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1.
Chem Biomed Imaging ; 2(3): 222-232, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38551011

RESUMEN

The Dual Imaging and Diffraction (DIAD) beamline at Diamond Light Source (Didcot, U.K.) implements a correlative approach to the dynamic study of materials based on concurrent analysis of identical sample locations using complementary X-ray modalities to reveal structural detail at various length scales. Namely, the underlying beamline principle and its practical implementation allow the collocation of chosen regions within the sample and their interrogation using real-space imaging (radiography and tomography) and reciprocal space scattering (diffraction). The switching between the two principal modes is made smooth and rapid by design, so that the data collected is interlaced to obtain near-simultaneous multimodal characterization. Different specific photon energies are used for each mode, and the interlacing of acquisition steps allows conducting static and dynamic experiments. Building on the demonstrated realization of this state-of-the-art approach requires further refining of the experimental practice, namely, the methods for gauge volume collocation under different modes of beam-sample interaction. To address this challenge, experiments were conducted at DIAD devoted to the study of human dental enamel, a hierarchical structure composed of hydroxyapatite mineral nanocrystals, as a static sample previously affected by dental caries (tooth decay) as well as under dynamic conditions simulating the process of acid demineralization. Collocation and correlation were achieved between WAXS (wide-angle X-ray scattering), 2D (radiographic), and 3D (tomographic) imaging. While X-ray imaging in 2D or 3D modes reveals real-space details of the sample microstructure, X-ray scattering data for each gauge volume provided statistical nanoscale and ultrastructural polycrystal reciprocal-space information such as phase and preferred orientation (texture). Careful registration of the gauge volume positions recorded during the scans allowed direct covisualization of the data from two modalities. Diffraction gauge volumes were identified and visualized within the tomographic data sets, revealing the underlying local information to support the interpretation of the diffraction patterns. The present implementation of the 4D microscopy paradigm allowed following the progression of demineralization and its correlation with time-dependent WAXS pattern evolution in an approach that is transferable to other material systems.

2.
bioRxiv ; 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38410482

RESUMEN

Pupillometry is a popular method because pupil size is an easily measured and sensitive marker of neural activity and associated with behavior, cognition, emotion, and perception. Currently, there is no method for monitoring the phases of pupillary fluctuation in real time. We introduce rtPupilPhase - a software that automatically detects trends in pupil size in real time, enabling novel implementations of real time pupillometry towards achieving numerous research and translational goals.

3.
bioRxiv ; 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38168380

RESUMEN

Afterimages are illusory, visual conscious perceptions. A widely accepted theory is that afterimages are caused by retinal signaling that continues after the physical disappearance of a light stimulus. However, afterimages have been reported without preceding visual, sensory stimulation (e.g., conditioned afterimages and afterimages induced by illusory vision). These observations suggest the role of top-down, brain mechanisms in afterimage conscious perception. Therefore, some afterimages may share perceptual features with sensory-independent conscious perceptions (e.g., imagery, hallucinations, and dreams) that occur without bottom-up, sensory input. In the current investigation, we tested for a link between the vividness of visual imagery and afterimage conscious perception. Participants reported their vividness of visual imagery and perceived sharpness, contrast, and duration of negative afterimages. The afterimage perceptual features were acquired using perception matching paradigms that were validated on image stimuli. Relating these perceptual reports revealed that the vividness of visual imagery positively correlated with afterimage contrast and sharpness. These behavioral results support shared neural mechanisms between visual imagery and afterimages. This study encourages future research combining neurophysiology recording methods and afterimage paradigms to directly examine the neural mechanisms of afterimage conscious perception.

4.
Cochrane Database Syst Rev ; 7: CD014592, 2023 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-37431855

RESUMEN

BACKGROUND: Pelvic organ prolapse (POP) is the descent of a woman's uterus, bladder, or rectum into the vagina. It affects 50% of women over 50 years old who have given birth to at least one child, and recognised risk factors are older age, higher number of births, and higher body mass index. This review assesses the effects of oestrogen therapy, alone or in combination with other treatments, on POP in postmenopausal women. OBJECTIVES: To assess the benefits and harms of local and systemic oestrogen therapy in the management of pelvic organ prolapse symptoms in postmenopausal women, and to summarise the principal findings of relevant economic evaluations. SEARCH METHODS: We searched the Cochrane Incontinence Specialised Register (up to 20 June 2022), which includes CENTRAL, MEDLINE, two trials registers, and handsearching of journals and conference proceedings. We also checked the reference lists of relevant articles for additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs), quasi-RCTs, multi-arm RCTs, and cross-over RCTs that evaluated the effects of oestrogen therapy (alone or in combination with other treatments) versus placebo, no treatment, or other interventions in postmenopausal women with any grade of POP. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data from the included trials using prespecified outcome measures and a piloted extraction form. The same review authors independently assessed the risk of bias of eligible trials using Cochrane's risk of bias tool. Had data allowed, we would have created summary of findings tables for our main outcome measures and assessed the certainty of the evidence using GRADE. MAIN RESULTS: We identified 14 studies including a total of 1002 women. In general, studies were at high risk of bias in terms of blinding of participants and personnel, and there were also some concerns about selective reporting. Owing to insufficient data for the outcomes of interest, we were unable to perform our planned subgroup analyses (systemic versus topical oestrogen, parous versus nulliparous women, women with versus without a uterus). No studies assessed the effects of oestrogen therapy alone versus no treatment, placebo, pelvic floor muscle training, devices such as vaginal pessaries, or surgery. However, we did identify three studies that assessed oestrogen therapy in conjunction with vaginal pessaries versus vaginal pessaries alone and 11 studies that assessed oestrogen therapy in conjunction with surgery versus surgery alone. AUTHORS' CONCLUSIONS: There was insufficient evidence from RCTs to draw any solid conclusions on the benefits or harms of oestrogen therapy for managing POP symptoms in postmenopausal women. Topical oestrogen in conjunction with pessaries was associated with fewer adverse vaginal events compared with pessaries alone, and topical oestrogen in conjunction with surgery was associated with reduced postoperative urinary tract infections compared with surgery alone; however, these findings should be interpreted with caution, as the studies that contributed data varied substantially in their design. There is a need for larger studies on the effectiveness and cost-effectiveness of oestrogen therapy, used alone or in conjunction with pelvic floor muscle training, vaginal pessaries, or surgery, for the management of POP. These studies should measure outcomes in the medium and long term.


Asunto(s)
Pelvis , Posmenopausia , Femenino , Humanos , Persona de Mediana Edad , Estrógenos/uso terapéutico , Pesarios , Vejiga Urinaria
5.
Cereb Cortex ; 33(4): 1347-1360, 2023 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-35446937

RESUMEN

The earliest cortical neural signals following consciously perceived visual stimuli in humans are poorly understood. Using intracranial electroencephalography, we investigated neural activity changes associated with the earliest stages of stimulus detection during visual conscious perception. Participants (N = 10; 1,693 electrode contacts) completed a continuous performance task where subjects were asked to press a button when they saw a target letter among a series of nontargets. Broadband gamma power (40-115 Hz) was analyzed as marker of cortical population neural activity. Regardless of target or nontarget letter type, we observed early gamma power changes within 30-180 ms from stimulus onset in a network including increases in bilateral occipital, fusiform, frontal (including frontal eye fields), and medial temporal cortex; increases in left lateral parietal-temporal cortex; and decreases in the right anterior medial occipital cortex. No significant differences were observed between target and nontarget stimuli until >180 ms post-stimulus, when we saw greater gamma power increases in left motor and premotor areas, suggesting a possible role in perceptual decision-making and/or motor responses with the right hand. The early gamma power findings support a broadly distributed cortical visual detection network that is engaged at early times tens of milliseconds after signal transduction from the retina.


Asunto(s)
Mapeo Encefálico , Electroencefalografía , Humanos , Percepción Visual/fisiología , Visión Ocular , Estado de Conciencia/fisiología
6.
Nat Commun ; 13(1): 7342, 2022 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-36446792

RESUMEN

The full neural circuits of conscious perception remain unknown. Using a visual perception task, we directly recorded a subcortical thalamic awareness potential (TAP). We also developed a unique paradigm to classify perceived versus not perceived stimuli using eye measurements to remove confounding signals related to reporting on conscious experiences. Using fMRI, we discovered three major brain networks driving conscious visual perception independent of report: first, increases in signal detection regions in visual, fusiform cortex, and frontal eye fields; and in arousal/salience networks involving midbrain, thalamus, nucleus accumbens, anterior cingulate, and anterior insula; second, increases in frontoparietal attention and executive control networks and in the cerebellum; finally, decreases in the default mode network. These results were largely maintained after excluding eye movement-based fMRI changes. Our findings provide evidence that the neurophysiology of consciousness is complex even without overt report, involving multiple cortical and subcortical networks overlapping in space and time.


Asunto(s)
Estado de Conciencia , Movimientos Oculares , Humanos , Percepción Visual , Encéfalo , Neurofisiología
7.
Conscious Cogn ; 105: 103411, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36156359

RESUMEN

Understanding the neural basis of consciousness is a fundamental goal of neuroscience, and sensory perception is often used as a proxy for consciousness in empirical studies. However, most studies rely on reported perception of visual stimuli. Here we present behavior, high density scalp EEG and eye metric recordings collected simultaneously during a novel tactile threshold perception task. We found significant N80, N140 and P300 event related potentials in perceived trials and in perceived versus not perceived trials. Significance was limited to a P100 and P300 in not perceived trials. We also found an increase in pupil diameter and blink rate and a decrease in microsaccade rate following perceived relative to not perceived tactile stimuli. These findings support the use of eye metrics as a measure of physiological arousal associated with conscious perception. Eye metrics may also represent a novel path toward the creation of tactile no-report tasks in the future.


Asunto(s)
Estado de Conciencia , Percepción del Tacto , Estado de Conciencia/fisiología , Electroencefalografía , Humanos , Cuero Cabelludo , Tacto/fisiología , Percepción Visual/fisiología
8.
J Synchrotron Radiat ; 29(Pt 4): 1004-1013, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35787567

RESUMEN

The DIAD beamline for Dual Imaging and Diffraction at Diamond Light Source has opted to use an industrial robot to position its Dectris Pilatus 2M CdTe diffraction detector. This setup was chosen to enable flexible positioning of the detector in a quarter-sphere around the sample position whilst reliably holding the large weight of 139 kg of detector, detector mount and cabling in a stable position. Metrology measurements showed that the detector can be positioned with a linear repeatability of <19.7 µm and a rotational repeatability of <16.3 µrad. The detector position stays stable for a 12 h period with <10.1 µm of movement for linear displacement and <3.8 µrad for rotational displacement. X-ray diffraction from calibration samples confirmed that the robot is sufficiently stable to resolve lattice d-spacings within the instrumental broadening given by detector position and beam divergence.

9.
Cerebellum ; 21(4): 592-605, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35334077

RESUMEN

Semi-structured interviews of patient accounts and caregiver, or informant, perspectives are a beneficial resource for patients suffering from diseases with complex symptomatology, such as cerebellar ataxia. The aim of this study was to identify, quantify, and compare the ways in which cerebellar ataxia patients' and informants' quality of life had changed as a result of living with ataxia. Using a semi-structured interview, responses were collected from patients and informants regarding motor, cognitive, and psychosocial variables. Responses were also collected from patients and informants to open-ended questions that were subsequently categorized into 15 quality of life themes that best represented changes experienced by the patients and informants. Ataxia patients and informants agreed as to the severity of posture/gait, daily activities/fine motor tasks, speech/feeding/swallowing, and oculomotor/vision impairment. It was also demonstrated that severity ratings for specific motor-related functions strongly correlated with corresponding functions within the International Cooperative Ataxia Rating Scale (ICARS), and that this interview identified frequency associations between motor impairments and specific psychosocial difficulties, which could be useful for prognostic purposes. Overall, the information obtained from this study characterized the symptoms and challenges to ataxia patients and their caregivers, which could serve as a useful educational resource for those affected by ataxia, clinicians, and researchers.


Asunto(s)
Ataxia Cerebelosa , Ataxia , Ataxia Cerebelosa/diagnóstico , Marcha/fisiología , Humanos , Calidad de Vida , Autoinforme
10.
J Synchrotron Radiat ; 28(Pt 6): 1985-1995, 2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-34738954

RESUMEN

The Dual Imaging and Diffraction (DIAD) beamline at Diamond Light Source is a new dual-beam instrument for full-field imaging/tomography and powder diffraction. This instrument provides the user community with the capability to dynamically image 2D and 3D complex structures and perform phase identification and/or strain mapping using micro-diffraction. The aim is to enable in situ and in operando experiments that require spatially correlated results from both techniques, by providing measurements from the same specimen location quasi-simultaneously. Using an unusual optical layout, DIAD has two independent beams originating from one source that operate in the medium energy range (7-38 keV) and are combined at one sample position. Here, either radiography or tomography can be performed using monochromatic or pink beam, with a 1.4 mm × 1.2 mm field of view and a feature resolution of 1.2 µm. Micro-diffraction is possible with a variable beam size between 13 µm × 4 µm and 50 µm × 50 µm. One key functionality of the beamline is image-guided diffraction, a setup in which the micro-diffraction beam can be scanned over the complete area of the imaging field-of-view. This moving beam setup enables the collection of location-specific information about the phase composition and/or strains at any given position within the image/tomography field of view. The dual beam design allows fast switching between imaging and diffraction mode without the need of complicated and time-consuming mode switches. Real-time selection of areas of interest for diffraction measurements as well as the simultaneous collection of both imaging and diffraction data of (irreversible) in situ and in operando experiments are possible.

11.
Neuroimage ; 244: 118608, 2021 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-34560270

RESUMEN

During visual conscious perception, the earliest responses linked to signal detection are little known. The current study aims to reveal the cortical neural activity changes in the earliest stages of conscious perception using recordings from intracranial electrodes. Epilepsy patients (N=158) were recruited from a multi-center collaboration and completed a visual word recall task. Broadband gamma activity (40-115Hz) was extracted with a band-pass filter and gamma power was calculated across subjects on a common brain surface. Our results show early gamma power increases within 0-50ms after stimulus onset in bilateral visual processing cortex, right frontal cortex (frontal eye fields, ventral medial/frontopolar, orbital frontal) and bilateral medial temporal cortex regardless of whether the word was later recalled. At the same early times, decreases were seen in the left rostral middle frontal gyrus. At later times after stimulus onset, gamma power changes developed in multiple cortical regions. These included sustained changes in visual and other association cortical networks, and transient decreases in the default mode network most prominently at 300-650ms. In agreement with prior work in this verbal memory task, we also saw greater increases in visual and medial temporal regions as well as prominent later (> 300ms) increases in left hemisphere language areas for recalled versus not recalled stimuli. These results suggest an early signal detection network in the frontal, medial temporal, and visual cortex is engaged at the earliest stages of conscious visual perception.


Asunto(s)
Corteza Visual/fisiología , Percepción Visual/fisiología , Adolescente , Adulto , Encéfalo , Corteza Cerebral , Cognición , Estado de Conciencia , Electroencefalografía , Epilepsia/fisiopatología , Femenino , Lóbulo Frontal/fisiología , Humanos , Lenguaje , Masculino , Memoria , Recuerdo Mental , Persona de Mediana Edad , Lóbulo Temporal/fisiología , Adulto Joven
12.
Arch Osteoporos ; 16(1): 90, 2021 06 07.
Artículo en Inglés | MEDLINE | ID: mdl-34100118

RESUMEN

INTRODUCTION: Hip fracture rates in Botswana were used to create a FRAX® model for fracture risk assessment. OBJECTIVE: This paper describes the development and characteristics of a country-specific FRAX model for Botswana. METHODS: Age-specific and sex-specific incidence of hip fracture and national mortality rates was incorporated into a FRAX model for Botswana. Ten-year fracture probabilities were compared with those from African countries having a FRAX model and African Americans from the USA. RESULTS: The probabilities of hip fracture and major osteoporotic fracture were low compared with those from South Africa (Black and Coloured) and US Blacks. Probabilities were marginally higher than for Tunisia. CONCLUSION: The creation of a FRAX model is expected to help guide decisions about the prevention and treatment of fragility fractures in Botswana.


Asunto(s)
Fracturas de Cadera , Fracturas Osteoporóticas , Botswana , Femenino , Humanos , Masculino , Medición de Riesgo , Factores de Riesgo , Sudáfrica
13.
Arch Osteoporos ; 16(1): 24, 2021 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-33550503

RESUMEN

A retrospective population-based survey in the Republic of Botswana determined the incidence of fractures at the hip over 3 years. The estimated number of such fractures nationwide for 2020 was 103 and is predicted to increase. OBJECTIVE: This article describes the epidemiology of hip fractures in the Republic of Botswana. METHODS: A retrospective patient chart review was conducted to identify from hospital registers the number of patients diagnosed with hip fracture in 2009, 2010, and 2011. Age- and sex-specific incidence of hip fracture was determined from which lifetime probabilities and future projections for hip fracture were calculated. RESULTS: The incidence of hip fracture was low and comparable to rates reported from Tunisia. The remaining lifetime risk of hip fracture at the age of 50 years in men and women was 1.4 and 1.1%, respectively. The incidence of hip fracture suggested that the estimated number of hip fractures nationwide in persons over the age of 50 years for 2020 was 103 and is predicted to increase by more than threefold to 372 in 2050. CONCLUSION: The hip fracture rates can be used for healthcare planning. Additionally, these data can be used to create a FRAX model to help guide decisions about treatment.


Asunto(s)
Fracturas de Cadera , Fracturas Osteoporóticas , Botswana/epidemiología , Femenino , Fracturas de Cadera/epidemiología , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Medición de Riesgo
14.
Cerebellum ; 20(2): 222-245, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33123963

RESUMEN

The cerebellum recognizes sequences from prior experiences and uses this information to generate internal models that predict future outcomes in a feedforward manner [Front Hum Neurosci 8: 475, 2014; Cortex 47: 137-44, 2011; Cerebellum 7: 611-5, 2008; J Neurosci 26: 9107-16, 2006]. This process has been well documented in the motor domain, but the cerebellum's role in cognitive sequencing, within the context of implicit versus explicit processes, is not well characterized. In this study, we tested individuals with cerebellar ataxia and healthy controls to clarify the role of the cerebellum sequencing using variations on implicit versus explicit and motor versus cognitive demands across five experiments. Converging results across these studies suggest that cerebellar feedforward mechanisms may be necessary for sequencing in the implicit domain only. In the ataxia group, rhythmic tapping, rate of motor learning, and implicit sequence learning were impaired. However, for cognitive sequencing that could be accomplished using explicit strategies, the cerebellar group performed normally, as though they shifted to extra-cerebellar mechanisms to compensate. For example, when cognitive and motor functions relied on cerebellar function simultaneously, the ataxia group's motor function was unaffected, in contrast to that of controls whose motor performance declined as a function of cognitive load. These findings indicated that the cerebellum is not critical for all forms of sequencing per se. Instead, it plays a fundamental role for sequencing within the implicit domain, whether functions are motor or cognitive. Moreover, individuals with cerebellar ataxia are generally able to compensate for cognitive sequencing when explicit strategies are available in order to preserve resources for motor function.


Asunto(s)
Ataxia Cerebelosa/fisiopatología , Cerebelo/fisiología , Aprendizaje/fisiología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad
15.
Cerebellum ; 20(2): 141-150, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33000380

RESUMEN

While cerebellar ataxia (CA) is a neurodegenerative disease known for motor impairment, changes in mood have also been reported. A full account of neuropsychiatric symptomology in CA may guide improvements in treatment regimes, measure the presence and severity of sub-clinical neuropsychiatric disturbance symptomology in CA, and compare patient versus informant symptom recognition. Neuropsychiatric phenomena were gathered from CA patients with genetic and unknown etiologies and their informants (e.g., spouse or parent). Information was obtained from in-person interviews and the Center for Epidemiologic Studies Depression Scale. Responses were converted to the Neuropsychiatric Inventory-Questionnaire (NPI-Q) scores by consensus ratings. Patient NPI-Q scores were evaluated for symptom prevalence and severity relative to those obtained from healthy controls. Patient-informant NPI-Q score disagreements were evaluated. In this cohort, 95% of patients presented with at least one neuropsychiatric symptom and 51% of patients with three or more symptoms. The most common symptoms were anxiety, depression, nighttime behaviors (e.g., interrupted sleep), irritability, disinhibition, abnormal appetite, and agitation. The prevalence of these neuropsychiatric symptoms was uniform across patients with genetic versus unknown etiologies. Patient and informant symptom report disagreements reflected that patients noted sleep impairment and depression, while informants noted irritability and agitation. Neuropsychiatric disturbance is highly prevalent in patients with CA and contributes to the phenomenology of CA, regardless of etiology. Clinicians should monitor psychiatric health in their CA patients, considering that supplemental information from informants can help gauge the impact on family members and caregivers.


Asunto(s)
Ataxia Cerebelosa/complicaciones , Trastornos Mentales/etiología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad
16.
Neuroimage ; 201: 116003, 2019 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-31295566

RESUMEN

Dynamic attention states are necessary to navigate the ever changing task demands of daily life. Previous investigations commonly utilize a block paradigm to study sustained and transient changes in attention networks. fMRI investigations have shown that sustained attention in visual block design attention tasks corresponds to decreased signal in the default mode and visual processing networks. While task negative networks are anticipated to decrease during active task engagement, it is unexpected that visual networks would also be suppressed during a visual task where event-related fMRI studies have found transient increases to visual stimuli. To resolve these competing results, the current investigations utilized intracranial EEG to directly interrogate visual and default mode network dynamics during a visual continuous performance task. We used the electrophysiological data to model expected fMRI signals and to maximize interpretation of current results with previous investigations. Results show broadband gamma power decreases in the default mode network, corresponding to previous EEG and fMRI findings. Meanwhile, visual processing regions including the primary visual cortex and fusiform gyrus demonstrate both sustained decreases during task engagement and stimuli-driven transient increases in gamma power. Modeled fMRI based on gamma power reproduces signal decreases reported in the fMRI literature, and emphasizes the insensitivity of fMRI to transient, regularly spaced signal changes embedded within sustained network dynamics. The signal processing functions of the dynamic visual and default mode network changes explored in this study are unknown but may be elucidated through further investigation.


Asunto(s)
Encéfalo/fisiología , Envejecimiento Cognitivo/fisiología , Toma de Decisiones/fisiología , Adulto , Anciano , Electrocorticografía , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Adulto Joven
17.
Neurosci Biobehav Rev ; 102: 184-194, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31039359

RESUMEN

Working memory is vital for basic functions in everyday life. During working memory, one holds a finite amount of information in mind until it is no longer required or when resources to maintain this information are depleted. Convergence of neuroimaging data indicates that working memory is supported by the motor system, and in particular, by regions that are involved in motor planning and preparation, in the absence of overt movement. These "secondary motor" regions are physically located between primary motor and non-motor regions, within the frontal lobe, cerebellum, and basal ganglia, creating a functionally organized gradient. The contribution of secondary motor regions to working memory may be to generate internal motor traces that reinforce the representation of information held in mind. The primary aim of this review is to elucidate motor-cognitive interactions through the lens of working memory using the Sternberg paradigm as a model and to suggest origins of the motor-cognitive interface. In addition, we discuss the implications of the motor-cognitive relationship for clinical groups with motor network deficits.


Asunto(s)
Ganglios Basales/fisiología , Cerebelo/fisiología , Memoria a Corto Plazo/fisiología , Corteza Motora/fisiología , Trastornos del Movimiento/fisiopatología , Red Nerviosa/fisiología , Ganglios Basales/diagnóstico por imagen , Ganglios Basales/fisiopatología , Cerebelo/diagnóstico por imagen , Cerebelo/fisiopatología , Humanos , Corteza Motora/diagnóstico por imagen , Corteza Motora/fisiopatología , Trastornos del Movimiento/diagnóstico por imagen , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiopatología
18.
Cerebellum ; 18(1): 33-46, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29949096

RESUMEN

Poor visuospatial skills can disrupt activities of daily living. The cerebellum has been implicated in visuospatial processing, and patients with cerebellar injury often exhibit poor visuospatial skills, as measured by impaired memory for the figure within the Rey-Osterrieth complex figure task (ROCF). Visuospatial skills are an inherent aspect of the ROCF; however, figure organization (i.e., the order in which the figure is reconstructed by the participant) can influence recall ability. The objective of this study was to examine and compare visuospatial and organization skills in people with cerebellar ataxia. We administered the ROCF to patients diagnosed with cerebellar ataxia and healthy controls. The cerebellar ataxia group included patients that carried a diagnosis of spinocerebellar ataxia (any subtype), autosomal dominant cerebellar ataxia, or cerebellar ataxia with unknown etiology. Primary outcome measures were organization and recall performance on the ROCF, with supplemental information derived from cognitive tests of visuospatial perception, working memory, processing speed, and motor function. Cerebellar ataxia patients revealed impaired figure organization relative to that of controls. Figure copy was impaired in the patients, but their subsequent recall performance was normal, suggesting compensation from initial organization and copying strategies. In controls, figure organization predicted recall performance, but this relationship was not observed in the patients. Instead, processing speed predicted patients' recall accuracy. Supplemental tasks indicated that visual perception was intact in the cerebellar ataxia group and that performance deficits were more closely tied to organization strategies than with visuospatial skills.


Asunto(s)
Ataxia Cerebelosa/psicología , Recuerdo Mental , Percepción Espacial , Memoria Espacial , Percepción Visual , Adulto , Anciano , Ataxia Cerebelosa/genética , Femenino , Mano , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Desempeño Psicomotor
19.
Cereb Cortex ; 29(2): 461-474, 2019 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-29194517

RESUMEN

Conscious perception occurs within less than 1 s. To study events on this time scale we used direct electrical recordings from the human cerebral cortex during a conscious visual perception task. Faces were presented at individually titrated visual threshold for 9 subjects while measuring broadband 40-115 Hz gamma power in a total of 1621 intracranial electrodes widely distributed in both hemispheres. Surface maps and k-means clustering analysis showed initial activation of visual cortex for both perceived and non-perceived stimuli. However, only stimuli reported as perceived then elicited a forward-sweeping wave of activity throughout the cerebral cortex accompanied by large-scale network switching. Specifically, a monophasic wave of broadband gamma activation moves through bilateral association cortex at a rate of approximately 150 mm/s and eventually reenters visual cortex for perceived but not for non-perceived stimuli. Meanwhile, the default mode network and the initial visual cortex and higher association cortex networks are switched off for the duration of conscious stimulus processing. Based on these findings, we propose a new "switch-and-wave" model for the processing of consciously perceived stimuli. These findings are important for understanding normal conscious perception and may also shed light on its vulnerability to disruption by brain disorders.


Asunto(s)
Corteza Cerebral/fisiología , Estado de Conciencia/fisiología , Ritmo Gamma/fisiología , Neuronas/fisiología , Tiempo de Reacción/fisiología , Percepción Visual/fisiología , Adulto , Mapeo Encefálico/métodos , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Estimulación Luminosa/métodos
20.
J Obstet Gynaecol ; 38(4): 556-561, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29431009

RESUMEN

The aim of this study was to explore the impressions of second year graduate-entry medical students of Obstetrics and Gynaecology, before their attachment in the speciality in the subsequent year, so as to improve its appeal to them and increase their recruitment into it. A total of 74 questionnaires were distributed at the end of the Learning Opportunities in Clinical Setting (LOCS) week in the speciality and 66 (89.19%) completed questionnaires were returned. Over 4% of the respondents were considering the speciality as their career choice and less than half would consider it as a second option. Whilst more than a third perceived some of the demerits of the speciality, more than a third endorsed its merits. This showed the need to explore and address their concerns about training and working in the speciality. Having a health-related primary degree, prior employment and being female were significantly associated with choosing the speciality as a career (p < .001). Barriers for male respondents were flagged, which need to be addressed, and a bias towards Obstetrics was noted, which reflects the narrow focus on the Labour Ward and necessitates a broader exposure to the speciality. Impact statement What is already known on this subject? The perception of third year graduate-entry medical students of Obstetrics and Gynaecology is biased towards Obstetrics, and they have apprehensions about the challenges of training and working in the speciality. What do the results of this study add? The views of second year graduate-entry medical students are consistent with the views of third year graduate-entry medical students, which shows that these views may be formed early. What are the implications of these findings for clinical practice and/or further research? More research is needed to establish and understand the perception of the speciality earlier than second year and explore the value of practical steps that may improve this perception and increase the interest in it and recruitment into its training programmes.


Asunto(s)
Selección de Profesión , Ginecología , Obstetricia , Estudiantes de Medicina/estadística & datos numéricos , Adulto , Femenino , Humanos , Masculino , Encuestas y Cuestionarios , Adulto Joven
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