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1.
Mem Cognit ; 51(6): 1404-1415, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36849759

RESUMO

Prior research has shown that searching for multiple targets in a visual search task enhances distractor memory in a subsequent recognition test. Three non-mutually exclusive accounts have been offered to explain this phenomenon. The mental comparison hypothesis states that searching for multiple targets requires participants to make more mental comparisons between the targets and the distractors, which enhances distractor memory. The attention allocation hypothesis states that participants allocate more attention to distractors because a multiple-target search cue leads them to expect a more difficult search. Finally, the partial match hypothesis states that searching for multiple targets increases the amount of featural overlap between targets and distractors, which necessitates greater attention in order to reject each distractor. In two experiments, we examined these hypotheses by manipulating visual working memory (VWM) load and target-distractor similarity of AI-generated faces in a visual search (i.e., RSVP) task. Distractor similarity was manipulated using a multidimensional scaling model constructed from facial landmarks and other metadata of each face. In both experiments, distractors from multiple-target searches were recognized better than distractors from single-target searches. Experiment 2 additionally revealed that increased target-distractor similarity during search improved distractor recognition memory, consistent with the partial match hypothesis.


Assuntos
Face , Reconhecimento Facial , Memória , Modelos Neurológicos , Reconhecimento Facial/fisiologia , Face/anatomia & histologia , Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Modelos Psicológicos , Atenção/fisiologia , Reconhecimento Psicológico/fisiologia , Memória/fisiologia , Reprodutibilidade dos Testes
2.
Memory ; 28(4): 582-587, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32270739

RESUMO

Research suggests testing improves the retention of previously learned information. Here, we examined whether this might be due (in part) to the fact that tests help learners stay on task during the review stages of learning. In two experiments, participants encoded a list of words and later had an opportunity to review the material via a free recall test or re-reading the words. During review, participants provided self-reports as to whether their minds were on or off task. Results from both experiments show testing decreased mind-wandering. Importantly, this reduction in mind-wandering was associated with improved performance on a final memory test. These results suggest the mnemonic benefits associated with testing may stem not only from act of retrieval itself, but also from the fact that taking tests encourages a more efficient and engaged review of the material.


Assuntos
Atenção , Aprendizagem , Humanos , Memória , Rememoração Mental , Autorrelato
3.
Memory ; 28(8): 957-967, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32723219

RESUMO

Do students learn better with material that is perceptually hard to process? While evidence is mixed, recent claims suggest that placing materials in Sans Forgetica, a perceptually difficult-to-process typeface, has positive impacts on student learning. Given the weak evidence for other similar perceptual disfluency effects, we examined the mnemonic effects of Sans Forgetica more closely in comparison to other learning strategies across three preregistered experiments. In Experiment 1, participants studied weakly related cue-target pairs with targets presented in either Sans Forgetica or with missing letters (e.g., cue: G_RL, the generation effect). Cued recall performance showed a robust effect of generation, but no Sans Forgetica memory benefit. In Experiment 2, participants read an educational passage about ground water with select sentences presented in either Sans Forgetica typeface, yellow pre-highlighting, or unmodified. Cued recall for select words was better for pre-highlighted information than an unmodified pure reading condition. Critically, presenting sentences in Sans Forgetica did not elevate cued recall compared to an unmodified pure reading condition or a pre-highlighted condition. In Experiment 3, individuals did not have better discriminability for Sans Forgetica relative to a fluent condition in an old-new recognition test. Our findings suggest that Sans Forgetica really is forgettable.


Assuntos
Sinais (Psicologia) , Aprendizagem , Rememoração Mental , Leitura , Humanos
4.
Memory ; 26(10): 1460-1466, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29938582

RESUMO

Researchers generally agree that retrieval practice of previously learned material facilitates subsequent recall of same material, a phenomenon known as the testing effect. There is debate, however, about when such benefits transfer to related (though not identical) material. The current study examines the phenomenon of transfer in the domain of analogical problem-solving. In Experiments 1 and 2, learners were presented a source text describing a problem and solution to read which was subsequently either restudied or recalled. Following a short (Experiment 1) or long (Experiment 2) delay, learners were given a new target text and asked to solve a problem. The two texts shared a common structure such that the provided solution for the source text could be applied to solve the problem in the target text. In a combined analysis of both experiments, learners in the retrieval practice condition were more successful at solving the problem than those in the restudy condition. Experiment 3 explored the degree to which retrieval practice promotes cued versus spontaneous transfer by manipulating whether participants were provided with an explicit hint that the source and target texts were related. Results revealed no effect of retrieval practice.


Assuntos
Aprendizagem/fisiologia , Rememoração Mental/fisiologia , Resolução de Problemas , Transferência de Experiência , Adulto , Sinais (Psicologia) , Feminino , Humanos , Masculino
5.
Am J Psychol ; 128(4): 419-29, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26721171

RESUMO

The enactment effect is the phenomenon whereby carrying out a simple action phrase results in superior memory compared with listening to the phrase or observing someone else carry out the action. Several early studies suggested that action memory processing is less effortful and strategic compared with traditional verbal processing, a perspective that is still argued today. In the current study, we reexamine a particularly compelling finding in support of this view (Cohen, 1985). Contrary to Cohen's original findings, we demonstrate that additional time to encode an action phrase leads to comparable gains in recall as seen with controls. These data fit well with a different perspective of action memory, namely that the processing of actions is guided by the same strategic, effortful processing as verbal memory.


Assuntos
Memória/fisiologia , Feminino , Humanos , Masculino , Rememoração Mental/fisiologia
6.
J Neurochem ; 128(3): 445-58, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24111919

RESUMO

Stress has been reported to activate the locus coeruleus (LC)-noradrenergic system. In this study, corticosterone (CORT) was orally administrated to rats for 21 days to mimic stress status. In situ hybridization measurements showed that CORT ingestion significantly increased mRNA levels of norepinephrine transporter (NET) and dopamine ß-hydroxylase (DBH) in the LC region. Immunofluorescence staining and western blotting revealed that CORT treatment also increased protein levels of NET and DBH in the LC, as well as NET protein levels in the hippocampus, the frontal cortex and the amygdala. However, CORT-induced increase in DBH protein levels only appeared in the hippocampus and the amygdala. Elevated NET and DBH expression in most of these areas (except for NET protein levels in the LC) was abolished by simultaneous treatment with combination of corticosteroid receptor antagonist mifepristone and spironolactone (s.c. for 21 days). Also, treatment with mifepristone alone prevented CORT-induced increases of NET expression and DBH protein levels in the LC. In addition, behavioral tasks showed that CORT ingestion facilitated escape in avoidance trials using an elevated T-maze, but interestingly, there was no significant effect on the escape trial. Corticosteroid receptor antagonists failed to counteract this response in CORT-treated rats. In the open-field task, CORT treatment resulted in less activity in a defined central zone compared to controls and corticosteroid receptor antagonist treatment alleviated this increase. In conclusion, this study demonstrates that chronic exposure to CORT results in a phenotype that mimics stress-induced alteration of noradrenergic phenotypes, but the effects on behavior are task dependent. As the sucrose consumption test strongly suggests CORT ingestion-induced depression-like behavior, further elucidation of underlying mechanisms may improve our understanding of the correlation between stress and the development of depression.


Assuntos
Corticosterona/farmacologia , Dopamina beta-Hidroxilase/biossíntese , Locus Cerúleo/metabolismo , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/biossíntese , Animais , Ansiedade/psicologia , Comportamento Animal/efeitos dos fármacos , Química Encefálica/efeitos dos fármacos , Comportamento Exploratório/efeitos dos fármacos , Imunofluorescência , Hibridização In Situ , Locus Cerúleo/efeitos dos fármacos , Masculino , Proteínas do Tecido Nervoso/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Ratos , Ratos Endogâmicos F344 , Paladar/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
7.
Dev Neurosci ; 36(3-4): 277-86, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24821360

RESUMO

This study analyzed the role of dopamine D1 and D2 receptors in methylphenidate (MPH) conditioned place preference (CPP) in adolescent male and female rats, in addition to the role of these receptors in the effects of MPH on brain-derived neurotrophic factor (BDNF) in the dorsal striatum and nucleus accumbens. Using a nonbiased CPP procedure, the animals were conditioned from postnatal day (PD) 33 to 37. On conditioning trials, animals were first administered saline or their respective antagonist (0.1 or 0.2 mg/kg SCH-23390; 0.01 or 0.03 mg/kg eticlopride HCl), followed by MPH (5 mg/kg). Approximately 10 min after MPH administration, the rats were placed into the paired context for a 10-min trial. One day after conditioning on PD38, a preference test was administered with dividers removed. One day following the preference test on PD39, brain tissue was removed, and the nucleus accumbens and striatum were analyzed for BDNF. Results revealed that MPH conditioning resulted in an increased preference that was blocked by either dose of SCH-23390, but generally not affected by either dose of eticlopride. Further, the higher dose of SCH-23390 resulted in a conditioned place aversion in males, presumably due to an increased number of dopamine D1 receptors in adolescent males. MPH produced a significant increase of striatal and accumbal BDNF alleviated by SCH-23390 or eticlopride. These results show that MPH results in CPP in adolescent male and female rats and these effects appear to be mediated by the dopamine D1 receptor, but the effects of MPH on BDNF appear to be mediated by both dopamine receptor families.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Condicionamento Operante/efeitos dos fármacos , Inibidores da Captação de Dopamina/farmacologia , Metilfenidato/farmacologia , Receptores de Dopamina D1/efeitos dos fármacos , Receptores de Dopamina D2/efeitos dos fármacos , Animais , Antagonistas de Dopamina/farmacologia , Inibidores da Captação de Dopamina/antagonistas & inibidores , Feminino , Masculino , Metilfenidato/antagonistas & inibidores , Ratos , Ratos Sprague-Dawley , Caracteres Sexuais
8.
Cogn Res Princ Implic ; 8(1): 68, 2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-37930437

RESUMO

When selecting fillers to include in a police lineup, one must consider the level of similarity between the suspect and potential fillers. In order to reduce misidentifications, an innocent suspect should not stand out. Therefore, it is important that the fillers share some degree of similarity. Importantly, increasing suspect-filler similarity too much will render the task too difficult reducing correct identifications of a guilty suspect. Determining how much similarity yields optimal identification performance is the focus of the proposed study. Extant research on lineup construction has provided somewhat mixed results. In part, this is likely due to the subjective nature of similarity, which forces researchers to define similarity in relative terms. In the current study, we manipulate suspect-filler similarity via a multidimensional scaling model constructed using objective facial measurements. In doing so, we test the "propitious heterogeneity" and the diagnostic-feature-detection hypotheses which predict an advantage of lineups with low-similarity fillers in terms of discriminability. We found that filler similarity did not affect discriminability. We discuss limitations and future directions.


Assuntos
Excipientes , Face , Humanos , Culpa , Análise de Escalonamento Multidimensional , Polícia
9.
Chembiochem ; 13(14): 2113-21, 2012 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-22961914

RESUMO

Histone acetyltransferase enzymes (HATs) are important therapeutic targets, but there are few cell-based assays available for evaluating the pharmacodynamics of HAT inhibitors. Here we present the application of a FRET-based reporter, Histac, in live-cell studies of p300/CBP HAT inhibition, by both genetic and pharmacologic disruption. shRNA knockdown of p300/CBP led to increased Histac FRET, thus suggesting a role for p300/CBP in the acetylation of the histone H4 tail. Additionally, we describe a new p300/CBP HAT inhibitor, C107, and show that it can also increase cellular Histac FRET. Taken together, these studies provide a live-cell strategy for identifying and evaluating p300/CBP inhibitors.


Assuntos
Fatores de Transcrição de p300-CBP/antagonistas & inibidores , Acetilação , Animais , Células COS , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Transferência Ressonante de Energia de Fluorescência , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Fatores de Transcrição de p300-CBP/genética , Fatores de Transcrição de p300-CBP/metabolismo
10.
Cogn Res Princ Implic ; 7(1): 55, 2022 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-35763165

RESUMO

There is an increasing need in eyewitness identification research to identify factors that not only influence identification accuracy but may also impact the confidence-accuracy (CA) relationship. One such variable that has a notable impact on memory for faces is viewing distance, with faces encoded from a shorter distance remembered better than faces encoded at longer differences. In four pre-registered experiments, using both laboratory and online samples, we compared faces viewed at a simulated viewing distance at two different levels (medium and far) to faces that were viewed at a very near-simulated distance. Distance was simulated using a Gaussian blur function with higher levels of blur corresponding to greater simulated distance. We found that both medium and far simulated distances impaired memory performance overall relative to no simulated distance, with increased distance resulting in poorer memory. However, only far simulated distances impaired the CA relationship. In a fourth experiment, we found that a pre-test warning did not ameliorate this impairment of the CA relationship for faces viewed at a far simulated distance. These findings suggest that even high-confidence identifications made for faces viewed from long distances should be disregarded, and that estimator variables that impact memory may degrade the CA relationship when memory is reduced to critical levels.


Assuntos
Cognição , Rememoração Mental , Humanos , Hiperplasia
11.
Cogn Res Princ Implic ; 7(1): 95, 2022 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-36271974

RESUMO

When selecting fillers to include in a police lineup, one must consider the level of similarity between the suspect and potential fillers. In order to reduce misidentifications, an innocent suspect should not stand out. Therefore, it is important that the fillers share some degree of similarity. Importantly, increasing suspect-filler similarity too much will render the task too difficult reducing correct identifications of a guilty suspect. Determining how much similarity yields optimal identification performance is the focus of the proposed study. Extant research on lineup construction has provided somewhat mixed results. In part, this is likely because similarity is often defined in relative terms due to the subjective nature of similarity. In the current study, we propose an experiment in which we manipulate suspect-filler similarity via a multidimensional scaling model constructed using objective facial measurements. In doing so, we test the "propitious heterogeneity" and the diagnostic-feature-detection hypotheses which predict an advantage of lineups with low similarity fillers in terms of discriminability.


Assuntos
Rememoração Mental , Reconhecimento Psicológico , Humanos , Crime , Culpa , Polícia
12.
J Immunol Methods ; 488: 112904, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33121975

RESUMO

BACKGROUND: Indirect immunofluorescence (IIF) is the most prevalent screening antinuclear antibody test for systemic autoimmune rheumatic disease (SARD). Certain IIF patterns have known antibody and disease associations, but the dense fine speckled (ANA-DFS) pattern has no confirmed clinical associations. Our objective was to determine the prevalence of SARD among a group of ANA-DFS positive individuals and to identify final diagnoses among non-SARD individuals in order to determine possible clinical associations with the ANA-DFS pattern. METHODS: A retrospective study of 425 patients from a university health care system with a positive ANA-DFS pattern consecutively between August 2017 and September 2018. Sera samples underwent ANA testing by IIF on HEp-2 cell substrates (Euroimmun, Germany). Clinical information was retrieved from electronic health records and stored in a de-identified database. RESULTS: The prevalence of SARD was 24%. Undetermined diagnosis (17%), skin disorders (12.1%), and fibromyalgia/chronic pain syndrome/chronic fatigue syndrome (11.8%) were the most common non-SARD diagnoses. Taking into account past medical history, the most common non-SARD were atopic disorders (21.2%), fibromyalgia/chronic pain syndrome/chronic fatigue syndrome (17.6%), and skin disorders (16.7%). CONCLUSIONS: The ANA-DFS pattern may be indicative of an underlying antigen-antibody interaction that plays a role in either the initiation or propagation of immunologic reactions. DFS70/LEDGF is a transcription factor involved in cell survival and stress protection, and autoantibodies may inhibit its function. It is likely that there are other antibodies producing the ANA-DFS pattern besides anti-DFS70/LEDGF, and more research is necessary to identify additional antibody specificities. The ANA-DFS pattern may be an indicator of a proinflammatory microenvironment given the high frequency of symptomatic patients and disease processes with an immunologic basis (including SARD).


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/imunologia , Anticorpos Antinucleares/sangue , Doenças Autoimunes/diagnóstico , Microambiente Celular , Técnica Indireta de Fluorescência para Anticorpo , Doenças Reumáticas/diagnóstico , Testes Sorológicos , Fatores de Transcrição/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Doenças Autoimunes/sangue , Doenças Autoimunes/epidemiologia , Doenças Autoimunes/imunologia , Biomarcadores/sangue , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prevalência , Reprodutibilidade dos Testes , Estudos Retrospectivos , Doenças Reumáticas/sangue , Doenças Reumáticas/epidemiologia , Doenças Reumáticas/imunologia , Estudos Soroepidemiológicos , Adulto Jovem
13.
Br J Radiol ; 94(1118): 20201000, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33180553

RESUMO

OBJECTIVES: To evaluate segmented diffusion tensor imaging (DTI) white matter tract fractional anisotropy (FA) and mean diffusivity (MD) values in acute cervical spinal cord injury (CSCI). METHODS: 15 patients with acute CSCI and 12 control subjects were prospectively recruited and underwent axial DTI as part of the spine trauma MRI. Datasets were put through a semi-automated probabilistic segmentation algorithm that analyzed white matter, motor and sensory tracts. FA and MD values were calculated for white matter, sensory (spinal lemniscal) and motor tracts (ventral/lateral corticospinal) at the level of clinical injury, levels remote from injury and in normal controls. RESULTS: There were significant differences in FA between the level of injury and controls for total white matter (0.65 ± .09 vs 0.68 ± .07; p = .044), motor tracts (0.64 ± .07 vs 0.7 ± .09; p = .006), and combined motor/sensory tracts (0.63 ± .09 vs 0.69 ± .08; p = .022). In addition, there were significant FA differences between the level of injury and one level caudal to the injury for combined motor tracts (0.64 ± .07 vs 0.69 ± .05; p = .002) and combined motor/sensory tracts (0.63 ± .09 vs 0.7 ± .07; p = .011). There were no significant differences for MD between the level of injury and one level caudal to the injury or normal controls. CONCLUSION: Abnormalities in DTI metrics of DTI-segmented white matter tracts were detected at the neurological level of injury relative to normal controls and levels remote from the injury site, confirming its value in CSCI assessment. ADVANCES IN KNOWLEDGE: Segmented DTI analysis can help identify microstructural spinal cord abnormalities in the setting of traumatic cervical spinal cord injury.


Assuntos
Imagem de Tensor de Difusão/métodos , Traumatismos da Medula Espinal/diagnóstico por imagem , Doença Aguda , Adulto , Medula Cervical/diagnóstico por imagem , Estudos de Avaliação como Assunto , Feminino , Humanos , Masculino , Estudos Prospectivos
14.
Mem Cognit ; 38(2): 233-43, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20173195

RESUMO

The enactment effect is one of a number of effects (e.g., bizarreness, generation, perceptual interference) that have been treated in common theoretical frameworks, most of them focusing on encoding processes. Recent results from McDaniel, Dornburg, and Guynn (2005) call into question whether bizarreness and, by association, related phenomena such as enactment are better conceptualized as arising due to retrieval processes. Four experiments investigated the degree to which retrieval processes are responsible for enhanced memory for enacted phrases. Participants were presented with two pure study lists and later recalled the lists separately (inducing pure retrieval sets) or recalled the lists together in a single test (inducing a combined or mixed retrieval set). Across all four experiments, the combined recall condition consistently failed to enhance the size of the enactment effect. The results provide no support for the retrieval account but are generally consistent with encoding accounts.


Assuntos
Aprendizagem , Humanos , Memória de Curto Prazo , Reconhecimento Psicológico
15.
J Exp Psychol Learn Mem Cogn ; 44(5): 752-763, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29094992

RESUMO

Although memory retrieval often enhances subsequent memory, Peterson and Mulligan (2013) reported conditions under which retrieval produces poorer subsequent recall-the negative testing effect. The item-specific-relational account proposes that the effect occurs when retrieval disrupts interitem organizational processing relative to the restudy condition. Rawson et al. (2015), in contrast, failed to replicate the negative testing effect despite repeated high-powered attempts. This article examines the discrepant results, ruling out differences in procedures, and concludes that differences in participant population produced the varying outcome. Specifically, participants from the University of North Carolina (UNC) and Kent State University (KSU) completed the same version of the negative-testing paradigm and were assessed on several measures of cognitive ability (working memory capacity, Raven's progressive matrices, and SAT or ACT score). For the UNC sample, free recall scores and the amount of category clustering (a measure of organizational processing) was greater in the restudy than retrieval condition (i.e., the negative testing effect was found); for the KSU sample, there was no difference on either measure. Furthermore, in the restudy condition, recall and clustering was greater for UNC than KSU students whereas in the retrieval condition, there was no effect of site on either measure. As expected, measures of cognitive ability were greater for the UNC than KSU sample. The results indicate that the negative testing effect is replicable but is subject to limitation related to the participant population. An analysis in terms of the relationship between cognitive ability and memory predicted this pattern of results. (PsycINFO Database Record


Assuntos
Aprendizagem por Associação/fisiologia , Sinais (Psicologia) , Rememoração Mental/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Prática Psicológica , Psicologia Experimental/métodos , Leitura , Projetos de Pesquisa , Adulto , Humanos , Adulto Jovem
16.
Curr Probl Diagn Radiol ; 47(4): 257-269, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28869104

RESUMO

Although diffusion-weighted imaging (DWI) has become a mainstay in modern brain imaging, it remains less utilized in the evaluation of the spinal cord. Many studies have shown promise in using DWI and diffusion-tensor imaging (DTI) for evaluation of the spinal cord; however, application has been stalled by technical obstacles and artifacts, and questions remain regarding its clinical utility on an individual examination level. This review discusses the background, concepts, and technical aspects of DWI and DTI, specifically for imaging of the spinal cord. The clinical and investigational applications of spinal cord DTI, as well as the practical difficulties and limitations of DWI and DTI for the evaluation of the spinal cord are examined.


Assuntos
Imagem de Tensor de Difusão/métodos , Doenças da Medula Espinal/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Anisotropia , Humanos , Aumento da Imagem , Interpretação de Imagem Assistida por Computador
17.
J Nat Sci ; 3(4)2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28670621

RESUMO

Before and after computerized writing instruction, participants completed assessment with normed measures and DTI and fMRI connectivity scanning. Evidence-based differential diagnosis was used at time 1 to assign them to diagnostic groups: typical oral and written language (n=6), dysgraphia (impaired handwriting, n=10), dyslexia (impaired word spelling and reading, n=20), and OWL LD (impaired syntax construction, n=6). The instruction was aimed at subword letter writing, word spelling, and syntax composing. With p <.001 to control for multiple comparisons, the following significant findings were observed in academic achievement, DTI (radial diffusivity RD, axial diffusivity AD, and mean diffusivity MD), and graph cluster coefficients for fMRI connectivity. A time effect (pre-post intervention increase) in handwriting and oral construction of sentence syntax was significant; but diagnostic group effects were significant for dictated spelling and creation of word-specific spellings, with the dyslexia and OWL LD groups scoring lower than the typical control or dysgraphia groups. For RD a time effect occurred in anterior corona radiata and superior frontal. For AD a time effect occurred in superior corona radiata, superior frontal region, middle frontal gyrus, and superior longitudinal fasciculus. For MD a time effect occurred in the same regions as AD and also anterior coronal radiata. A diagnostic group effect occurred for graph cluster coefficients in fMRI connectivity while writing the next letter in alphabet from memory; but the diagnostic group × time interaction was not significant. The only significant time × treatment interaction occurred in right inferior frontal gyrus associated with orthographic coding. Compared to time 1, cluster coefficients increased at time 2 in all groups except in the dysgraphia group in which they decreased. Implications of results are discussed for response to instruction (RTI) versus evidence-based differential diagnosis for identifying students with SLDs in writing which may be best understood at both the behavioral and brain levels of analysis.

18.
Front Neuroinform ; 11: 17, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28270762

RESUMO

Correction of echo planar imaging (EPI)-induced distortions (called "unwarping") improves anatomical fidelity for diffusion magnetic resonance imaging (MRI) and functional imaging investigations. Commonly used unwarping methods require the acquisition of supplementary images during the scanning session. Alternatively, distortions can be corrected by nonlinear registration to a non-EPI acquired structural image. In this study, we compared reliability using two methods of unwarping: (1) nonlinear registration to a structural image using symmetric normalization (SyN) implemented in Advanced Normalization Tools (ANTs); and (2) unwarping using an acquired field map. We performed this comparison in two different test-retest data sets acquired at differing sites (N = 39 and N = 32). In both data sets, nonlinear registration provided higher test-retest reliability of the output fractional anisotropy (FA) maps than field map-based unwarping, even when accounting for the effect of interpolation on the smoothness of the images. In general, field map-based unwarping was preferable if and only if the field maps were acquired optimally.

19.
Front Neurol ; 8: 118, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28424656

RESUMO

As diffusion tensor imaging gains widespread use, many researchers have been motivated to go beyond the tensor model and fit more complex diffusion models, to gain a more complete description of white matter microstructure and associated pathology. Two such models are diffusion kurtosis imaging (DKI) and diffusion basis spectrum imaging (DBSI). It is not clear which DKI parameters are most closely related to DBSI parameters, so in the interest of enabling comparisons between DKI and DBSI studies, we conducted an empirical survey of the interrelation of these models in 12 healthy volunteers using the same diffusion acquisition. We found that mean kurtosis is positively associated with the DBSI fiber ratio and negatively associated with the hindered ratio. This was primarily driven by the radial component of kurtosis. The axial component of kurtosis was strongly and specifically correlated with the restricted ratio. The joint spatial distributions of DBSI and DKI parameters are tissue-dependent and stable across healthy individuals. Our contribution is a better understanding of the biological interpretability of the parameters generated by the two models in healthy individuals.

20.
J Psychopharmacol ; 31(1): 75-85, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27940499

RESUMO

This study analyzed the interaction of adolescent methylphenidate on the behavioral response to nicotine and the effects of these drug treatments on brain-derived neurotrophic factor in the nucleus accumbens and hippocampus in male and female Sprague-Dawley rats. Animals were intraperitoneal administered 1 mg/kg methylphenidate or saline using a "school day" regimen (five days on, two days off) beginning on postnatal day (P)28 and throughout behavioral testing. In Experiment 1, animals were intraperitoneal administered 0.5 mg/kg (free base) nicotine or saline every second day for 10 days from P45-P63 and tested after a three-day drug washout on the forced swim stress task on P67-P68. Results revealed that adolescent methylphenidate blunted nicotine behavioral sensitization. However, methylphenidate-treated rats given saline during sensitization demonstrated decreased latency to immobility and increased immobility time on the forced swim stress task in males that was reduced by nicotine. In Experiment 2, a different set of animals were conditioned to nicotine (0.6 mg/kg free base) or saline using the conditioned place preference behavioral paradigm from P44-P51, and given a preference test on P52. On P53, the nucleus accumbens and hippocampus were analyzed for brain-derived neurotrophic factor. Methylphenidate enhanced nicotine-conditioned place preference in females and nicotine produced conditioned place preference in males and females pre-exposed to saline in adolescence. In addition, methylphenidate and nicotine increased nucleus accumbens brain-derived neurotrophic factor in females and methylphenidate enhanced hippocampus brain-derived neurotrophic factor in males and females. Methylphenidate adolescent exposure using a clinically relevant dose and regimen results in changes in the behavioral and brain-derived neurotrophic factor responses to nicotine in adolescence that are sex-dependent.


Assuntos
Comportamento Animal/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Metilfenidato/farmacologia , Nicotina/farmacologia , Fatores Etários , Animais , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Gravidez , Ratos , Ratos Sprague-Dawley , Caracteres Sexuais
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