Communication Impairments in Mice Lacking Shank1: Reduced Levels of Ultrasonic Vocalizations and Scent Marking Behavior

Autism is a neurodevelopmental disorder with a strong genetic component. Core symptoms are abnormal reciprocal social interactions, qualitative impairments in communication, and repetitive and stereotyped patterns of behavior with restricted interests. Candidate genes for autism include the SHANK gene family, as mutations in SHANK2 and SHANK3 have been detected in several autistic individuals. SHANK genes code for a family of scaffolding proteins located in the postsynaptic density of excitatory synapses. To test the hypothesis that a mutation in SHANK1 contributes to the symptoms of autism, we evaluated Shank1−/− null mutant mice for behavioral phenotypes with relevance to autism, focusing on social communication. Ultrasonic vocalizations and the deposition of scent marks appear to be two major modes of mouse communication. Our findings revealed evidence for low levels of ultrasonic vocalizations and scent marks in Shank1−/− mice as compared to wildtype Shank1+/+ littermate controls. Shank1−/− pups emitted fewer vocalizations than Shank1+/+ pups when isolated from mother and littermates. In adulthood, genotype affected scent marking behavior in the presence of female urinary pheromones. Adult Shank1−/− males deposited fewer scent marks in proximity to female urine than Shank1+/+ males. Call emission in response to female urinary pheromones also differed between genotypes. Shank1+/+ mice changed their calling pattern dependent on previous female interactions, while Shank1−/− mice were unaffected, indicating a failure of Shank1−/− males to learn from a social experience. The reduced levels of ultrasonic vocalizations and scent marking behavior in Shank1−/− mice are consistent with a phenotype relevant to social communication deficits in autism.National Institute of Mental Health (U.S.) (Intramural Research Program)Simons Foundatio

Vocal Learning and Auditory-Vocal Feedback

Vocal learning is usually studied in songbirds and humans, species that can form auditory templates by listening to acoustic models and then learn to vocalize to match the template. Most other species are thought to develop vocalizations without auditory feedback. However, auditory input influences the acoustic structure of vocalizations in a broad distribution of birds and mammals. Vocalizations are dened here as sounds generated by forcing air past vibrating membranes. A vocal motor program may generate vocalizations such as crying or laughter, but auditory feedback may be required for matching precise acoustic features of vocalizations. This chapter discriminates limited vocal learning, which uses auditory input to fine-tune acoustic features of an inherited auditory template, from complex vocal learning, in which novel sounds are learned by matching a learned auditory template. Two or three songbird taxa and four or ve mammalian taxa are known for complex vocal learning. A broader range of mammals converge in the acoustic structure of vocalizations when in socially interacting groups, which qualifies as limited vocal learning. All birds and mammals tested use auditory-vocal feedback to adjust their vocalizations to compensate for the effects of noise, and many species modulate their signals as the costs and benefits of communicating vary. This chapter asks whether some auditory-vocal feedback may have provided neural substrates for the evolution of vocal learning. Progress will require more precise definitions of different forms of vocal learning, broad comparative review of their presence and absence, and behavioral and neurobiological investigations into the mechanisms underlying the skills.PostprintPeer reviewe

The dopamine D3-preferring D2/D3 dopamine receptor partial agonist, cariprazine, reverses behavioral changes in a rat neurodevelopmental model for schizophrenia

Current antipsychotic medication is largely ineffective against the negative and cognitive symptoms of schizophrenia. One promising therapeutic development is to design new molecules that balance actions on dopamine D2 and D3 receptors to maximise benefits and limit adverse effects. This study used two rodent paradigms to investigate the action of the dopamine D3-preferring D3/D2 receptor partial agonist cariprazine. In adult male rats, cariprazine (0.03-0.3mg/kg i.p.), and the atypical antipsychotic aripiprazole (1-3mg/kg i.p.) caused dose-dependent reversal of a delay-induced impairment in novel object recognition (NOR). Treating neonatal rat pups with phencyclidine (PCP) and subsequent social isolation produced a syndrome of behavioral alterations in adulthood including hyperactivity in a novel arena, deficits in NOR and fear motivated learning and memory, and a reduction and change in pattern of social interaction accompanied by increased ultrasonic vocalisations (USVs). Acute administration of cariprazine (0.1 and 0.3mg/kg) and aripiprazole (3mg/kg) to resultant adult rats reduced neonatal PCP-social isolation induced locomotor hyperactivity and reversed NOR deficits. Cariprazine (0.3mg/kg) caused a limited reversal of the social interaction deficit but neither drug affected the change in USVs or the deficit in fear motivated learning and memory. Results suggest that in the behavioral tests investigated cariprazine is at least as effective as aripiprazole and in some paradigms it showed additional beneficial features further supporting the advantage of combined dopamine D3/D2 receptor targeting. These findings support recent clinical studies demonstrating the efficacy of cariprazine in treatment of negative symptoms and functional impairment in schizophrenia patients

Affiliative Behavior, Ultrasonic Communication and Social Reward Are Influenced by Genetic Variation in Adolescent Mice

Social approach is crucial for establishing relationships among individuals. In rodents, social approach has been studied primarily within the context of behavioral phenomena related to sexual reproduction, such as mating, territory defense and parental care. However, many forms of social interaction occur before the onset of reproductive maturity, which suggests that some processes underlying social approach among juvenile animals are probably distinct from those in adults. We conducted a longitudinal study of social investigation (SI) in mice from two inbred strains to assess the extent to which genetic factors influence the motivation for young mice to approach one another. Early-adolescent C57BL/6J (B6) mice, tested 4–6 days after weaning, investigated former cage mates to a greater degree than BALB/cJ (BALB) mice, irrespective of the sex composition within an interacting pair. This strain difference was not due to variation in maternal care, the phenotypic characteristics of stimulus mice or sensitivity to the length of isolation prior to testing, nor was it attributable to a general difference in appetitive motivation. Ultrasonic vocalization (USV) production was positively correlated with the SI responses of mice from both strains. Interestingly, several USV characteristics segregated with the genetic background of young mice, including a higher average frequency and shorter duration for the USVs emitted by B6 mice. An assessment of conditioned place preference responses indicated that there was a strain-dependent difference in the rewarding nature of social contact. As adolescent mice aged, SI responses gradually became less sensitive to genetic background and more responsive to the particular sex of individuals within an interacting pair. We have thus identified a specific, genetic influence on the motivation of early-adolescent mice to approach one another. Consistent with classical theories of motivation, which propose a functional relationship between behavioral approach and reward, our findings indicate that reward is a proximal mechanism through which genetic factors affect social motivation during early adolescence

Ultrasonic vocalisation rate tracks the diurnal pattern of activity in winter phenotype Djungarian hamsters (Phodopus sungorus)

Vocalisations are increasingly being recognised as an important aspect of normal rodent behaviour yet little is known of how they interact with other spontaneous behaviours such as sleep and torpor, particularly in a social setting. We obtained chronic recordings of the vocal behaviour of adult male and female Djungarian hamsters (Phodopus sungorus) housed under short photoperiod (8 h light, 16 h dark, square wave transitions), in different social contexts. The animals were kept in isolation or in same-sex sibling pairs, separated by a grid which allowed non-physical social interaction. On approximately 20% of days hamsters spontaneously entered torpor, a state of metabolic depression that coincides with the rest phase of many small mammal species in response to actual or predicted energy shortages. Animals produced ultrasonic vocalisations (USVs) with a peak frequency of 57 kHz in both social and asocial conditions and there was a high degree of variability in vocalisation rate between subjects. Vocalisation rate was correlated with locomotor activity across the 24-h light cycle, occurring more frequently during the dark period when the hamsters were more active and peaking around light transitions. Solitary-housed animals did not vocalise whilst torpid and animals remained in torpor despite overlapping with vocalisations in social-housing. Besides a minor decrease in peak USV frequency when isolated hamsters were re-paired with their siblings, changing social contexts did not influence vocalisation behaviour or structure. In rare instances, temporally overlapping USVs occurred when animals were socially-housed and were grouped in such a way that could indicate coordination. We did not observe broadband calls (BBCs) contemporaneous with USVs in this paradigm, corroborating their correlation with physical aggression which was absent from our experiment. Overall, we find little evidence to suggest a direct social function of hamster USVs. We conclude that understanding the effects of vocalisations on spontaneous behaviours, such as sleep and torpor, will inform experimental design of future studies, especially where the role of social interactions is investigated

Female- and intruder-induced ultrasonic vocalizations as proxy indicators for animal well-being and postoperative pain recognition in C57BL/6J mice

2019 Spring.Includes bibliographical references.Mice are the most commonly used research animal and often undergo painful procedures. It is important to minimize pain and distress in research animals. However, recognizing pain and distress in mice is challenging. There is a need for new objective techniques to assess pain, distress, and animal well-being in laboratory mice. Female urine-induced male mice ultrasonic vocalizations (FiUSV) are ultrasonic vocalizations produced by adult male mice following presentation of adult female urine, while intruder-induced ultrasonic vocalizations (IiUSV) are produced by resident adult females when interacting with an intruder female mouse. These affiliative behaviors may be reduced with pain, distress, or decreased well-being. Two studies were completed to determine if FiUSV and IiUSV can be used as proxy indicator assays to assess animal well-being and postoperative pain in mice. First, the role of FiUSV and IiUSV in identifying decreased animal well-being were assessed in mice using an acute inflammatory sickness model. Second, using a vasectomy pain model, the role of FiUSV in detecting postoperative pain was assessed in male mice. Findings from the first study showed mice injected with lipopolysaccharide (LPS) intraperitoneally produced significantly fewer FiUSV and IiUSV compared to saline-injected mice, and the decrease in the number of USV occurred prior to showing overt clinical signs of sickness. In the second study, vasectomized mice given no postoperative analgesics produced fewer FiUSV compared to baseline, while vasectomized mice given postoperative analgesics had no change in the number of FiUSV compared to baseline. The findings from these studies provide evidence that FiUSV and IiUSV can be used as proxy indicator assays to assess animal well-being associated with acute inflammatory sickness, and FiUSV can be used to assess postoperative pain

Parenthood-Associated Plasticity of Sensory Processing in the Biparental California Mouse (Peromyscus californicus)

Many mammalian species are born altricial and rely entirely on a caregiver to provide food, warmth, and protection. At this helpless stage, infants rely on cues such as odors and calls to elicit parental care, and new mothers undergo extensive physiological, neural, and behavioral changes that facilitate parental behavior. Mothers also experience plasticity in their sensory systems, which aids them in responding efficiently to infant cues. This is an active area of research in mothers, and very little is known about sensory plasticity in mammalian fathers. To bridge this gap, I investigated the biparental California mouse (Peromyscus californicus) on three fronts: First, I characterized pup calls across the postpartum period and assessed the hearing range of adults to determine if auditory processing changes in parents and I found that hearing thresholds for 24 kHz stimuli were lower in parents than in virgins regardless of sex and auditory nerve latencies were shorter in parents than in virgins at 4 kHz. Next, I assessed the effects of becoming a father on males’ behavioral responses to pup cues by determining how first-time fathers and virgin males behaved when presented with pup stimuli. Fathers spent significantly more time with pup stimuli than control stimuli regardless of the sensory modality while virgins showed no differences. Finally, I tested whether fatherhood increases neural activity in brain regions involved in auditory processing and parental care by exposing first-time fathers and virgin males to either prerecorded pup calls or white noise. Fathers exhibited increased activity in the superficial layers of the auditory cortex regardless of the auditory stimulus compared to virgin males, while virgin males exposed to pup calls had marginally less activity in the medial preoptic area of the hypothalamus compared to the other groups of males. In sum, my findings provide some of the first crucial pieces of evidence that there is both behavioral and neural plasticity of the sensory systems in new mammalian fathers

Two pup vocalization types are genetically and functionally separable in deer mice

Vocalization is a widespread vertebrate social behavior that is essential for fitness in the wild. While many vocal behaviors are highly conserved, heritable features of specific vocalization types can vary both within and between species, raising the questions of why and how some vocal behaviors evolve. Here, using new computational tools to automatically detect and cluster vocalizations into distinct acoustic categories, we compare pup isolation calls across neonatal development in eight taxa of deer mice (genusPeromyscus) and compare them to laboratory mice (C57Bl6/j strain) and free-living, wild house mice (Mus musculus musculus). Whereas bothPeromyscusandMuspups produce ultrasonic vocalizations (USVs),Peromyscuspups also produce a second call type with acoustic features, temporal rhythms, and developmental trajectories that are distinct from those of USVs. In deer mice, these tonal and low frequency “cries” are predominantly emitted in postnatal days one through nine, while USVs are primarily made after day nine. Using playback assays, we show that cries result in a more rapid approach byPeromyscusmothers than USVs, suggesting a role for cries in eliciting parental care early in neonatal development. Using genetic crosses between two sister species of deer mice exhibiting large, innate differences in the acoustic structure of cries and USVs, we find that variation in vocalization rate, duration, and pitch display different degrees of genetic dominance and that cry and USV features can be uncoupled in second-generation hybrids. Taken together, this work shows that vocal behavior can evolve quickly between closely related rodent species in which vocalization types, likely serving distinct functions in communication, are controlled by distinct genetic loci

The impact of tickling rats on human-animal interactions and rat welfare

Rats initially fear humans which can lead to negative affect, poor welfare, and difficult handling. Also, modeling and measuring positive affect states in rats can pose an additional challenge. Heterospecific play, or “tickling,” is a handling habituation technique that mimics rat rough-and-tumble play that is being used to study positive affect. It can also be used to reduce fear of human, improve welfare, and elicit a positive affect state. However, current studies implementing the technique in laboratory rats use a wide variety of protocols to achieve differential results. Unlike in laboratory environment, pet store rats experience high levels of novelty and potentially inconsistent human interactions which may reinforce fearful human-rat relationships. Thus, pet rats may experience benefits from tickling. Also, although anecdotal information suggests tickling may have positive effects on humans, this assertion has not yet been empirically validated. The central hypothesis for this thesis was that tickling rats would improve rat welfare and human-rat interactions. A systematic review of empirical research using rat tickling identified 55 experiments within 32 articles. Although a wide variety of methods were used, main outcomes of tickling compared to a control condition included increased number of positive vocalizations and approach behavior, decreased anxiety and fear metrics, improved handling reactivity, and, in some cases, decreased stress hormones. There were also specific factors that could moderate outcomes from tickling including rat age, housing type, presence of bedding, and inter-individual differences. The most consistent effect found was that there are distinct inter-individual differences in rat response to tickling in that some rats consistently produce more 50-kilohertz vocalizations, a measure of positive affect, than others. Rats that produce more 50-kHz vocalizations are termed high-callers. Overall, our review showed that tickling is a promising method for improving rat welfare and investigating positive affect, but that further investigation into best practices is warranted. To expand the current research conducted on laboratory rats into the pet store setting, we investigated the effects of tickling pet store rats on human-rat interactions, animal welfare, as well as all the people that interact with the rats. We predicted that tickled high-calling rats would show the most positive responses and that humans would be positively affected by tickling. In each replicate, rats were first randomly split into control handling and tickling groups; tickled rats were further split into two groups based on their number of vocalizations produced during 3 days of tickling for 5 minutes a day. Once the rats were allocated to their groups, trained employees tickled animals from both tickling conditions for 4 days. We assessed employees using the Animal Empathy Scale and the Positive and Negative Affect Scale. Using a survey, we asked customers which cage of rats they would purchase and which cage of rats looked happiest. Finally, we assessed new rat owners with surveys and the Lexington Attachment to Pets Scale. We assessed rats using in cage video behavior, fecal corticosterone, and an unfamiliar human approach and restraint test. Our results showed that tickled rats were easier and faster to restrain and were less inactive than control rats. Additionally, behavioral factors such as high activity were cited as very important to selection by both in-store customers and new rat owners. Employee affect and overall animal empathy were unaffected by short-term tickling, but at the point of sale employees were slightly more positive about selling control rats. Finally, customers were more likely to identify tickled high-calling and control rats as being happier. In the unfamiliar approach tests, tickled low-calling rats showed more behaviors indicative of anxiety and fear than tickled high-calling rats. Taken together, the results of this thesis build upon previous tickling literature by presenting an original application of tickling in pet stores as well as evaluating the technique’s effects on humans. Overall, based on the welfare benefits of tickling for rats combined with short-term minimal to positive effects for humans, we recommend using tickling as a habituation technique for pet store rats, particularly high-callers