How Do Apps Work? An Analysis of Physical Activity App Users' Perceptions of Behavior Change Mechanisms.

Background: Physical activity apps are commonly used to increase levels of activity and health status. To date, the focus of research has been to determine the potential of apps to influence behavior, to ascertain the efficacy of a limited number of apps to change behavior, and to identify the characteristics of apps that users prefer.

Objective: The purpose of this study was to identify the mechanisms by which the use of physical activity apps may influence the users' physical activity behavior.

Seasonal variations in auditory processing in the inferior colliculus of Eptesicus fuscus.

Eptesicus fuscus is typical of temperate zone bats in that both sexes undergo marked seasonal changes in behavior, endocrine status, and reproductive status. Acoustic communication plays a key role in many seasonal behaviors. For example, males emit specialized vocalizations during mating in the fall, and females use different specialized vocalizations to communicate with infants in late spring.

Hepatic Lipidosis in a Research Colony of Big Brown Bats (Eptesicus fuscus).

During a nearby construction project, a sudden decrease in food intake and guano production occurred in an outdoor colony of big brown bats (Eptesicus fuscus), and one animal was found dead. Investigation revealed that the project was generating a large amount of noise and vibration, which disturbed the bats' feeding. Consequently the bats were moved into an indoor enclosure away from the construction noises, and the colony resumed eating.

Decoding stimulus duration from neural responses in the auditory midbrain.

Neurons with responses selective for the duration of an auditory stimulus are called duration-tuned neurons (DTNs). Temporal specificity in their spiking suggests that one function of DTNs is to encode stimulus duration; however, the efficacy of duration encoding by DTNs has yet to be investigated. Herein, we characterize the information content of individual cells and a population of DTNs from the mammalian inferior colliculus (IC) by measuring the stimulus-specific information (SSI) and estimated Fisher information (FI) of spike count responses.

Organization and trade-off of spectro-temporal tuning properties of duration-tuned neurons in the mammalian inferior colliculus.

Neurons throughout the mammalian central auditory pathway respond selectively to stimulus frequency and amplitude, and some are also selective for stimulus duration. First found in the auditory midbrain or inferior colliculus (IC), these duration-tuned neurons (DTNs) provide a potential neural mechanism for encoding temporal features of sound. In this study, we investigated how having an additional neural response filter, one selective to the duration of an auditory stimulus, influences frequency tuning and neural organization by recording single-unit responses and measuring the dorsal-ventral position and spectral-temporal tuning properties of auditory DTNs from the IC of the awake big brown bat (Eptesicus fuscus).

Monaural and binaural inhibition underlying duration-tuned neurons in the inferior colliculus.

Duration-tuned neurons (DTNs) in the mammalian inferior colliculus (IC) arise from a combination of excitatory and inhibitory synaptic inputs. Previous research has shown that the inhibition responsible for creating DTNs has a shorter latency than that of excitation and lasts longer than the stimulus duration. We used monotic and dichotic paired tone stimulation and recorded responses of DTNs from the IC of the bat to assess the relative contributions of each ear in forming duration-tuned circuits.

Stimulus-specific adaptation in specialized neurons in the inferior colliculus of the big brown bat, Eptesicus fuscus.

The inferior colliculus (IC) of the big brown bat (Eptesicus fuscus) contains specialized neurons that respond exclusively to highly specific spectrotemporal patterns such as sinusoidally frequency modulated (SFM) signals or directional frequency modulated sweeps (FM). Other specialized cells with I-shaped frequency response areas (FRAs) are tuned to very narrow frequency bands (1-2 kHz) in an amplitude-tolerant manner. In contrast, non-specialized neurons respond to any stimulus with energy in their frequency response area.

GABA(A)-mediated inhibition modulates stimulus-specific adaptation in the inferior colliculus.

The ability to detect novel sounds in a complex acoustic context is crucial for survival. Neurons from midbrain through cortical levels adapt to repetitive stimuli, while maintaining responsiveness to rare stimuli, a phenomenon called stimulus-specific adaptation (SSA). The site of origin and mechanism of SSA are currently unknown.

Development of echolocation and communication vocalizations in the big brown bat, Eptesicus fuscus.

Big brown bats form large maternity colonies of up to 200 mothers and their pups. If pups are separated from their mothers, they can locate each other using vocalizations. The goal of this study was to systematically characterize the development of echolocation and communication calls from birth through adulthood to determine whether they develop from a common precursor at the same or different rates, or whether both types are present initially.

Social transmission of fear in rats: the role of 22-kHz ultrasonic distress vocalization.

Background: Social alarm calls alert animals to potential danger and thereby promote group survival. Adult laboratory rats in distress emit 22-kHz ultrasonic vocalization (USV) calls, but the question of whether these USV calls directly elicit defensive behavior in conspecifics is unresolved.

Methodology/principal Findings: The present study investigated, in pair-housed male rats, whether and how the conditioned fear-induced 22-kHz USVs emitted by the 'sender' animal affect the behavior of its partner, the 'receiver' animal, when both are placed together in a novel chamber.

Comparison of auditory responses in the medial geniculate and pontine gray of the big brown bat, Eptesicus fuscus.

The inferior colliculus has been well studied for its role of transmitting information from the brainstem to the thalamocortical system. However, it is also the source of a major pathway to the cerebellum, via the pontine gray (PG). We compared auditory responses from single neurons in the medial geniculate body (MGB) and PG of the awake big brown bat.

Stimulus-specific adaptation in the auditory thalamus of the anesthetized rat.

The specific adaptation of neuronal responses to a repeated stimulus (Stimulus-specific adaptation, SSA), which does not fully generalize to other stimuli, provides a mechanism for emphasizing rare and potentially interesting sensory events. Previous studies have demonstrated that neurons in the auditory cortex and inferior colliculus show SSA. However, the contribution of the medial geniculate body (MGB) and its main subdivisions to SSA and detection of rare sounds remains poorly characterized.

Stimulus-specific adaptation in the inferior colliculus of the anesthetized rat.

To identify sounds as novel, there must be some neural representation of commonly occurring sounds. Stimulus-specific adaptation (SSA) is a reduction in neural response to a repeated sound. Previous studies using an oddball stimulus paradigm have shown that SSA occurs at the cortex, but this study demonstrates that neurons in the inferior colliculus (IC) also show strong SSA using this paradigm.

Functional role of GABAergic and glycinergic inhibition in the intermediate nucleus of the lateral lemniscus of the big brown bat.

The intermediate nucleus of the lateral lemniscus (INLL) is a major input to the inferior colliculus (IC), the auditory midbrain center where multiple pathways converge to create neurons selective for specific temporal features of sound. However, little is known about how INLL processes auditory information or how it contributes to integrative processes at the IC. INLL receives excitatory projections from the cochlear nucleus and inhibitory projections from the medial nucleus of the trapezoid body (MNTB), so it must perform some form of integration.

A discontinuous tonotopic organization in the inferior colliculus of the rat.

Audible frequencies of sound are encoded in a continuous manner along the length of the cochlea, and frequency is transmitted to the brain as a representation of place on the basilar membrane. The resulting tonotopic map has been assumed to be a continuous smooth progression from low to high frequency throughout the central auditory system. Here, physiological and anatomical data show that best frequency is represented in a discontinuous manner in the inferior colliculus, the major auditory structure of the midbrain.

[Detection of novel sounds. Multiple manifestations of the same phenomenon?].

Introduction: Detection of novel sounds must be a basic function of the auditory system, but the underlying neuronal mechanisms are largely unknown.

Development: During repetitive stimulation or a monotonous auditory scene, many auditory neurons show a decrease in their response, presumably due to adaptation. However, these neurons are able to recover and respond again any time there is a change in the stimuli.

Response properties and location of neurons selective for sinusoidal frequency modulations in the inferior colliculus of the big brown bat.

Most animal vocalizations, including echolocation signals used by bats, contain frequency-modulated (FM) components. Previous studies have described a class of neurons in the inferior colliculus (IC) of the big brown bat that respond exclusively to sinusoidally frequency modulated (SFM) signals and fail to respond to pure tones, noise, amplitude-modulated tones, or single FM sweeps. The aims of this study were to further characterize these neurons' response properties and to determine whether they are localized within a specific area of the IC.

Relation between intrinsic connections and isofrequency contours in the inferior colliculus of the big brown bat, Eptesicus fuscus.

Information processing in the inferior colliculus depends on interactions between ascending pathways and intrinsic circuitry, both of which exist within a functional tonotopic organization. To determine how local projections of neurons in the inferior colliculus are related to tonotopy, we placed a small iontophoretic injection of biodextran amine at a physiologically characterized location in the inferior colliculus. We then used electrophysiological recording to place a grid of small deposits of Chicago Sky Blue throughout the same frequency range to specify an isofrequency contour.

Novelty detector neurons in the mammalian auditory midbrain.

Novel stimuli in all sensory modalities are highly effective in attracting and focusing attention. Stimulus-specific adaptation (SSA) and brain activity evoked by novel stimuli have been studied using population measures such as imaging and event-related potentials, but there have been few studies at the single-neuron level. In this study we compare SSA across different populations of neurons in the inferior colliculus (IC) of the rat and show that a subclass of neurons with rapid and pronounced SSA respond selectively to novel sounds.

Neurobiological specializations in echolocating bats.

Although the bat's nervous system follows the general mammalian plan in both its structure and function, it has undergone a number of modifications associated with flight and echolocation. The most obvious neuroanatomical specializations are seen in the cochleas of certain species of bats and in the lower brainstem auditory pathways of all microchiroptera. This article is a review of peripheral and central auditory neuroanatomical specializations in echolocating bats.

Duration selective neurons in the inferior colliculus of the rat: topographic distribution and relation of duration sensitivity to other response properties.

Many animals use duration to help them identify the source and meaning of a sound. Duration-sensitive neurons have been found in the auditory midbrain of mammals and amphibians, where their selectivity seems to correspond to the lengths of species-specific vocalizations. In this study, single neurons in the rat inferior colliculus (IC) were tested for sensitivity to sound duration.

Duration selectivity of neurons in the inferior colliculus of the big brown bat: tolerance to changes in sound level.

At and above the level of the inferior colliculus (IC), some neurons respond maximally to a limited range of sound durations, with little or no excitatory response to durations outside of this range. Such neurons have been termed "duration tuned" or "duration selective." In this study we examined the effects of varying signal amplitude on best duration, width of tuning, and first spike latency of duration tuned neurons in the IC of the big brown bat, Eptesicus fuscus.

Expression of the Kv1.1 ion channel subunit in the auditory brainstem of the big brown bat, Eptesicus fuscus.

Voltage-gated potassium channels play an important role in shaping membrane properties that underlie neurons' discharge patterns and the ways in which they transform their input. In the auditory system, low threshold potassium currents such as those created by Kv1.1 subunits contribute to precise phaselocking and to transient onset responses that provide time markers for temporal features of sounds.

Temporal masking reveals properties of sound-evoked inhibition in duration-tuned neurons of the inferior colliculus.

The inferior colliculus (IC) is the first place in the central auditory pathway where duration-selective neurons are found. Previous neuropharmacological and electrophysiological studies have shown that they are created there and have led to a conceptual model in which excitatory and inhibitory inputs are offset in time so that the cell fires only when sound duration is such that onset- and offset-evoked excitation coincide; the response is suppressed by inhibition at other durations. We tested predictions from the model using paired tone stimulation and extracellular recording in the IC of the big brown bat, Eptesicus fuscus.

Medial superior olive of the big brown bat: neuronal responses to pure tones, amplitude modulations, and pulse trains.

The structure and function of the medial superior olive (MSO) is highly variable among mammals. In species with large heads and low-frequency hearing, MSO is adapted for processing interaural time differences. In some species with small heads and high-frequency hearing, the MSO is greatly reduced in size; in others, including those echolocating bats that have been examined, the MSO is large.