Object Novelty Research Articles

Dissecting the contribution of human chromosome 21 syntenic regions to recognition memory processes in adult and aged mouse models of Down syndrome.

Trisomy of human chromosome 21 (Hsa21) results in a constellation of features known as Down syndrome (DS), the most common genetic form of intellectual disability. Hsa21 is orthologous to three regions in the mouse genome on mouse chromosome 16 (Mmu16), Mmu17 and Mmu10. We investigated genotype-phenotype relationships by assessing the contribution of these three regions to memory function and age-dependent cognitive decline, using three mouse models of DS, Dp1Tyb, Dp(17)3Yey, Dp(10)2Yey, that carry an extra copy of the Hsa21-orthologues on Mmu16, Mmu17 and Mmu10, respectively. Prior research on cognitive function in DS mouse models has largely focused on models with an extra copy of the Mmu16 region and relatively little is known about the effects of increased copy number on Mmu17 and Mmu10 on cognition and how this interacts with the effects of aging. As aging is is a critical contributor to cognitive and psychiatric changes in DS, we hypothesised that ageing would differentially impact memory function in Dp1Tyb, Dp(17)3Yey, and Dp(10)2Yey, models of DS. Young (12-13 months and old (18-20 months mice Dp1Tyb, Dp(17)3Yey and Dp(10)2Yey mice were tested on a battery of object recognition memory test that assessed object novelty detection, novel location detection and associative object-in place memory. Following behavioral testing, hippocampal and frontal cortical tissue was analysed for expression of glutamatergic receptor proteins using standard immunoblot techniques. Young (12-13 months and old (18-20 months mice Dp1Tyb, Dp(17)3Yey and Dp(10)2Yey mice were tested on a battery of object recognition memory test that assessed object novelty detection, novel location detection and associative object-in place memory. Following behavioral testing, hippocampal and frontal cortical tissue was analysed for expression of glutamatergic receptor proteins using standard immunoblot techniques. Our results show that distinct Hsa21-orthologous regions contribute differentially to cognitive dysfunction in DS mouse models and that aging interacts with triplication of Hsa21-orthologous genes on Mmu10.

Contribution of the lateral occipital and parahippocampal cortices to pattern separation of objects and contexts.

Contextual features are integral to episodic memories; yet, we know little about context effects on pattern separation, a hippocampal function promoting orthogonalization of overlapping memory representations. Recent studies suggested that various extrahippocampal brain regions support pattern separation; however, the specific role of the parahippocampal cortex-a region involved in context representation-in pattern separation has not yet been studied. Here, we investigated the contribution of the parahippocampal cortex (specifically, the parahippocampal place area) to context reinstatement effects on mnemonic discrimination, using functional magnetic resonance imaging. During scanning, participants saw object images on unique context scenes, followed by a recognition task involving the repetitions of encoded objects or visually similar lures on either their original context or a lure context. Context reinstatement at retrieval improved item recognition but hindered mnemonic discrimination. Crucially, our region of interest analyses of the parahippocampal place area and an object-selective visual area, the lateral occipital cortex indicated that while during successful mnemonic decisions parahippocampal place area activity decreased for old contexts compared to lure contexts irrespective of object novelty, lateral occipital cortex activity differentiated between old and lure objects exclusively. These results imply that pattern separation of contextual and item-specific memory features may be differentially aided by scene and object-selective cortical areas.

Qualitative feed restriction affects frustration, fear, motivation to explore, and feather fault bars in Ross 308 broiler breeder cockerels

Broiler breeders show behaviours indicative of hunger and frustration stemming from unfulfilled behavioural needs for feeding. This is largely due to quantitative feed restriction which is common practice in the management of these birds, particularly in the rearing period. As an alternative, qualitative feed restriction allows a larger portion of feed to be provided without increasing the caloric intake. While several studies have assessed the effects of qualitative feeding on female broiler breeders, no such assessment has been done on broiler breeder cockerels. The aim of this study was to investigate the effects of feed dilution and roughage on the level of stress, fear and motivation to explore of broiler breeder cockerels. 200 Ross 308 broiler breeder cockerels (between 5 and 10 weeks of age) were housed in 12 pens (6 pens/treatment), 17 birds/pen. The treatments were standard feed (Control) and feed diluted with 20 % insoluble oat hulls and 150 g of alfalfa roughage daily/pen (D+R). The D+R birds received 20 % more feed per day. Novel object (NO) and frustration during thwarted feeding tests were performed in the home pen and the response recorded with video cameras. In addition, four birds from each pen were subjected to a tonic immobility test (TI). All behavioural tests were performed once a week at 6, 8 and 10 weeks of age. Finally, after euthanasia, two feathers from each bird were plucked and macroscopically examined for the presence of fault bars. The control birds showed a tendency to approach the NO faster than the D+R birds (P = 0.07) and were more likely to approach at 10 weeks of age (P = 0.006). In the frustration test, D+R birds spent less time pecking the feed container (P = 0.049), more time standing (P = 0.01) and tended to have fewer behavioural transitions (P = 0.09) than control birds, which indicates a reduction in frustration levels. In addition, Control birds stayed in TI longer than D+R birds (160.7 ± 15.5 s and 98.1 ± 15.4, respectively. P = 0.005). However, D+R had more fault bars compared to Control birds (P = 0.02), highlighting that care is needed to interpret these contradicting results. Nevertheless, the results show that the combination of feed dilution and daily roughage can have positive effects on the welfare of broiler breeder cockerels by reducing the sensation of hunger as indicated by fear, frustration, and motivation to explore.

Gilts prefer an open pen to a stall

Stalls or crates are a very common type of housing used on pig farms that restrict an animal’s movement. How this confinement impacts the animal’s affective states is seldom investigated. We conducted a preference test over 7 days where trios of gilts (n = 10 trios, 27.4 ± 1.5 weeks old) had free access between individual self-locking stalls (~ 1.2 m2) and a shared open area allowing 2.8 m2/animal (71% of total area). Gilts had access to ad libitum feed and water both inside the crates and in the open area. After 7 days, personality traits of the animals were assessed with open field (OF) and novel object (NO) tests. Principal Component Analysis (PCA) yielded two main components, which we defined as Passivity and Engagement. The median time spent outside the crate was 95.2% as 21/29 of the gilts exhibited a significant preference for pen over crate during the 7-day trial (p < 0.05). Passivity had no relationship with time spent in the open area, but engagement during OF/NO was associated with less use of the open area (OR = 0.39, 95CI = [0.25, 0.60]). Interestingly, gilts were likely to spend less time in the open area at nighttime compared to daytime (Odds Ratio = 0.49, 95CI = [0.40, 0.60]), as well as experimental days passed (OR = 0.70, 95CI = [0.66, 0.73]). During the first daytime and nighttime, 1/29 and 2/29 animals preferred the crate respectively, whereas by the last daytime and nighttime 5 and 9 gilts preferred the crate respectively (p < 0.05). While both intrinsic (personality) and extrinsic (time of day, experimental day) factors appear to influence the gilt’s housing preferences, most gilts significantly prefer an open area to a crate when free access is provided between the two. A smaller subpopulation of animals developed a preference for stalls but still utilize both the stall and the pen throughout the day.

Young children and adults use reasoning by exclusion rather than attraction to novelty to disambiguate novel word meanings.

Upon hearing a novel label, listeners tend to assume that it refers to a novel, rather than a familiar object. While this disambiguation or mutual exclusivity (ME) effect has been robustly shown across development, it is unclear what it involves. Do listeners use their pragmatic and lexical knowledge to exclude the familiar object and thus select the novel one? Or is the effect, at least in early childhood, simply based on an attraction to novelty and a direct mapping of the novel label to a novel object? In a preregistered online study with 2- to 3-year-olds (n = 75) and adults (n = 112), we examined (a) whether relative object novelty alone (without pragmatic or lexical information) could account for participants' disambiguation and (b) whether participants' decision processes involved reasoning by exclusion. Participants encountered either a known and an unknown object (classic ME condition) or two unknown objects, one completely novel and one preexposed (novelty condition) as potential referents of a novel label. Reasoning by exclusion was assessed by children's looking patterns and adults' explanations. In the classic ME condition, children and adults significantly chose the novel object and both used reasoning by exclusion. In contrast, in the novelty condition, children and adults chose randomly. Across conditions, a retention test revealed that adults remembered their prior selections, while children's performance was fragile. These results suggest that referent disambiguation is not based on relative object novelty alone. Instead, to resolve referential ambiguity, both young children and adults seem to make use of pragmatic and/or lexical sources of information and to engage in reasoning by exclusion strategies. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Raising laying hens: housing complexity and genetic strain affect startle reflex amplitude and behavioural response to fear-inducing stimuli.

Individual variation in fearfulness can be modified during ontogeny, and high levels of fear can affect animal welfare. We asked whether early-life environmental complexity and genetic strain affect fear behaviour in young laying hens (pullets). Four replicates of brown (B) and white (W) genetic strains (breeds) of layers were each raised in four environmental treatments (housing): conventional cages (Conv) and different rearing aviaries with increasing space and complexity (Low < Mid < High). We used a startle reflex test (weeks 4 and 14) to measure startle amplitude and autonomic response (i.e. comb temperature). A combination of novel arena (NA) and novel object (NO) tests was used (week 14) to assess NA exploration and alertness, latency to approach the centre and initial NO avoidance and investigation. Housing × strain affected startle amplitude (B-Conv, B-High < B-Low, B-Mid; B > W; no housing effect in W) but not autonomic response. Fear behaviour was affected by housing (NA exploration, investigation: Conv < Low, Mid, High; NO avoidance: Conv, High < Low, Mid), strain (NA alertness: B > W, NO avoidance: W > B) and their interaction (NA centre approach: B-Conv < all other groups). We present evidence for strain-specific fear responses depending on early experience.

Association between personality traits of dairy cows and their peripubertal heifer offspring

This study aimed to determine if personality traits identified in dairy cows during the transition phase are correlated with those of their peripubertal heifer calves. At ~24 d before calving and ~24 d after being first introduced to the automated milking system, the personality traits of 23 Holstein cows were assessed using a combined arena test [consisting of exposure to consecutive novel environment (NE), novel object (NO), and novel human (NH) tests]. Personality traits were established by principal component analysis (PCA) of behaviors expressed in these tests. The PCA of cow behaviors during the precalving test revealed 3 factors, or personality traits, interpreted as exploratory, active, and bold. The PCA of cow behaviors during the postcalving test revealed 2 factors, interpreted as active and exploratory. From these cows, 23 female Holstein heifers were produced and enrolled in this study at 7 mo of age. Heifers were personality tested once through a similar combined arena test. The PCA of heifer behaviors during the NO test revealed 3 factors, interpreted as bold, exploratory-active, and social. The PCA of heifer behaviors during the NH test revealed 2 factors, interpreted as exploratory-active and social. All factor scores from each cow and heifer pair were tested for association. An association between cows with higher scores on the factor interpreted as exploratory and heifers with lower scores on the factor interpreted as bold was detected. There were tendencies for cows with higher scores on the factor interpreted as active to be associated with heifers that scored highly on the factors interpreted as exploratory-active and bold. The data suggests that there are some limited associations between personality traits of cows and their heifer offspring; further exploration of these associations may lead to the prediction of heifer personality based on cow personality.

Inheriting the sins of their fathers: boar life experiences can shape the emotional responses of their offspring

IntroductionThe welfare of breeding boars is often overlooked, resulting in limited scientific data to foster discussion of the topic. We aimed to investigate the effect of different boar housing conditions on their offspring’s emotionality.MethodsEighteen boars were housed in three different conditions: crates (C; n = 6), pens (P; n = 6), or enriched pens (E; n = 6). Boars were distributed by semen quality (SQ; high, medium, or low). Three semen pools were used to inseminate 13 gilts housed in outdoor paddocks. At 25 days of age, 138 suckling piglets were subjected to open field (OF), novel object (NO), and elevated plus-maze (EPM) tests. Saliva was collected before and after the OF and NO tests to measure cortisol concentrations. At the end of the experiment, hair samples were collected for DNA paternity tests. Piglets were classified based on their behavioral responses using hierarchical cluster analysis of the principal components extracted from factor analysis of mixed data. The variables were reduced to seven principal components (dimensions, Dims), which explained 73% of the total variation, and were analyzed using linear mixed models. The models included each Dim as a dependent variable, paternal treatment and body weight (BW) as fixed effects, and paternal SQ as a random effect. Kruskal−Wallis and Wilcoxon rank-sum tests were used to compare the cortisol concentration ratios (before and after the OF and NO tests) between groups.ResultsThere was an effect of treatment on Dim 3 (EPM; activity/fear), with higher values in C piglets than E piglets (p = 0.047). Although C piglets had significantly higher values than P piglets in Dim 4 (EPM; anxiety; p = 0.029) and Dim 6 (NO; inactivity far from the object/exploration; p &amp;lt; 0.0001), the effect of the paternal treatment × BW interaction was significant in both dimensions (p &amp;lt; 0.05). The cortisol ratio in E piglets was greater than that in P and C piglets (p &amp;lt; 0.05).Discussion and conclusionOur findings indicate that boar breeding environments affect the stress response and emotionality (anxiety, fear, and exploration) of their offspring.

Association with Different Housing and Welfare Parameters on Results of a Novel Object Test in Laying Hen Flocks on Farm.

The objective of this on-farm study was to determine if flocks showing feather damage and/or cannibalism would have a higher fear response to the novel object (NOT) and the association between different housing and welfare parameters on results of the NOT. Therefore, 16 flocks were observed during the laying period in Germany. In total, there were six barns, seven free-range, and three organic flocks. The plumage and integument condition of 50 birds of each flock were evaluated at 4 different times during the laying period (V1: 18th to 23rd week of life, V2: 26th to 35th week of life, V3: 49th to 57th week of life, V4: 61st to 73rd week of life). At the same observation times, the NOT was performed in the flocks (at four different locations per visit time). Based on the average number of hens gathered around the novel object (NO) within the period of two minutes, conclusions can be made about the fearfulness of the flock. The present study shows that the more fearful a flock was, the more frequent feather damage (p < 0.001) and cannibalism (p < 0.01) occurred. Age and flock size were associated with fearfulness. Fearfulness of hens increased with the increasing age of hens (p < 0.001) and with an increasing flock size (p < 0.001). Hens of white feather color appeared to be more fearful than brown hens (p < 0.001). Hens kept on barn farms showed significantly lower numbers of hens around the novel object (p < 0.001) than on free-range farms, which possibly indicates that having permanent access to outdoor space generally appears to be associated with the fearfulness of a flock.

106 Use of biobehavioral responses during a novel object test to assess suitability of horses for equine assisted services

Many recent studies have demonstrated positive outcomes for human participants in a variety of equine assisted services (EAS). Horses by nature are highly sensitive and their responses to unfamiliar stimuli can have important consequences for horse and human safety. Individual variation in the personality characteristics of horses, including their reactivity, may not only create safety concerns but also influence therapeutic outcomes. To date, there are no available standardized guidelines for the selection of equine in EAS. Observation of horse behavior by equine professionals has historically been used to assess the potential suitability of equine participants. However, overall behavior of individual horses can be challenging to objectively measure. Novel object (NO) tests are often used to measure reactivity in many animal species. To our knowledge, no study has yet evaluated the reactivity of horses in response to a NO test to assess their suitability for groundwork-based EAS. The purpose of this study was to compare biobehavioral responses of 11 Quarter Horse mares (11.6 ± 4.9 yr) before, during, and after exposure to a NO (stationary flamingo pool float) as a potential measure of their suitability for participation in EAS. The experiment consisted of 3 consecutive 5 min periods: Pre-NO test (P1), NO test (P2), and Post-NO test (P3) in the same 27 × 26 mpaddock. HR was recorded using a Polar H10 equine HR monitor. Behavior was video recorded and scan sampling of video every 10 s was used to determine counts. Data were analyzed using PROC MIXED in SAS v 9.4. Horse HR differed by horse and decreased with time within all 3 periods (P < 0.01). During the NO test, locomotion increased with increasing proximity to the NO (P < 0.05). Standing alert and exploratory behaviors decreased during the NO test but were not influenced by the horse's location (P < 0.03). Interestingly, eating behaviors increased during and after the NO test (P < 0.05). This study illustrates that behavioral and physiological responses of horses are influenced by their individuality which may ultimately influence their interactions during EAS. The reduction in HR over time within each period suggests that horses can quickly acclimate to changes in their environment and the overall lack of differences in their behavioral responses across periods suggests low reactivity among this study population. However, future studies with additional novel objects and horses are needed to determine if the use of this methodology can serve to evaluate suitability for horses for participation in EAS.

Fearfulness in commercial laying hens: a meta-analysis comparing brown and white egg layers

High fearfulness in commercial laying hens can negatively affect production parameters and animal welfare. Brown and white egg layers differ in several behavioral characteristics, though reported differences in fearfulness are inconsistent. A meta-analysis was conducted to determine whether there are systematic differences in measures of fearfulness between brown and white layers. Twenty-three studies that examined either 1 or both of 2 behavioral tests were included: tonic immobility (TI) (longer duration=higher fearfulness, 16 studies) and novel object (NO) test (lower approach rate=higher fearfulness, 11 studies). The 2 tests were analyzed separately. TI analyses: A generalized linear mixed effect model (GLMM) with a lognormal distribution was fitted to describe the data with experiment nested in study as a random effect. Explanatory (X) variables were considered through backward selection, where potential X-variables included color (brown vs. white layers), decade (1980s, 2000s, 2020s), age (prelay vs. in lay), genetic stock (hybrid vs. grand-/parent stock), and methodology (back vs. side position). NO test analyses: univariable GLMMs with a beta distribution were fitted with approach rate as the Y-variable and color, decade, age, stock, or 2 methodological factors (test duration, single vs. group testing) as X-variables. Models were evaluated by assessing information criteria, residuals/random effect normality, significance of X-variables and model evaluation statistics (mean square prediction error, concordance correlation coefficient). TI duration was best explained by a color-by-decade interaction (P=0.0006). Whites in the 1980s had longer TI durations (709.43 ± 143.88 s) than browns in the 1980s (282.90 ± 59.70 s), as well as in comparison to browns (208.80 ± 50.82 s) or whites (204.85 ± 49.60 s) in the 2020s. The NO approach rate was best explained by color (P ≤ 0.05 in 3 models), age (P < 0.05 in 3 models), and decade (P=0.04). Whites had a higher approach rate (0.7 ± 0.07) than browns (0.5 ± 0.11), birds in lay a higher rate (0.8 ± 0.07) than birds prelay (0.4 ± 0.12), and approach rate for papers published in the 2000s (0.8 ± 0.09) was higher than in the 2020s (0.2 ± 0.12). The phylogenetic difference in the 1980s was no longer detectable after enforcing an upper limit on TI durations (10 min), as became common practice in later studies. Our findings suggest that phylogenetic differences in fearfulness and changes over time are test dependent, and this raises important questions and potential consequences for assessing hen welfare in commercial egg production.

Pragmatics aid referent disambiguation and word learning in young children and adults.

How do children succeed in learning a word? Research has shown robustly that, in ambiguous labeling situations, young children assume novel labels to refer to unfamiliar rather than familiar objects. However, ongoing debates center on the underlying mechanism: Is this behavior based on lexical constraints, guided by pragmatic reasoning, or simply driven by children's attraction to novelty? Additionally, recent research has questioned whether children's disambiguation leads to long-term learning or rather indicates an attentional shift in the moment of the conversation. Thus, we conducted a pre-registered online study with 2- and 3-year-olds and adults. Participants were presented with unknown objects as potential referents for a novel word. Across conditions, we manipulated whether the only difference between both objects was their relative novelty to the participant or whether, in addition, participants were provided with pragmatic information that indicated which object the speaker referred to. We tested participants' immediate referent selection and their retention after 5min. Results revealed that when given common ground information both age groups inferred the correct referent with high success and enhanced behavioral certainty. Without this information, object novelty alone did not guide their selection. After 5min, adults remembered their previous selections above chance in both conditions, while children only showed reliable learning in the pragmatic condition. The pattern of results indicates how pragmatics may aid referent disambiguation and learning in both adults and young children. From early ontogeny on, children's social-cognitive understanding may guide their communicative interactions and support their language acquisition. RESEARCH HIGHLIGHTS: We tested how 2-3-year-olds and adults resolve referential ambiguity without any lexical cues. In the pragmatic context both age groups disambiguated novel word-object-mappings, while object novelty alone did not guide their referent selection. In the pragmatic context, children also showed increased certainty in disambiguation and retained new word-object-mappings over time. These findings contribute to the ongoing debate on whether children learn words on the basis of domain-specific constraints, lower-level associative mechanisms, or pragmatic inferences.

Fmr1-KO mice failure to detect object novelty associates with a post-test decrease of structural and synaptic plasticity upstream of the hippocampus

Mice with deletion of the FMR1 gene show episodic memory impairments and exhibit dendritic spines and synaptic plasticity defects prevalently identified in non-training conditions. Based on evidence that synaptic changes associated with normal or abnormal memory emerge when mice are cognitively challenged, here we examine whether, and how, fragile entorhinal and hippocampal synapses are remodeled when mice succeed or fail to learn. We trained Fmr1 knockout (KO) and wild-type C57BL/6J (WT) mice in the novel object recognition (NOR) paradigm with 1 h or 24 h training-to-test intervals and then assessed whether varying the time between the presentation of similar and different objects modulates NOR performance and plasticity along the entorhinal cortex-hippocampus axis. At the 1 h-interval, KO mice failed to discriminate the novel object, showed a collapse of spines in the lateral entorhinal cortex (LEC), and of long-term potentiation (LTP) in the lateral perforant path (LPP), but a normal increase in hippocampal spines. At the 24 h, they exhibited intact NOR performance, typical LEC and hippocampal spines, and exaggerated LPP-LTP. Our findings reveal that the inability of mice to detect object novelty primarily stands in their impediment to elaborate, and convey to the hippocampus, sensory/perceptive object representations.

Folic Acid and Vitamin B12 Prevent Deleterious Effects of Rotenone on Object Novelty Recognition Memory and Kynu Expression in an Animal Model of Parkinson's Disease.

Parkinson's disease (PD) is characterized by a range of motor signs, but cognitive dysfunction is also observed. Supplementation with folic acid and vitamin B12 is expected to prevent cognitive impairment. To test this in PD, we promoted a lesion within the substantia nigra pars compacta of rats using the neurotoxin rotenone. In the sequence, the animals were supplemented with folic acid and vitamin B12 for 14 consecutive days and subjected to the object recognition test. We observed an impairment in object recognition memory after rotenone administration, which was prevented by supplementation (p &lt; 0.01). Supplementation may adjust gene expression through efficient DNA methylation. To verify this, we measured the expression and methylation of the kynureninase gene (Kynu), whose product metabolizes neurotoxic metabolites often accumulated in PD as kynurenine. Supplementation prevented the decrease in Kynu expression induced by rotenone in the substantia nigra (p &lt; 0.05), corroborating the behavioral data. No differences were observed concerning the methylation analysis of two CpG sites in the Kynu promoter. Instead, we suggest that folic acid and vitamin B12 increased global DNA methylation, reduced the expression of Kynu inhibitors, maintained Kynu-dependent pathway homeostasis, and prevented the memory impairment induced by rotenone. Our study raises the possibility of adjuvant therapy for PD with folic acid and vitamin B12.

Fearfulness in aviary housed laying hens – Effects of management and potential confounding effects of the Novel Object test

Few studies have assessed fearfulness and how it relates to feather condition and management strategies in end-of-lay hens housed in commercial aviaries. As aviary housing for laying hens grows with the phasing out of cages, there is a need to ensure the currently used methods of assessing on-farm flock fearfulness are robust and to avoid confounding effects. The aim of this study was to investigate the relationship between daily management routines and plumage condition and the fearfulness of aviary housed laying hens as assessed by the Novel Object (NO) test. In addition, the study aimed at investigating potential confounding effects when performing the NO test in commercial flocks. Forty-five indoor multitiered aviary-system flocks of laying hens from across Norway were visited at the end of lay (range: 70–76 wk of age). The flocks consisted of either Lohmann LSL (n = 30) or Dekalb White (n = 15) non-beak-trimmed hens. During the visits, flock fearfulness was assessed using the NO test with 4 different objects, plumage condition was assessed using the NorWel method, and information on how the daily inspections were performed (duration and by how many different people) was collected. More hens tended to approach the NO with less damage to the breast feathers and more damage to the tail feathers in the Lohmann flocks but not in the Dekalb flocks (0.05 < P < 0.07). There was no effect of the number of people involved in the daily inspections of the hens (P = 0.56) or the amount of time spent inside the hen house per day (P = 0.80) on the number of hens approaching the NO. There was also no effect of in which corridor the NO test was carried out (wall vs inner corridors; P = 0.27). But there was an effect of the type of objects (P < 0.0001). More hens approached the “virus” NO compared to the three other objects used. The results support previous works showing a relationship between fearfulness and feather pecking and highlight the need for caution regarding hybrid differences. The results also suggest that, when performing the NO test in commercial aviaries, corridor does not have a confounding effect on this test while the type of novel object can be a confounder.

Reducing stocking density benefits behaviour of fast- and slower-growing broilers

The broiler industry has come under sustained pressure from welfare organizations to improve broiler welfare. Breed and stocking density are important factors for broiler welfare and are often specified as criteria for higher welfare systems. However, it remains unknown how slower-growing broilers respond to a reduction in stocking density with regard to their behaviour, and whether this response differs from fast-growing broilers. Therefore, we compared fast- (Ross 308) and slower-growing broilers (Ranger Classic) housed at 4 different stocking densities (24, 30, 36 and 42 kg/m2, based on slaughter weight) with regard to their behaviour, responses to behavioural tests (i.e., novel object (NO), human approach (HA) and free-space (FS) test) and enrichment use at 4 target body weights (TBW’s, 0.4, 1.1, 1.7 and 2.1 kg). The experiment had a 2 × 4 factorial design with 4 replicates (pens) per treatment (total of 32 pens). Thinning (15%) was done in a 50/50 male/female ratio at 38 (Ross 308) and 44 (Ranger Classic) days of age (estimated body weight of 2.2 kg). We hypothesized that slower-growing broilers would respond more strongly to a reduction in stocking density with regard to their behaviour. As slower-growing broilers are more active and show more comfort and foraging behaviours, it is expected that with increasing space they will respond with a larger increase in these types of behaviours compared to fast-growing broilers. Contrary to our hypothesis, hardly any interactions between breed and stocking density were found, indicating that fast- and slower-growing broilers showed similar responses to a reduction in stocking density. Broilers housed at lower stocking densities (24 and/or 30 kg/m2) showed more comfort and foraging behaviour, and showed more frolicking, running and sparring in the FS test compared to those housed at higher stocking densities (36 and/or 42 kg/m2). Slower-growing broilers showed less ingestion, more locomotion, standing, comfort and foraging behaviour, made better use of the enrichment by sitting on the bale, and more slower-growing broilers approached a human and NO compared to fast-growing broilers. In conclusion, reducing stocking density positively affected performance of comfort, foraging and play behaviours, indicating improved welfare. Slower-growing broilers showed more locomotive, comfort and foraging behaviours, less fear and a better use of enrichments, suggesting improved welfare compared to fast-growing broilers. Thus, reducing stocking density and using slower-growing broilers would benefit broiler welfare, where combining both would further improve broiler welfare with regard to their behaviour.

Surprise and recency in novelty detection in the primate brain

Primates and other animals must detect novel objects. However, the neuronal mechanisms of novelty detection remain unclear. Prominent theories propose that visual object novelty is either derived from the computation of recency(how long ago a stimulus was experienced) or is a form of sensory surprise(stimulus unpredictability). Here, we use high-channel electrophysiology in primates to show that in many primate prefrontal, temporal, and subcortical brain areas, object novelty detection is intertwined with the computations of recency and sensory surprise. Also, distinct circuits could be engaged by expected versus unexpected sensory surprise. Finally, we studied neuronal novelty-to-familiarity transformations during learning across many days. We found a diversity of timescales in neurons' learning rates and between-session forgetting rates, both within and across brain areas, that are well suited to support flexible behavior and learning in response to novelty. Our findings show that novelty sensitivity arises on multiple timescales across single neurons due to diverse but related computations of sensory surprise and recency and shed light on the computational underpinnings of novelty detection in the primate brain.

Novel object test in farmed fallow deer (Dama dama) – The impact on appearance, diurnal rhythm and behaviour in the foraging area

The fallow deer (Dama dama) represents a typical example of a species in the early stage of domestication, where selection for tameness is not yet complete. In contrast to fully domesticated species, there is still a lack of studies on the behaviour of deer under farm conditions and their response to changes in their environment. Therefore, this study aimed to investigate the behaviour of fallow deer after the introduction of the novel object (NO) into the enclosure. The herd was observed at the most frequently visited part of the enclosure, i.e. the foraging area near the feeding station. We installed several different Non-animal NOs (abstract object/installation, camping chair, colourful boxes) and Animal NO (animal-shaped toy) with intervening Controls (periods without NO). Results generally showed that time spent at the foraging area decreased in the presence of NO (p < 0.05). This effect was significantly stronger when NO had an animal shape (horse-shaped toy), with the frequency of animal appearance also being lower with frequent complete absence of animals at the foraging area. However, diurnal rhythm of animal appearance did not differ, nor did group size. When looking at the ratio among different behaviours that animals performed in the foraging area (movement, stationary, feeding), we found no differences between the Control and Non-animal NO (feeding 42−43 %, stationary 38–39 %). However, in the presence of Animal NO, feeding behaviours increased significantly (57 %), while the stationary behaviours decreased significantly (24 %). While resting predominated among stationary behaviours in the Control and Non-animal NO treatments (72–75 %), vigilance represented the most stationary behaviours in the presence of Animal NO (58 %). Movement was consistently performed to the same extent (18–20 %). Therefore, the presence of the novel object reduced foraging activity and increased vigilance in fallow deer, and deer breeders should consider this. Avoidance of the foraging area within the enclosure, where animals have fewer alternative food sources, can be particularly problematic. Therefore, preventing or disturbing their regular foraging routine should be minimized to meet basic welfare requirements.

Dynamics of Neural Microstates in the VTA-Striatal-Prefrontal Loop during Novelty Exploration in the Rat.

Neural activity at the large-scale population level has been suggested to be consistent with a sequence of brief, quasistable spatial patterns. These "microstates" and their temporal dynamics have been linked to myriad cognitive functions and brain diseases. Most of this research has been performed using EEG, leaving many questions, such as the existence, dynamics, and behavioral relevance of microstates at the level of local field potentials (LFPs), unaddressed. Here, we adapted the standard EEG microstate analysis to triple-area LFP recordings from 192 electrodes in rats to investigate the mesoscopic dynamics of neural microstates within and across brain regions during novelty exploration. We performed simultaneous recordings from the prefrontal cortex, striatum, and ventral tegmental area in male rats during awake behavior (object novelty and exploration). We found that the LFP data can be accounted for by multiple, recurring microstates that were stable for ∼60-100 ms. The simultaneous microstate activity across brain regions revealed rhythmic patterns of coactivations, which we interpret as a novel indicator of inter-regional, mesoscale synchronization. Furthermore, these rhythmic coactivation patterns across microstates were modulated by behavioral states such as movement and exploration of a novel object. These results support the existence of a functional mesoscopic organization across multiple brain areas and present a possible link of the origin of macroscopic EEG microstates to zero-lag neuronal synchronization within and between brain areas, which is of particular interest to the human research community.SIGNIFICANCE STATEMENT The coordination of neural activity across the entire brain has remained elusive. Here we combine large-scale neural recordings at fine spatial resolution with the analysis of microstates (i.e., short-lived, recurring spatial patterns of neural activity). We demonstrate that the local activity in different brain areas can be accounted for by only a few microstates per region. These microstates exhibited temporal dynamics that were correlated across regions in rhythmic patterns. We demonstrate that these microstates are linked to behavior and exhibit different properties in the frequency domain during different behavioral states. In summary, LFP microstates provide an insightful approach to studying both mesoscopic and large-scale brain activation within and across regions.

Do you see the same cat that I see? Relationships between Qualitative Behaviour Assessment and indicators traditionally used to assess temperament in domestic cats

AbstractThis study into the behaviour of domestic cats (Felis catus) aimed to assess the relationship between behavioural expressions obtained via the Qualitative Behaviour Assessment (QBA) and quantitative outcomes of temperament tests. Four behavioural tests were used: Unfamiliar person (UP); Novel object (NO); Conspecific reaction (CR); and Food offering (FO) tests. Tests were filmed and assessed using an ethogram that included 25 discrete behavioural categories, generating quantitative information (coding method) on the existing temperament dimensions. Videos were also assessed by another observer using the QBA method, based on a list of 20 adjectives rated in visual analogue scales (rating method). Data were analysed using Principal Component Analysis. Spearman's rank correlation coefficients were used to relate the principal components (PC) of QBA to the temperament dimensions obtained with the coding method. The QBA allowed us to identify three PC, explaining 76.63% of the total variance. PC1 ranged from ‘calm/relaxed/friendly’ to ‘tense/fearful/alert’, reflecting the valence of cats’ behavioural and emotional expressions towards the stimuli tested. PC2 ranged from ‘indifferent’ to ‘agitated/active’, indicating the level of emotional arousal, and PC3 ranged from ‘aggressive’ to ‘suspicious’ and could be interpreted as an axis of ‘aggressiveness — caution’ in response to the stimuli. The first PC obtained for each test by using the coding method was significantly correlated with the PC1 of QBA, suggesting that the variations in cats’ behavioural and emotional expressions identified by QBA were correlated with the main quantitative outcomes of temperament tests traditionally applied for domestic cats. QBA could be a promising tool for identifying and differentiating cat temperament profiles. Further research is required to assess the potential use of QBA as a feasible and practical method for use in shelters.