22kHz and 55kHz ultrasonic vocalizations differentially influence neural and behavioral outcomes: Implications for modeling anxiety via auditory stimuli in the rat.
Behav Brain Res. 2018 Dec 03;:
Authors: Demaestri C, Brenhouse HC, Honeycutt JA
The communicative role of ultrasonic vocalizations (USVs) in rats is well established, with distinct USVs indicative of different affective states. USVs in the 22 kHz range are typically emitted by adult rats when in anxiety- or fear-provoking situations (e.g. predator odor, social defeat), while 55 kHz range USVs are typically emitted in appetitive situations (e.g., play, anticipation of reward). Previous work indicates that USVs (real-time and playback) can effectively communicate these affective states and influence changes in behavior and neural activity of the receiver. Changes in cFos activation following 22 kHz USVs have been seen in cortical and limbic regions involved in anxiety, including the basolateral amygdala (BLA). However, it is unclear how USV playback influences cFos activity within the bed nucleus of the stria terminalis (BNST), a region also thought to be critical in processing anxiety-related information, and the nucleus accumbens, a region associated with reward. The present work sought to characterize distinct behavioral, physiological, and neural responses in rats presented with aversive (22 kHz) compared to appetitive (55 kHz) USVs or silence. Our findings show that rats exposed to 22 kHz USVs: 1) engage in anxiety-like behaviors in the elevated zero maze, and 2) show distinct patterns of cFos activation within the BLA and BNST that contrast those seen in 55 kHz playback and silence. Specifically, 22 kHz USVs increased cFos density in the anterodorsal nuclei, while 55 kHz playback increased cFos in the oval nucleus of the BNST, without significant changes within the nucleus accumbens. These results provide important groundwork for leveraging ethologically-relevant stimuli in the rat to improve our understanding of anxiety-related responses in both typical and pathological populations.
PMID: 30521931 [PubMed - as supplied by publisher]
The long-term effect of previous dental treatment under general anaesthesia on children's dental fear and anxiety.
Int J Paediatr Dent. 2018 Dec 02;:
Authors: Aldossari GS, Aldosari AA, Alasmari AA, Aldakheel RM, AlNatsha RR, Aldossary MS
BACKGROUND: Dental treatment under general anaesthesia (DGA) is deemed to contribute to children's dental fear and anxiety (DFA), both in the short and long term OBJECTIVE: To compare DFA between children who had previous DGA and those who did not.
METHODS: A cross-sectional survey included 5-12 years old children who had undergone DGA (n=43) and a control group who had not (n=55). Questionnaires were completed by parents regarding sociodemographic and dental profiles. Children's Fear Survey Schedule-Dental Subscale (CFSS-DS), and the Modified Child Dental Anxiety Scale (faces) (MCDASf) were completed by children.
RESULTS: The mean age of the control group and the DGA group were 9.5 +/- 1.7, and 8.8 +/- 1.5 years old, respectively (P>0.05). The time passed since DGA was experienced ranged between 1.2 to 6.9 years ago (mean: 4.2 +/- 1.1 years). The mean CFSS-DS and MCDASf scores for the DGA group (34.3 and 20.4 respectively) were significantly greater when compared to the control group (23.6 and 12.7 respectively) (P<0.001).
CONCLUSION: Children who experienced DGA are a high-risk group for DFA several years after the procedure. The DGA status could be used for identifying anxious children to promote better behaviour management. This article is protected by copyright. All rights reserved.
PMID: 30506997 [PubMed - as supplied by publisher]
Neuroepigenetic mechanisms underlying fear extinction: emerging concepts.
Psychopharmacology (Berl). 2018 Nov 30;:
Authors: Marshall PR, Bredy TW
An understanding of how memory is acquired and how it can be modified in fear-related anxiety disorders, with the enhancement of failing memories on one side and a reduction or elimination of traumatic memories on the other, is a key unmet challenge in the fields of neuroscience and neuropsychiatry. The latter process depends on an important form of learning called fear extinction, where a previously acquired fear-related memory is decoupled from its ability to control behaviour through repeated non-reinforced exposure to the original fear-inducing cue. Although simple in description, fear extinction relies on a complex pattern of brain region and cell-type specific processes, some of which are unique to this form of learning and, for better or worse, contribute to the inherent instability of fear extinction memory. Here, we explore an emerging layer of biology that may compliment and enrich the synapse-centric perspective of fear extinction. As opposed to the more classically defined role of protein synthesis in the formation of fear extinction memory, a neuroepigenetic view of the experience-dependent gene expression involves an appreciation of dynamic changes in the state of the entire cell: from a transient change in plasticity at the level of the synapse, to potentially more persistent long-term effects within the nucleus. A deeper understanding of neuroepigenetic mechanisms and how they influence the formation and maintenance of fear extinction memory has the potential to enable the development of more effective treatment approaches for fear-related neuropsychiatric conditions.
PMID: 30506235 [PubMed - as supplied by publisher]
Effects of the perinatal exposure of Gum Arabic on the development, behavior and biochemical parameters of mice offspring.
Saudi J Biol Sci. 2018 Nov;25(7):1332-1338
Authors: Binjumah M, Ajarem J, Ahmad M
The effects of the perinatal oral exposure to Gum Arabic (GA) on mice offspring was examined. GA was added to the drinking water of pregnant female Swiss-Webster strain mice at doses of 1 and 4 g/kg body weight, starting from the first day of pregnancy. The treatment continued until the fifteenth day after delivery, after which mothers were switched to plain tap water. A number of tests were carried out on offspring starting one day after birth and extending up to postnatal day 30 (PD30). Pups showed a reduced gain of body weight and delayed opening of the eyes in comparison to the control group and only pups exposed to 1 g/kg body weight GA had a faster appearance of hair. Sensory motor reflex tests carried out during the weaning period (from day of birth to PD21) showed enhanced motor reflexes in pups exposed to GA. During the adolescent period (from PD22 to PD30), offspring showed dose-dependent enhanced motor activity (on PD22), reduced anxiety and fear (on PD27) and slightly enhanced memory and learning abilities (on PD30). Biochemical tests of a number of blood parameters were conducted during and after the weaning period (on PD15 and PD30, respectively). Our results indicated that GA might have a hypoglycemic and a beneficial effect on red and white blood cell counts. This study gives a first insight on the effect of GA consumption on offspring, providing a starting point for further studies.
PMID: 30505178 [PubMed]
When translational neuroscience fails in the clinic: Dexamethasone prior to virtual reality exposure therapy increases drop-out rates.
J Anxiety Disord. 2018 Oct 29;:
Authors: Maples-Keller JL, Jovanovic T, Dunlop BW, Rauch S, Yasinski C, Michopoulos V, Coghlan C, Norrholm S, Rizzo AS, Ressler K, Rothbaum BO
Posttraumatic stress disorder (PTSD) is characterized by exaggerated expression of fear responses to danger and safety cues. Translational research suggests that dexamethasone facilitates fear extinction in animal and human fear conditioning models. For this randomized, placebo-controlled trial (N = 27), we aimed to translate these findings to the clinic by using virtual reality exposure (VRE) therapy for OEF/OIF/OND veterans with PTSD to determine whether dexamethasone will increase the efficacy of exposure therapy for VRE relative to placebo. VRE sessions involved imaginal exposure to the most traumatic war memories while viewing a computer-generated view of virtual Iraq or Afghanistan with multisensory stimulus options used to match patient's description of the trauma. VRE was effective in reducing PTSD symptoms but there was no interaction with dexamethasone. Drop-out rate was significantly higher in the dexamethasone group, with 10 of 13 (76.9%) participants in this group discontinuing, compared to only 4 of 14 (28.5%) in the placebo group, χ2 = 6.31, p = 0.02. Results indicate that the dexamethasone group may have experienced an increase in PTSD symptoms, particularly re-experiencing, at session 2 following first drug administration. Contrary to study hypotheses, dexamethasone did not enhance exposure therapy outcomes and was associated with increased drop-out. This demonstrates potential pitfalls in translating neuroscience models to the clinic; future research carefully examining glucocorticoid mechanisms involved in therapy augmentation is warranted.
PMID: 30502903 [PubMed - as supplied by publisher]