Dedicated hippocampal inhibitory networks for locomotion and immobility

Network activity is strongly tied to animal movement; however, hippocampal circuits selectively engaged during locomotion or immobility remain poorly characterized. Here we examined whether distinct locomotor states are encoded differentially in genetically defined classes of hippocampal interneurons. To characterize the relationship between interneuron activity and movement, we usedin vivo, two-photon calcium imaging in CA1 of male and female mice, as animals performed a virtual-reality (VR) track running task. We found that activity in most somatostatin-expressing and parvalbumin-expressing interneurons positively correlated with locomotion. Surprisingly, nearly one in five somatostatin or one in seven parvalbumin interneurons were inhibited during locomotion and activated during periods of immobility. Anatomically, the somata of somatostatin immobility-activated neurons were smaller than those of movement-activated neurons. Furthermore, immobility-activated interneurons were distributed across cell layers, with somatostatin-expressing cells predominantly in stratum oriens and parvalbumin-expressing cells mostly in stratum pyramidale. Importantly, each cell's correlation between activity and movement was stable both over time and across VR environments. Our findings suggest that hippocampal interneuronal microcircuits are preferentially active during either movement or immobility periods. These inhibitory networks may regulate information flow in “labeled lines” within the hippocampus to process information during distinct behavioral states.SIGNIFICANCE STATEMENTThe hippocampus is required for learning and memory. Movement controls network activity in the hippocampus but it's unclear how hippocampal neurons encode movement state. We investigated neural circuits active during locomotion and immobility and found interneurons were selectively active during movement or stopped periods, but not both. Each cell's response to locomotion was consistent across time and environments, suggesting there are separate dedicated circuits for processing information during locomotion and immobility. Understanding how the hippocampus switches between different network configurations may lead to therapeutic approaches to hippocampal-dependent dysfunctions, such as Alzheimer's disease or cognitive decline.</jats:p

Structured inhibitory activity dynamics in new virtual environments

Inhibition plays a powerful role in regulating network excitation and plasticity; however, the activity of defined interneuron types during spatial exploration remain poorly understood. Using two-photon calcium imaging, we recorded hippocampal CA1 somatostatin- and parvalbumin-expressing interneurons as mice performed a goal-directed spatial navigation task in new visual virtual reality (VR) contexts. Activity in both interneuron classes was strongly suppressed but recovered as animals learned to adapt the previously learned task to the new spatial context. Surprisingly, although there was a range of activity suppression across the population, individual somatostatin-expressing interneurons showed consistent levels of activity modulation across exposure to multiple novel environments, suggesting context-independent, stable network roles during spatial exploration. This work reveals population-level temporally dynamic interneuron activity in new environments, within which each interneuron shows stable and consistent activity modulation

Predictors of Enhancing Human Physical Attractiveness: Data from 93 Countries

People across the world and throughout history have gone to great lengths to enhance their physical appearance. Evolutionary psychologists and ethologists have largely attempted to explain this phenomenon via mating preferences and strategies. Here, we test one of the most popular evolutionary hypotheses for beauty-enhancing behaviors, drawn from mating market and parasite stress perspectives, in a large cross-cultural sample. We also test hypotheses drawn from other influential and non-mutually exclusive theoretical frameworks, from biosocial role theory to a cultural media perspective. Survey data from 93,158 human participants across 93 countries provide evidence that behaviors such as applying makeup or using other cosmetics, hair grooming, clothing style, caring for body hygiene, and exercising or following a specific diet for the specific purpose of improving ones physical attractiveness, are universal. Indeed, 99% of participants reported spending \u3e10 min a day performing beauty-enhancing behaviors. The results largely support evolutionary hypotheses: more time was spent enhancing beauty by women (almost 4 h a day, on average) than by men (3.6 h a day), by the youngest participants (and contrary to predictions, also the oldest), by those with a relatively more severe history of infectious diseases, and by participants currently dating compared to those in established relationships. The strongest predictor of attractiveness-enhancing behaviors was social media usage. Other predictors, in order of effect size, included adhering to traditional gender roles, residing in countries with less gender equality, considering oneself as highly attractive or, conversely, highly unattractive, TV watching time, higher socioeconomic status, right-wing political beliefs, a lower level of education, and personal individualistic attitudes. This study provides novel insight into universal beauty-enhancing behaviors by unifying evolutionary theory with several other complementary perspectives

Dedicated Interneuronal Microcircuits Regulated by Behavioral State

The hippocampus is a critical brain structure for learning and memory. Neuronal inhibition within the hippocampus, performed by a wide variety of inhibitory interneuron subtypes, is required to organize and regulate the cell activity and circuit operations which underly memory formation. Despite the importance of inhibitory interneurons to the function of the hippocampus, detailed descriptions of the role of interneurons in the regulation of network activity have been limited by difficulties associated with identifying and recording from these cells using traditional electrophysiology techniques, especially in awake, behaving animals. To better investigate the function of hippocampal interneurons in awake, behaving animals, we used 2-photon calcium imaging to record from genetically identified interneurons in region CA1 of the hippocampus of mice performing a virtual reality navigation task.Animal movement is a powerful determinant in hippocampal network states, yet the mechanism through which the hippocampus is alternately engaged in distinct states during periods of locomotion or immobility are poorly understood. We investigated the role of hippocampal interneuron during different movement states using in vivo, two-photon calcium imaging in awake, behaving mice performing a virtual reality navigation task. In both somatostatin- and parvalbumin-expressing populations of interneurons, the majority of cells were active during periods of locomotion. However, small subpopulations within these interneuron groups were most active during periods of immobility. These associations between locomotor state and cell activity were stable across days and virtual environments. Anatomically, somatostatin immobility-activated neurons were distinguished by smaller somata than movement-activated neurons. These findings are consistent with a model of distinct hippocampal interneuronal microcircuits differentially activated during either movement or immobility periods. These inhibitory networks may regulate information flow in “labeled lines” within the hippocampus to process information during distinct behavioral states. Next, we investigated the role of hippocampal interneurons during learning. Inhibition, primarily mediated by interneurons, is well known to regulate network excitation and plasticity; however, the relationship between learning and inhibitory activity dynamics remains unclear. We recorded hippocampal CA1 somatostatin- and parvalbumin-expressing interneurons as mice learned a virtual reality task in new visual contexts. Interneuron activity was strongly suppressed upon initial exposure to novel environments, this suppression gradually diminished over subsequent exposures to the same, initially novel, contexts. When learning was prevented through the use of a context in which learning was impossible, activity suppression did not diminish. Interneurons displayed a high degree of stability of suppression response to multiple instances of novelty. These findings suggest that interneurons play an active role in modulating network activity during learning. Their remarkably stable functional architecture suggests that individual interneurons play specific roles during learning, perhaps by differentially regulating excitatory neuron ensembles

Conversations in Cochlear Implantation: The Inner Ear Therapy of Today

As biomolecular approaches for hearing restoration in profound sensorineural hearing loss evolve, they will be applied in conjunction with or instead of cochlear implants. An understanding of the current state-of-the-art of this technology, including its advantages, disadvantages, and its potential for delivering and interacting with biomolecular hearing restoration approaches, is helpful for designing modern hearing-restoration strategies. Cochlear implants (CI) have evolved over the last four decades to restore hearing more effectively, in more people, with diverse indications. This evolution has been driven by advances in technology, surgery, and healthcare delivery. Here, we offer a practical treatise on the state of cochlear implantation directed towards developing the next generation of inner ear therapeutics. We aim to capture and distill conversations ongoing in CI research, development, and clinical management. In this review, we discuss successes and physiological constraints of hearing with an implant, common surgical approaches and electrode arrays, new indications and outcome measures for implantation, and barriers to CI utilization. Additionally, we compare cochlear implantation with biomolecular and pharmacological approaches, consider strategies to combine these approaches, and identify unmet medical needs with cochlear implants. The strengths and weaknesses of modern implantation highlighted here can mark opportunities for continued progress or improvement in the design and delivery of the next generation of inner ear therapeutics

Electronic Health Record Use Among American Neurotology Society Members

To describe the use of electronic health records (EHR) among members of the American Neurotology Society (ANS). Cross-sectional. Active ANS members in November 2017. Internet-based survey. Survey that assessed the use of EHR in practice, types of EHR programs, different elements of EHR employed, and respondents' satisfaction and efficiency with EHR. One hundred twenty-seven ANS members responded to the survey with 67 (52.8%) respondents working in academic practice and 60 (47.2%) respondents working in private practice. Epic was the most commonly used EHR with 89 (70.1%) respondents using this system. Among all respondents, 84 (66.1%) respondents reported their efficiency was reduced by EHR use, and there was an even split between respondents who reported they were satisfied versus dissatisfied with their EHR (∼40% each). We found that younger members were more likely to feel EHR increased their efficiency compared with the older members (p = 0.04). In all other analyses, we found no significant difference in efficiency and satisfaction between age groups, practice settings, presence of residents or fellows, or specific EHR used. The main challenges reported by ANS members related to the EHR were increased time burden, poor user interface, lack of customizability, and the focus away from patients. The majority of ANS members felt their efficiency decreased as a result of EHR. These findings provide specific changes to the EHR that would improve efficiency and satisfaction among neurotologists

Endoscopic Inside-Out Mastoidectomy with the Ultrasonic Bone Aspirator

We report our experience using the ultrasonic bone aspirator (UBA) for transcanal endoscopic “inside out” mastoidectomy. The UBA has irrigation, suction, and nonrotatory ultrasonic bone-removing technology in 1 handpiece, which makes it appropriate for bone removal during this procedure. The results of our study show that this technique is safe and effective for patients with cholesteatoma in a small sclerotic mastoid. We also discuss the nuances associated with using the UBA during endoscopic ear surgery