demonstrating that visual area MT+ presents a brain activity pattern usually found in brain regions that are actively involved in working memory maintenance.


Asunto(s)
Memoria a Corto Plazo/fisiología , Reconocimiento Visual de Modelos , Corteza Visual/fisiología , Adulto , Mapeo Encefálico , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Estimulación Luminosa , Tiempo de Reacción , Factores de Tiempo , Adulto Joven
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