Animals Of Different Sex Research Articles

Parasitic fauna of wild boars (Sus scrofa) from the northwestern region of São Paulo state, Brazil.

In Brazil, the wild boar (Sus scrofa) is the main invasive exotic species, responsible for causing various economic, environmental, and health damages to biodiversity. In view of the above, we aimed in our study to investigate the occurrence of endo and ectoparasites in free-ranging wild boars in the northwest region of the state of São Paulo, Brazil. In total, 45 animals of different sexes and ages were examined in this research. Fecal and urine samples were processed using coproparasitological techniques. Multiple incisions in muscles, liver, and pancreas were also made to investigate cestodes and trematodes, and the entire epidermal region of the animals was analyzed for ectoparasites search. In our study, we demonstrate an occurrence of 97.77% (44/45) and 43.33% (13/30) of endo and ectoparasites, respectively, in wild boars, with the identification of eggs of Metastrongylus spp., Strongyloides ransomi, Trichuris suis, Stephanurus dentatus, and nematodes of the order Strongylida, as well as oocysts of Eimeriidae protozoa. Ectoparasite infestations were mainly caused by ixodids of the genus Amblyomma spp. and by larvae of Cochliomyia hominivorax.

Using semantic verbal fluency to estimate the relative and absolute vocabulary size of bilinguals: An exploratory study of children and adolescents

IntroductionThe full assessment of bilingual children often involves at least one language for which formal vocabulary tests are lacking and which the examiner does not speak. We examined, in a sample of children with typical development (TD), whether a semantic verbal fluency task, typically used in research as a measure of executive function, could be used in the place of a formal vocabulary test to estimate vocabulary knowledge when formal tests are not available. Method113 TD monolingual French speakers and TD bilinguals and with varying degrees of exposure to French, age 6 to 17 years, completed tests of vocabulary knowledge and semantic verbal fluency. A subset of 64 participants spoke French and English and were tested in both languages. Verbal fluency measures calculated using a traditional method which uses specific rules for superordinate categories and for animals of different sex and age and a simplified scoring method which simply counts all words produced, included the total number of words produced in each language, Total Vocabulary and Conceptual Vocabulary measures combining both languages, as well as analyses of lexical composition and word frequency within the study sample. ResultsLinear regressions revealed that the number of words produced predicted vocabulary size in a language-specific way, with slightly stronger predictions made by the simplified scoring method. As expected, bilinguals produced more words and more unique words in their language of greater exposure, while different exposure groups were equivalent in measures combining both languages, including their Total vocabulary and Conceptual vocabulary. Producing unusual words (infrequently produced in the study sample) indicated higher vocabulary scores. ConclusionsThis study supports the use of the verbal fluency task as a quick and simple tool to obtain a rough estimate of vocabulary size in TD monolinguals and bilinguals. This tool shows promise as well in clinical work with other populations, subject to further verification.

Sex-Specific Effects of Estradiol and Progesterone in Ischemic Kidney Injury.

The positive effects of female sex hormones, particularly estradiol and progesterone, have been observed in treatment of various pathologies. Acute kidney injury (AKI) is a common condition in hospitalized patients in which the molecular mechanisms of hormone action are poorly characterized. In this study, we investigated the influence of estradiol and progesterone on renal cells during ischemic injury. We performed both in vivo experiments on female and male rats and in vitro experiments on renal tubular cells (RTCs) obtained from the kidneys of intact animals of different sexes. Since mitochondria play an important role in the pathogenesis of AKI, we analyzed the properties of individual mitochondria in renal cells, including the area, roundness, mitochondrial membrane potential, and mitochondrial permeability transition pore (mPTP) opening time. We found that pre-treatment with progesterone or estradiol attenuated the severity of ischemia/reperfusion (I/R)-induced AKI in female rats, whereas in male rats, these hormones exacerbated renal dysfunction. We demonstrated that the mPTP opening time was higher in RTCs from female rats than that in those from male rats, which may be one of the reasons for the higher tolerance of females to ischemic injury. In RTCs from the kidneys of male rats, progesterone caused mitochondrial fragmentation, which can be associated with reduced cell viability. Thus, therapy with progesterone or estradiol displays quite different effects depending on sex, and could be only effective against ischemic AKI in females.

Prospective fecal microbiomic biomarkers for chronic wasting disease.

Chronic wasting disease (CWD) is a naturally occurring prion disease in cervids that has been rapidly proliferating in the United States. Here, we investigated a potential link between CWD infection and gut microbiome by analyzing 50 fecal samples obtained from CWD-positive animals of different sexes from various regions in the USA compared to 50 CWD-negative controls using high throughput sequencing of the 16S ribosomal RNA and targeted metabolomics. Our analysis reveals promising trends in the gut microbiota that could potentially be CWD-dependent, including several bacterial taxa at each rank level, as well as taxa pairs, that can differentiate between CWD-negative and CWD-positive deer. Through machine-learning, these taxa and taxa pairs at each rank level could facilitate identification of around 70% of both the CWD-negative and the CWD-positive samples. Our results provide a potential tool for diagnostics and surveillance of CWD in the wild, as well as conceptual advances in our understanding of the disease.IMPORTANCEThis is a comprehensive study that tests the connection between the composition of the gut microbiome in deer in response to chronic wasting disease (CWD). We analyzed 50 fecal samples obtained from CWD-positive animals compared to 50 CWD-negative controls to identify CWD-dependent changes in the gut microbiome, matched with the analysis of fecal metabolites. Our results show promising trends suggesting that fecal microbial composition can directly correspond to CWD disease status. These results point to the microbial composition of the feces as a potential tool for diagnostics and surveillance of CWD in the wild, including non-invasive CWD detection in asymptomatic deer and deer habitats, and enable conceptual advances in our understanding of the disease.

Вариабельность биохимических показателей крови и установление референтных интервалов в доклинических исследованиях. Сообщение 11: собаки

Dogs are a common in vivo test system in preclinical studies due to the relatively large body size sufficient for surgical manipulations, as well as the pathophysiology of various diseases similar to humans. A separate point of application of the animal species in question in preclinical studies is the study and therapy of oncological diseases. The aim of the work was to create its own database of reference intervals of biochemical blood parameters of Beagle dogs. These norms are necessary in preclinical studies when asses­sing the state of animal health, monitoring the formed pathological model, as well as checking the safety of the studied drugs. Biological samples used for the formation of reference intervals were obtained from intact animals in research and manufacturing company “Home оf Pharmacy”. All manipulations and experiments carried out were approved by the bioethical commission. The study included 56 males and 48 females. The age of the animals corresponded to the range of 10–18 months, the body weight of females was 7–11 kg, and males 8–14 kg. In order to implement a uniform approach when creating reference intervals, all manipulations were carried out under the same conditions. For the study, blood was used, which was taken from the lateral subcutaneous vein of the leg of the studied animals on an empty stomach, without sedation and anesthesia. The following parameters were recorded in the blood serum of animals: creatinine, urea, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, cholesterol, triglycerides, total protein, albumin, glucose, creatine kinase, lactate dehydrogenase and total bilirubin, the albumin-globulin coefficient was calculated. Statistical outliers were estimated using the Tukey method, the type of distribution was determined using the Shapiro—Wilk criterion, paired comparisons between animals of different sexes were carried out using the Mann—Whitney U-test and the Student t-test. The obtained ranges of values of males and females correlated with each other for all the considered indicators, no statistical difference was revealed. When comparing the obtained intervals with the reference ranges of dogs from other literature sources, it was shown that, in general, the ranges of the considered indicators are similar, but there are also differences that can be explained by a wide list of factors. These include the image of keeping animals, as well as the preanalytical and analytical stages of the study. A comparative analysis of the interindividual variability of the biochemical parameters of the blood of dogs and humans showed the presence of some species differences that need to be taken into account in experimental activities.

Features of blood parameters and adaptational status of Balb/c and C57Bl/6 mice lines in the absence of special influences

Purpose of the study. A comparative analysis of blood parameters and some characteristics of the adaptation status of intact Balb/c and C57Bl/6 mice of both sexes.Materials and methods. We investigated intact mice of both sexes belonging to the C57Bl/6 (n = 18) and Balb/c (n = 20) lines. The age characteristics of these animals corresponded to the first half of the reproductive period. We studied the parameters of the complete and biochemical blood tests, the weight characteristics of the thymus, spleen and adrenal glands. The character and tension of general nonspecific adaptational reactions of the body (AR) were assessed as well. In statistical analysis we used the coefficient of variation (CV), Student's t-test, Mann-Whitney test.Results. In mice of both studied lines, the dominance of females over males was noted in terms of the weight characteristics of the thymus and spleen, the development of the most favorable antistress AR, and the number of indicators with low variability. At the same time, in C57Bl/6 mice, animals of different sexes had a similar nature of AR (AR of elevated activation),but differed in signs of tension, this might indicate the difference in the range of levels of reactivity, appropriate to AR in males and females C57Bl/6. Unlike C57Bl/6, mice Balb/c mice of different sexes were distinguished with the predominant antistress AR. Differences between C57Bl/6 mice and Balb/c mice in terms of amylase and ALT activity indicated a shift towards carbohydrate metabolism in Balb/c mice and a shift towards protein metabolism in C57Bl/6 mice. Animals of the С57Bl/6 line had an advantage over Balb/c mice (especially pronounced in females) in some indicators of the adaptation status.Conclusion. The results of the study indicated possible difference in the ratio of carbohydrate and protein metabolism in the animals of the studied lines and testified a more favorable state of the regulatory systems in C57Bl/6 mice compared to animals of the Balb/c line. The revealed regulatory and metabolic interlinear differences can determine the features in the reaction of the body of animals belonging to different lines to the malignant process and efficiency of antitumor therapy.

Ionomic Variation Among Tissues in Fallow Deer (Dama dama) by Sex and Age.

(1) In mammals, the mineral nutrient and trace elemental composition of the body - the ionome - differs among individuals. It has been hypothesized that these differences may be related to age and sex, both for ecotoxic and essential elements. (2) We investigated whether and how intraspecific ionomic variation is related to age and sex in Fallow deer (Dama dama). We tested the predictions that concentrations of ecotoxic elements increase with age, that ionomic variation is lower among young individuals than among older individuals, and that reproductive females (does) have the lowest concentrations of essential elements. (3) Culled animals of different sex and age were obtained from a single protected area. The animals were dissected to collect 13 tissues, and concentrations of 22 different elements were measured in a sample of each tissue. (4) We described substantial ionomic variation between individuals. Some of this variation was related to age and sex, as predicted. Based on the limited existing knowledge on chemical element allocation and metabolism in the body, sex-related differences were more difficult to interpret than age-related differences. Since reference values are absent, we could not judge about the consequences of the elemental values that we found. (5) More extensive ionomic surveys, based on a wide range of elements and tissues, are needed to enlarge the understanding of within-species ionomic variation and potential biological, ecological, and metabolic consequences.

Establishment of a 2-dimensional echocardiographic protocol and reference parameters for clinically healthy southern stingrays (Hypanus americanus).

To establish an echocardiographic technique and 2-dimensional reference parameters for southern stingrays (Hypanus americanus). A second objective was to compare echocardiographic measurements obtained from animals of different sex, size, environment, handling technique, and position. 84 presumed healthy, wild, semiwild, and aquarium-housed southern stingrays. Animals, anesthetized and manually restrained, were positioned in dorsal recumbency, and echocardiography was performed. A subset of this population was also imaged in ventral recumbency for comparison. Echocardiography was feasible, and reference parameters were established for this species. While some standard measurements could not be assessed due to body habitus, all valves, chambers, and the conus were clearly visualized in the majority of animals. Statistical significance was reached for some variables when comparing animals from different environments and handling methods, but these differences were not considered clinically relevant. The data were therefore separated into 2 subsets of echocardiographic reference parameters based on disc width since some of the measurements were dependent on body size. This approach mostly separated the sexes due to strong sexual dimorphism. Limited information is available regarding cardiac disease in elasmobranchs; most of the available information on cardiac physiology focuses on a few shark species. Two-dimensional echocardiography is a noninvasive tool utilized to evaluate cardiac structure and functionality. Southern stingrays are one of the most commonly displayed elasmobranchs in public aquaria. This article expands on the growing body of information regarding veterinary care in elasmobranchs and provides clinicians and researchers with another diagnostic modality to utilize in screening for health/disease.

Social Behaviour of Bush Dogs, <i>Speothos Venaticus (Lund, 1842)</i> in Captivity

In the present study, we analysed the social behaviour of a family group of bush dogs, Speothos venaticus (Lund, 1842), at Moscow Zoo. A unique situation has developed at Moscow Zoo, which makes it possible to observe a family group of bush dogs, consisting of 23 individuals. The group consisted of the parent couple and five litters of cubs (10 males and 11 females). The study was carried out in the summer and autumn of 2022 by observing a focal group of animals of different sex and age, consisting of 12 individuals (5 females and 6 males). The hierarchical structure of a group of bush dogs, the ratio of various forms of social behaviour of animals, as well as the nature of their aggressive interactions were evaluated. It was shown that in the studied family group, the dominant parent couple and their off spring were distinguished, which corresponds to the data known from the literature. The predominant form of behavior in animals was group movement around the enclosure, which accounted for 47.3% of all social interactions between dogs. The level of aggression was low among older individuals. Probably, the hierarchical structure of the group of bush dogs is not based on the aggression of high-ranking individuals, but on the demonstration of submission by low-ranking ones. Other social interactions observed included play, communication, marking, parental, and sexual behaviour. There were sex differences in the way territory was marked with urine. Females marked territory by adopting a standing posture on their forelegs, while males sprayed urine. At the same time, sequential urinary marking prevailed (71.6%).

Морфологические изменения в печени экспериментальных животных на фоне сочетанного введения адрибластина и FOXO4-DRI

Doxorubicin is actively used in scientific practice not only as a chemotherapeutic drug, but also as a senescence inducer due to its mechanism of action, namely, the blocking of mitosis, the development of mitochondrial dysfunction and DNA intercalation, which is most pronounced in labile cell populations. The senescent phenotype is currently considered as one of the possible options for the induction of prooncogenes, failure of repair processes and local inflammatory response. The combined use of senolytics together with chemotherapy drugs has been used for a long time (quercetin and dasatinib), however, the combination of peptide-based senolytics (FOXO4-DRI) with doxorubicin seems to be one of the most promising. This article discusses the combined use of FOXO4-DRI and doxorubicin in female and male mice in the early stages. As a result, microscopic examination showed a moderate protective effect of the senolytic peptide on the liver cell population, a decrease in the degree of leukocyte infiltration, and a decrease in the degree of fatty infiltration. There was a significant difference in responses between animals of different sexes.

The influence of two- or three-breed crossing of young animals of different sexes and directions of productivity on the intake and use of dietary nutrients

The aim of the study was to study the effect of crossing dairy cows with bulls of different genotypes on the intake and use of dietary nutrients. It has been established that the leading position in the consumption of all types of nutrients was occupied by three-breed Simmental crossbreeds, which is due to their higher body weight and greater consumption of all types of feed. At the same time, bulls of all genotypes were characterized by the largest intake of nutrients, heifers — bythe smallest, castrated bulls occupied an intermediate position. As a result of the studies, it was found that the efficiency of the digestibility of individual nutrients in the diet of experimental subjects is significantly influenced by the genetic factor. It has been proven that two- or three-breed crossing of Black-and-White cows affects the increase in the efficiency of the use of nutrients in the ration feed.

Impact of food load test on microcirculation parameters in the liver of rats of different gender and age

Introduction. One of the promising directions of studying liver microcirculation is searching for age-related features of its hemodynamics and early markers of pathological changes. Objective – to study the parameters of microcirculation in the liver of animals of different sex and age during a load test. Materials and methods. The study was conducted on 60 mongrel rats of both sexes weighing 120–270 g, divided into three age groups. The first group included 20 rats aged 1 month, the second – 20 rats aged 6–12 months and the third – 20 rats aged more than 18–24 months. The study of microcirculation was performed using a laser Doppler flowmeter LAKK-02 (Russia) under zoletil-xylazine anesthesia. Then, the rats were injected per os with mixture for enteral nutrition Nutridrink (Nutricia) in a ratio of 5 mg/kg of body weight. After 15 minutes the microcirculation parameters were determined again. Digital data were processed by methods of variation statistics. Results. In the liver of rats, the basic parameters of microcirculation were slightly higher in females compared to males: by 8.22 % (R=0.31) in the I, by 8.66 % (R= 0.05) in the II and by 1.19 % (R=0.48) in the III age group. With an increase in the age of the animals, the microcirculation indicators decreased. After the load test, an increase in microcirculation indexes was noted in the liver of rats in all age groups: by 45.13 % (R=0.82) in the I, by 27.99 % (R=0.64) in the II and by 15.88 % (R=0.91) in the III age group. Conclusion. There was no statistically significant dependence of the parameters of microcirculation in the liver of rats on the sex of the animals. With an increase in the rat’s age, the microcirculation rates decreased. After a food load test in the liver of rats, a statistically significant increase of the parameters of microcirculation was noted in all age groups. With an increase in the age of animals, the increase in microcirculation rates after a food load test significantly decreased.

Особенности суточной динамики некоторых биохимических показателей у разнополых крыс линии Вистар в возрасте 6 месяцев

Aim. To investigate the features of circadian rhythms (CR) of some biochemical constants in male and female Wistar rats at the age of 6 months. Materials and methods. The work was performed on 80 rats of the outbred Wistar drain at the age of 6 months, with a body weight of 350 g. The animals were kept under a fixed light regime (light / dark – 10 / 14 hours with the light turned on at 8.00 and off at 18.00). According to the sex, the rats were divided into 2 equal groups of 40 animals each. Blood sampling for biochemical studies was carried out 4 times a day with an interval of 6 hours. The levels of total protein, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, glucose were determined in blood plasma using an analyzer. Results. The features of the daily dynamics and characteristics of the CR of the studied parameters in animals of different sexes are established. Conclusion. The results obtained indicate the need to take into account the features of the chronostructure of heterosexual organisms in research and practical activities.

ИСТОРИЯ СОЗДАНИЯ И ПРОДУКТИВНОСТЬ ОВЕЦ ПОРОДЫ ЧЕРНОЗЕМЕЛЬСКИЙ МЕРИНОС

The article presents: the history of the creation of sheep of the Chernozemelsky Merino breed; indicators of live weight and wool shearing of animals of diff erent sex and age groups; characteristics of the main lines are given.

Combined pathologies of liver, kidneys and pancreas in domestic cats

Various infectious and invasive diseases, as well as individual metabolic disorders caused by poisoning and non-infectious diseases lead to multiple organ pathologies. The pathogenesis of combined lesions in parenchymal organs is due to their anatomical and functional relationship. The aim of the research was to study the nosological forms of non-infectious diseases of liver, kidneys and pancreas in domestic cats, to establish the proportion of multiple organ pathologies and to compare their clinical indicators. The article presents the results of multiple organ pathologies spreading in domestic cats, describes the main nosological forms of diseases, their clinical picture, biochemical and ultrasound indicators. 234 animals of different sexes and different ages were studied in the experiment. Diseased animals were diagnosed based on the results of clinical, biochemical and ultrasound studies. Liver diseases were diagnosed in 18.3 % of cats, kidney - 16.3 %, pancreas - 11.5 % of cats. Multiple organ pathologies were established in 28.7 % of animals, including hepatonephritis in 16.7 %, hepatopancreatitis - 9.0 %, hepatopancreonephritis - 3.0 %. Among nosological forms of diseases in sick cats, hepatonephritis, chronic glomerulonephritis, chronic hepatitis, and fatty degeneration of liver were more common, and only in one case - cirrhosis.

The differences in intestinal growth and microorganisms between male and female ducks

There are great differences in physiological and biological functions between animals of different sexes. However, whether there is a consensus between sexes in duck intestinal development and microorganisms is still unknown. The current study used Nonghua ducks to estimate the effect of sex on the intestine by evaluating differences in intestinal growth indexes and microorganisms. The intestines of male and female ducks were sampled at 2, 5, and 10 wk from the duodenum, jejunum, ileum, and cecum. Then, the intestinal length and weight were measured, the morphology was observed with HE staining, and the intestinal content was analyzed by 16S rRNA sequencing. The results showed that male ducks have shorter intestinal lengths with higher relative weights/relative lengths. The values of jejunal villus height (VH)/crypt depth (CD) of female ducks were significantly higher at 2 wk, whereas the jejunal VH/CD was significantly lower at 10 wk. There was obvious separation of microorganisms in each intestinal segment of ducks of different sexes at the 3 time periods. The dominant phyla at different stages were Firmicutea, Proteobacteria, Bacteroidetes, and Actinobacteria. The duodenal Chao index at the genus level of male ducks was significantly higher at 10 wk than that of female ducks. Significantly different genera were found only in the jejunum, and the abundances of Escherichia_Shigella, Pseudomonas, Clostridium_sensu_stricto_1, Sphingomonas, and Desulfovibrio in male ducks were higher than those in female ducks, whereas the abundance of Rothia was lower, and the abundance of viral infectious diseases, lipid metabolism, metabolism of terpenoids and polyketides, parasitic infectious diseases, xenobiotic biodegradation and metabolism, cardiovascular disease, and metabolism of other amino acids in male ducks were higher than that in female ducks, whereas gene folding, sorting and degradation pathways, and nucleotide metabolism were lower. This study provides a basic reference for the intestinal development and microbial symbiosis of ducks of different sexes.

Sex-Related Differences in Anxious-Depressive and Defensive Behavior in Wistar Rats

Sex-related differences in the behavior of animals in aversive situations were identified by comparing male and female Wistar rats in tests for anxiety, depression-like behavior, assessments of the dynamics of the acquisition and extinction of a classical defensive reflex and a passive avoidance reflex, and also acquisition of an active avoidance reflex. In tests for anxiety, females differed from males in having lower levels of anxiety and greater movement and exploratory activity. In the Porsolt test, females showed less extensive signs of depression-like behavior. After stress, the blood corticosterone content in females was greater than that in males. Females showed higher pain sensitivity. Conditioned reflex fear in the passive avoidance reflex was greater in males than females; there was no difference in animals of different sexes in the classical defensive reflex. Extinction of conditioned reflex fear in these two types of reflex occurred more quickly in females than males. Acquisition of the active avoidance reflex was easier in females than males. It is suggested that females are more inclined to the active defensive strategy and to overestimate danger, while males, conversely, prefer passive defensive responses.

Variation in Features of the Cranium of the Musk Deer Moschus moschiferus L. in Different Phases of the Population Cycle

The variation in four characters (three craniometrical and one nonmetric with supplemental bones) was investigated in 105 craniums of musk deer in different phases (depression and growth) of the population cycle from the East Sayan mountains. The duration of the cycle was 50 years, which corresponds to ten generations of animals. The results obtained show the multidirectional relation of skull sizes (craniometric variation) with phases in the population number in animals of different sexes. The variability of nonmetric characteristics of the skull is characterized by the greatest frequency of manifestation and the maximum quantity of additional bones during the phase of population depression in animals of both sexes, a gradual decrease in their quantity during the growth phase, and then complete loss of supplemental bones when there is an increase in population numbers. The revealed phene of the skull is a key cranial variation and may be used as a way for monitoring natural populations of rare and disappearing subspecies of musk deer.

Association of CAPN1 and GH genes with productivity traits in Kazakh Whiteheaded cattle

The Kazakh Whiteheaded cattle was developed by crossing local breeds with the Hereford breed in Kazakhstan in the 30s of the last century. This breed is adapted to arid conditions of extreme continental climate. The goal of the investi-gations was the assessment of the genetic structure of the Kazakh Whiteheaded breed based on the genes of calpain (CAPN1) and somatotropic hormone (GH) and analysis of the association of genotypes for these genes with productivity traits. The main argument for this aim is research works illustrated that both genes could affect on meat productivity traits in other breeds of cattle. 352 blood samples from representatives of Kazakh Whiteheaded animals of different sex and age groups were genotyped for the CAPN1 and GH loci. As a result, it was firstly proved that Kazakh Whiteheaded animals, who are CC homozygosis at the CAPN1 locus and VV homozygosis at the GH locus, reliably exceed animals without C and V alleles on the productivity traits such as milk production, average daily body weight gain, and pre-slaughter body weight, slaughter weight, carcass weight, flesh weight, chemical composition and histological characteristics of meat. It was also shown that the frequencies of the desired alleles and genotypes of these loci are rather low the frequency of the C allele was 0.11–0.17, and the frequency of the CC genotype was 0.03–0.06 in different age and sex groups; the frequency of the V allele was 0.19-0.40, and the frequency of the VV genotype was 0.03-0.31. Thus, planning selection for Kazakh Whiteheaded cattle, it would be useful to take into account the assessment of ani-mal genotypes at the CAPN1 and GH loci to increase the proportion of animals with the desired genotypes.

A cortical rat hemodynamic response function for improved detection of BOLD activation under common experimental conditions

For a reliable estimation of neuronal activation based on BOLD fMRI measurements an accurate model of the hemodynamic response is essential. Since a large part of basic neuroscience research is based on small animal data, it is necessary to characterize a hemodynamic response function (HRF) which is optimized for small animals. Therefore, we have determined and investigated the HRFs of rats obtained under a variety of experimental conditions in the primary somatosensory cortex. Measurements were performed on animals of different sex and strain, under different anesthetics, with and without ventilation and using different stimulation modalities. All modalities of stimulation used in this study induced neuronal activity in the primary somatosensory cortex or in subcortical regions. Since the HRFs of the BOLD responses in the primary somatosensory cortex showed a close concordance for the different conditions, we were able to determine a cortical rat HRF. This HRF is based on 143 BOLD measurements of 76 rats and can be used for statistical parametric mapping. It showed substantially faster progression than the human HRF, with a maximum after 2.8 ± 0.8 s, and a following undershoot after 6.1 ± 3.7 s. If the rat HRF was used statistical analysis of rat data showed a significantly improved detection performance in the somatosensory cortex in comparison to the commonly used HRF based on measurements in humans.