From cookies to carrots; the effect of inhibitory control training on children's snack selections.

Children consume too much sugar and not enough fruit and vegetables, increasing their risk of adverse health outcomes. Inhibitory control training (ICT) reduces children's and adults' intake of energy-dense foods in both laboratory and real-life settings. However, no studies have yet examined whether ICT can increase healthy food choice when energy-dense options are also available. We investigated whether a food-specific Go/No-Go task could influence the food choices of children aged 4-11, as measured by a hypothetical food choice task using healthy and unhealthy food images printed on cards. Participants played either an active game (healthy foods = 100% go, unhealthy foods = 100% no-go; Studies 1 & 2), a food control game (both healthy and unhealthy foods = 50% go, 50% no-go; Studies 1 & 2) or a non-food control game (sports equipment = 100% go, technology = 100% no-go; Study 2 only) followed by the choice task. In Study 2, food card choices were also measured before training to examine change in choices. A post-training real food choice task was added to check that choices made in the card-based task were representative of choices made when faced with real healthy and unhealthy foods. Overall, the active group chose the greatest number of healthy food cards. Study 2 confirmed that this was due to increases in healthy food card choice in this group only. Active group participants chose a greater number of healthy foods in the real food choice task compared to children in the non-food control group only. The results are discussed with reference to methodological issues and the development of future healthy eating interventions.

Subcortical volumetric abnormalities in bipolar disorder.

Considerable uncertainty exists about the defining brain changes associated with bipolar disorder (BD). Understanding and quantifying the sources of uncertainty can help generate novel clinical hypotheses about etiology and assist in the development of biomarkers for indexing disease progression and prognosis. Here we were interested in quantifying case-control differences in intracranial volume (ICV) and each of eight subcortical brain measures: nucleus accumbens, amygdala, caudate, hippocampus, globus pallidus, putamen, thalamus, lateral ventricles. In a large study of 1710 BD patients and 2594 healthy controls, we found consistent volumetric reductions in BD patients for mean hippocampus (Cohen's d=-0.232; P=3.50 × 10-7) and thalamus (d=-0.148; P=4.27 × 10-3) and enlarged lateral ventricles (d=-0.260; P=3.93 × 10-5) in patients. No significant effect of age at illness onset was detected. Stratifying patients based on clinical subtype (BD type I or type II) revealed that BDI patients had significantly larger lateral ventricles and smaller hippocampus and amygdala than controls. However, when comparing BDI and BDII patients directly, we did not detect any significant differences in brain volume. This likely represents similar etiology between BD subtype classifications. Exploratory analyses revealed significantly larger thalamic volumes in patients taking lithium compared with patients not taking lithium. We detected no significant differences between BDII patients and controls in the largest such comparison to date. Findings in this study should be interpreted with caution and with careful consideration of the limitations inherent to meta-analyzed neuroimaging comparisons.

Why decision making may not require awareness.

Newell & Shanks (N&S) argue against the idea that any significant role for unconscious influences on decision making has been established by research to date. Inasmuch as this conclusion applies to the idea of an "intelligent cognitive unconscious," we would agree. Our concern is that the article could lead the unwary to conclude that there are no unconscious influences on decision making - and never could be. We give reasons why this may not be the case.

To discard or not to discard: the neural basis of hoarding symptoms in obsessive-compulsive disorder.

Preliminary neuroimaging studies suggest that patients with the 'compulsive hoarding syndrome' may be a neurobiologically distinct variant of obsessive-compulsive disorder (OCD) but further research is needed. A total of 29 OCD patients (13 with and 16 without prominent hoarding symptoms) and 21 healthy controls of both sexes participated in two functional magnetic resonance imaging experiments consisting of the provocation of hoarding-related and symptom-unrelated (aversive control) anxiety. In response to the hoarding-related (but not symptom-unrelated) anxiety provocation, OCD patients with prominent hoarding symptoms showed greater activation in bilateral anterior ventromedial prefrontal cortex (VMPFC) than patients without hoarding symptoms and healthy controls. In the entire patient group (n=29), provoked anxiety was positively correlated with activation in a frontolimbic network that included the anterior VMPFC, medial temporal structures, thalamus and sensorimotor cortex. Negative correlations were observed in the left dorsal anterior cingulate gyrus, bilateral temporal cortex, bilateral dorsolateral/medial prefrontal regions, basal ganglia and parieto-occipital regions. These results were independent from the effects of age, sex, level of education, state anxiety, depression, comorbidity and use of medication. The findings are consistent with the animal and lesion literature and several landmark clinical features of compulsive hoarding, particularly decision-making difficulties. Whether the results are generalizable to hoarders who do not meet criteria for OCD remains to be investigated.

GABA transmission in the ventral pallidum is not involved in the control of latent inhibition in the rat.

Latent inhibition describes a process of learning to ignore stimuli of no consequence, and is disrupted in acute, positive-symptomatic schizophrenia. Understanding the neural basis of latent inhibition in animals may help to elucidate the neural dysfunction underlying positive schizophrenic symptoms in man. Evidence suggests a crucial role for dopamine transmission in the nucleus accumbens in the control of latent inhibition. The present studies investigated the role of the GABA-ergic efferent from the nucleus accumbens to the ventral pallidum in latent inhibition. The GABA(A) agonist muscimol (4.56 ng/microl), and antagonist picrotoxin (0.2 microg/microl), were infused into the ventral pallidum, and effects on latent inhibition were assessed using a conditioned suppression procedure. Neither drug produced specific effects on latent inhibition when given alone and, in the case of muscimol, failed to reverse the disruption of latent inhibition induced by systemic amphetamine. In addition to significant non-specific drug effects, a positive control experiment revealed that intra-pallidal picrotoxin significantly enhanced locomotion, suggesting that our manipulations of ventral pallidal GABA function were behaviourally effective. We conclude that modulating ventral pallidal GABA transmission does not affect latent inhibition. The implications of this finding for theories of the neural circuitry mediating latent inhibition and for understanding the functional role of ventral pallidal GABA transmission are discussed.

Bioanalytical utility of sonovoltammetry.

Dopamine dissolved within egg homogenate was used as a model system to study the effects of electrode contamination and its subsequent reactivation through ultrasonically mediated in situ cleaning effects. The merits in conducting electroanalytical investigations under the influence of the ultrasonic field were also appraised. Maintaining the ultrasound field during oxidative measurements was found to yield hydrodynamic profiles that were linear over the concentration range 2-20 microM dopamine. The resulting sonolinear sweep voltammograms were compared with conventional rotating disk measurements, with the former found to provide significantly increased limiting currents that were attenuable through the manipulation of the field intensity. The problem of retaining selectivity in the presence of high concentrations of ascorbate was also assessed with the addition of cupric ion prior to commencing the measurements found to efficiently negate an otherwise substantive interference.

Electroanalytical exploitation of quinone-thiol interactions: application to the selective determination of cysteine.

Square wave voltammetry was applied to the detection of cysteine through the use of an indirect assay that exploits the reaction of the thiol with a quinone indicator. Voltammetric discrimination between unreacted quinone and the corresponding quinone-cysteine adduct is possible with clear resolution of the latter peak providing a linear response from 5 to 47 microM. The selectivity of the approach was assessed with no interference from cystine, lysine, paracetamol or 4-aminophenol. The response recorded in the presence of a massive excess of ascorbic acid was also investigated and the integrity of the approach confirmed. The effects of other sulfhydryl thiols, homocysteine and glutathione, were also assessed and found to present no appreciable change in the voltammetric profile. The practical utility of the approach was investigated through examining the response to cysteine in urine.

Voltammetric investigation of hair dye constituents: application to the quantification of p-phenylenediamine.

The application of electrochemical techniques to the determination of common hair dye constituents was investigated. Cyclic voltammetry was used to probe the electrode response to p-phenylenediamine (PPD), 4-chlororesorcinol and m-aminophenol with square wave voltammetry used to effect quantitative measurements. The nature of the electrode response was characterised and issues of surface fouling resulting from the deposition of electrogenerated reaction products were addressed. A procedure designed to allow the facile determination of PPD in hair care products is presented.

Electrochemical detection of thiols in biological media.

The utilisation of catechol as an electrochemical indicator for the presence of sulphydryl thiols (RSH) has been investigated. The electrochemical oxidation of the catechol within tissue culture media was examined with the influence exerted on the redox chemistry by cysteine evaluated in terms of the development of an analytical protocol. The electro-generation of o-quinone was found to be followed by a 1,4-addition reaction with available cysteine such that an increase in the current, attributed to the re-oxidation of the thiol-catechol adduct, could be exploited as means of quantifying the concentration of the thiol. The selectivity of the reaction has been assessed with no interference from lysine, tyrosine, methionine or cystine. Other amino acids possessing sulphydryl thiol functionalities (homocysteine and glutathione) were, however, found to react through a similar route to that observed with cysteine.

Sonoelectrochemically enhanced determination of 5-aminosalicylic acid.

The electrochemical detection of the anti-inflammatory drug 5-aminosalicylic acid (5-ASA) has been evaluated through the application of linear sweep, square wave and sonolinear sweep voltammetry. The introduction of ultrasound is shown to significantly enhance the oxidation signal intensity thereby enabling the detection of low concentrations with the linear range (1-57 muM) adequate for assessing free drug within physiological samples. Interference from ascorbic acid can be effectively negated through the introduction of cupric ion without any appreciable cost to the voltammetric response to 5-ASA. The efficacy of employing sonolinear sweep voltammetry to the determination of this compound within a compositionally complex tissue culture medium has been assessed with the recovery of 5 muM 5-ASA found to be 102% (RSD=5%, N=3).

Analytical strategies for the detection of sulfide: a review.

The detection of sulfide, particularly hydrogen sulfide, has long held the attention of the analytical community and, as such, a large number of protocols have arisen. Built around a core of reactions, some of which are highly specific to sulfide, there is considerable scope for exploitation across a number of instrumental platforms. Such flexibility may provide options for alleviating potentially intractable matrix effects through switching to an alternative detection methodology. This review details the need for sulfide measurements and describes the basis of many of the current approaches to sulfide detection. The collation of information from a broad range of sources, covering the major approaches, has been achieved and the salient points of each technique presented and critically appraised. The various peculiarities of the systems are compared and contrasted and a summary of the analytical characteristics (matrix, methodology and detection range) from each has been constructed.