Development of a Haptic Training Simulation for the Administration of Dental Anaesthesia based upon Accurate Anatomical Data

In the dental curriculum, the initial administration of local anaesthesia injection on live patients is critical and students may experience a high degree of anxiety. Low self-confidence often caused by insufficient knowledge of anatomy has been repeatedly reported as one of the major causes. In this paper, we focus on the development of a haptic training system based upon an accurate anatomical model, which aims to encourage self-paced learning of the practical skills that are required in such procedures and to increase students’ self-confidence. We first present the workflow we have considered to develop an accurate anatomical model of the human head and neck and introduce a Virtual Reality-based application commissioned by NHS Education for Scotland to support the learning of the anatomy in a safe and repeatable manner. Finally, we describe the functionalities of the haptic training system and discuss further developments with regard to existing research outcomes

Pharmacologically Distinct Nicotinic Acetylcholine Receptors Drive Efferent-Mediated Excitation in Calyx-Bearing Vestibular Afferents

Electrical stimulation of vestibular efferent neurons rapidly excites the resting discharge of calyx/dimorphic (CD) afferents. In turtle, this excitation arises when acetylcholine (ACh), released from efferent terminals, directly depolarizes calyceal endings by activating nicotinic ACh receptors (nAChRs). Although molecular biological data from the peripheral vestibular system implicate most of the known nAChR subunits, specific information about those contributing to efferent-mediated excitation of CD afferents is lacking. We sought to identify the nAChR subunits that underlie the rapid excitation of CD afferents and whether they differ from α9α10 nAChRs on type II hair cells that drive efferent-mediated inhibition in adjacent bouton afferents. We recorded from CD and bouton afferents innervating the turtle posterior crista during electrical stimulation of vestibular efferents while applying several subtype-selective nAChR agonists and antagonists. The α9α10 nAChR antagonists, α-bungarotoxin and α-conotoxin RgIA, blocked efferent-mediated inhibition in bouton afferents while leaving efferent-mediated excitation in CD units largely intact. Conversely, 5-iodo-A-85380, sazetidine-A, varenicline, α-conotoxin MII, and bPiDDB (N,N-dodecane-1,12-diyl-bis-3-picolinium dibromide) blocked efferent-mediated excitation in CD afferents without affecting efferent-mediated inhibition in bouton afferents. This pharmacological profile suggested that calyceal nAChRs contain α6 and β2, but not α9, nAChR subunits. Selective blockade of efferent-mediated excitation in CD afferents distinguished dimorphic from calyx afferents by revealing type II hair cell input. Dimorphic afferents differed in having higher mean discharge rates and a mean efferent-mediated excitation that was smaller in amplitude yet longer in duration. Molecular biological data demonstrated the expression of α9 in turtle hair cells and α4 and β2 in associated vestibular ganglia

Altered outer hair cell mitochondrial and subsurface cisternae connectomics are candidate mechanisms for hearing loss in mice

Organelle crosstalk is vital for cellular functions. The propinquity of mitochondria, ER, and plasma membrane promote regulation of multiple functions, which include intracellular C

Functional, Morphological, and Evolutionary Characterization of Hearing in Subterranean, Eusocial African Mole-Rats

Naked mole-rats are highly vocal, eusocial, subterranean rodents with, counterintuitively, poor hearing. The causes underlying their altered hearing are unknown. Moreover, whether altered hearing is degenerate or adaptive to their unique lifestyles is controversial. We used various methods to identify the factors contributing to altered hearing in naked and the related Damaraland mole-rats and to examine whether these alterations result from relaxed or adaptive selection. Remarkably, we found that cochlear amplification was absent from both species despite normal prestin function in outer hair cells isolated from naked mole-rats. Instead, loss of cochlear amplification appears to result from abnormal hair bundle morphologies observed in both species. By exploiting a well-curated deafness phenotype-genotype database, we identified amino acid substitutions consistent with abnormal hair bundle morphology and reduced hearing sensitivity. Amino acid substitutions were found in unique groups of six hair bundle link proteins. Molecular evolutionary analyses revealed shifts in selection pressure at both the gene and the codon level for five of these six hair bundle link proteins. Substitutions in three of these proteins are associated exclusively with altered hearing. Altogether, our findings identify the likely mechanism of altered hearing in African mole-rats, making them the only identified mammals naturally lacking cochlear amplification. Moreover, our findings suggest that altered hearing in African mole-rats is adaptive, perhaps tailoring hearing to eusocial and subterranean lifestyles. Finally, our work reveals multiple, unique evolutionary trajectories in African mole-rat hearing and establishes species members as naturally occurring disease models to investigate human hearing loss

Development of a Haptic Training Simulation for the Administration of Dental Anaesthesia based upon Accurate Anatomical Data

In the dental curriculum, the initial administration of local anaesthesia injection on live patients is critical and students may experience a high degree of anxiety. Low self-confidence often caused by insufficient knowledge of anatomy has been repeatedly reported as one of the major causes. In this paper, we focus on the development of a haptic training system based upon an accurate anatomical model, which aims to encourage self-paced learning of the practical skills that are required in such procedures and to increase students’ self-confidence. We first present the workflow we have considered to develop an accurate anatomical model of the human head and neck and introduce a Virtual Reality-based application commissioned by NHS Education for Scotland to support the learning of the anatomy in a safe and repeatable manner. Finally, we describe the functionalities of the haptic training system and discuss further developments with regard to existing research outcomes