Dins el bosc de la cultura visual. Apunts per a una actualització pedagògica

L'era de la comunicació acara la comunitat educativa davant de nous reptes, especialment en l'àmbit de la cultura visual. La cultura visual es manifesta avui arreu i no hi ha àmbit ni familiar ni social ni educatiu que no en participi. Més enllà de la visualització i experimentació d'alguns procediments artístics canònics, l'ensenyament de les arts visuals i plàstiques observa la necessitat d'ampliar el seu radi d'acció, reflexió i anàlisi de manera coparticipada. Un repàs a la trajectòria històrica de l'aprenentatge artístic dóna peu a algunes preguntes rellevants com ara, quins aprenentatges per a quines competències? Per a quina societat i amb quins instruments cal educar els infants? Quines inèrcies i teories s¿hereten del passat i quin lloc cal que tinguin en el futur? Quines aportacions cognitives o empíriques permetrien una renovació positiva en l'àmbit de l¿educació visual i plàstica? Són preguntes difícils però peremptòries si no es vol girar l'esquena a l'evidència dels canvis comunicatius i socials del nostre temps.

Methods for Determining Frequency- and Region-Dependent Relationships Between Estimated LFPs and BOLD Responses in Humans

The relationship between electrophysiological and functional magnetic resonance imaging (fMRI) signals remains poorly understood. To date, studies have required invasive methods and have been limited to single functional regions and thus cannot account for possible variations across brain regions. Here we present a method that uses fMRI data and singe-trial electroencephalography (EEG) analyses to assess the spatial and spectral dependencies between the blood-oxygenation-level-dependent (BOLD) responses and the noninvasively estimated local field potentials (eLFPs) over a wide range of frequencies (0-256 Hz) throughout the entire brain volume. This method was applied in a study where human subjects completed separate fMRI and EEG sessions while performing a passive visual task. Intracranial LFPs were estimated from the scalp-recorded data using the ELECTRA source model. We compared statistical images from BOLD signals with statistical images of each frequency of the eLFPs. In agreement with previous studies in animals, we found a significant correspondence between LFP and BOLD statistical images in the gamma band (44-78 Hz) within primary visual cortices. In addition, significant correspondence was observed at low frequencies (<14 Hz) and also at very high frequencies (>100 Hz). Effects within extrastriate visual areas showed a different correspondence that not only included those frequency ranges observed in primary cortices but also additional frequencies. Results therefore suggest that the relationship between electrophysiological and hemodynamic signals thus might vary both as a function of frequency and anatomical region.

Factors affecting visual analysis in single-case designs

Visual inspection remains the most frequently applied method for detecting treatment effects in single-case designs. The advantages and limitations of visual inference are here discussed in relation to other procedures for assessing intervention effectiveness. The first part of the paper reviews previous research on visual analysis, paying special attention to the validation of visual analysts" decisions, inter-judge agreement, and false alarm and omission rates. The most relevant factors affecting visual inspection (i.e., effect size, autocorrelation, data variability, and analysts" expertise) are highlighted and incorporated into an empirical simulation study with the aim of providing further evidence about the reliability of visual analysis. Our results concur with previous studies that have reported the relationship between serial dependence and increased Type I rates. Participants with greater experience appeared to be more conservative and used more consistent criteria when assessing graphed data. Nonetheless, the decisions made by both professionals and students did not match sufficiently the simulated data features, and we also found low intra-judge agreement, thus suggesting that visual inspection should be complemented by other methods when assessing treatment effectiveness.

Dyslexia in a French-Spanish bilingual girl: behavioural and neural modulations following a visual attention span intervention.

We report the case study of a French-Spanish bilingual dyslexic girl, MP, who exhibited a severe visual attention (VA) span deficit but preserved phonological skills. Behavioural investigation showed a severe reduction of reading speed for both single items (words and pseudo-words) and texts in the two languages. However, performance was more affected in French than in Spanish. MP was administered an intensive VA span intervention programme. Pre-post intervention comparison revealed a positive effect of intervention on her VA span abilities. The intervention further transferred to reading. It primarily resulted in faster identification of the regular and irregular words in French. The effect of intervention was rather modest in Spanish that only showed a tendency for faster word reading. Text reading improved in the two languages with a stronger effect in French but pseudo-word reading did not improve in either French or Spanish. The overall results suggest that VA span intervention may primarily enhance the fast global reading procedure, with stronger effects in French than in Spanish. MP underwent two fMRI sessions to explore her brain activations before and after VA span training. Prior to the intervention, fMRI assessment showed that the striate and extrastriate visual cortices alone were activated but none of the regions typically involved in VA span. Post-training fMRI revealed increased activation of the superior and inferior parietal cortices. Comparison of pre- and post-training activations revealed significant activation increase of the superior parietal lobes (BA 7) bilaterally. Thus, we show that a specific VA span intervention not only modulates reading performance but further results in increased brain activity within the superior parietal lobes known to housing VA span abilities. Furthermore, positive effects of VA span intervention on reading suggest that the ability to process multiple visual elements simultaneously is one cause of successful reading acquisition.

Visual cortex in Alzheimer's disease: occurrence of neuronal death and glial proliferation, and correlation with pathological hallmarks.

Visual areas 17 and 18 were studied with morphometric methods for numbers of neurons, glia, senile plaques (SP), and neurofibrillary tangles (NFT) in 13 cases of Alzheimer's disease (AD) as compared to 11 controls. In AD cases, the mean neuronal density was significantly decreased by about 30% in both areas 17 and 18, while the glial density was increased significantly only in area 17. The volume of area 17 was unchanged in AD cases but its total number of neurons was decreased by 33% and its total number of glia increased by 45% compared to controls. In AD the number of SP was similar in areas 17 and 18, while that of NFT was significantly higher in area 18. The number of neurons with NFT was only 2% in area 17 and about 10% in area 18. The discrepancy between the loss of neurons and the amount of NFT suggests that neuronal loss can occur without passing through NFT degeneration. The deposition of SP was correlated with glial proliferation, but not with neuronal loss or neurofibrillary degeneration.

Development of In Situ Detection Methods for Materials-Related Distress (MRD) in Concrete Pavements: Phase 2, HR-1081, 2005

This project utilized information from ground penetrating radar (GPR) and visual inspection via the pavement profile scanner (PPS) in proof-of-concept trials. GPR tests were carried out on a variety of portland cement concrete pavements and laboratory concrete specimens. Results indicated that the higher frequency GPR antennas were capable of detecting subsurface distress in two of the three pavement sites investigated. However, the GPR systems failed to detect distress in one pavement site that exhibited extensive cracking. Laboratory experiments indicated that moisture conditions in the cracked pavement probably explain the failure. Accurate surveys need to account for moisture in the pavement slab. Importantly, however, once the pavement site exhibits severe surface cracking, there is little need for GPR, which is primarily used to detect distress that is not observed visually. Two visual inspections were also conducted for this study by personnel from Mandli Communications, Inc., and the Iowa Department of Transportation (DOT). The surveys were conducted using an Iowa DOT video log van that Mandli had fitted with additional equipment. The first survey was an extended demonstration of the PPS system. The second survey utilized the PPS with a downward imaging system that provided high-resolution pavement images. Experimental difficulties occurred during both studies; however, enough information was extracted to consider both surveys successful in identifying pavement surface distress. The results obtained from both GPR testing and visual inspections were helpful in identifying sites that exhibited materials-related distress, and both were considered to have passed the proof-of-concept trials. However, neither method can currently diagnose materials-related distress. Both techniques only detected the symptoms of materials-related distress; the actual diagnosis still relied on coring and subsequent petrographic examination. Both technologies are currently in rapid development, and the limitations may be overcome as the technologies advance and mature.

Rehabilitation of Concrete Pavements Utilizing Rubblization and Crack and Seat Methods (Phase II): Performance Evaluation of Rubblized Pavements in Iowa, TR-550, 2008

This Phase II follow-up study of IHRB Project TR-473 focused on the performance evaluation of rubblized pavements in Iowa. The primary objective of this study was to evaluate the structural condition of existing rubblized concrete pavements across Iowa through Falling Weight Deflectometer (FWD) tests, Dynamic Cone Penetrometer (DCP) tests, visual pavement distress surveys, etc. Through backcalculation of FWD deflection data using the Iowa State University's advanced layer moduli backcalculation program, the rubblized layer moduli were determined for various projects and compared with each other for correlating with the long-term pavement performance. The AASHTO structural layer coefficient for rubblized layer was also calculated using the rubblized layer moduli. To validate the mechanistic-empirical (M-E) hot mix asphalt (HMA) overlay thickness design procedure developed during the Phase I study, the actual HMA overlay thicknesses from the rubblization projects were compared with the predicted thicknesses obtained from the design software. The results of this study show that rubblization is a valid option to use in Iowa in the rehabilitation of portland cement concrete pavements provided the foundation is strong enough to support construction operations during the rubblization process. The M-E structural design methodology developed during Phase I can estimate the HMA overlay thickness reasonably well to achieve long-lasting performance of HMA pavements. The rehabilitation strategy is recommended for continued use in Iowa under those conditions conducive for rubblization.

Remaining rod activity mediates visual behavior in adult Rpe65-/- mice.

Purpose: C57/Bl6, Cpfl1-/- (Cone photoreceptors function loss 1; pure rod function), Gnat1alpha-/- (rod alpha-transducin; pure cone function) and Rpe65-/-;Rho-/- double knock-out mice were studied in order to distinguish the respective contributions of the different photoreceptor (PR) systems that enable light perception and mediate a visual reflex in adult Rpe65-/- mice using a simple behavioural procedure. Methods: Visual function was estimated using a rotating automatized optomotor drum covered with vertical black and white stripes at spatial frequencies of 0.025 to 0.5 cycles per degree (cpd) in both photopic and scotopic conditions. To evaluate the contribution as well as the light intensity threshold of each PR system, we tested the mouse strains with different luminances. Results: Stripe rotation elicits head movements in wild-type (WT) animals in photopic and scotopic conditions depending on the spatial frequency, whereas Cpfl1-/- mice show a reduced activity in the photopic condition and Gnat1alpha-/- mice an almost absent response in the scotopic condition. Interestingly, a robust visual response is obtained with Rpe65-/- knockout mice at 0.075 cpd and 0.1 cpd in the photopic condition. The residual rod function in the Rpe65-/- animals was demonstrated by testing Rpe65-/-;Rho-/- mice that present no response in photopic conditions. Conclusions: The optomotor test is a simple method to estimate the visual function, and to evaluate the respective contributions of rod and cone systems. Using this test, we demonstrate that in Rpe65-/- mice, devoid of functional cones and of detectable 11-cis-retinal protein, rods mimic in part the cone function by mediating vision in photopic conditions.

Is tagging with visual implant elastomer a reliable technique for marking earthworms?

Visual implant elastomer (VIE) has recently been employed to investigate different aspects of earthworm ecology. However, a number of fundamental questions relating to the detection and positioning of the tag, its persistence and potential effects on earthworms remain unknown. Seven earthworm species belonging to three ecological groupings, with different pigmentation and burrowing behaviour, were tagged using different coloured VIE. External inspection after two days, one week and 1, 10 and 27 months were followed by preservation, dissection and internal inspection. Tags could be seen in living specimens to 27 months, and dissection revealed that in most cases they were lodged in the coelomic cavity, held in place by septa. However, over longer time periods (more than two years), the chlorogogenous tissue tended to bind to the tags and made external observation increasingly difficult. Migration of the VIE material towards the posterior of the earthworm and potential loss of the tag were only observed on rare occasions, and a recovery rate in excess of 98% was recorded. By introducing a reasonable amount of VIE into segments, just after the clitellum, this technique can become a valuable tool in earthworm ecology and life history studies, particularly in short-medium term laboratory and field experiments.

Sensitivity of single-voxel 1H-MRS in investigating the metabolism of the activated human visual cortex at 7 T.

Proton magnetic resonance spectroscopy (1H-MRS) has been used in a number of studies to noninvasively assess the temporal changes of lactate in the activated human brain. However, the results have not been consistent. The aim of the present study was to test the sensitivity of 1H-MRS during functional experiments at the highest magnetic field currently available for human studies (7 T). Stability and reproducibility of the measurements were evaluated from LCModel analysis of time series of spectra measured during a visual stimulation paradigm and by examination of the difference between spectra obtained at rest and during activation. The sensitivity threshold to detect concentration changes was 0.2 micromol/g for most of the quantified metabolites. The possible variations of metabolite concentrations during visual stimulation were within the same range (+/-0.2 micromol/g). In addition, the influence of a small line-narrowing effect due to the blood oxygenation level-dependent (BOLD) T2* changes on the estimated concentrations was simulated. Quantification of metabolites was, in general, not affected beyond 1% by line-width changes within 0.5 Hz.

Visual vertigo: an observational case series of eleven patients.

BACKGROUND: Dizziness is a common symptom which is frequently due to either peripheral or central vestibular dysfunction. However, some patients may lack typical signs suggesting a vestibular or cerebellar lesion and they mostly complain of vertigo or posture imbalance induced by visual stimulation. The symptoms immediately improve either on cessation of the visual input or upon closure of the eyes. Such a presentation is typical of visual vertigo. PATIENTS AND METHODS: From 1993 to 2003, 242 patients were examined for either "vertigo" or "dizziness". The diagnosis of visual vertigo was based on both history and clinical examination and was present in 11 patients. RESULTS: Visual vertigo was diagnosed in 11/242 patients (4.5 %). Age range was 31 - 77 years (mean 47 years) with a sex ratio of 8 females for 3 males. Neuro-ophthalmological examination was normal in all cases. CONCLUSIONS: Visual vertigo is not a rare condition but the disease is underdiagnosed. The symptoms result from a mismatch between vestibular, proprioceptive and visual inputs. Neuro-ophthalmological, neurological and neuro-otological examination are often normal or not relevant and the diagnosis is largely based on history. It is important to recognize this entity because the symptoms might improve if the patients are treated with psycho-motor rehabilitation.

Visual signs and symptoms in patients with the visual variant of Alzheimer disease.

BACKGROUND: Prominent visual symptoms can present in the visual variant of Alzheimer's disease (VVAD). Ophthalmologists have a significant role to play in the early diagnosis of VVAD. METHODS: We retrospectively reviewed the files of ten consecutive patients diagnosed with VVAD. All patients had a full neuro-ophthalmologic examination, a formal neurological and neuro-psychological testing, and cerebral MRI to confirm diagnosis. In addition, functional neuroimaging was obtained in seven patients. RESULTS: The common primary symptom at presentation with all patients was difficulty with near vision (reading difficulty n = 8, "visual blur" in near vision n = 2), and difficulty writing (n = 3). Following assessment, impaired reading and writing skills were evident in 9/10 and 8/10 patients respectively. Median distance visual acuity was 20/25 and at near the median visual acuity was J6. Partial homonymous visual field defect was detected in 80 % (8/10) of the patients. Color vision was impaired in all patients when tested with Ishihara pseudoisochromatic plates, but simple color naming was normal in 8/9 tested patients. Simultanagnosia was present in 8/10 patients. Vision dysfunction corresponded with cerebral MRI findings where parieto-occipital cortical atrophy was observed in all patients. PET scan (5 patients) or SPECT (2 patients) revealed parieto-occipital dysfunction (hypometabolism or hypoperfusion) in all 7 tested patients CONCLUSIONS: Visual difficulties are prominent in VVAD. Dyslexia, incomplete homonymous hemianopia, preserved color identification with abnormal color vision on Ishihara, and simultanagnosia were all symptoms observed frequently in this patient series. Ophthalmologists should be aware of the possibility of neurodegenerative disorders such as VVAD in patients with unexplained visual complaints, in particular reading difficulties.

Tolerance and Relative Utility: Two Proposed Indices for Comparing Change in Clinical Measurement Noise Between Different Populations (Repeatability) or Measurement Methods (Agreement).

Reaching a consensus in terms of interchangeability and utility (i.e., disease detection/monitoring) of a medical device is the eventual aim of repeatability and agreement studies. The aim of the tolerance and relative utility indices described in this report is to provide a methodology to compare change in clinical measurement noise between different populations (repeatability) or measurement methods (agreement), so as to highlight problematic areas. No longitudinal data are required to calculate these indices. Both indices establish a metric of least to most effected across all parameters to facilitate comparison. If validated, these indices may prove useful tools when combining reports and forming the consensus required in the validation process for software updates and new medical devices.

Refractory subretinal fluid in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab: visual acuity outcome.

PURPOSE: To investigate the functional outcome of eyes with neovascular AMD (nAMD) and subretinal fluid (SRF) refractory to treatment with ranibizumab. METHODS: Retrospective chart review of consecutive treatment-refractory SRF in nAMD despite monthly ranibizumab injections during 12 months or more. Data were evaluated for baseline characteristics, location of the refractory SRF, mean visual acuity (VA) change, number of injections, and timepoint of first complete disappearance of SRF. RESULTS: Forty-five eyes in 44 patients (mean age of 76 years) were included. The mean follow-up was 32.4 months (range 12-73 months). The mean number of injections was 11.6 in the first year and 27.5 over follow-up. The refractory SRF was located subfoveally in 66.7 %. In 12 eyes (26.7 %), complete absorption of SRF was found after a mean of 22.6 months (range, 13-41 months). Mean VA increased by 10.4, 8.2, and 8.6 letters by month 12, 24, and 36, respectively. CONCLUSIONS: Neovascular AMD with SRF refractory to monthly retreatment with ranibizumab may still allow good and maintained visual improvement, even if the fluid is located subfoveally. SRF may progressively absorb under continuous monthly treatment. The necessity to treat refractory SRF with monthly injections could be questioned and would need future investigations.