Amphibian spatial cognition, medial pallium and other supporting telencephalic structures.

Vertebrate hippocampal formation is central to conversations on the comparative analysis of spatial cognition, especially in light of variation found in different vertebrate classes. Assuming the medial pallium (MP) of extant amphibians resembles the hippocampal formation (HF) of ancestral stem tetrapods, we propose that the HF of modern amniotes began with a MP characterized by a relatively undifferentiated cytoarchitecture, more direct thalamic/olfactory sensory inputs, and a more generalized role in associative learning-memory processes. As such, hippocampal evolution in amniotes, especially mammals, can be seen as progressing toward a cytoarchitecture with well-defined subdivisions, regional connectivity, and a functional specialization supporting map-like representations of space. We then summarize a growing literature on amphibian spatial cognition and its underlying brain organization. Emphasizing the MP/HF, we highlight that further research into amphibian spatial cognition would provide novel insight into the role of the HF in spatial memory processes, and their supporting neural mechanisms. A more complete reconstruction of hippocampal evolution would benefit from additional research on non-mammalian vertebrates, with amphibians being of particular interest.

Analysis of Verticality Perception in Older Adults With and Without Acute Stroke in Half-Lying Versus Sitting Positions.

Currently, there is no research consensus regarding the influence of body position on verticality perception in acute stroke. In this study, we aimed to compare the influence of half-lying and sitting positions on measurements of the subjective visual vertical (SVV) and the subjective haptic vertical (SHV) of individuals in the acute stroke phase. In this cross-sectional study, we compared these positional experiences in two groups of participants: adults in the acute stroke phase and elderly individuals without stroke. Independent variables were stroke versus no-stroke groups, in half-lying versus sitting positions. Analyzed variables of related interest were cognition (Mini-Mental State Examination or MMSE), stroke severity (National Institutes of Health Stroke Scale or NIHSS), and trunk control (Trunk Impairment Scale or TIS). Dependent variables were visual and haptic verticality, as evaluated by SVV and SHV. There were observed differences in absolute SVV in sitting position between groups (p = 0.021), absolute SVV in half-lying position between groups (p = 0.033), absolute SHV in sitting position between groups (p = 0.003), absolute SHV in half-lying position between groups (p = 0.002), and constant SVV in half-lying position between groups (p = 0.007). In the stroke group there was a higher coefficient of variation of SVV and SHV in the half-lying position compared to sitting position. In the sitting position, we observed a very strong correlation between the TIS and absolute SHV (p = 0.008). We concluded that individuals in the acute phase of stroke had greater misperceptions of visual and haptic verticality than older adults without strokes and that individuals in the acute phase of stroke showed less variability in visual and haptic vertical perception in the sitting position than in the half-lying position. By implication, we should encourage the sitting position in the acute stroke phase and develop early strategies to increase the verticality perception.

Type 1 diabetes affects the brain functional connectivity underlying working memory processing.

Visuospatial working memory (VSWM) deficits have been demonstrated to occur during the development of type-1-diabetes (T1D). Despite confirming the early appearance of distinct task-related brain activation patterns in T1D patients compared to healthy controls, the effect of VSWM load on functional brain connectivity during task performance is still unknown. Using electroencephalographic methods, the present study evaluated this topic in clinically well-controlled T1D young patients and healthy individuals, while they performed a VSWM task with different memory load levels during two main VSWM processing phases: encoding and maintenance. The results showed a significantly lower number of correct responses and longer reaction times in T1D while performing the task. Besides, higher and progressively increasing functional connectivity indices were found for T1D patients in response to cumulative degrees of VSWM load, from the beginning of the VSWM encoding phase, without notably affecting the VSWM maintenance phase. In contrast, healthy controls managed to solve the task, showing lower functional brain connectivity during the initial VSWM processing steps with more gradual task-related adjustments. Present results suggest that T1D patients anticipate high VSWM load demands by early recruiting supplementary processing resources as the probable expression of a more inefficient, though paradoxically better adjusted to task demands cognitive strategy.

Influence of E/I balance and pruning in peri-personal space differences in schizophrenia: A computational approach.

The encoding of the space close to the body, named peri-personal space (PPS), is thought to play a crucial role in the unusual experiences of the self observed in schizophrenia (SCZ). However, it is unclear why SCZ patients and high schizotypal (H-SPQ) individuals present a narrower PPS and why the boundaries of the PPS are more sharply defined in patients. We hypothesise that the unusual PPS representation observed in SCZ is caused by an imbalance of excitation and inhibition (E/I) in recurrent synapses of unisensory neurons or an impairment of bottom-up and top-down connectivity between unisensory and multisensory neurons. These hypotheses were tested computationally by manipulating the effects of E/I imbalance, feedback weights and synaptic density in the network. Using simulations we explored the effects of such impairments in the PPS representation generated by the network and fitted the model to behavioural data. We found that increased excitation of sensory neurons could account for the smaller PPS observed in SCZ and H-SPQ, whereas a decrease of synaptic density caused the sharp definition of the PPS observed in SCZ. We propose a novel conceptual model of PPS representation in the SCZ spectrum that can account for alterations in self-world demarcation, failures in tactile discrimination and symptoms observed in patients.

Spatial incompatibility training can prevent the occurrence of the enhanced Simon effect in elderly / Treinamento de incompatibilidade espacial pode prevenir a ocorrência do efeito Simon ampliado em idosos

The Simon effect is typically larger for older people than for young adults, maybe due to age-related decline in inhibitory capabilities. 32 right-handed aged people (5 male, 27 female; mean of 67,1 years ± 5,5) participated in this study. In screening were used the Mini-Mental State Examination and the Center for Epidemiological Study Depression Scale. Then, half of the participants practiced the spatial incompatibility task before the Simon task and the other group was only tested on the Simon task. The analysis of variance considering practice (incompatible, no-practice group) and correspondence (corresponding, non-corresponding) revealed a two-way interaction (F = 7.07; p = 0.012; ηp2 = 0.191) showing that the Simon effect was eliminated in the incompatible practice group, but remained intact in the group with no previous practice. These results indicated that cognitive processes required to the transfer of learning are preserved in elderly, being potentially useful to influence spatial inhibitory capabilities.

O efeito Simon é tipicamente maior em pessoas idosas do que em adultos jovens, talvez devido ao declínio de capacidades inibitórias em função da idade. Participaram deste estudo 32 pessoas idosas e destras (5 homens e 27 mulheres; média de 67,1 anos ± 5,5). Para rastreio, foram usados o Mini Exame do Estado Mental e a escala de depressão do Center for Epidemiological Studies. Metade dos participantes praticou a tarefa de incompatibilidade espacial antes da tarefa de Simon e o outro grupo foi testado apenas na tarefa de Simon. A análise de variância, considerando a prática prévia (incompatível ou sem prática) e correspondência (correspondente, não correspondente), indicou uma interação dupla (F = 7,07; p = 0,012; ηp2 = 0,191), demonstrando que o efeito Simon foi eliminado no grupo de prática incompatível, mas permaneceu ampliado no grupo sem prática anterior. Esses resultados indicaram que os processos cognitivos necessários para transferir a aprendizagem estão preservados em idosos, sendo potencialmente úteis para influenciar as capacidades inibitórias espaciais.

Do automotive window films affect drivers' safety by decreasing vision sensitivity? A Cross-sectional study / Películas automotivas e perda de acuidade visual? Estudo transversal

ABSTRACT Objective: To measure visual acuity in high contrast and low contrast sensitivities in different grades of visible light transmission films in three different positions (front, lateral and rear windows). Methods: Forty-four healthy volunteers between 30-75 y-o, with BCVA better than 0,5, were tested in the 5 following vehicles with different grades of visible light transmission films. Vehicle 1: 75% in the front and 70% in the lateral and rear windows; Vehicle 2: 70% in the front and lateral windows and 28% in the rear; Vehicle 3: 70% in the front, 28% in the lateral and 15% rear; Vehicle 4: 35% in all 3 windows; Vehicle 5: 50% in the front, 20% in the lateral and 15% in the rear. Descriptive statistics were used and the average of the 3 measurements of VA was considered. Wilcoxon Test was applied to compare the average visual acuity in each vehicle and position. P value<0.05 was considered statistically significant. Results: According to the Brazilian Traffic Regulations for driving in categories C/D/E, when low contrast was tested in the front window, all visible light transmissions were borderline, in the lateral window they were all outside the limit, while in the rear window for both low and high contrast, all visible light transmissions tested were outside the limit and also borderline for driving in categories A/B, with the exception of the vehicle with visible light transmission of 35%. Conclusion: Visual acuity is affected, especially in the rear window, by the use of automotive films. The study is an alert that window films is a possible cause of accidents and may contribute to the revision of traffic regulations worldwide.

RESUMO Objetivo: Medir a acuidade visual em alto e baixo contraste nas diversas graduações de transparência de filmes em três janelas de veículos: frontal, lateral e traseira. Métodos: Foram avaliados 44 voluntários saudáveis entre 30 e 75 anos, com acuidade visual melhor corrigida acima de 0,5, em cinco veículos, sendo: veículo 1, com 75% de transparência frontal e 70% na lateral e traseira; veículo 2, com 70% na frontal e na lateral e 28% na traseira; veículo 3, com 70% na frontal, 28% na lateral e 15% na traseira; veículo 4, com 35% nas três janelas; e veículo 5, com 50% na frontal, 20% na lateral e 15% na traseira. Foi realizada estatística descritiva utilizando a média de três medidas consecutivas, com teste de Wilcoxon para comparar a média de acuidade visual em cada janela, e foi considerado estatisticamente significativo quando valor de p<0,05. Resultados: Todas as transparências testadas nos vidros reduziram a acuidade visual em situação de baixo contraste para níveis limítrofes na janela frontal e níveis ilegais na lateral para conduzir veículos nas categorias C/D/E. Na janela traseira, tanto em alto quanto em baixo contraste, todas as transparências mostraram redução da acuidade visual para níveis ilegais para categorias C/D/E e limítrofes para as categorias A/B, exceto na transparência de 35%. Conclusão: A acuidade visual é reduzida pelo uso dos filmes automotivos, especialmente na janela traseira. Condutores de veículos com filmes devem ser alertados pelo risco aumentado de acidentes. Esse dado científico propõe revisões nas regulações de tráfego mundiais.

Conceitos básicos de percepção de cena / Basic concepts of scene perception

A pesquisa sobre percepção de cenas é um esforço da comunidade científica em superar as dificuldades apresentadas ao estudo de estímulos complexos. As consistentes descobertas provaram a viabilidade do tema e encorajam uma abordagem mais holística e integrada nas investigações em percepção visual. Esse esforço e seus achados são, entretanto, pouco conhecidos pelos leitores em língua portuguesa e, até mesmo, entre alguns especialistas que se interessam pelo tema. O objetivo deste trabalho é fazer uma apresentação do campo, esboçar seu desenvolvimento, identificar suas principais questões e demonstrar sua pertinência e importância. Para isso, uma revisão seletiva de textos foi executada entre os autores que construíram os fundamentos da percepção de cenas. Ao concluir a leitura, espera-se que o leitor constate o papel relevante dos processos mnemônicos e do sujeito que observa no processo de captação visual do ambiente natural.

Scene perception research is a scientific community effort to overcome difficulties presented to the study of complex stimuli. Consistent findings support feasibility of the theme and encourage a more holistic and integrated approach to visual perception research. This effort and its findings are, however, poorly known by readers in Portuguese language, even among experts interested in the subject. The purpose of this paper is to introduce this field of research, outline its development, identify its main issues and demonstrate its relevance and importance. This task was accomplished by a selective review of papers from authors who built the foundations of scene perception. Upon completion of the reading, it is expected that the reader understands the relevant role of mnemonic processes and of the observer in the process of visual capture of natural environments.

Evaluation of subjective vertical perception among stroke patients: a systematic review.

BACKGROUND: Verticality misperception is relatively common among patients after stroke, and it may be evaluated in terms of (a) subjective visual vertical (SVV), (b) subjective haptic vertical (SHV) and (c) subjective postural vertical (SPV). To better understand these assessment methods, we conducted a systematic review of the methodological characteristics of different protocols for evaluating SVV, SHV and SPV among individuals after stroke. OBJECTIVE: To standardize the methodological characteristics of protocols for evaluating verticality perception after stroke. METHODS: We searched the following databases: PUBMED, regional BVS portal (MEDLINE, LILACS, IBECS, CUBMED, Psychology Index and LIS), CINAHL, SCOPUS, Web of Science, Science Direct, Cochrane Library and PEDro. Two review authors independently used the QUADAS method (Quality Assessment of Diagnostic Accuracy Studies) and extracted data. RESULTS: We included 21 studies in the review: most (80.9%) used SVV, eight (38.1%) used SPV and four (19.0%) used SHV. We observed high variability in assessments of verticality perception, due to patient positions, devices used, numbers of repetitions and angle of inclination for starting the tests. CONCLUSION: This systematic review was one of the first to explore all the methods of assessing verticality perception after stroke, and it provides crucial information on how to perform the tests, in order to guide future researchers/clinicians.

Evaluation of subjective vertical perception among stroke patients: a systematic review / Avaliação da percepção vertical subjetiva em pacientes com acidente vascular cerebral: uma revisão sistemática

Abstract Background: Verticality misperception is relatively common among patients after stroke, and it may be evaluated in terms of (a) subjective visual vertical (SVV), (b) subjective haptic vertical (SHV) and (c) subjective postural vertical (SPV). To better understand these assessment methods, we conducted a systematic review of the methodological characteristics of different protocols for evaluating SVV, SHV and SPV among individuals after stroke. Objective: To standardize the methodological characteristics of protocols for evaluating verticality perception after stroke. Methods: We searched the following databases: PUBMED, regional BVS portal (MEDLINE, LILACS, IBECS, CUBMED, Psychology Index and LIS), CINAHL, SCOPUS, Web of Science, Science Direct, Cochrane Library and PEDro. Two review authors independently used the QUADAS method (Quality Assessment of Diagnostic Accuracy Studies) and extracted data. Results: We included 21 studies in the review: most (80.9%) used SVV, eight (38.1%) used SPV and four (19.0%) used SHV. We observed high variability in assessments of verticality perception, due to patient positions, devices used, numbers of repetitions and angle of inclination for starting the tests. Conclusion: This systematic review was one of the first to explore all the methods of assessing verticality perception after stroke, and it provides crucial information on how to perform the tests, in order to guide future researchers/clinicians.

Resumo Antecedentes: A percepção errônea da verticalidade é relativamente comum em pacientes após Acidente Vascular Cerebral (AVC) e pode ser avaliada pelas: (a) vertical visual subjetiva (SVV), (b) vertical háptica subjetiva (SVH) e (c) vertical postural subjetiva (SPV). Para melhor compreender esses métodos de avaliação, realizamos uma revisão sistemática das características metodológicas de diferentes protocolos para avaliações de SVV, SHV e SVP em indivíduos após AVC. Objetivo: Padronizar as características metodológicas de protocolos de avaliação da verticalidade após AVC. Métodos: Foi realizada busca nas bases de dados PUBMED, Portal Regional da BVS (MEDLINE, LILACS, IBECS, CUBMED, Psychology Index, LIS), CINAHL, SCOPUS, Web of Science, Science Direct, Biblioteca Cochrane e PEDro. Dois revisores avaliaram independentemente o QUADAS (Avaliação da Qualidade dos Estudos de Precisão de Diagnóstico) e extraíram os resultados. Resultados: Foram incluídos 21 estudos: a maioria (80,9%) utilizando a SVV, oito (38,1%) a SPV e quatro (19,0%) a SHV. Observou-se grande variabilidade na avaliação da verticalidade, devido às posições dos pacientes, dispositivos utilizados, número de repetições e ângulo de inclinação para iniciar os testes. Conclusão: Esta revisão sistemática é uma das primeiras a explorar todos os métodos de avaliação da verticalidade após o AVC e fornece informações cruciais sobre como realizar os testes para orientar os futuros pesquisadores e clínicos.

Visual and haptic verticality misperception and trunk control within 72 h after stroke.

INTRODUCTION: Stroke patients often exhibit an altered perception of verticality, but there are no studies evaluating verticality perception in the first 72 h after stroke and its relationship with trunk control. Therefore, this study aimed to analyze visual and haptic verticality in the acute phase of stroke. METHODS: This was a cross-sectional study conducted with two groups: (a) 13 individuals with stroke and (b) 12 healthy participants. We assessed verticality via the subjective visual vertical (SVV) and the subjective haptic vertical (SHV); and we measured trunk control with the Trunk Impairment Scale (TIS). We performed t-tests to compare the SVV and SHV between groups. Pearson correlation was performed between verticality tests with National Institutes of Health Stroke Scale (NIHSS) and the TIS. RESULTS: Participants with recent stroke presented higher true and absolute SVV deviation values than did the control group. There was significant negative correlation between absolute (r = -0.57; p = 0.02) and true SVV (r = -0.54; p = 0.01) with TIS scores There was also significant positive correlation between absolute (r = 0.63; p = 0.009) and true SVV (r = 0.61; p = 0.003) with NIHSS. A significant negative correlation between NIHSS and TIS scores also was found (r = -0.80; p = 0.005). CONCLUSION: Individuals with acute stroke presented larger variability in their perceptions of visual verticality than did healthy controls, and verticality perceptions were positively correlated with trunk impairment.

Frontal functional connectivity and disease duration interactively predict cognitive decline in Parkinson's disease.

OBJECTIVE: Cognitive decline does not always follow a predictable course in Parkinson's disease (PD), with some patients remaining stable while others meet criteria for dementia from early stages. Functional connectivity has been proposed as a good correlate of cognitive decline in PD, although it has not been explored whether the association between this connectivity and cognitive ability is influenced by disease duration, which was our objective. METHODS: We included 30 patients with PD and 15 healthy controls (HC). Six cognitive domains were estimated based on neuropsychological assessment. Phase-based connectivity at frontal and posterior cortical regions was estimated from a resting EEG. RESULTS: The PD group showed significant impairment for the executive, visuospatial, and language domains compared with HC. Increased connectivity at frontal regions was also found in the PD group. Frontal delta and theta connectivity negatively influenced general cognition and visuospatial performance, but this association was moderated by disease duration, with increased connectivity predicting worse performance after 8 years of disease duration. CONCLUSION: Subtle neurophysiological changes underlie cognitive decline along PD progression, especially around a decade after motor symptoms onset. SIGNIFICANCE: Connectivity of EEG slow waves at frontal regions might be used as a predictor of cognitive decline in PD.

Motor imagery in children with unilateral cerebral palsy: a case-control study.

AIM: To evaluate whether children with cerebral palsy (CP) are able to engage in a motor imagery task. Possible associations between motor imagery and functional performance, working memory, age, and intelligence were also investigated. METHOD: This is a case-control study that assessed 57 children (25 females, 32 males) with unilateral CP, aged 6 to 14 years (mean age: 10y 4mo; SD 2y 8mo) and 175 typically developing (control) children, aged 6 to 13 years (87 females, 88 males; mean age: 9y 4mo; SD 1y 11mo). The hand laterality judgment task was used to measure motor imagery ability. Reaction time, accuracy, and the effect of the biomechanical constraints were assessed in this task. RESULTS: Performance in both groups followed the biomechanical constraints of the task, that is, longer reaction times to recognize stimuli rotated laterally when compared to medial stimuli. Reaction time means did not differ significantly between groups (p>0.05). Significant differences between the unilateral CP and control groups were observed for accuracy (p<0.05). Functional performance and working memory were correlates of motor imagery tasks. INTERPRETATION: Results suggest that children with unilateral CP can engage in motor imagery; however, they commit more errors than typically developing controls. In addition, their performance in tasks of motor imagery is influenced by functional performance and working memory.

Neuropsychological assessment of Chilean children with a history of extreme prematurity: An exploratory study.

This study was conducted to explore the neuropsychological abilities of premature Chilean children. Two groups (Premature and Control, 10 children each, age ranging from 5 to 7.11) were established based on weeks of gestation and/or weight at birth. Relevant variables such as age, gender, schooling, and socioeconomic level were matched considering Chile's particular demographic context. Children were assessed by means of the Evaluación Neuropsicológica Infantil (ENI-2) battery, measuring nine cognitive domains encompassing 23 subscales. In turn, subscales are grouped in two scales: Cognitive Functions and Executive Functions. Since the ENI-2 battery provides norms for Spanish-speaking children, obtained data were inspected both for possible between-group differences and either adjustment or deviance from average range. Results show that premature children perform within typical ranges in all subscales except for Visual attention and Graphic fluency. When comparing both groups, some differences emerged. These differences are most prominent in subscales related to visuoperceptual skills. Interestingly, between-group linguistic performance is very similar. The point is made that early linguistic interventions conducted on premature children seem to positively impact on oral language expression and comprehension. On the contrary, early interventions focused on visuospatial abilities did not seem to attain the same impact. This may be a consequence of visual-information processing problems derived from cortical dorsal stream's vulnerability, which literature correlates with prematurity.

On the transfer of spatial learning between geometrically different shaped environments in the terrestrial toad, Rhinella arenarum.

When trained in a rectangular arena, some research has suggested that rats are guided by local features rather than overall boundary geometry. We explored this hypothesis using the terrestrial toad, Rhinella arenarum, as a comparative contrast. In two experiments, toads were trained to find a water-reward goal location in either a featureless rectangular arena (Experiment 1) or in a rectangular arena with a removable colored feature panel covering one short wall (Experiment 2). After learning to successfully locate the water reward, probe trials were carried out by changing the shape of the arena into a kite form with two 90°-angled corners, and in the case of Experiment 2, also shifting the location of the color panel. The results of Experiment 1 indicated that the toads, in contrast to rats, relied primarily on overall shape or boundary geometry to encode the location of a goal. Under the probe conditions of the altered environmental geometry in Experiment 2, the toads seemed to preferentially choose a corner that was generally correct relative to the feature panel experienced during training. Together, the data of the current study suggest that toads and rats differ in the strategies they employ to represent spatial information available in a rectangular arena. Further, the results support the hypothesis that amphibians and mammals engage different neural mechanisms, perhaps related to different evolutionary selective pressures, for the representation of environmental geometry used for navigation.

Altered Visual and Proprioceptive Spatial Perception in Individuals with Parkinson's Disease.

Difficulties in the integration of visual, vestibular, and somatosensory information in individuals with Parkinson's disease (PD) may alter perception of verticality. Accordingly, in this cross-sectional study, we analyzed PD patients' (n = 13) subjective visual vertical (SVV) and subjective haptic vertical (SHV) perceptions and compared them to those of healthy controls (n = 14). We compared SVV and SHV findings among participants with PD, healthy controls, and cutoff points of normality based on prior research literature, using the parametric nonpaired t test (at p < .05) and Cohen's d (at d > 0.8) to determine clinical relevance. We analyzed SVV with the bucket test and SHV with the rod rotations task in clockwise and counterclockwise directions. We calculated Pearson correlations to analyze the association between verticality tests and the most clinically affected body side. We calculated both the percentage of A-effect (expression of body tilt underestimation to the midline) and E-effect (expression of body tilt overestimation in the upright position). Individuals with PD showed greater variability in right SHV supination compared to the healthy control participants (p = .002). There was greater clinical relevance in right (as opposed to left) SVV (d = 0.83), right (as opposed to left) SHV pronation (d = 0.91), and left (as opposed to right) SHV pronation (d = 0.88). We observed a higher proportion of E-effect in individuals with PD. A significantly higher proportion of patients with PD, compared to patients in past literature, had right SHV pronation (p = .001), left SHV pronation (p = .023), right SHV supination (p = .001), left SHV supination (p = .046), and left SHV pronation (p = .046). Thus, subjective visual and proprioceptive perception of verticality is altered in patients with PD, compared to individuals without PD.

Differential involvement of left and right frontoparietal areas in visuospatial planning: An rTMS study.

The planning process consists of pre-determining an ordered series of actions to accomplish a goal. Previous research showed that the left prefrontal cortex (PFC) is likely to create the strategy for a plan, while the right PFC could be relevant for its update. These roles for the two PFCs need to be ascertained for visuospatial planning, whether communalities or differences exist with other planning tasks. Moreover, the contribution of the posterior parietal cortex (PPC) to planning still lacks evidence. Online repetitive transcranial magnetic stimulation (1 Hz) was used, and 32 participants were involved in the visuospatial planning task in a within-subject design to inhibit either the frontal or the parietal cortex of either the left or the right hemisphere. The goal consisted of evaluating the contribution of these cortical regions, also controlling for gender, in a computerized version of the travelling salesman problem (TSP), the "Maps" task. The results showed that all the stimulated sites produced significant differences in their involvement, reflected in several parameters (such as initial planning and execution times, strategies and heuristics used), with respect to the control group. The roles for the two PFCs were generally confirmed in all measures except path length, while the contribution of the PPC emerged throughout the measures related to the ongoing execution. We concluded that the results obtained with the TSP paradigm were consistent with results obtained using other tasks used to study the planning process (such as the Tower of London) for the evaluation of PFC contribution. In addition, we showed that the contribution of the PPC to the planning process has probably been underestimated.

Desenvolvimento e validação de medidas psicofísicas de sensibilidade ao contraste de segunda-ordem / Development and validation of second-order psychophysical contrast sensitivity measures / Desarrollo y validación de medidas de sensibilidad al contraste psicofísico de segundo-orden

A medida de Sensibilidade ao Contraste (SC) de primeira ordem é frequentemente utilizada para avaliação da percepção espacial. Nosso objetivo foi desenvolver e validar um teste de SC de segunda ordem para aplicação clínica. Modificações metodológicas foram realizadas na rotina psicofísica para redução do tempo de testagem em um primeiro experimento, validamos a nova metodologia. Em um segundo experimento, valores de normalidade foram derivados do resultado de 16 participantes e foram testados nas mesmas condições do primeiro experimento. As medidas de validade foram obtidas por meio do Spearman-Brown Split-Half Reliability Coefficient para todas as frequências espaciais testadas (r> 0,90). O desenvolvimento e a validação deste novo experimento para as medidas de SC de segunda ordem permitirão avançar nos estudos dos mecanismos básicos da percepção de espaço para estímulos complexos, assim como a aplicação clínica em diversas doenças.

The first-order Contrast Sensitivity (SC) measure is often used to assess spatial perception. Our goal was to develop and validate a second-order SC test for clinical application. Methodological changes were made in the psychophysical routine to reduce testing time and in the first experiment we validated the new methodology. In a second experiment, normal values were derived from the result of sixteen participants who were tested under the same conditions as the first experiment. Validity measures were obtained using Spearman-Brown Split-Half Reliability Coefficient for all tested spatial frequencies (r> 0.90). The development and validation of this new experiment for second-order SC measures will allow to advance in the studies of the basic mechanisms of the perception of space for complex stimuli, as well as the clinical application in several diseases.

La medida de sensibilidad al contraste (SC) de primer orden se utiliza a menudo para evaluar la percepción espacial. Nuestro objetivo era desarrollar y validar una prueba SC de segundo orden para aplicación clínica. Se realizaron cambios metodológicos en la rutina psicofísica para reducir el tiempo de prueba y en el primer experimento validamos la nueva metodología. En un segundo experimento, los valores normales se derivaron del resultado de dieciséis participantes que fueron evaluados en las mismas condiciones que el primer experimento. Las medidas de validez se obtuvieron utilizando el coeficiente de confiabilidad de la mitad dividida de Spear-man-Brown para todas las frecuencias espaciales probadas (r> 0.90). El desarrollo y validación de este nuevo experimento para medidas CS de segundo orden permitirá avanzar en los estudios de los mecanismos básicos de percepción del espacio para estímulos complejos, así como la aplicación clínica en diversas enfermedades.

Percepção auditiva e orientação e mobilidade em pessoas com deficiência visual usuárias de cão-guia / Guidance, mobility and auditory perception in guide dog users with visual impairment

RESUMO Objetivo Investigar a percepção auditiva temporal, a orientação e a mobilidade de deficientes visuais. Métodos Estudo exploratório de intervenção, com amostra de conveniência composta por nove sujeitos cegos ou com baixa visão, com idades entre 23 e 64 anos, usuários de cão-guia e que realizaram os seguintes procedimentos: avaliação funcional de orientação e mobilidade, avaliação audiológica básica (audiometria tonal limiar, pesquisa do índice de reconhecimento de fala), avaliação do processamento auditivo temporal (teste de resolução temporal (random gap detection test - RGDT), teste de padrão de frequência (TPF), teste dicótico de dígitos (TDD), teste rápido de sentenças no ruído (TRIS). Resultados Todos os sujeitos apresentavam limiar audiométrico de grau normal, porém, um deles apresentava curva audiométrica do tipo neurossensorial e configuração descendente, sugerindo perda auditiva relacionada à idade. A avaliação das habilidades auditivas temporais mostrou valores dentro dos padrões de normalidade para todos os sujeitos, com exceção do teste RGDT, em que os sujeitos apresentaram valores menores (3,5 a 7,5 ms) do que os esperados para população de adultos com visão e audição normais. A avaliação da OM mostrou que todos os sujeitos necessitavam de adaptações técnicas, pois falhas foram observadas no percurso por eles executado. Conclusão A percepção auditiva temporal dos sujeitos deste estudo está adequada e a avaliação da OM mostra falhas que necessitam ser corrigidas.

ABSTRACT Purpose To investigate the temporal auditory perception, and OM of visually impaired people. Methods This is an exploratory intervention study including a convenience sample composed of nine blind or low vision subjects, aged between 23 and 64 years, guide dog users and who performed the following procedures: functional evaluation of OM, basic audiological evaluation (Pure tone audiometry, speech recognition index), temporal auditory processing assessment (random gap detection test (RGDT), frequency pattern test (FPT), dichotic digit Test (DDT), quick speech-in-noise test (QuickSIN). Results Although all subjects had normal-level audiometric thresholds, one subject had a sensorineural audiometric curve and descending configuration, suggesting an age-related hearing loss. Evaluation of the temporal auditory processing showed values within the normal for all subjects, except for the RGDT, in which test subjects had lower (3.5 to 7.5 ms.) than the expected values for the adult population with normal vision and hearing. Evaluation of OM showed that all subjects require technical adjustments as problems were observed in the route taken. Conclusion The temporal auditory processing of these subjects is appropriate and the evaluation of OM shows flaws that need to be corrected.

Higher soluble CD14 levels are associated with lower visuospatial memory performance in youth with HIV.

OBJECTIVE: HIV-associated neurocognitive disorders persist despite early antiretroviral therapy (ART) and optimal viral suppression. We examined the relationship between immunopathogenesis driven by various pathways of immune activation and discrete neurocognitive performance domains in youth with HIV (YWH). DESIGN: Observational cross-sectional study. METHODS: YWH, ages 20-28 years, enrolled in Adolescent Medicine Trials Network 071/101 were assessed for biomarkers of macrophage, lymphocyte activation, and vascular inflammation using ELISA/multiplex assays. Standardized neurocognitive tests were performed, and demographically adjusted z-scores were combined to form indices of attention, motor, executive function, verbal, and visuospatial memory. Cross-sectional analysis of the relationship between 18 plasma inflammatory biomarkers and each neurocognitive domain was performed. Linear regression models were fit for each combination of log-transformed biomarker value and neurocognitive domain score, and were adjusted for demographics, socioeconomic status, substance use, depression, CD4 T-cell count, HIV viral load, and ART status. RESULTS: Study included 128 YWH [mean age 23.8 (SD 1.7) years, 86% men, 68% African American]. Verbal and visuospatial memory domains were most significantly impaired in the cohort (z = -1.59 and -1.0, respectively). Higher sCD14 was associated with impaired visuospatial memory, which remained robust after adjusting for other biomarkers, demographics, and HIV-associated covariates. Among biomarkers of vascular inflammation, sICAM-1 was negatively associated with verbal memory and attention, whereas sVCAM-1 was positively associated with executive function and visuospatial memory. Specific neurocognitive domains were not associated with sCD163, LPS, or CCL2 levels. CONCLUSION: Impaired visuospatial memory in YWH is associated with immune activation, as reflected by higher sCD14.

Hippocampal place cells are topographically organized, but physical space has nothing to do with it.

Topographical organization can be found in many areas of the cerebral cortex, although its presence in higher order cortices is debated. Some studies evaluated whether this pattern of organization is present in the hippocampus, trying to determine whether hippocampal place cells are organized around a topographical map of space. Those studies indicated that the topographical organization of hippocampal place cells is either very limited or simply nonexistent. In this paper, we argue for a different interpretation of available evidence and suggest that there is a topographical organization in hippocampal place cells, but the topographical map formed is not a map of the physical space. Although place cell firing is correlated with the animal's position and is important to spatial navigation, place cells encode much more information than just location. Thus, we should not expect the topographical map to be organized around physical space, but around an abstract, multidimensional space containing the receptive fields of place cells. We show that this conclusion is supported by two of the main theories of hippocampal function-cognitive map theory and index theory-which, when carefully analyzed, make exactly the same predictions about hippocampal topography. Such abstract topographical map would be extremely hard to find using the methods commonly employed in the literature, but there are some approaches that may, in the future, make possible to characterize the topographical organization in the hippocampus and other high-order brain regions.