The impact of vitamin D deficiency on behaviour and brain function in rodents

Transcription

1 *Manuscript The impact of vitamin D deficiency on behaviour and brain function in rodents Overeem, K. 1, Eyles, D.W. 1,2, McGrath, J.J. 1,2 and Burne, T.H.J. 1,2 * 1. Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia 2. Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Richlands, QLD 4076, Australia *Address for correspondence Assoc. Prof. Thomas Burne Queensland Brain Institute The University of Queensland, St Lucia, Qld 4072 Australia. t.burne@uq.edu.au Fax: Phone: Words: Abstract: 225 Body: 2,142/2,000

2 Abstract Vitamin D deficiency has been proposed as an environmental risk factor for several neurological disorders. To investigate the biological plausibility of this risk factor, vitamin D (DVD) deficiency rodent models have been used to examine the impact of DVD deficiency on neurobiology and behaviour. The majority of these studies have taken a developmental stance and examined the impact of vitamin D deficiency during gestation on the adult behaviour of the offspring. In the rat, the most constant behavioural phenotypes include hyperlocomotion in response to novelty, psychostimulant sensitively, impulsivity, and augmented motivation. However, in the mouse increased exploratory behaviour and motivational alterations are observed. Researchers have also examined the affect of adult vitamin D deficiency in rodents. The resultant behavioural alterations include increased exploratory activity and impulsivity in the rat, while increased hyperlocomotion and sensory sensitivity is observed in the mouse. Thus, both the developing and adult brain are sensitive to dietary vitamin D status. However, the behavioural alterations are subtle and influenced by factors such as species, strain, sex, and age. This illustrates the amenability and complexity of neurobiological systems that are influenced by vitamin D status. Nonetheless, with increasing evidence for epidemiological associations between neuropathological disorders and vitamin D, carefully designed rodent models are well placed as a tool to explore the neurobiological and behavioural domains that may be sensitive to vitamin D.

3 Introduction Vitamin D deficiency has been proposed as an environmental risk factor for several neurological disorders including ADHD, autism, Parkinson s disease and schizophrenia [1-5]. Consequently, vitamin D deficiency rodent models have been established to investigate the underlying neurobiology and discrete behavioral domains that are altered alongside dietary vitamin D. Vitamin D acts as a neuorosteroid via the nuclear vitamin D receptor (VDR), which appears in the rodent brain during the second half of embryonic development and continues to be expressed into adulthood [6,7]. Here, the VDR modulates processes such as neurogenesis, cell proliferation, differentiation, and neurotransmitter metabolism [8]. Thus, alterations in vitamin D status are well placed to impact normal brain physiology, accordingly a range of behavior alterations have been observed in the rodent following changes in dietary vitamin D intake. Here we review recent studies examining the impact of vitamin D deficiency on behaviour in rodent models [9]. The majority of such studies have examined the impact of developmental vitamin D (DVD) deficiency on the subsequent adult behaviour of the offspring. In this model, females are fed a vitamin D deficient diet from 6 weeks prior to mating until birth. This six-week timeframe prior to gestation is required to deplete the females of vitamin D, the levels then remain deplete over the course of in utero development [10]. Most DVD studies discussed below follow this protocol unless otherwise mentioned. This research has demonstrated that adult behaviour is altered by DVD deficiency during

4 gestation. A number of studies have also examined how adult vitamin D status can impact behaviour. In this model, adult animals are fed a vitamin D deficient diet at least 10 weeks prior to and during behavioural testing. The results have also revealed that adult vitamin D (AVD) deficient also induces alterations across a range of behavioural domains [11]. In the following review we discuss and compare the current literature describing behavioural deficits induced by vitamin D deficiency either during gestation or adulthood relative to species and strain of rodent. DVD deficiency in the rat Hyperlocomotion One of the most replicated adult behavioural changes following DVD-deficiency in the Sprague Dawley rat is hyperlocomotion in a novel arena, which has been observed across a range of tests including the hole-board, elevated plus maze, and the open field [12,13]. Brief restraint stress prior to testing also abolishes this affect. This occurred in the absence of diet-induced alterations in the resulting corticosterone response, indicating normal HPA functioning in the model [15]. Hyperlocomotion has also been observed in juvenile Sprague Dawley animals, however this was examined when the developmental restriction of dietary vitamin D was extended until weaning. However, under this dietary condition the hyperlocomoter response was not observed when the animals reached adulthood [16]. Similarity, deficiency until weaning does not impact locomotion when assessed using the hole-board apparatus [13].

5 DVD-deficiency in the rat also increases sensitivity to psychostimulant-induced hyperlocomotion in the novel arena. Systemic administration of MK-801 or amphetamine both increase hyperlocomotion in DVD-deficient animals [14,17-19]. MK-801 predominantly acts as a N-methyl-D-aspartic acid (NMDA) antagonist [20], whereas amphetamine interacts with the dopamine (DA) reuptake transporter increasing extracellular DA concentrations [21]. Thus, illustrating that DVD-deficiency in the rat is associated with changes in DA and NMDA-receptor associated systems. Indeed, administration of the antipsychotic haloperidol alleviates both spontaneous and MK-801 induced hyperlocomotion in the novel open field [14]. Interestingly, the effects of both MK-801 and amphetamine can be dissociated according to age and sex of the animals. The hyperlocomotion induced by amphetamine was observed in adult but not juvenile animals [19]. Furthermore, this amphetamine-induced hyperlocomotion was more pronounced in female Sprague Dawley rats at postnatal-day (PD) 70 when compared to males [19]. Although the MK-801 induced effect was apparent in males at this age [14,18], it was not observed at an equivalent level in females until PD 140 [17]. Additionally, MK801 sensitivity in young adult male animals was reduced by haloperidol [14], and is predominantly mediated by vitamin D deficiency during late gestation as DVD deficiency limited to early gestation failed to induce MK801 sensitivity [18]. This demonstrates that the timing of vitamin D deficiency can influence psychostimulant-induced hyperlocomotion in DVD animals [22]. Cognitive phenotypes

6 Researchers examining cognitive phenotypes that follow DVD-deficiency have focused on tests that assess attention, vigilance, decision-making, impulsivity, and memory. The 5-choice continuous performance task (5C-CPT) is used to measure sustained attention and vigilance in rodents. During this task, DVDdeficient adult Sprague Dawley rats exhibit impulsivity and decreased reward latency, while impulsivity was subsequently ameliorated by clozapine [23]. Reduced reward latency is suggestive of DVD-deficiency induced increase in motivation. Indeed, this was also observed in the rodent gambling task where DVD-deficient rats earned more food rewards per session and also required fewer trails to reach criterion, without showing any other behavioural impairments [24]. Thus, alterations in impulsivity and motivation are characteristic of DVD-deficiency in rats. Memory processing is also altered following DVD deficiency. DVD-deficient animals trained on a footshock motivated brightness discrimination task have superior retention [25], which appears to correlate with changes in plasticity in the dentate gyrus [26]. At a systems level, this alteration in behaviour could also be underpinned by the abovementioned DVD-induced augmentations in motivational brain systems, which are thought to facilitate the processing of aversive advents [27]. In line with this, DVD deficient animals have also exhibited impaired latent inhibition (LI) [25]. LI is typically an aversive learning paradigm where prior presentation of an innocuous cue impairs subsequent conditioning using that cue. However, following DVD deficiency rats show superior learning ability for conditioned avoidance reactions following the unreinforced presentations of the conditioned stimulus. That is, in both the

7 footshock motivated discrimination task and the LI paradigm DVD deficient animals show enhanced memory for an aversive event. Impaired sensorimotor gating, assessed using pre-pulse inhibition (PPI) of the acoustic startle reflex is used to examine sensory gating [28]. Research has constantly shown that sensorimotor gating is normal in DVD deficient rats [13,14]. There is one exception, PPI was enhanced after administration of delta- 9-terohydrocanabinol [29]; a psychoactive substance that has potential to induce psychotic symptoms [30]. Thus, DVD-deficiency can influence, but alone is not sufficient to cause, impairment in attention when assessed using PPI. Thus, DVDdeficiency can cause a long-term vulnerability to a second hit that can precipitate subsequent behavioural impairment [22,31]. DVD deficiency in the mouse The DVD deficient model has been examined in three strains of mice; 129/SvJ, C57BL/6J and BALB/c. Compared to rats, results have revealed gross species differences in DVD-deficiency induced changes in brain development. Specifically lateral ventricle size, while increased in rats following DVD-deficiency [32,33], is reduced in mice [34,35]. Accordingly, species differences in some aspects of behaviour have also been observed, as well as distinctions across strains of mice. Hyperlocomotion Hyperlocomotion in response to a novel open arena has been examined in both the C57BL/6J and 129/SvJ strains. Only the 129/SvJ mice showed increased motility [36]. However, when both strains were tested on the hole-board

8 apparatus they both exhibited increased exploratory behaviour on the first day of testing. On the second day this affect was abolished for the C57BL/6J but not the 129/SvJ strain. Consistent with the result in the open field, the 129/SvJ strain also exhibited an increased in distance travelled on the second day of the holeboard test. This hyperlocomotion across the two tests indicates a general increase in locomotion following DVD deficiency in 129/SvJ mice and not an increase in response to novelty. In contrast to rats, both C57BL/6J and 129/SvJ failed to show increased locomotor sensitivity to amphetamine or MK801 [34]. However, anatomical analyses in C57BL/6J mice have revealed smaller ventricles and a larger striatum. The altered striatal volume could be consequential of altered nigrostiatal innervation. However, if there are such alterations in the DA system these were not prominent enough to be precipitated behaviourally by amphetamine in the novel arena [34]. Alterations in the DA system were confirmed in the BALB/c strain as reduced tyrosine hydroxylase was observed in the substantia nigra of females [35]. These results reveal that following DVD-deficiency the mouse and rat both show alterations in the DA system, however behaviourally the rat appears more amenable. Cognitive phenotypes Cognitive processes that have been examined in the mouse following DVD deficiency include tests of attention, vigilance, decision-making, impulsivity, and memory. However, to date only the C57BL/6J has been used to examine DVD deficiency induced cognitive impairments. In line with the results found in the rat, PPI was not impaired in the C57BL/6J DVD-deficient mouse. With regards to memory, olfactory spatial memory is impaired in C57BL/6J mice, with

9 impairments correlated with a replicated decrease in ventricular size [37]. However, DVD deficiency does not result in a global memory impairment within this strain because both associative fear conditioning and LI were normal [38]. Furthermore, rates of learning in the 5 choice serial reaction time (5C-SRT ) task were equivalent to controls in C57BL/6J [38]. However, when C57BL/6J were trained on the more cognitively demanding 5C-CP task male C57BL/6J demonstrated perseverative behaviour [38], revealing compulsive and reward seeking phenotypes in this particular strain following DVD-deficiency. Adult vitamin D deficiency Adult vitamin D (AVD) deficiency has so far been examined in rats (Sprague Dawley, Wistar, and Fisher 344); and two mouse strains (C57BL/6J and BALB/c). While the results have demonstrated that a reduction in adult dietary vitamin D levels can influence behaviour, they have also shown that the behavioural alterations are distinct relative to those observed after restriction during gestation. AVD-deficiency in rats Unlike their DVD deficient counterparts, AVD-deficient Sprague Dawley male rats do not show hyperlocomoter activity in the open field, although they do show increased exploratory horizontal activity during the test [39]. AVDdeficient rats were not sensitive to the locomotor enhancing effects of MK801 or amphetamine, and like DVD animals, did not exhibit alterations in PPI responding. However, AVD deficiency did result in an impulsive phenotype, similar to that observed in the DVD-deficient rat. Specifically, AVD-deficient

10 Sprague Dawley rats show increased impulsivity in the 5C-SRT on longer inter trial intervals [39]. In contrast to DVD-deficient rats, impulsivity was not impaired on the 5C-CPT in AVD-deficient rats. However, AVD-deficient rats did take longer to make false alarm responses while the latency to respond on other trial types were normal. These behavioural alterations were associated with an increase in baseline GABA and altered DA metabolism [39]. With regards to memory, to date, only impaired performance has been reported for the Wistar rat in Morris water maze after AVD [40]. However, a novel study has examined the affect of increasing dietary vitamin D on cognitive ability in adult animals. F344 rats approximating one year of age were maintained on varying concentrations of dietary vitamin D for 5-6 months. Those fed a diet high in vitamin D showed superior spatial reversal memory relative to both a control and AVD deficient group, revealing that an increase in dietary vitamin D can ameliorate cognitive decline in aging animals [41]. Overall, aberrant behaviour that follows vitamin D deficiency appears to fall within similar domains, however the resulting phenotypes of AVD deficiency appear to be more subtle than seen with DVD deficiency. AVD-deficiency in mice Both C57BL/6J and BALB/c AVD-deficient mice show increased hyperlocomotion in a novel arena [42]. This was reduced in both strains on the second day of testing, although to a greater degree in BALB/c mice. Sensitivity to psychomimetics is also not present in this model [42]. Sensorimotor gating assessed using the PPI paradigm was also normal in C57BL/6J and BALB/c mice [42]. However, BALB/c mice did show enhance acoustic startle responding

11 during testing. This does not appear to result from an anxious phenotype, as BALB/c exhibited decreased anxiety on the elevated plus maze [42]. Instead it seems to result from potentiated sensory processing as this strain of mice also show increased sensitivity to nociception, which potentially contributed to their superior memory performance on the footshock motivated active avoidance paradigm [42]. Overall, the BALB/c strain was more sensitive to AVD-deficiency relative to the C57BL/6J. Indeed, molecular analyses confirmed differences between the two strains; BALB/c exhibited alterations in excitatory and inhibitory amino acid metabolism, while C67BL/J6 demonstrated changes in DA and serotonin. Although both strains exhibited a decreased in the GABA synthesising enzymes (GAD65/67). Conclusion Vitamin D status during pregnancy or adulthood can impact on behaviour across a range of domains in rodent models. The most constant behavioural alterations include changes in locomotor or exploratory behaviour and motivational salience. However, the resultant behavioural phenotypes are largely dependent on a number of factors, including the timing of vitamin D deficiency (e.g. prenatal, adulthood), additional adverse exposures, species, strain, sex and age of behavioural testing. Overall, rodent models of vitamin D status have provided novel insights into how vitamin D impacts on brain development and brain function. While the results from the strains and species models are largely heterogeneous each provides an opportunity to examine specific phenotypes characteristics of neurological disorders linked to vitamin D deficiency [1-5].. Thus, rodent models of vitamin D deficiency contribute to our understanding

12 how low vitamin D may influence the onset and course of a range of clinical brain disorders. Acknowledgements We acknowledge the support of the National Health and Medical Research Council of Australia and from Project Grants APP , APP

13 Figure 1. This figure illustrates that both the developing and adult brain are sensitive to dietary vitamin D status. In the rat, prenatal vitamin D deficiency results in a behavioural phenotype that includes hyperlocomotion in response to novelty, psychostimulant sensitively, impulsivity, and augmented motivation. However, in the mouse increased exploratory behaviour and motivational alterations are observed. The resultant behavioural alterations following adult vitamin D deficiency include increased exploratory activity and impulsivity in the rat, while increased hyperlocomotion and sensory sensitivity is observed in the mouse.

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15 schizophrenia and related disorders. In: Springer science+business media. O D, P. (Ed) New York (2011): Groves NJ, McGrath J, Burne TH: Vitamin d as a neurosteroid affecting the developing and adult brain. Annu Rev Nutr (2014) 34.** An extensive review of the affect of AVD with reference to the biological actions and links to neuropsychaitric and neurodegenerative disorders. 12. Burne THJ, O'Loan J, McGrath JJ, Eyles DW: Hyperlocomotion associated with transient prenatal vitamin d deficiency is ameliorated by acute restraint stress. Behav Brain Res (2006) 174: Burne THJ, Becker A, Brown J, Eyles DW, Mackay-Sim A, McGarth JJ: Transient prenatal vitamin d deficiency is associated with hyperlocomotion in adult rats. Behav Brain Res (2004) 154: Kesby JP, Burne THJ, McGarth JJ, Eyles DW: Developmental vitamin d deficiency alters mk-801-induced hyperlocomotion in the adult rat: An animal model of schizophrenia. Biol Psychiatry (2006) 60: Eyles DW, Rogers F, Buller K, McGrath JJ, Ko P, French K, Burne THJ: Developmental vitamin d (dvd) deficiency in the rat alters adult behaviour independently of hpa functioning. Psychoneuroendocrinology (2006) 31: Pan P, Jin DHS, Chatterjee-Chakraborty M, Halievski K, Lawson D, Remedios D, Cassandra S, Pinto V, Parra E, Fleming A: The effects of vitamin d3 during pregnancy and lactation on offspring physiology and behavior in sprague-dawley rats. Developmental Psychobiology (2014) 56:12-22.* A study that examined the affect of both low and high levels of dietry vitamin D during gestation on the behavioral of offspring, with results revealing that both excessive and defiencent levels can impact behaviour. 17. Kesby JP, O'Loan J, Alexander S, Deng C, Huang XF, McGrath JJ, Eyles DW, Burne THJ: Developmental vitamin d deficiency alters mk-801- induced behaviours in adult offspring. Psychopharmacology (2012) 220: O'Loan J, Eyles DW, Kesby JP, Ko P, McGarth JJ, Burne THJ: Vitamin d deficiency during various stages of pregnancy in the rat; its impact on development and behaviour in adult offspring. Psychoneuroendocrinology (2007) 32: Kesby JP, Cui X, O'Loan J, McGarth JJ, Burne THJ, Eyles DW: Developmental vitamin d deficiency alters dopamine-mediated behaviors and dopamine transporter function in adult female rats. Psychopharmacology (2010) 208: Kovacic P, Somanathan R: Clinical physiology and mechanism of dizocilpine (mk-801). Oxid Med Cell Longev (2010) 3:13-22.

16 21. Kahlig KM, Binda F, Khoshbouei H, Blakely RD, McMahon DG, Javitch JA, Galli A: Amphetamine induces dopamine efflux through a dopamine transporter channel. PNAS (2005) 102: Cui X, Gooch H, Groves NJ, Sah P, Burne TH, Eyles DW, McGrath JJ: Vitamin d and the brain: Key questions for future research. J Steroid Biochem Mol Biol (2015) 148: ** A review highlighting the importance of timing and duration of vitamin D deficiency and the venerability it can induce to second aversive exposures. 23. Turner KM, Young JW, McGrath JJ, Eyles DW, Burne THJ: Cognitive performance and response inhibition in developmentally vitamin d (dvd)-deficient rats. Behav Brain Res (2013) 242.* Research examining DVD-deficiency induced cognitive deficits in two cognitive tasks (5C-SRT and 5C-CPR). The results show that under the additional load of the 5C- CPT the animals exhibited deficits that were not apparent in the 5C-SRT. Furthermore, the researchers were also able to show that administration of antipsychotics reversed some of the cognitive deficits. 24. Peak JN, Turner KM, Burne THJ: The effect of developmental vitamin d deficiency in male and female sprague-dawley rats on decisionmaking using a rodent gambling task. Physio Behav (2015) 138: * An analysis of risk behaviour following DVD-deficiency. The results reveal subtle differences in male and female animal responding; females exhibited a lower percentage of omissions, males were less accurate on the force choice trials. Overall, however, the DVD-deficient animals required fewer training sessions to reach criterion, received a greater number of rewards, and like controls selected the most optimal decision strategy. 25. Becker A, Eyles DW, McGarth JJ, Grecksch G: Transient prenatal vitamin d deficiency is associated with subtle alterations in learning and memory functions in adult rats. Behav Brain Res (2005) 161: Grecksch G, Ruthrich H, Hollt V, Becker A: Transient prenatal vitamin d deficiency is associated with changes of synaptic plasticity in the dentate gyrus in adult rats. Psychoneuroendocrinology (2009) 34:Suppl 1:S258-S Bromberg-Martin ES, Masayuki M, Hikosaka O: Dopamine in motivational control: Rewarding, aversive, and alerting. Neuron (2010) 68: van den Buuse M: Modeling the positive symptoms of schizophrenia in genetically modified mice: Pharmacology and methodology aspects. Schizophr Bull (2010) 36: Burne THJ, Alexander S, Turner KM, Eyles DW, McGarth JJ: Developmentally vitamin d-deficient rats show enhanced prepulse inhibition after acute delta-9-tetrahydrocannabinol. Behav Pharmacol

17 (2014) 25: * Research demonstrating that a "second hit" can induce alterations in a attentional processing that was otherwise unimpaired in the developmental vitamin D model 30. Nottage JF, Stone J, Murray RM, Sumich A, Bramon-Bosch E, Ffytche D, Morrison PD: Delta-9-tetrahydrocannabinol, neural oscillations above 20 hz and induced acute psychosis. Psychopharmacology (Berl) (2015) 232: Bayer TA, Falkai P, Maier W: Genetic and non-genetic vulnerability factors in schizophrenia: The basis of the two hit hypothesis. J Psychiatr Res (1999) 33: Feron F, Burne THJ, Brown J, Smith E, McGarth JJ, Mackay-Sim A, Eyles DW: Developmental vitamin d3 deficiency alters the adult rat brain. Brain Res Bull (2005) 65: Eyles D, Brown J, Mackay-Sim A, McGrath J, Feron F: Vitamin d3 and brain development. Neuroscience (2003) 118: Harms LR, Cowin G, Eyles DW, Kurniawan ND, McGrath JJ, Burne TH: Neuroanatomy and psychomimetic-induced locomotion in c57bl/6j and 129/x1svj mice exposed to developmental vitamin d deficiency. Behav Brain Res (2012) 230: Hawes JE, Tesic D, Whitehouse AJ, Zosky GR, Smith JT, Wyrwoll CS: Maternal vitamin d deficiency alters fetal brain development in the balb/c mouse. Behav Brain Res (2015) 286: ** Novel research examining the fetal neurobiological phenotype that follows maternal vitamin D deficiency in the BALB/c mouse. The authors report alterations in brain morphology, gene expression and dopamine synthesis. 36. Harms LR, Eyles D, McGrath JJ, Mackay-Sim A, Burne THJ: Developmental vitamine d deficiency alters adult behaviour in 129/svj and c57bl/6j mice. Behav Brain Res (2008) 187: de Abreu DAF, Nivet E, Baril N, Khrestchatisky M, Roman F, Feron F: Developmental vitamin d deficiency alters learning in c57b1/6j mice. Behav Brain Res (2010) Harms LR, Turner KM, Eyles DW, Young JW, McGarth JJ, Burne THJ: Attentional processing in c57bl/6j mice exposed to developmental vitamin d deficiency. PLoS One (2012) 7:e Byrne JH, Voogt M, Turner KM, Eyles DW, McGrath JJ, Burne THJ: The impact of adult vitamin d deficiency on behaviour and brain function in male sprague dawley rats. PLoS One (2013) 8:e Taghizadeh M, Talaei SA, Salami M: Vitamin d deficiency impairs spatial learning in adult rats. Iran Biomed J (2013) 17:42-48.*Research that is the first to show spatial memory impairments following AVD-

18 deficiency, which were not ameliorated by their regime of vitamin D supplementation. 41. Latimer CS, Brewer LD, Searcy JL, Chen KC, Popovic J, Kraner SD, Thibault O, Blalock EM, Landfield PW, Landfield PW, Porter NM: Vitamin d prevents cognitive decline and enhances hippocampal synaptic function in aging rats. Proc Natl Acad Sci USA (2014) 111:E ** A research study interesting as it demonstrates an interaction between dietary vitamin D status and cognitive performance in middle aged animals, the results indicated that a diet high in vitamin D can reduce normal cognitive decline in ageing animals. 42. Groves NJ, Kesby JP, Eyles DW, McGrath JJ, Mackay-Sim A, Burne THJ: Adult vitamin d deficiency leads to behavioural and brain neurochemical alterations in c57bl/6j and balb/c mice. Behav Brain Res (2013) 241: ** The first study to show an alteration in behavioural phenotypes following adult vitamin D deficiency in two strains of mice C57BL/6J and BALB/c. The study examined a broad range of behavioural domains: anxiety, exploration, locomotor, learned helplessness, sensorimotor gating, associative learning, social interaction, and nociception. As well as brain neurochemistry. The results revealed differences in how the two strains of mouse reacted to AVD deficiency.

19 Figure 1 Rat Mouse Gestation Vitamin D Deficient Vitamin D Sufficient Birth Lifespan Adulthood - Hyperlocomotion - Psychostimulant sensitivity - Impulsivity - Motivation - Exploratory behaviour - Motivation - Exploratory behaviour - Impulsivity - Hyperlocomotion - Sensory sensitivity