Assessing the pattern electroretinogram as a proxy measure for dopamine in the context of iron deficiency.

OBJECTIVES: Animal studies have suggested that dietary iron deficiency (ID) negatively affects dopamine (DA) synthesis and re-uptake, which in turn negatively affects memory and cognition. This study was intended to assess whether the pattern electroretinogram (pattern ERG) could be used as an indirect measure of DA in college-age women with and without ID by determining the extent to which features of the ERG were sensitive to iron status and were related to other indirect measures of DA. METHODS: The pattern ERG was measured in 21 iron deficient non-anemic (IDNA) and 21 iron sufficient (IS) women, who also performed a contrast detection and probabilistic selection task, both with concurrent electroencephalography (EEG). Both spontaneous and task-related blink rates were also measured. RESULTS: The implicit times of the A- and B-waves were significantly longer for the IDNA than for the IS women. Both the amplitudes and implicit times of the A- and B-waves were significantly correlated with levels of serum ferritin (sFt). Only the amplitude of the A-wave was correlated with spontaneous blink rate. It was possible to accurately identify a woman's iron status solely on the basis of the implicit time of the B-wave. Finally, the implicit times of the ERG features mediated the relationship between iron levels and accuracy in the probabilistic selection task. CONCLUSIONS: Results suggest the utility of the pattern ERG in testing the hypothesis that iron deficiency affects DA levels in humans and that this may be one of the mechanisms by which iron deficiency negatively affects cognition.

Electrophysiological resting state brain network and episodic memory in healthy aging adults.

Recent studies have emphasized the changes in large-scale brain networks related to healthy aging, with the ultimate purpose to aid in differentiating normal neurocognitive aging from neurodegenerative disorders that also arise with age. Emerging evidence from functional Magnetic Resonance Imaging (fMRI) indicates that connectivity patterns within specific brain networks, especially the Default Mode Network (DMN), distinguish those with Alzheimer's disease from healthy individuals. In addition, disruptive alterations in the large-scale brain systems that support high-level cognition are shown to accompany cognitive decline at the behavioral level, which is commonly observed in the aging populations, even in the absence of disease. Although fMRI is useful for assessing functional changes in brain networks, its high costs and limited accessibility discourage studies that need large populations. In this study, we investigated the aging-effect on large-scale networks of the human brain using high-density electroencephalography and electrophysiological source imaging, which is a less costly and more accessible alternative to fMRI. In particular, our study examined a group of healthy subjects in the age range from middle- to older-aged adults, which is an under-studied range in the literature. Employing a high-resolution computation model, our results revealed age associations in the connectivity pattern of DMN in a consistent manner with previous fMRI findings. Particularly, in combination with a standard battery of cognitive tests, our data showed that in the posterior cingulate / precuneus area of DMN higher brain connectivity was associated with lower performance on an episodic memory task. The findings demonstrate the feasibility of using electrophysiological imaging to characterize large-scale brain networks and suggest that changes in network connectivity are associated with normal aging.

Modeling relationships between iron status, behavior, and brain electrophysiology: evidence from a randomized study involving a biofortified grain in Indian adolescents.

BACKGROUND: Iron deficiency (ID) and iron deficiency anemia (IDA) are highly-prevalent nutrient deficiencies and have been shown to have a range of negative effects on cognition and brain function. Human intervention studies including measures at three levels-blood, brain, and behavior-are rare and our objective was to model the relationships among measures at these three levels in school-going Indian adolescents. METHODS: Male and female adolescents in rural India were screened for ID/IDA. Subjects consumed 2 meals/day for 6 months; half were randomly assigned to consume meals made from a standard grain (pearl millet) and half consumed meals made from an iron biofortified pearl millet (BPM). Prior to and then at the conclusion of the feeding trial, they completed a set of cognitive tests with concurrent electroencephalography (EEG). RESULTS: Overall, serum ferritin (sFt) levels improved over the course of the study. Ten of 21 possible measures of cognition showed improvements from baseline (BL) to endline (EL) that were larger for those consuming BPM than for those consuming the comparison pearl millet (CPM). Critically, the best model for the relationship between change in iron status and change in cognition had change in brain measures as a mediating factor, with both change in serum ferritin as a primary predictor and change in hemoglobin as a moderator. CONCLUSIONS: A dietary intervention involving a biofortified staple grain was shown to be efficacious in improving blood iron biomarkers, behavioral measures of cognition, and EEG measures of brain function. Modeling the relationships among these variables strongly suggests multiple mechanisms by which blood iron level affects brain function and cognition. TRIAL REGISTRATION: Registered at ClinicalTrials.gov, NCT02152150 , 02 June 2014.

Changes in Iron Status Are Related to Changes in Brain Activity and Behavior in Rwandan Female University Students: Results from a Randomized Controlled Efficacy Trial Involving Iron-Biofortified Beans.

BACKGROUND: Evidence suggests that iron deficiency (ID) affects cognitive performance, as measured in behavior. Although such effects must be mediated by changes in the brain, very few studies have included measures of brain activity to assess this relation. OBJECTIVE: We tested the hypothesis that provision of iron-biofortified beans would result in improvements in measures of iron status, brain dynamics, and behavior. METHODS: A double-blind, randomized, intervention study was conducted in 55 women aged 18-27 y with low iron status (serum ferritin <20 µg/L). Women were randomly assigned to consume iron-biofortified (86.1 ppm iron) or comparison beans (50.1 ppm iron) daily for 18 wk. Iron status was assessed by hemoglobin, ferritin, transferrin receptor, and body iron; cognitive performance with 5 computerized tasks; and brain dynamics by concurrent electroencephalography (EEG). All measures were taken at baseline and endline. RESULTS: The groups did not differ on any measures at baseline. Intention-to-treat analyses revealed significant (all P < 0.05) improvements in hemoglobin (partial effect size attributable to the independent variable, η2 = 0.16), ferritin (η2 = 0.17), and body iron (η2 = 0.10), speed of responding in attentional and mnemonic tasks (η2 = 0.04-0.29), sensitivity and efficiency of memory retrieval (η2 = 0.12-0.55), and measures of EEG amplitude and spectral power (η2 = 0.08 to 0.49). Mediation models provided evidence in support of the hypothesis that changes in iron status produce changes in behavior by way of changes in brain activity. CONCLUSIONS: Behavioral performance and brain activity, as measured by EEG, are sensitive to iron status, and the consumption of iron-biofortified beans for 18 wk resulted in improvements in measures of both, relative to what was obtained with a comparison bean, in a sample of female university students. Furthermore, the results support the conclusion that changes in brain activity resulting from consumption of biofortified beans mediate the relations between changes in iron biomarkers and changes in cognition. Clinical trial registry: ClinicalTrials.gov Reg No. NCT01594359.

Effect of iron deficiency on simultaneous measures of behavior, brain activity, and energy expenditure in the performance of a cognitive task.

OBJECTIVES: Iron deficiency (ID) - the highly prevalent nutritional deficiency - has been shown to have deleterious effects on measures of cognitive performance and brain activity. Many of these results are suggestive of the impact of ID on neurotransmitter regulation and myelination. A third critical potential effect of ID on brain function is at the level of brain energy expenditure; however, to date there has not been any method for indirectly estimating the impact of ID on energy expenditure in humans in the context of cognitive work. METHODS: We report here a study comparing ID and iron sufficient (IS) college students in which simultaneous behavioral, encephelographic (EEG), and metabolic data were collected in a task designed as a cognitive analog to standard physical exertion tasks. RESULTS: We show that increases in cognitive demands produced decrements in behavioral measures of performance, and increases in EEG and metabolic measures of work. Critically, we found that the magnitudes of those changes were directly related to iron levels. DISCUSSION: We find support for the idea that brain activity mediates the relationship between cognitive demands and energy expenditure, with ferritin and hemoglobin moderating those relationships in distinct ways. Finally, we show that levels of energy expenditure can be indirectly estimated by measures of EEG spectral power.

Cognitive Performance in Indian School-Going Adolescents Is Positively Affected by Consumption of Iron-Biofortified Pearl Millet: A 6-Month Randomized Controlled Efficacy Trial.

BACKGROUND: Iron deficiency remains the most prevalent micronutrient deficiency globally, but few studies have examined how iron status relates to cognition in adolescents. Iron biofortification of staple food crops is being scaled up, yet it is unknown whether consuming biofortified crops can benefit cognition. Objective: Our objective was to determine the efficacy of iron-biofortified pearl millet in improving attention and memory in Indian school-going adolescents. Methods: A double-blind, randomized, intervention study was conducted in 140 Indian boys and girls, aged 12-16 y, who were assigned to consume iron-biofortified [Fe = 86 parts per million (ppm)] or conventional (Fe = 21-52 ppm) pearl millet. Hemoglobin, ferritin, and transferrin receptor (TfR) were measured and body iron (BI) was calculated at baseline and after 4 and 6 mo. Five measures of cognitive function were obtained at baseline and 6 mo: simple reaction time (SRT), Go/No-Go (GNG) task, Attentional Network Task (ANT), Composite Face Effect (CFE) task, and Cued Recognition Task (CRT). Intention-to-treat analysis was used. Results: Daily iron intake from pearl millet was higher in those consuming biofortified compared with conventional pearl millet (19.6 compared with 4.8 mg/d). Effects on ferritin, TfR, and BI at 4 mo, and on TfR at 6 mo (all P < 0.05), indicated efficacy of biofortified pearl millet over conventional pearl millet in improving iron status. Compared with conventional pearl millet, the consumption of biofortified pearl millet resulted in greater improvement in attention (SRT, GNG, and ANT) and memory (CFE and CRT). Reaction time decreased twice as much from 0 to 6 mo in those consuming biofortified compared with conventional pearl millet on attention tasks (SRT: -123 compared with -63 ms; GNG: -67 compared with -30 ms; ANT double cue: -74 compared with -32 ms; all P < 0.01). Conclusion: Consuming iron-biofortified pearl millet improves iron status and some measures of cognitive performance in Indian adolescents. This trial was registered at http://www.clinicaltrials.gov as NCT02152150.

Converging operations and the role of perceptual and decisional influences on the perception of faces: Neural and behavioral evidence.

Theoretical analyses suggest that the regularities indicative of holistic processing can be obtained by combinations of perceptual and decisional factors. Kuefner and colleagues used electrophysiological results to suggest that the composite face effect is driven solely by perceptual factors. Two limitations of their approach are (a) it did not involve behavioral measures of perceptual sensitivity or bias, and (b) it is unclear how the measures used in that study are consistent with other measures of perceptual and decisional processing. Eight observers completed three tasks involving the stimuli used by Kuefner et al.. The first was a direct replication. The second was a complete identification task, associated with the perceptual and decisional distinctions formalized in general recognition theory. The third was an implementation of the Eriksen fianker task, which allows for a pattern of results that have been interpreted in terms of perceptual and decisional influences. While the empirical distinctions used by Kuefner et al. were not consistent with either the EEG data from the other tasks or the established behavioral measures of perceptual sensitivity and decisional bias, the inferences drawn from the EEG and behavioral data from those tasks were consistent with one another, underscoring the importance of converging operations.

Consumption of Iron-Biofortified Beans Positively Affects Cognitive Performance in 18- to 27-Year-Old Rwandan Female College Students in an 18-Week Randomized Controlled Efficacy Trial.

Background: Evidence shows that iron deficiency in adulthood may affect cognitive performance, possibly by disrupting neurotransmitter regulation or brain energy metabolism. Women of reproductive age (WRA) are among those who are most vulnerable to iron deficiency; however, they have been largely ignored in the literature relating iron status to cognition.Objective: Our aim was to determine the efficacy of iron-biofortified beans in improving cognition in WRA compared with control beans.Methods: A double-blind, randomized intervention study was conducted in 150 women aged 18-27 y with low iron status (ferritin <20 µg/L). Women were randomly assigned to consume iron-biofortified beans (86.1 ppm iron) or control beans (50.1 ppm iron) daily for 18 wk. Iron status was assessed based on hemoglobin, ferritin, transferrin receptor, and body iron values and on cognitive performance on 5 computerized tasks at baseline and endline.Results: Groups did not differ on any variables at baseline. Per protocol analyses revealed that consumption of the biofortified beans resulted in a 17% larger improvement in the speed of spatial selective attention; a nearly 7-fold larger improvement in the speed, a 68% greater improvement in the efficiency, and a >2-fold greater improvement in the specificity of memory retrieval; and a >2-fold larger improvement in the speed and a >3-fold larger improvement in the efficiency of memory search-all of which are relative to consumption of the control beans (P < 0.01 for all comparisons).Conclusions: Cognitive performance is sensitive to iron status, and consumption of iron-biofortified beans for 18 wk improved cognitive performance, especially the efficiency of search and the speed of retrieval on memory tasks, in young adult women. This trial was registered at clinicaltrials.gov as NCT01594359.

Consumption of a Double-Fortified Salt Affects Perceptual, Attentional, and Mnemonic Functioning in Women in a Randomized Controlled Trial in India.

Background: Iron deficiency and iron deficiency anemia have been shown to have negative effects on aspects of perception, attention, and memory.Objective: The purpose of this investigation was to assess the extent to which increases in dietary iron consumption are related to improvements in behavioral measures of perceptual, attentional, and mnemonic function.Methods: Women were selected from a randomized, double-blind, controlled food-fortification trial involving ad libitum consumption of either a double-fortified salt (DFS) containing 47 mg potassium iodate/kg and 3.3 mg microencapsulated ferrous fumarate/g (1.1 mg elemental Fe/g) or a control iodized salt. Participants' blood iron status (primary outcomes) and cognitive functioning (secondary outcomes) were assessed at baseline and after 10 mo at endline. The study was performed on a tea plantation in the Darjeeling district of India. Participants (n = 126; 66% iron deficient and 49% anemic at baseline) were otherwise healthy women of reproductive age, 18-55 y.Results: Significant improvements were documented for iron status and for perceptual, attentional, and mnemonic function in the DFS group (percentage of variance accounted for: 16.5%) compared with the control group. In addition, the amount of change in perceptual and cognitive performance was significantly (P < 0.05) related to the amount of change in blood iron markers (mean percentage of variance accounted for: 16.0%) and baseline concentrations of blood iron markers (mean percentage of variance accounted for: 25.0%). Overall, there was evidence that the strongest effects of change in iron status were obtained for perceptual and low-level attentional function.Conclusion: DFS produced measurable and significant improvements in the perceptual, attentional, and mnemonic performance of Indian female tea pickers of reproductive age. This trial was registered at clinicaltrials.gov as NCT01032005.

Consuming Iron Biofortified Beans Increases Iron Status in Rwandan Women after 128 Days in a Randomized Controlled Feeding Trial.

BACKGROUND: Food-based strategies to reduce nutritional iron deficiency have not been universally successful. Biofortification has the potential to become a sustainable, inexpensive, and effective solution. OBJECTIVE: This randomized controlled trial was conducted to determine the efficacy of iron-biofortified beans (Fe-Beans) to improve iron status in Rwandan women. METHODS: A total of 195 women (aged 18-27 y) with serum ferritin <20 µg/L were randomly assigned to receive either Fe-Beans, with 86 mg Fe/kg, or standard unfortified beans (Control-Beans), with 50 mg Fe/kg, 2 times/d for 128 d in Huye, Rwanda. Iron status was assessed by hemoglobin, serum ferritin, soluble transferrin receptor (sTfR), and body iron (BI); inflammation was assessed by serum C-reactive protein (CRP) and serum α1-acid glycoprotein (AGP). Anthropometric measurements were performed at baseline and at end line. Random weekly serial sampling was used to collect blood during the middle 8 wk of the feeding trial. Mixed-effects regression analysis with repeated measurements was used to evaluate the effect of Fe-Beans compared with Control-Beans on iron biomarkers throughout the course of the study. RESULTS: At baseline, 86% of subjects were iron-deficient (serum ferritin <15 µg/L) and 37% were anemic (hemoglobin <120 g/L). Both groups consumed an average of 336 g wet beans/d. The Fe-Beans group consumed 14.5 ± 1.6 mg Fe/d from biofortified beans, whereas the Control-Beans group consumed 8.6 ± 0.8 mg Fe/d from standard beans (P < 0.05). Repeated-measures analyses showed significant time-by-treatment interactions for hemoglobin, log serum ferritin, and BI (P < 0.05). The Fe-Beans group had significantly greater increases in hemoglobin (3.8 g/L), log serum ferritin (0.1 log µg/L), and BI (0.5 mg/kg) than did controls after 128 d. For every 1 g Fe consumed from beans over the 128 study days, there was a significant 4.2-g/L increase in hemoglobin (P < 0.05). CONCLUSION: The consumption of iron-biofortified beans significantly improved iron status in Rwandan women. This trial was registered at clinicaltrials.gov as NCT01594359.

Does Number of Perceptions or Cross-Modal Auditory Cueing Influence Audiovisual Processing Speed?

What factors contribute to redundant target processing speed besides statistical facilitation? One possibility is that multiple percepts may drive these effects. Another, although not mutually exclusive hypothesis, is that cross-channel cueing from one modality to another may influence response times. We implemented an auditory-visual detection task using the sound-induced flash illusion to examine whether one or both of these possibilities contributes to changes in processing speed; we did so by examining the data of individual participants. Our results indicated shorter response times in several participants when multiple flashes were perceived in the standard sound-induced flash illusion, thereby replicating previous work in the literature. Additionally, we found evidence for faster responses in several participants when carrying out the same analysis in trials in which 1 beep was presented with 2 real flashes. Overall, our analysis indicates that some observers benefit from cross-modal facilitation, whereas others may benefit from a combination of cross-modal facilitation and increased perceptual judgments.

A Randomized Trial of Iron-Biofortified Pearl Millet in School Children in India.

BACKGROUND: Iron deficiency is the most widespread nutritional deficiency in the world. OBJECTIVE: The objective of this randomized efficacy trial was to determine the effects of iron-biofortified pearl millet (Fe-PM) on iron status compared with control pearl millet (Control-PM). METHODS: A randomized trial of biofortified pearl millet (Pennisetum glaucum), bred to enhance iron content, was conducted in 246 children (12-16 y) for 6 mo in Maharashtra, India. Iron status [hemoglobin, serum ferritin (SF), soluble transferrin receptor (sTfR), and total body iron (TBI)], inflammation (C-reactive protein and α-1 acid glycoprotein), and anthropometric indices were evaluated at enrollment and after 4 and 6 mo. Hodges-Lehmann-Sen 95% CIs were used to examine the effect of the Fe-PM on iron status compared with commercially available Control-PM. Linear and binomial regression models were used to evaluate the effects of Fe-PM on iron status and incidence of anemia and iron deficiency, compared with Control-PM. RESULTS: At baseline, 41% of children were iron deficient (SF <15 µg/L) and 28% were anemic (hemoglobin <12.0 g/dL). Fe-PM significantly increased SF concentrations and TBI after 4 mo compared with Control-PM. Among children who were iron deficient at baseline, those who received Fe-PM were 1.64 times more likely to become iron replete by 6 mo than were those receiving Control-PM (RR: 1.64, 95% CI: 1.07, 2.49, P = 0.02). The effects of Fe-PM on iron status were greater among children who were iron deficient at baseline than among children who were not iron deficient at baseline. CONCLUSIONS: Fe-PM significantly improved iron status in children by 4 mo compared with Control-PM. This study demonstrated that feeding Fe-PM is an efficacious approach to improve iron status in school-age children and it should be further evaluated for effectiveness in a broader population context. This trial was registered at clinicaltrials.gov as NCT02152150.

Learning to associate auditory and visual stimuli: behavioral and neural mechanisms.

The ability to effectively combine sensory inputs across modalities is vital for acquiring a unified percept of events. For example, watching a hammer hit a nail while simultaneously identifying the sound as originating from the event requires the ability to identify spatio-temporal congruencies and statistical regularities. In this study, we applied a reaction time and hazard function measure known as capacity (e.g., Townsend and AshbyCognitive Theory 200-239, 1978) to quantify the extent to which observers learn paired associations between simple auditory and visual patterns in a model theoretic manner. As expected, results showed that learning was associated with an increase in accuracy, but more significantly, an increase in capacity. The aim of this study was to associate capacity measures of multisensory learning, with neural based measures, namely mean global field power (GFP). We observed a co-variation between an increase in capacity, and a decrease in GFP amplitude as learning occurred. This suggests that capacity constitutes a reliable behavioral index of efficient energy expenditure in the neural domain.

Double-fortified salt is efficacious in improving indicators of iron deficiency in female Indian tea pickers.

Poor iron status affects 50% of Indian women and compromises work productivity, cognitive performance, and reproduction. Among the many strategies to reduce iron deficiency is the commercial fortification of iodized table salt with iron to produce a double-fortified salt (DFS). The objective of this study was to test the efficacy of DFS in reducing iron deficiency in rural women of reproductive age from northern West Bengal, India. The participants were 212 women between 18 and 55 y of age who worked as full-time tea pickers on a large tea estate. Participants in the randomized, controlled, double-blind study were assigned to use either DFS or a control iodized salt for 7.5 to 9 mo. The DFS was fortified with 3.3-mg ferrous fumarate (1.1-mg elemental iron) per kg of iodized salt, whereas the control salt contained only iodine (47 mg/kg potassium iodate), and both salt varieties were distributed gratis to the families of participants at 0.5 kg/mo for each 2 household members. At baseline, 53% of participants were anemic (hemoglobin <120 g/L), 25% were iron deficient (serum ferritin <12 µg/L), and 23% were iron-deficient anemic. Also, 22% had a transferrin receptor concentration >8.6 mg/L and 22% had negative (<0.0 mg/kg) body iron stores. After 9 mo the participants receiving DFS showed significant improvements compared with controls in hemoglobin (+2.4 g/L), ferritin (+0.13 log10 µg/L), soluble transferrin receptor (-0.59 mg/L), and body iron (+1.43 mg/kg), with change in status analyzed by general linear models controlling for baseline values. This study demonstrated that DFS is an efficacious approach to improving iron status and should be further evaluated for effectiveness in the general population. This trial was registered at clinicaltrials.gov as NCT01032005.

A measure for assessing the effects of audiovisual speech integration.

We propose a measure of audiovisual speech integration that takes into account accuracy and response times. This measure should prove beneficial for researchers investigating multisensory speech recognition, since it relates to normal-hearing and aging populations. As an example, age-related sensory decline influences both the rate at which one processes information and the ability to utilize cues from different sensory modalities. Our function assesses integration when both auditory and visual information are available, by comparing performance on these audiovisual trials with theoretical predictions for performance under the assumptions of parallel, independent self-terminating processing of single-modality inputs. We provide example data from an audiovisual identification experiment and discuss applications for measuring audiovisual integration skills across the life span.

Changes in Brain Activity Immediately Post-Exercise Indicate a Role for Central Fatigue in the Volitional Termination of Exercise.

Electroencephalography (EEG) allows for the evaluation of real time changes in brain (electrocortical) activity during exercise. A few studies have examined changes in electrocortical activity using stationary cycling, but the findings have been mixed. Some of these studies have found increases in brain activity following exercise, while others have found decreases in brain activity following exercise. Hence, it is of importance to identify post-exercise changes in brain activity. Sixteen healthy, untrained subjects (8 males; 8 females) participated in the study. All 16 participants performed a graded exercise test (GXT) to volitional exhaustion on an upright cycle ergometer. Continuous EEG recordings were sampled before (PRE) and immediately following (IP) the GXT. Regions of interest were primarily the dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex (VLPFC), and left and right motor cortex (MC). In the DLPFC, a frontal asymmetry index was also identified. There was a statistically significant increase in theta power in the DLPFC, VLPFC, and left and right MC from PRE to IP (all p < 0.05). There was also a shift towards right hemisphere asymmetry at the IP time point in the DLPFC (p < 0.05). Finally, there was an increase in alpha power from PRE to IP in the right MC (p < 0.05). EEG could prove to be an important way to measure the effects of central fatigue on brain activity before and immediately following exercise.

Don't be a Square: The processing mechanisms characterising the elemental dimensions of width and height.

What are the geometric and information processing characteristics of elementary figures composed of simple physical dimensions? There have been a number of investigations of perception of rectangles, including debate about configurality (e.g., integrality and gestalt properties) as well as the prime perceptual dimensions. Yet, because of ambiguity even in the "right" definition of configurality and an absence of penetrating methodologies, there is still little known concerning the information processing of these patterns. To this end, the present study brings together two separate theory-driven methodologies, general recognition theory (GRT) and systems factorial technology (SFT). The first attacks the problem of dimensional interactions while the latter seeks to uncover process characteristics such as architecture, decisional stopping rules, and workload capacity. The same observers and as much as possible, the same stimuli were used in both approaches. Through our GRT analyses, we found strong evidence for dependencies between the percepts of height and width on both within-stimulus and cross-stimulus bases. Height perception was better with narrow widths and width perception was superior with short heights. In addition, a significant positive within-trial correlation of dimensions was evidenced within squares but not with rectangles. Our SFT initiative uncovered consistent signatures of parallelism paired with super capacity, the latter appearing both through the traditional conditioning on being correct and still present when modest speed accuracy trade-off was accounted for. Thus, the SFT and GRT inferences were quite compatible with a plausible cause of the positive correlations being across-channel facilitatory interactions which led to super capacity processing.

The Effect of Iron-Fortified Lentils on Blood and Cognitive Status among Adolescent Girls in Bangladesh.

BACKGROUND: Iron deficiency is highly prevalent in South Asia, especially among women and children in Bangladesh. Declines in cognitive performance are among the many functional consequences of iron deficiency. OBJECTIVE: We tested the hypothesis that, over the course of a 4-month iron fortification trial, cognitive performance would improve, and that improvement would be related to improvements in iron status. METHODS: Participants included 359 adolescent girls attending Bangladesh Rural Advancement Committee (BRAC) clubs as a subsample of a larger double-blind, cluster-randomized community trial in which participants were assigned to one of three conditions: a condition in which no lentils were supplied (NL, n = 118, but which had the usual intake of lentils), a control (non-fortified) lentil condition (CL, n = 124), and an iron-fortified lentil condition (FL, n = 117). In the FL and CL conditions, approximately 200 g of cooked lentils were served five days per week for a total of 85 feeding days. In addition to biomarkers of iron status, five cognitive tasks were measured at baseline (BL) and endline (EL): simple reaction time task (SRT), go/no-go task (GNG), attentional network task (ANT), the Sternberg memory search Task (SMS), and a cued recognition task (CRT). RESULTS: Cognitive performance at EL was significantly better for those in the FL relative to the CL and NL conditions, with this being true for at least one variable in each task, except for the GNG. In addition, there were consistent improvements in cognitive performance for those participants whose iron status improved. Although there were overall declines in iron status from BL to EL, the declines were smallest for those in the FL condition, and iron status was significantly better for those in FL condition at EL, relative to those in the CL and NL conditions. CONCLUSIONS: the provision of iron-fortified lentils provided a protective effect on iron status in the context of declines in iron status and supported higher levels of cognitive performance for adolescent girls at-risk of developing iron deficiency.

Effects of shifts in response preferences on characteristics of representation and real-time processing: An application to the Hering illusion.

The multidimensional generalization of signal detection theory known as General Recognition Theory (GRT, Ashby & Townsend, Psychological Review, 93, 154-179 1986) has been used to model and characterize the ways in which changes in encoded perceptual information and the application of decisional operators can produce patterns in behavior that are consistent with notions such as configural processing and representation. In particular, a set of studies (e.g., Cornes et al.,, 2011; Wenger & Ingvalson; 2002, 2003) have shown how decisional influences might exert themselves in situations of configural perception, such that effects such as the Thatcher illusion can be obtained by way of shifts in decisional criteria. The present investigation brought to bear the combined tools of GRT and Systems Factorial Technology (SFT, Little et al.,, 2017; Townsend & Nozawa, 1995) with a classical illusion, to show that it is possible to induce a shift in a decisional criterion by way of varying payoffs and that this shift is accompanied by regular changes in the workload capacity statistic. The combined sets of analyses on the same stimuli reveal orderly effects on the decisional criteria (i.e., the signal detection parameter c), report independence (suggesting perceptual independence), invariant measures of sensitivity (i.e., the signal detection parameter [Formula: see text]),and exhaustive parallel processing accompanied by super capacity. We therefore propose wider use of the combined sets of tools, further exploration of the ability of decisional alterations to affect processing times while leaving accuracy largely unscathed, and reaching out to explore more of the information processing mechanisms of classical illusions.