Pica Behavior Research Articles

Pica practices of pregnant women in Nairobi, Kenya

To establish the prevalence of pica behaviour during pregnancy; to identify the substances commonly ingested and their prevalence; and to determine the characteristics of women who reported practising pica. Descriptive, cross sectional study involving use of questionnaire administered in interview format. Pumwani Maternity Hospital, Nairobi, Kenya. One hundred and seventy one antenatal women with a mean age of 28.1 (+/-7.3) years. Subjects were selected based on availability; accessibility and willingness to participate in the study. Seven hundred and ninety three (74.0%) participants reported practising pica regularly on daily basis. Pica prevalence categorised by substances ingested was as follows: soft stones (odowa); 89.8%; soil, 61.2%; and others, 9.6% and no pica, 26.0%. Majority of women who reported practising pica (62.5%) ingested more than one substance. Most women who practised pica reported having experienced strong cravings prior to ingestion of pica items, childhood pica, pica before pregnancy, pica in previous pregnancy and a history of pica in family members and significant others in the community. Pica prevalence was significantly high among the subjects indicating that pica in pregnancy might be more common and independent in Kenya than health care providers assume or observe. There is need to routinely screen pregnant women for pica during antenatal visits as this will provide a more systematic and a less expensive way of establishing its epidemiological status. A nation-wide investigation of pica prevalence is also recommended in order to establish pica prevalence at national level and among different socio-economic groups. Further studies are also needed to establish possible health consequences of pica on mother and child.

Differential effects of common hepatic, gastric, and celiac branch vagotomy on food intake and pica behavior following chemotherapy in the rat

Differential effects of common hepatic, gastric, and celiac branch vagotomy on food intake and pica behavior following chemotherapy in the rat

Pica Behavior Induced by Body Rotation in Mice

Objectives: To study whether rotational stimulus induced pica and whether the vestibular apparatus was necessary for obtaining rotation-induced pica in mice. Methods: Pica behavior in mice was investigated following 60 min of rotation once daily at 70 rpm (15 s on with 5 s off) for 3 consecutive days. After evaluating vestibular function and histology of vestibular epithelia, we examined rotation-induced kaolin intake, so-called pica, in sham-lesioned and chemically labyrinthectomized mice. Results: The labyrinthectomized mice exhibited loss of the contact righting and swimming capability while the destruction of hair cells of vestibular epithelia was observed. Moreover, mice subjected to rotation, but not labyrinthectomized mice, showed a significant increase in kaolin intake at the last 2 rotation sessions and the first postrotation session. Conclusions: The findings indicated that a functioning vestibular system is necessary for rotation-evocating pica in mice and thus pica can be a behavioral index of motion sickness in mice.

The incidence of pica in a sample of dialysis patients

End Stage Renal Disease (ESRD) occurs when the kidneys are no longer able to function at a level necessary for day to day life. Pica refers to the persistent, compulsive craving for and ingestion of nonfood items and certain food items. ESRD may constitute a potent stress and stimulus for pica, especially in those patients with an underlying cultural predisposition. The occurrence of pica in a South Florida dialysis unit was studied via a carefully designed a pica questionnaire aimed towards creating a human connection. A significantly greater proportion of subjects endorsing pica practices were found in the dialysis group (38.3%) as compared to the control group (16%). Dialysis patients endorsing pica behaviors were significantly younger than those who denied pica behavior. Additionally there was a significantly greater proportion of females endorsing pica behaviors. Odds ratios analyses revealed greater odds of engaging in pica behaviors for Black participants than Hispanics or Whites. Pagophagia (ice pica) was the most frequently reported type of pica practice. The incidence of pica in this study was considerably higher than that which had been found in past studies. This likely resulted from the unique manner in which the information was educed. Implications and suggestions for future research directions are discussed.

Treatment of Pica Behavior with Olanzapine

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Bioaccessibility of metals in urban playground soils

Children ingest soil. The amount ingested varies with the child's behaviour, and daily ingestion rates have been calculated to be between 39 and 270 mg day− 1. During play, children ingest soil both involuntarily and deliberately, and it can be assumed that the latter may result in ingestion of a larger soil particle size fraction and a larger soil mass than the former. Measurements of soil metal contents commonly display the total metal content, where soil sieved to < 2 mm has been digested with strong acids. This procedure does not consider differences in metal contents between size fractions or ingested soil masses. Moreover, it does not consider the difference between bioaccessible and total metal content, possibly resulting in an incorrect evaluation of the potential health risks from soil intake. Intervention and guideline values are commonly calculated via tolerable daily intake values, in turn derived from toxicological studies where the contaminant is administered to a test animal in feed or water. It is then assumed that the bioavailability of a contaminant in soil equals the bioavailability in the matrix used in the toxicology study. However, the complexity and heterogeneity of soil often results in a lower bioavailability than from food or water. The current study investigated the bioaccessibility of soil As, Cd, Cr, Ni and Pb from two different particle size fractions representing deliberate (< 4 mm) and involuntary (< 50 μ m) ingestion, as well as from two different soil masses representing deliberate soil intake; 2 g for a child with pica behaviour and 0.6 g for a non-pica child. The bioaccessibility was investigated using an in vitro digestion model and urban playground soils collected away from any point pollution sources. The bioaccessibility (%) of the different metals increased in the order Ni = Cr = Pb < < As < Cd for the involuntary ingestion (< 50 μ m, 0.6 g) and pica behaviour (< 4 mm, 2 g) scenarios, while the deliberate non-pica scenario (< 4 mm, 0.6 g) displayed increasing bioaccessibility in the order Ni = Cr < Pb < As = Cd. The difference in bioaccessibility between elements was concluded to be due to differences in origin, sorption behaviour and pH dependence. The study also found that the bioaccessible amount of metal in ingested soil is not always related to particle size or to soil mass in soils with low contaminant levels. Factors such as pH dependence of the metal and the soil's clay content are also significant in determining bioaccessibility.

Geophagia is not associated with Trichuris or hookworm transmission in Zanzibar, Tanzania

Geophagia may be harmful as a method for the transmission of geohelminths. In this study, we pose two questions in a representative sample of 970 pregnant women from Pemba Island, Zanzibar, Tanzania. Can consumed earth be a vector for geohelminth infection? And do geophagists have differential parasitic infection? The parasitological content of 59 non-food substance samples was analysed. Cross-sectional data regarding pica behaviour were collected through interviews conducted by local researchers. Ascaris, Trichuris and hookworm status was ascertained through Kato-Katz smears. The prevalence of geophagia at baseline was 5.6% and the overall prevalence of Ascaris, Trichuris and hookworm infection was 5.6%, 33.2% and 32.9%, respectively. No consumed soil samples contained infectious parasitic stages, and only one of the consumed pica substances (charcoal) contained parasites of potential risk to human health. In bivariate analyses, neither the prevalence nor the intensity of infection with Ascaris, Trichuris or hookworm differed significantly by geophagia status. Furthermore, in multivariate models, geophagia was not a significant predictor of helminth infection status. We conclude that geophagia is not a source of Trichuris or hookworm infection among pregnant women in Pemba (insufficient power to evaluate the effect of Ascaris), which is in contrast to existing findings of helminth infection and geophagia.

家族介護者における在宅認知症高齢者の問題行動由来の介護負担の特性

The purpose of this study was to measure the caregiver burden caused by behavioral and psychological symptoms of dementia (CBBD) using an originally developed scale and to estimate the CBBD scores in a large sample of family caregivers of elderly people. The subjects were 1,818 users of the public Long-term Care Insurance, randomly stratified and sampled in Higashi-osaka city, Osaka prefecture. Data were collected through mailed, anonymous self-report questionnaires. The survey was conducted in October 2003. We created a 10-item CBBD scale based on previous studies on caregivers of dementia. The CBBD scale was applied to all caregivers regardless of dementia symptoms, and we also collected the following information: demographic data of the care-recipients and caregivers, the level of cognitive disorders of the care-recipient and the overall subjective caregiver burden. All items of the CBBD scale were selected at higher percentages by caregivers of care-recipients with cognitive disorders than caregivers of care-recipients without cognitive disorders. In particular, the relative risk and odds ratio of caregivers of care-recipients with cognitive disorder was higher in items such as 'the caregiver feels fear and anxiety about the care-recipient's unpredictable behavior', 'the care-recipient doesn't understand what the caregiver says', 'the caregiver feels irritated with incomprehensible care-recipient's behavior' which pose psychological stress or pressure on caregivers. On the other hand, the relative risk and odds ratio of the overall subjective caregiver burden was lower than that of any item of the CBBD scale. Furthermore, all CBBD items were related to symptoms of dementia (aroused/paranoid behavior, memory disorder, cognitive dysfunction, pica behavior). The CBBD scale had sensitivity for the care-recipient's cognitive disorder. In addition, it can detect more precisely the caregiver burden such as psychological stress or pressure due to the care-recipient's cognitive disorders, and it is also useful to assess the needs of caregivers who care for elderly family members with dementia.

Monoclonal antibody antagonists of hypothalamic FGFR1 cause potent but reversible hypophagia and weight loss in rodents and monkeys

We generated three fully human monoclonal antibody antagonists against fibroblast growth factor receptor-1 (FGFR1) that potently block FGF signaling. We found that antibodies targeting the c-splice form of the receptor (FGFR1c) were anorexigenic when administered intraperitoneally three times weekly to mice, resulting in rapid, dose-dependent weight loss that plateaued (for doses>4 mg/kg) at 35-40% in 2 wk. Animals appeared healthy during treatment and regained their normal body weights and growth trajectories upon clearance of the antibodies from the bloodstream. Measurements of food consumption and energy expenditure indicated that the rapid weight loss was induced primarily by decreased energy intake and not by increased energy expenditure or cachexia and was accompanied by a greater reduction in fat than lean body mass. Hypophagia was not caused through malaise or illness, as indicated by absence of conditioned taste aversion, pica behavior, and decreased need-induced salt intake in rats. In support of a hypothalamic site of action, we found that, after intraperitoneal injections, anti-FGFR1c (IMC-A1), but not a control antibody, accumulated in the median eminence and adjacent mediobasal hypothalamus and that FGFR1c is enriched in the hypothalamus of mice. Furthermore, a single intracerebroventricular administration of 3 microg of IMC-A1 via the 3rd ventricle to mice caused an approximately 36% reduction in food intake and an approximately 6% weight loss within the ensuing 24 h. Our data suggest that FGF signaling through FGFR1c may play a physiological role in hypothalamic feeding circuit and that blocking it leads to hypophagia and weight loss.

Metal and arsenic distribution in soil particle sizes relevant to soil ingestion by children

Ingestion of soil is a common behaviour in young children as a means of exploring their surroundings. Much attention has been given to remediation of point-source polluted sites with regard to potential health risks for children. However, because of diffuse pollution and long-range atmospheric deposition, soil contaminant levels are generally increased in urban areas compared to their rural counterparts, even in areas located away from any point sources of pollution. Intake of urban soil can thereby result in significant amounts of the child’s daily metal intake. In the present study, soil samples were collected from 25 playgrounds around urban Uppsala, Sweden and analysed for contents of Al, As, Fe, Cr, Cu, Cd, Hg, Mn, Ni, Pb, W and Zn. Prior to aqua regia digestion, the samples were wet-sieved in order to separate soil particle fractions representing deliberate (<4 mm) and involuntary (<50 μm) soil ingestion by children, as well as a third size fraction of 50–100 μm representing soil that is easily transported by suspension. While the metal and As contents in the 50–100 μm fraction were similar to those of the <4 mm fraction, the <50 μm fraction had metal and As contents on average one and a half times higher than those of the <4 mm fraction. The metal and As contents correlated negatively with the sand content in both particle size fractions <4 mm and 50–100 μm, suggesting a general decrease in metal and As content with increasing sand content. However, a positive correlation was found between sand content and the metal and As contents of the finest fraction (<50 μm), suggesting that when the sand content is high, the bulk of the sorbed elements are on the finest particles. The difference between metal and As contents in the different size fractions was greater in the soil sample with the highest sand content than in the sample with the lowest sand content. This implies that texture is a significant factor in metal and As distribution in soils with moderate metal and As contents, when the number of binding sites associated with small particles is low. Tolerable daily intake (TDI) values for Pb and As were exceeded at all sites, and at two sites for Cd, for children with pica behaviour. A high ingestion rate of mainly small particles could also result in the TDI value for Pb being exceeded at 10 sites and that for As at one site. This study also found that soil analysis by the procedure recommended by Swedish authorities accurately represents the metal intake from deliberate soil ingestion, whereas involuntary soil ingestion of mainly small particles could result in metal intakes which are up to twice as high.

A case of acute lead poisoning in a 2‐year‐old child

Lead poisoning still remains a matter of concern, especially in children, in spite of widespread preventive practices [1]. Children are particularly vulnerable through mouthing behaviour [2–4] and high absorption from the gastrointestinal tract as compared with adults. This may adversely affect the developing nervous system, with neurocognitive effects and IQ decline in chronic intoxication [5]. We describe a sporadic case of severe lead poisoning rapidly treated by therapeutic means including surgery, thereby avoiding possible death through encephalopathy. In January 2004 while his parents were looking on, a 2-year-old boy with pica behaviour swallowed toy money made from pure metallic lead. No specific abdominal pain or vomiting was noted by the attending physician. What is more, the child’s behaviour did not change, and he showed no loss of appetite. On the second day (D2), possible elimination of the object in stools was found to be negative, so the child was admitted to a hospital paediatric ward, which ordered blood lead (Pb) measurement, a blood and urine check-up and an X-ray abdominal examination. Blood Pb concentrations were assessed by electrothermal atomic absorption spectrometry with Zeeman background correction. Analytical efficiencies have been monitored by participation in an interlaboratory survey, the Quebec Toxicology Centre Interlaboratory Comparison Programme [6]. The results of 1.51 ± 0.02 µmol l−1 (mean ± SD, in triplicate) already indicated Pb overload in this child, largely exceeding the threshold defined by the 1998 Centers for Disease Control and Prevention [1] (CDC) ( 2.17 µmol l−1, chelation therapy is strongly recommended [1]. On D4, calcium disodium edetate (CaNa2 EDTA) diluted in 5% isotonic glucose solution was infused slowly by intravenous administration (500 mg m−2 day−1) over 5 h for 5 days. No symptoms such as headache, fatigue and nausea were noted. Samples of urine were collected on D3 to D7. High urinary lead excretion from D3 to D5 (1560 µg 24 h−1, 810 µg 24 h−1 and 510 µg 24 h−1, respectively) indicated accelerated elimination of this toxic metal (reference value in urine: <100 µg 24 h−1) [7] and thereby confirmed body lead burden in the child. After the results for D6-D7 in urine (190 µg 24 h−1 and 150 µg 24 h−1, respectively), body pools tended to equilibrate. A decrease of blood lead was observed from D4 to D8 (2.04 ± 0.39 µmol l−1, 1.86 ± 0.02 µmol l−1, 1.54 ± 0.04 µmol l−1, 1.50 ± 0.04 µmol l−1, 1.52 ± 0.04 µmol l−1) vs. D2 (2.95 ± 0.04 µmol l−1). Over the months of February, March, April and May 2004, we noted a relative stability in blood Pb concentrations (1.45 ± 0.01 µmol l−1, 1.25 ± 0.01 µmol l−1, 1.20 ± 0.01 µmol l−1, 1.20 ± 0.01 µmol l−1, respectively), but the concentrations remained high for a child [1]. Figure 1 (A) Child’s anteroposterior abdominal radiography. Toy money is located in the gastric area (black arrow) with minimal colon dilatation. (B) Picture of toy money. Specifications of the toy money: 4 g pure metallic lead, diameter 2 cm Furthermore, in May, an increase of zinc protoporphyrin (ZPP) and a microcytic anaemia (5 µg g−1 Hb; reference value: <1 µg g−1 Hb) was noted. In this acute lead poisoning, clinically speaking, no symptom or loss of appetite was observed, nor was there any intellectual impairment or decline in cognitive function. Lastly, a decrease of blood Pb concentrations appeared over the course of June, July, August and September 2004 (0.85 ± 0.02 µmol l−1, 0.82 ± 0.04 µmol l−1, 0.82 ± 0.04 µmol l−1, 0.75 ± 0.02 µmol l−1, respectively), and was likewise correlated with the ZPP determination in August (1.9 µg g−1 Hb). These concentrations constantly remained above the CDC [1]. It was only during the tenth month (October 2004) that the child’s blood Pb and ZPP concentrations (0.48 ± 0.01 µmol l−1 and 1 µg g−1 Hb, respectively) came within the previously mentioned reference values. It is a well-known fact that the average fractional gastrointestinal absorption of lead is much greater in children than in adults [5] and subsequently, without rapid medical intervention, the extremely high concentrations in this child could have provoked possibly devastating effects on his nervous system [8].

Behavioural responses to hypergravity in the CD-1 mouse

Male and female mice were subjected to rotationally-generated hypergravity of different duration (1 or 2 h) and linear acceleration (2 or 1.08 G). Pica behaviour and spontaneous activity were investigated before, during, and after rotation. Moreover, hole-board and plus-maze tests were performed 20 min and 24 h after the end of rotation. Pica behaviour arose in the post-rotation days and was more pronounced after 1 h of 2 G exposure. Spontaneous activity was almost or totally suppressed during rotation and failed to regain the pre-rotational levels in the group exposed to 2 G for 1 h. Exploratory behaviour in the hole-board was also impaired. A clear effect of hypergravity exposure emerged in the plus maze, with 2 G mice totalizing a minor number of arm entries than the other groups and also showing an altered emotional/anxiety profile. Generally, females were more susceptible than males to the changes in gravitational environment.

Novel approach on the risk assessment of oxidized fats and oils for perspectives of food safety and quality. I. Oxidized fats and oils induces neurotoxicity relating pica behavior and hypoactivity

Food poisoning caused by deteriorated fat and oil in instant noodles was first reported in Japan approximately 40 years ago. In these cases, many people developed neurotoxic symptoms such as emesis and discomfort. The degree of oxidation of the fat and oil in the instant noodles that induced food poisoning was at least 100 meq/kg in peroxide value (PV). No general toxicity studies with animals, however, have examined the toxicity of fat and oil oxidized to that extent. In this study, pica behavior, a behavior characterized by eating a nonfood material such as kaolin and that relates to the degree of discomfort in animals, and alterations of locomotor activity of rats eating deteriorated fat and oil were measured. The groups fed fat and oil with at least 138.5 meq/kg PV consumed significantly more kaolin compared to the control group. Furthermore, rats that ate deteriorated fat and oil with at least 107.2 meq/kg PV had significantly decreased locomotor activity compared to control rats. These phenomena suggest that oxidized fat and oil with at least 100 meq/kg PV induce neurotoxicity. The toxicity of oxidized fat and oil has only been addressed using general toxicity tests, but the present results reveal the importance of evaluating toxicity by using other measures.

Influence of a selective histamine H3 receptor antagonist on hypothalamic neural activity, food intake and body weight

This study was conducted to elucidate whether antagonistic targeting of the histamine H3 receptor increases hypothalamic histamine levels, in parallel with decreases in food intake and body weight. The competitive antagonist potency of a recently synthesized histamine H3 receptor antagonist, NNC 38-1049, was studied in intact HEK293 cells expressing human or rat histamine H3 receptor, in which NNC 38-1049 was allowed to antagonize the effect of the H3 receptor agonist R-alpha-methylhistamine on isoprenaline-induced accumulation of cAMP. The affinity of NNC 38-1049 for a number of variants of the histamine receptor was also determined. Following single dosing of normal rats with NNC 38-1049, hypothalamic histamine levels were assessed by means of microdialysis. Plasma and brain levels of NNC 38-1049 and acute effects on food intake and energy expenditure were followed after oral doses of 3-60 mg/kg. Potential side effects were examined with rat models of behaviour satiety sequence (BSS), pica behaviour and conditioned taste aversion (CTA). Intakes of food and water together with body weight were recorded for 15 days during daily dosing of dietary obese rats. NNC 38-1049 was found to be a highly specific and competitive antagonist towards both human and rat histamine H3 receptors, and measurable amounts of NNC 38-1049 were found in the plasma of rats following single oral doses of 3-60 mg/kg and in the brain after 15-60 mg/kg. Following single intraperitoneal injections of NNC 38-1049 (20 mg/kg), significant increases in extracellular histamine concentrations were observed. The same dose did not change BSS or pica behaviour acutely, nor did it induce CTA following repeated administration for 7 days. Reductions in food intake were seen very soon after administration, and occurred in a dose-dependent fashion. Energy expenditure was unchanged, but the respiratory quotient (RQ) tended to decrease at higher doses, indicating an increase in lipid oxidation. Twice daily administration of 20 mg/kg of NNC 38-1049 in old and dietary obese rats resulted in sustained reduction of food intake throughout a 2-week study, and was associated with a highly significant (P<0.01) decrease in body weight compared with controls (-18.4+/-3.4 vs +0.4+/-2.7 g). The same dose of NNC 38-1049 produced an acute decrease of water intake, but 24 h intakes were not significantly changed. The results of this study strongly support the idea that an increase in the hypothalamic concentration of histamine produces a specific reduction of food intake and that this effect can be translated into a decrease in body weight.

Parental Report of Eating Problems and Gastrointestinal Symptoms in Children With Pervasive Developmental Disorders

Parents of children of 89 children with pervasive developmental disorder were surveyed about their child's eating, gastrointestinal symptoms, and behavior problems. Results revealed potentially interesting relationships among self-injurious behavior, pica, feeding problems, and gastrointestinal symptoms in this population. Although over 60% of children were reported to have strong food preferences, only 6.7% of parents reported that their child had a feeding problem. Most children exhibited high rates of pica and self-injurious behavior that affected the family's quality of life. Some children experienced at least one symptom of gastrointestinal distress weekly, and bowel problems appeared to be related to some aspects of feeding. Although methodological issues limit these data, future research should focus on further relations among these factors in this population.

Understanding Pica Behavior

Pica is defined as the compulsive, recurrent consumption of nonnutritive items. Pica behavior often occurs in individuals With developmental disabilities; therefore, education and clinical professionals may be required to participate in various aspects of management, including identification, assessment, and treatment. This article Will discuss several facets of the pica phenomenon, including the scope of human populations involved, the variety of items ingested, possible etiologies, health risks, and a number of treatment programs that are reported in the literature.

Differential activity of drugs to induce emesis and pica behavior in Suncus murinus (house musk shrew) and rats

We have previously reported that emetic stimuli induce kaolin ingestion behavior (pica behavior) in rats and mice (i.e., species that do not have the emetic reflex) and that the behavior may be analogous to gastrointestinal discomfort, such as nausea and emesis. We hypothesized that pica behavior may also occur in species capable of vomiting and that it may serve as an additional index of discomfort relevant to antiemetic drug development. The present experiments were conduced using Suncus murinus and rats and kaolin consumption was measured at 24 h after the administration of nicotine (1.25–5 mg/kg, s.c.), copper sulfate (10–120 mg/kg, p.o.), lithium chloride (50–200 mg/kg, i.p.) and cisplatin (1–30 mg/kg, i.p.). In S. murinus, all treatments, excepting lithium chloride, were emetic but none induce kaolin consumption. Conversely, all treatments induced kaolin consumption in rats without inducing emesis. The results indicate that pica behavior is not likely to be useful to assess gastrointestinal discomfort in S. murinus.

Differential activity of drugs to induce emesis and pica behavior in Suncus murinus (house musk shrew) and rats

We have previously reported that emetic stimuli induce kaolin ingestion behavior (pica behavior) in rats and mice (i.e., species that do not have the emetic reflex) and that the behavior may be analogous to gastrointestinal discomfort, such as nausea and emesis. We hypothesized that pica behavior may also occur in species capable of vomiting and that it may serve as an additional index of discomfort relevant to antiemetic drug development. The present experiments were conduced using Suncus murinus and rats and kaolin consumption was measured at 24 h after the administration of nicotine (1.25–5 mg/kg, s.c.), copper sulfate (10–120 mg/kg, p.o.), lithium chloride (50–200 mg/kg, i.p.) and cisplatin (1–30 mg/kg, i.p.). In S. murinus, all treatments, excepting lithium chloride, were emetic but none induce kaolin consumption. Conversely, all treatments induced kaolin consumption in rats without inducing emesis. The results indicate that pica behavior is not likely to be useful to assess gastrointestinal discomfort in S. murinus.

Fos induction in the amygdala by vestibular information during hypergravity stimulation

Altered gravity environments including both hypo- and hypergravity can elicit motion sickness. Vestibular information is known to be essential for motion sickness, but its other neural substrates are poorly understood. We previously showed that bilateral lesions of the amygdala suppressed hypergravity-induced motion sickness in rats, using pica behavior as an emetic index. We show in the present study that during hypergravity stimulation, vestibular information activated the central nucleus of the amygdala (CeA), as determined by the induction of Fos expression, in comparison between normal and bilaterally labyrinthectomized rats. The finding that Fos expression was confined to the CeA and almost completely absent in other subnuclei of the amygdala contrasted with many previous studies that used other stressful stimuli such as foot shock, restraint and forced swimming, suggesting a specific vestibular effects on the amygdala. Prolongation of hypergravity resulted in reduction of Fos expression in the CeA, suggesting a process of habituation. Such decreases appeared earlier than in the vestibular nucleus, suggesting that adaptive changes in the CeA to hypergravity were independent of changes in the vestibular input. Our results suggest the amygdala is a neural substrate involved in the development of and habituation to motion sickness.

Issues of Informed Consent in Conducting Medical Research Involving People with Intellectual Disability

Background People with severe intellectual disability are considered vulnerable to exploitation in research. Discovery of exploitative practices in recent history has motivated the development of guidelines for informed consent and proxy decision‐making procedures when involving these individuals in research.Methods Issues for determining capability to provide informed consent and the proxy decision process are reviewed according to the literature, current ethics guidelines and recent legislature in Victoria, Australia.Results The complex process of involving in research people with severe intellectual disability who are particularly vulnerable by virtue of their institutionalized residential status is discussed within the context of a recent project into examining potential nutritional determinants of Pica behaviour (i.e. the eating of inedible items).Conclusions This example serves to highlight the role of legislation, various government bodies and researchers in balancing principles of protection of vulnerable groups and rights to self‐determination.