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We thank Bo Gao and Paul Julienne for discussion and Robert Moszynski for providing theoretical transition dipole moments of NaCs. This work is supported by the NSF (PHY-1806595), the AFOSR (FA9550-19-1-0089), ARO DURIP (W911NF1810194), and the Arnold and Mabel Beckman foundation. J. T. Z. is supported by a National Defense Science and Engineering Graduate Fellowship. W. B. C. is supported by a Max PlanckHarvard Research Center for Quantum Optics fellowship. K. W. is supported by an NSF GRFP fellowship. J. M. H. is supported by the UK Engineering and Physical Sciences Research Council (EPSRC) Grants No. EP/N007085/1, No. EP/P008275/1, and No. EP/P01058X/1. R. G.-F. acknowledges financial support of the Spanish Project FIS2017-89349-P (MINECO) and the Andalusian research group FQM-207., We report coherent association of atoms into a single weakly bound NaCs molecule in an optical tweezer through an optical Raman transition. The Raman technique uses a deeply bound electronic excited intermediate state to achieve a large transition dipole moment while reducing photon scattering. Starting fromtwo atoms in their relative motional ground state, we achieve an optical transfer efficiency of 69%. The molecules have a binding energy of 770.2 MHz at 8.83(2) G. This technique does not rely on Feshbach resonances or narrow excited-state lines and may allow a wide range of molecular species to be assembled atom by atom., National Science Foundation (NSF) PHY-1806595, United States Department of Defense, Air Force Office of Scientific Research (AFOSR) FA9550-19-1-0089, ARO DURIP W911NF1810194, Arnold and Mabel Beckman foundation, National Defense Science and Engineering Graduate Fellowship, Max PlanckHarvard Research Center for Quantum Optics fellowship, National Science Foundation (NSF), NSF - Office of the Director (OD), UK Research & Innovation (UKRI), Engineering & Physical Sciences Research Council (EPSRC) EP/N007085/1 EP/P008275/1 EP/P01058X/1, MINECO FIS2017-89349-P, Andalusian research group FQM-207

We demonstrate the formation of a single NaCs molecule in an optical tweezer by magnetoassociation through an s-wave Feshbach resonance at 864.11(5) G. Starting from single atoms cooled to their motional ground states, we achieve conversion efficiencies of 47(1)%, and measure a molecular lifetime of 4.7(7) ms. By construction, the single molecules are predominantly [77(5)%] in the center-of-mass motional ground state of the tweezer. Furthermore, we produce a single p-wave molecule near 807 G by first preparing one of the atoms with one quantum of motional excitation. Our creation of a single weakly bound molecule in a designated internal state in the motional ground state of an optical tweezer is a crucial step towards coherent control of single molecules in optical tweezer arrays.

We reduce the intensity noise of laser light by using an electro-optic modulator and a cousto-optic modulator in series. The electro-optic modulator reduces noise at high frequency(10 kHz to 1 MHz), while the acousto-optic modulator sets the average power of the light and reduces noise at low frequency (up to 10 kHz). The light is then used to trap single sodium atoms in an optical tweezer, where the lifetime of the atoms is limited by parametric heating due to laser noise at twice the trapping frequency. With our noise eater, the noise is reduced by up to 15 dB at these frequencies, and the lifetime is increased by an order of magnitude to around 6 seconds. Our technique is general and acts directly on the laser beam, expanding laser options for sensitive optical trapping applications., Comment: 7 pages, 4 figures, submitted to Optics Express

We demonstrate full quantum state control of two species of single atoms using optical tweezers and assemble the atoms into a molecule. Our demonstration includes 3D ground-state cooling of a single atom (Cs) in an optical tweezer, transport by several microns with minimal heating, and merging with a single Na atom. Subsequently, both atoms occupy the simultaneous motional ground state with 61(4)\% probability. This realizes a sample of exactly two co-trapped atoms near the phase-space-density limit of one, and allows for efficient stimulated-Raman transfer of a pair of atoms into a molecular bound state of the triplet electronic ground potential $a^3\Sigma^+$. The results are key steps toward coherent creation of single ultracold molecules, for future exploration of quantum simulation and quantum information processing.

The multichannel Na-Cs interactions are characterized by a series of measurements using two atoms in an optical tweezer, along with a multichannel quantum defect theory (MQDT). The triplet and singlet scattering lengths are measured by performing Raman spectroscopy of the Na-Cs motional states and least-bound molecular state in the tweezer. Magnetic Feshbach resonances are observed for only two atoms at fields which agree well with the MQDT. Our methodology, which promotes the idea of an effective theory of interaction, can be a key step towards the understanding and the description of more complex interactions. The tweezer-based measurements in particular will be an important tool for atom-molecule and molecule-molecule interactions, where high densities are experimentally challenging and where the interactions can be dominated by intra-species processes.

Lighting the way to molecules, one by one When chemists run reactions, what they are really doing is mixing up an enormous number of reacting partners and then hoping that they collide productively. It is possible to manipulate atoms more deliberately with a scanning tunneling microscope tip, but the process is then confined to a surface. Liu et al. directly manipulated individual atoms with light to form single molecules in isolation (see the Perspective by Narevicius). They used optical tweezers of two different colors to selectively steer ultracold sodium (Na) and cesium (Cs) atoms together. A subsequent optical excitation formed NaCs. Science , this issue p. 900 ; see also p. 855

We report Raman sideband cooling of a single sodium atom to its three-dimensional motional ground state in an optical tweezer. Despite a large Lamb-Dicke parameter, high initial temperature, and large differential light shifts between the excited state and the ground state, we achieve a ground state population of $93.5(7)$% after $53$ ms of cooling. Our technique includes addressing high-order sidebands, where several motional quanta are removed by a single laser pulse, and fast modulation of the optical tweezer intensity. We demonstrate that Raman sideband cooling to the 3D motional ground state is possible, even without tight confinement and low initial temperature., Comment: 5 pages, 4 figures

Tailoring the interactions between quantum emitters and single photons constitutes one of the cornerstones of quantum optics. Coupling a quantum emitter to the band edge of a photonic crystal waveguide (PCW) provides a unique platform for tuning these interactions. In particular, the crossover from propagating fields $E(x) \propto e^{\pm ik_x x}$ outside the bandgap to localized fields $E(x) \propto e^{-\kappa_x |x|}$ within the bandgap should be accompanied by a transition from largely dissipative atom-atom interactions to a regime where dispersive atom-atom interactions are dominant. Here, we experimentally observe this transition for the first time by shifting the band edge frequency of the PCW relative to the $\rm D_1$ line of atomic cesium for $\bar{N}=3.0\pm 0.5$ atoms trapped along the PCW. Our results are the initial demonstration of this new paradigm for coherent atom-atom interactions with low dissipation into the guided mode.

We report observations of superradiance for atoms trapped in the near field of a photonic crystal waveguide (PCW). By fabricating the PCW with a band edge near the D$_1$ transition of atomic cesium, strong interaction is achieved between trapped atoms and guided-mode photons. Following short-pulse excitation, we record the decay of guided-mode emission and find a superradiant emission rate scaling as $\bar{\Gamma}_{\rm SR}\propto\bar{N}\cdot\Gamma_{\rm 1D}$ for average atom number $0.19 \lesssim \bar{N} \lesssim 2.6$ atoms, where $\Gamma_{\rm 1D}/\Gamma_0 =1.1\pm0.1$ is the peak single-atom radiative decay rate into the PCW guided mode and $\Gamma_{0}$ is the Einstein-$A$ coefficient for free space. These advances provide new tools for investigations of photon-mediated atom-atom interactions in the many-body regime., Comment: 11 pages, 10 figures

We describe two-dimensional photonic crystals that support atom trapping as well as strong radiative coupling to guided modes. We explore tailoring interactions between atoms and photons, as well as ongoing experimental progress.

We present a comprehensive study of dispersion-engineered nanowire photonic crystal waveguides suitable for experiments in quantum optics and atomic physics with optically trapped atoms. Detailed design methodology and specifications are provided, as are the processing steps used to create silicon nitride waveguides of low optical loss in the near-IR. Measurements of the waveguide optical properties and power-handling capability are also presented.

We present one-dimensional photonic crystal waveguides which can stably trap neutral atoms and achieve single-atom reflectivities of ro ≳ 0.9, as well as experimental progress towards fabrication and optical testing of such structures.

The integration of nanophotonics and atomic physics has been a long-sought goal that would open new frontiers for optical physics. Here, we report the development of the first integrated optical circuit with a photonic crystal capable of both localizing and interfacing atoms with guided photons in the device. By aligning the optical bands of a photonic crystal waveguide (PCW) with selected atomic transitions, our platform provides new opportunities for novel quantum transport and many-body phenomena by way of photon-mediated atomic interactions along the PCW. From reflection spectra measured with average atom number N = 1.1$\pm$0.4, we infer that atoms are localized within the PCW by Casimir-Polder and optical dipole forces. The fraction of single-atom radiative decay into the PCW is $\Gamma_{\rm 1D}/\Gamma'$ = 0.32$\pm$0.08, where $\Gamma_{1D}$ is the rate of emission into the guided mode and $\Gamma'$ is the decay rate into all other channels. $\Gamma_{\rm 1D}/\Gamma'$ is quoted without enhancement due to an external cavity and is unprecedented in all current atom-photon interfaces., Comment: 11 pages, 12 figures

Eye movements were recorded in 42 patients with CNS and labyrinthine lesions during optokinetic (OK) stimulation with a small drum, a full field angular drum and a large linear screen. Gain (slow phase eye velocity/stimulus velocity) and symmetry of the response were measured. In the whole patient group the asymmetry of optokinetic nystagmus (OKN) with the small drum was larger than that elicited with the large field OK stimuli; this indicates that the small drum is a more sensitive stimulus for eliciting abnormal OKN asymmetry (directional preponderance). In some patients with parietal and cerebellar lesions, there was slow build-up of the nystagmic response which was selective to the full field angular OK stimulus. This finding suggests that the ‘old subcortical OKN system, responsible for slow build-up of the response, is specifically related to angular motion. Linear OKN may be coupled to otolith-ocular reflexes.

If a short duration pulse is added periodically every 30 s to a continuous tone, then the loudness of the continuous tone, which would otherwise remain unchanged, appears to undergo a progressive decline over a period of 3 min. The question at issue is whether the loss of loudness is actually induced by the pulse or merely made obvious. In support of the latter proposition a model has been developed which indicates how the loudness difference between the pulsed and continuous tone will increase as a result of adaptation. However, the model also predicts that a loudness loss should, in addition, be apparent in the pulsed tone itself. This has been confirmed by balancing the loudness in one ear of a 10 dB increment to a continuous tone of 60 dB at 1 kHz with an intermittent pulsed tone of the same frequency in the other. The magnitude of the loudness loss (of the order of 5 dB) accords well with the model prediction. The functional implications are that adaptation of continuous background noise should serve to reduce its masking effect upon speech and other transitory auditory stimuli rendering them more easily detectable.

The role of vision in the control of balance in patients with Parkinson's disease (PD) and cerebellar disease (CD) was studied by measuring body sway with eyes open, closed, and in response to visual stimuli generated by discrete lateral displacements of a moveable room which enclosed the subjects. In response to room movement, normal subjects swayed by an amount intermediate between sway with eyes open and eyes closed and their response attenuated on repetition of the movement, a process depending on shifting from predominantly visual to proprioceptive control. CD patients swayed more than controls with eyes open or closed and as shown by high 'Romberg quotients' (eyes closed/eyes open sway ratio) were able to use visual information to control much of their unsteadiness. CD patients had a normal attenuation of response to repetition of the room movement. PD patients had normal sway with eyes open or closed but their responses to room movement were abnormal, being proportionately larger and failing to attenuate during successive stimuli. The results indicate that cerebellar lesions seem largely to spare the visuopostural loop and also spare the ability to shift from a visual to a proprioceptive control of postural sway. In contrast, the findings in PD suggest that the visuopostural loop is hyperactive and that its influence cannot easily be de-emphasized when visual information is misleading. The latter finding suggests that basal ganglia participation in posture is concerned with the reweighting of the various sensorimotor loops controlling posture in the process of adapting to novel situations.

Bilateral sensorineural hearing loss may introduce grossly dissimilar cochlear distortion at the two ears, causing abnormal demands to be made upon the cortical analytical centres which normally receive congruent information. As a result, the prescription of binaural hearing aids may be a handicap rather than a help. In order to explore this possibility, 10 normal subjects were presented with simulated, dissimilar cochlear distortion at the two ears. Discrimination scores with binaural presentation were poorer than the best monaural score and there were clear indications that in the former, subjects selectively attended to one ear and neglected the other. In contrast, binaural presentation of the same simulated distortion resulted in a significant improvement, compared with the monaural discrimination score. Inability of the cortex to contend with discongruent speech input from the two ears may be a factor contributing to the rejection of binaural hearing aids in some individuals.

An analysis was carried out of the pattern of errors in those words which were incorrectly perceived by patients during the course of routine speech audiometric tests using consonant-vowel-consonant words. Responses were examined from 20 patients with conductive hearing loss, and 20 with cochlear hearing loss due to Ménière's disease. Word errors result from misinterpretations of a single consonant in 70% of the conductive group and 56% of the Ménière group. The latter make slightly more errors involving both consonants. Errors in vowels alone are rare in both groups and, even in combination, with one or other consonant, never exceed 25%. Word recognition appears to fail for the same reason in the two groups.

We recently demonstrated that nitric oxide (NO) significantly contributes to the mitogenic effect of vascular endothelial growth factor (VEGF), suggesting a role for the NO pathway in the signaling cascade following kinase-derivative receptor activation in vascular endothelium. The aim of this study was to investigate the intracellular pathways linked to VEGF/NO-induced endothelial cell proliferation. We assessed the activity of the mitogen-activated protein kinase (MAPK) that is specifically activated by growth factors, extracellular-regulated kinase (ERK1/2), on cultured microvascular endothelium isolated from coronary postcapillary venules. ERK1/2 was immunoprecipitated, and its activity was assessed with an immunocomplex kinase assay. In endothelial cells exposed for 5 min to the NO donor drug sodium nitroprusside at a concentration of 100 microM, ERK1/2 activity significantly increased. VEGF produced a time- and concentration-dependent activation of ERK1/2. Maximal activity was obtained after 5 min of stimulation at a concentration of 10 ng/ml. The specific MAPK kinase inhibitor PD 98059 abolished ERK1/2 activation and endothelial cell proliferation in a concentration-dependent manner in response to VEGF and sodium nitroprusside. The NO synthase inhibitor Nomega-monomethyl-L-arginine, as well as the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, blocked the activation of ERK1/2 induced by VEGF, suggesting that NO and cGMP contributed to the VEGF-dependent ERK1/2 activation. These results demonstrate for the first time that kinase-derivative receptor activation triggers the NO synthase/guanylate cyclase pathway to activate the MAPK cascade and substantiates the hypothesis that the activation of ERK1/2 is necessary for VEGF-induced endothelial cell proliferation.

Mechanosensitive ion channels may play a key role in transducing vascular smooth muscle (VSM) stretch into active force development. To test this hypothesis, we recorded single-channel and macroscopic currents during mechanical stimulation of enzymatically dispersed vascular smooth muscle cells. Patch pipette suction activated a nonselective cation channel that was permeable to K+, Na+, and Ca2+. Whole cell stretch was accomplished using two patch-type micropipettes attached to the cell ends with suction. Stretch elicited a sustained depolarization with a magnitude similar to that observed in pressurized arteries. Under whole cell voltage clamp, stretch activated an inward current with a reversal potential near -15 mV. In another series of experiments, whole cell stretch failed to modify the current-voltage relationship for voltage-gated calcium currents. Thus, in VSM, both single-channel and whole cell data are consistent with activation of a nonselective cation channel by stretch. This mechanism may, in part, account for pressure-induced activation of intact blood vessels.

A novel series of milbemycin antibiotics were isolated from the fermentation broth of a Streptomyces species designated E225. The structures of the four main metabolites VM 44857 (1), VM 44864 (2), VM 44865 (3) and VM 44866 (4) were determined by NMR techniques. In addition we describe the solution conformations of the major metabolite VM 44857 (1).

It is a common misconception that all disorders of balance can be attributed to derangements of the vestibular system. In fact spatial orientation is dependent upon the proper coordination of a number of sensory inputs and each of these is susceptible to damage by disease or injury. A variety of new tests is described which have as their aim the inden tinea tion of balance disorders resulting specifically from derangements of visual processing, proprioception and the neck reflexes. In addition, attention is given to the differential impairment of linear and circular vection and to the possible clinical application of vestibular evoked potentials.

Controversy has arisen over the claim that melanin content of the iris as determined by eye colouration bears a direct relationship to susceptibility to temporary threshold shifts (TTS). A more comprehensive investigation of TTS has now been carried out which not only confirms the relationship but also indicates that earlier discordant results can be attributed to differences in methodology. The new evidence suggests that for stimulus intensities below 110 dB. (HTL re ISO, 1964) melanin content of the iris exerts its influence predominantly upon auditory adaptation while fatigue effects only become apparent at intensities above this level. The relevance of these findings to hearing conservation measures aimed at the prevention of noise-induced hearing loss is discussed.

Although international agreement has long been reached on a standard threshold for air conduction audiometry, no similar standard exists for bone conduction autiometry. It is argued that the techniques applied to the determination of the air conduction thresholds are not applicable to those for bone conduction which should instead be brought into line with ISO 1964 and not established independently. A pilot study has been carried out which shows that by adopting the new approach now advocated international agreement could be attained with the expenditure of minimal time and effort.

A comparison of the speech audiograms of patients with bilateral and unilateral hearing loss due to Menière's disease has shown that when matched in respect of pure-tone hearing levels, speech discrimination at the better ear of the former is appreciably better than that at the impaired ear of the latter. In addition, while roll-over is a characteristic feature of the unilateral group it is conspicuously absent in the bilateral group. More surprisingly, in the bilateral group, despite relatively small differences in the pure-tone hearing levels at the two ears, speech discrimination at the better ear is strikingly superior to that at the poorer ear. It is concluded that patients with bilateral hearing loss selectively make use of the better ear to the neglect of the poorer ear. This could have important implications in the prescription of binaural hearing aids.

Coles and Priede have recommended that in the alternate binaural loudness balance test use of the normal ear as the reference standard be now abandoned in favour of the worse ear. Their data are critically reviewed and shown to be subject to cumulative errors of methodology and interpretation.ResumeColes et Priede [1976] ont recommande que, pour le test d'equilibrage alterne de la sonie, l'utilisation de paliers fixes d'intensite sur I'oreille normale soit abandonnee au profit de l'oreille malade. Leurs donnees sont examinees et paraissent ětre entachees a la fois d'erreurs d'interpretation et de methodologie.

20 phonetically balanced word lists comprising 25 words in each and recorded on tape by a professional announcer have been tested on 45 subjects. Analysis of the results has enabled each of the 500 words to be assigned a grade of difficulty within the range 1-35. 25 'difficult' and 25 'easy' words re-recorded from the original tapes to form two new lists have been shown to retain their same grade of difficulty. With the same lists recorded by two additional speakers, however, word order difficulty was dramatically altered. Consideration has been given to various factors likely to affect word intelligibility including phonetic construction, word familiarity and word environment. None appeared to exert any marked influence. It is concluded that the characteristics of any recorded word articulation material are determined predominantly by the speaker and the recording technique adopted and are largely independent of other factors. Given sufficient experimental data upon recorded material, words can be selected out of context and re-recorded to provide test lists with virtually any desired characteristics.

Above a critical level (CL) of fatiguing tone, temporary threshold shift (TTS) rises rapidly with intensity. Using a fatiguing tone of 1000 Hz, threshold shift following 1 min stimulation at varying intensities was measured at the same frequency in 55 normal subjects and the CL determined for each. In a second and more limited study, TTS was measured at a frequency half an octave above that of the fatiguing tone. A significant inverse correlation was established between hearing level (HL) and CL at the same frequency with a fall of 2.5 dB in the latter for every 10 dB rise in the former. CLs measured half an octave above the fatiguing tone frequency were appreciably lower by 5 to 11 dB. No correlation was apparent between TTS and HTL, implying that TTS and CL are subserved by differing physiological mechanisms. The findings have relevance to the topic of susceptibility to noise-induced hearing loss and the formulation of damage risk criteria.

In the course of previous investigations, Dix, Hallpike, and Hood have concluded that the phenomenon of loudness recruitment is attributable to disordered function resulting from injury or disease of the hair cells of Corti's organ.In the present paper, an account is given of an experimental study of certain loudness changes caused by adaptation of the hair cell responses to pure tone stimulation.Two outstanding characteristics of the adapted state are defined: “on‐effect normality” and “relapse.” Both resemble very closely those described by Matthews in the case of adaptation occurring the muscle stretch receptors of the frog.Further studies in a number of human subjects show that both of these characteristics are exhibited regularly by the unadapted hair cell responses of individuals suffering from degenerative changes of the hair cells.These studies appear to establish a very close similarity between “on‐effect normality” occurring in the case of the adapted normal sense organ and the phenomenon of lou...

(1968). Speech Discrimination & Its Relationship to Disorders of the Loudness Function. International Audiology: Vol. 7, No. 3, pp. 232-238.

The results of Free-field speech audiometry, carried out upon 30 subjects with conductive deafness and 43 subjects with ‘cochlear’ deafness have been analysed with reference to their average ‘hearing levels’ for the frequencies 500, 1000 and 2000Hz, to give approximately 10dB differences in the ‘group average hearing levels’.The speech audiograms of the conductive group follow the same course as the normal curve and all attain 100% recognition. In the ‘cochlear’ group with deafness in excess of 31dB it has been possible to demonstrate a systematic deterioration of speech discrimination with hearing levels. The resultant correlation has practical application in (a) scales of compensation for occupational hearing loss, (b) the correction of cochlear hearing loss by means of hearing aids and (c) the use of speech audiometry in the differential diagnosis of cochlear and retrocochlear hearing loss.

Studies carried out upon subjects with normal hearing have shown that (a) the mean sound‐pressure level at which a tone of 1000 Hz is judged to be unpleasantly loud is 100 dB and (b) following sustained stimulation with intensities above 100 dB, there occurs a dramatic increase in the resultant temporary threshold shift. The intensity at which both these events occur is independent of sensation level. It follows that variations in normal threshold of the order of ±10 dB are largely sensorineural in orgin. In addition, the fact that both these unrelated events occur at the same sound‐pressure level suggests that it marks a physiological limit of loudness perception. The results lead to the conclusion that the loudness function shows considerable intersubject variability and is dependent upon hearing acuity. Their application to loudness computations and to hearing conservation is discussed.

In the normal‐hearing subject, a sensation of unpleasant loudness is invariably associated with intensities of the order of 100 dB within the frequency range 500–4000 cps. This is referred to as the loudness‐discomfort level (LDL). The intensity distribution of LDL has been established in a large group of subjects with unilateral end‐organ deafness, in all of whom the presence of loudness recruitment had been verified by means of the alternate binaural loudness balancing procedure. In these, the distribution was similar to that of a normal‐hearing group. By contrast, the LDL's of subjects with conductive or nerve‐fibre deafness exceeded the maximum available audiometer intensity of 120 db. The test, therefore, is of particular value in establishing the presence or absence of loudness recruitment in bilateral deafness. These findings suggest a physiological limit of loudness perception, the theoretical implications of which are discussed.

The very great advances in our knowledge of bone conduction that have been made by Bekesy's fundamental investigations are outlined and considered in relationship to the influence they have brought to bear upon the investigations of later workers in this field. The topics considered include the mode of vibration of the skull, the theoretical mechanisms of bone conduction, the so‐called occlusion effect, bone conduction in a free sound field, and the interaural attenuation across the head.

1. The loudness recruitment angle is defined. It is found to provide a useful quantitative index of the recruitment phenomenon.2. The results are described of a study of the angle based upon 200 cases of unilateral deafness due to Meniere's disease. The magnitude of the angle is found to vary linearly and within close limits, with the amount of the deafness.3. The recruitment angle shows some dependence upon the frequency characteristic of the deafness, being greater with low than with high frequency types of hearing loss.4. The results of a comparative study of two small selected groups of subjects, with and without severe symptoms, suggest that the recruitment angle tends to be increased during the active phases of the disease.5. The results are discussed in the light of recent work on the electromechanical behaviour of the cochlea, and an explanation is suggested of the neurological mechanism of the loudness recruitment phenomenon based upon the dual excitation theory of Hallowell Davis.

Modern audiological diagnosis is based for the most part upon the recognition of certain characteristic patterns of response which have been found to result from the application of various test procedures. The SISI test, the types l-IV Bekesy audiograms and the various tests of loudness recruitment are cases in point. Nevertheless the fundamental principles underlying these tests are ill understood. These can be simply expressed in terms analogous to well known physiological phenomena. Thus the terms auditory fatigue and auditory adaptation which are frequently used synonymously can be shown to be entirely physiologically distinct and separate responses of the receptor which in turn have their auditory subjective counterparts. Likewise it can be shown that the on-effect of the end organ response plays a dominant role in the phenomenon of loudness recruitment.Recognition of these basic physiological features is important not only for the proper interpretation of existing audiological test procedures but al...

Schuknecht and his co-workers have shown that partial lesions of the cochlear nerve in cats may be associated with normal hearing at threshold for pure tones. Comparable findings are described in two human subjects.