Synaptic Transformations Underlying Highly Selective Auditory Representations of Learned Birdsong

Stimulus-specific neuronal responses are a striking characteristic of several sensory systems, although the synaptic mechanisms underlying their generation are not well understood. The songbird nucleus HVC (used here as a proper name) contains projection neurons (PNs) that fire temporally sparse bursts of action potentials to playback of the bird\u27s own song (BOS) but are essentially silent when presented with other acoustical stimuli. To understand how such remarkable stimulus specificity emerges, it is necessary to compare the auditory-evoked responsiveness of the afferents of HVC with synaptic responses in identified HVC neurons. We found that inactivating the interfacial nucleus of the nidopallium (NIf) could eliminate all auditory-evoked subthreshold activity in both HVC PN types, consistent with NIf serving as the major auditory afferent of HVC. Simultaneous multiunit extracellular recordings in NIf and intracellular recordings in HVC revealed that NIf population activity and HVC subthreshold responses were similar in their selectivity for BOS and that NIf spikes preceded depolarizations in all HVC cell types. These results indicate that information about the BOS as well as other auditory stimuli is transmitted synaptically from NIf to HVC. Unlike HVC PNs, however, HVC-projecting NIf neurons fire throughout playback of BOS as well as non-BOS stimuli. Therefore, temporally sparse BOS-evoked firing and enhanced BOS selectivity, manifested as an absence of suprathreshold responsiveness to non-BOS stimuli, emerge in HVC. The transformation to a sparse auditory representation parallels differences in NIf and HVC activity patterns seen during singing, which may point to a common mechanism for encoding sensory and motor representations of song

'Kindness and empathy beyond all else' : Challenges to professional identities of Higher Education teachers during COVID-19 times

COVID-19 has continued to effect higher education globally in significant ways. During 2020, many institutions shifted learning online overnight as the sector closed its doors and opened new sites for remote teaching. This article reports on an international study [Phillips et al., 2021] that sought to capture how cross-sectoral teachers experienced these emergency changes during the first months of restrictions. The data, analysed using narrative identity theory, revealed concerns that fall into two broad categories: technologies and relationships. Significantly, it was not a loss of content delivery or changes to assessment that prompted the greatest anxiety for our colleagues, but that they held significant concerns about their students’ mental health; inequities of access to a range of services including technological; and challenges connecting emotionally with their students at a distance. The results provide actionable strategies for higher education institutions to apply in future emergencies where remote teaching is necessary

STORIES FOUND WITHIN THE LEARNINGS OF TEACHING IN COVID-19

COVID-19 has disrupted the educational landscape around the world, putting new pressures on schools, colleges and universities, and more specifically on teaching, learning and assessment. Educators feel fragmented, as their identities as well as their roles pivoted when the pandemic directed them home to teach. This paper explores a global story-based educational research project that sought to capture the pressures, stress and self-efficacy of educators across the world. Our digital ethnographic study sought to explore what educators were experiencing; to archive the worries, hopes, concerns and issues encountered by teachers in new spaces and sites as remote emergency practice began. What has emerged from the 635-educator participant study that includes 105 respondents in the higher education/tertiary sector that we have chosen to focus on here, is an attentiveness to the place of learning and teaching. More importantly, the relations between people and place, and the teachers and their students. This paper explores four stories from the higher education data that have been re-storied as an opening to this pandemic and the effects of the pivot on teaching practice to indicate the times and provide voice to our participants

Functional Consequences of Compartmentalization of Synaptic Input

Intra-axonal recordings of stomatogastric nerve axon 1 (SNAX1) indicate that there are synaptic inputs onto the SNAX1 terminals in the stomatogastric ganglion (STG) of the crab Cancer borealis (Nusbaum et al., 1992b). To determine whether this synaptic input only influenced SNAX1 activity within the STG, we identified the SNAX1 soma in the commissural ganglion (CoG). We found that this neuron has a neuropilar arborization in the CoG and also receives synaptic inputs in this ganglion. Based on its soma location, we have renamed this neuron modulatory commissural neuron 1 (MCN1). While intracellular stimulation of MCN1soma and MCN1SNAX has the same excitatory effects on the STG motor patterns, MCN1 receives distinct synaptic inputs in the STG and CoG. Moreover, the synaptic input that MCN1 receives within the STG compartmentalizes its activity. Specifically, the lateral gastric (LG) neuron synaptically inhibits MCN1SNAX-initiated activity within the STG (Nusbaum et al., 1992b), and while LG did not inhibit MCN1soma- initiated activity in the CoG, it did inhibit these MCN1 impulses when they arrived in the STG. As a result, during MCN1soma-elicited gastric mill rhythms, MCN1soma is continually active in the CoG but its effects are rhythmically inhibited in the STG by LG neuron impulse bursts. One functional consequence of this local control of MCN1 within the STG is that the LG neuron thereby controls the timing of the impulse bursts in other gastric mill neurons. Thus, local synaptic input can functionally compartmentalize the activity of a neuron with arbors in distinct regions of the nervous system

A Computational Approach to Uncertainty in DNA Sequences

DNA sequencing is the process of reading individual base pairs from a section of DNA. Genes are the name given to parts of the DNA which encode proteins; for example ion channels are proteins that maintain concentrations of ions within cells. The sequencing of these genes can offer insights into factors such as evolution and disease. During the sequencing process, unknown values 'N' can be substituted in the sequence where the sequencing machine is unable to identify a nucleotide as Adenine (A), Cytosine (C), Thymine (T), or Guanine (G). These gene sequences vary in length; this includes individual genes across the same species. This has led to the use of a process known as k-mer encoding so that a machine learning algorithm can assess these genes without the need for pre-alignment. K-mer encoding works by taking small sections of the sequence and tallying the number of times that such a sequence appears, such as, how many times the k-mer 'ACCT' appears in the overall sequence. The unknown 'N' value presents a problem in k-mer encoding, as this value increases the size of the k-mer feature vector exponentially as the k-mer length increases. In this paper we research the accuracy and computational impact of including, removing, or ignoring this 'N' value for the k-mer lengths 3, 6, and 9 across four Machine Learning algorithms: Random Forest, Multinomial Naive Bayes, Neural Networks, and Linear Support Vector Machine

Effects of Temperature on Sound Production and Auditory Abilities in the Striped Raphael Catfish Platydoras armatulus (Family Doradidae)

Background: Sound production and hearing sensitivity of ectothermic animals are affected by the ambient temperature. This is the first study investigating the influence of temperature on both sound production and on hearing abilities in a fish species, namely the neotropical Striped Raphael catfish Platydoras armatulus. Methodology/Principal Findings: Doradid catfishes produce stridulation sounds by rubbing the pectoral spines in the shoulder girdle and drumming sounds by an elastic spring mechanism which vibrates the swimbladder. Eight fish were acclimated for at least three weeks to 22 degrees, then to 30 degrees and again to 22 degrees C. Sounds were recorded in distress situations when fish were hand-held. The stridulation sounds became shorter at the higher temperature, whereas pulse number, maximum pulse period and sound pressure level did not change with temperature. The dominant frequency increased when the temperature was raised to 30 degrees C and the minimum pulse period became longer when the temperature decreased again. The fundamental frequency of drumming sounds increased at the higher temperature. Using the auditory evoked potential (AEP) recording technique, the hearing thresholds were tested at six different frequencies from 0.1 to 4 kHz. The temporal resolution was determined by analyzing the minimum resolvable click period (0.3-5 ms). The hearing sensitivity was higher at the higher temperature and differences were more pronounced at higher frequencies. In general, latencies of AEPs in response to single clicks became shorter at the higher temperature, whereas temporal resolution in response to double-clicks did not change

Recent Changes to Reference Services in Academic Libraries and Their Relationship to Perceived Quality: Results of a National Survey

A national survey of academic librarians was conducted to examine relationships among reference service staffing changes, reference service innovations, adoption of reference technology, library type and size, and service quality. Analysis of the 606 response sets reveals trends toward reduced use of librarians and increased use of student staff at in-person service points, widespread increases in appointment-based and self-service reference, intensive efforts to reduce demand for reference by improving library instruction, and general improvements in reference service quality. Factors strongly associated with decreases or increases in quality are discussed in detail and implications for reference managers are provided.Citation: Jason Coleman, Melissa N. Mallon & Leo Lo (2015): Recent Changes to Reference Services in Academic Libraries and Their Relationship to Perceived Quality: Results of a National Survey, Journal of Library Administration, DOI: 10.1080/01930826.2015.110987

Common Features of Neural Activity during Singing and Sleep Periods in a Basal Ganglia Nucleus Critical for Vocal Learning in a Juvenile Songbird

Reactivations of waking experiences during sleep have been considered fundamental neural processes for memory consolidation. In songbirds, evidence suggests the importance of sleep-related neuronal activity in song system motor pathway nuclei for both juvenile vocal learning and maintenance of adult song. Like those in singing motor nuclei, neurons in the basal ganglia nucleus Area X, part of the basal ganglia-thalamocortical circuit essential for vocal plasticity, exhibit singing-related activity. It is unclear, however, whether Area X neurons show any distinctive spiking activity during sleep similar to that during singing. Here we demonstrate that, during sleep, Area X pallidal neurons exhibit phasic spiking activity, which shares some firing properties with activity during singing. Shorter interspike intervals that almost exclusively occurred during singing in awake periods were also observed during sleep. The level of firing variability was consistently higher during singing and sleep than during awake non-singing states. Moreover, deceleration of firing rate, which is considered to be an important firing property for transmitting signals from Area X to the thalamic nucleus DLM, was observed mainly during sleep as well as during singing. These results suggest that songbird basal ganglia circuitry may be involved in the off-line processing potentially critical for vocal learning during sensorimotor learning phase

Measuring Radiation Exposure in Human Blood using Gene Expression

Mammalian cells are known to express genes that are associated with repairing damaged DNA. The transcript CDKN1A is one of several cell cycle regulator genes expressed in response to cell damage by ionizing radiation (IR). In this study, male and female lymphocytes; previously exposed ex vivo to IR, were used to demonstrate linear gene expression responses that may vary between genders. We used qRT-PCR to generate response curves for CDKN1A. No differences were identified for the endogenous control gene GAPDH. CDKN1A expression demonstrated average fold changes well above three fold for three of the four healthy patient donors at 24 hours after 2, 3, and 4 Gy exposures. Doses 2 and 3 Gy were significantly up-regulated at 24 hours. No significant difference was seen between genders for CDKN1A. Our data confirms that genes involved in DNA repair, cell cycle arrest, and apoptosis can be used as biomarkers of exposure to IR. Because of growing concern of IR exposure through different mechanisms; either by nuclear catastrophe or medical radiation, gene expression analysis is a promising method for identification and estimation of IR exposure