Protocol for the playback of phantom echoes from approaching objects to scanning bats.

Because bats emit ultrasound and listen to echoes to perceive their surroundings, presenting phantom echoes is useful for understanding their perception of echolocation. Here, we present a protocol for the real-time playback of phantom echoes, especially from approaching objects. We describe steps for presenting virtual objects using a microphone, digital signal processor, and loudspeaker to induce the escape behavior of bats.

Safety evaluations for transtympanic laser stimulation of the cochlea in Mongolian gerbils (Meriones unguiculatus).

Infrared laser stimulation of the cochlea has been proposed as a possible alternative to conventional auditory prostheses. Whereas previous studies have focused primarily on the short-term effects of laser stimulation, the practical application of this technics requires an investigation into whether prolonged laser exposure can induce neural responses and safely. This study assessed the effect of laser-induced damage to the cochlea on auditory perception using Mongolian gerbils (Meriones unguiculatus) trained with a classical conditioning task.

Doppler detection triggers instantaneous escape behavior in scanning bats.

Animals must instantaneously escape from predators for survival, which requires quick detection of approaching threats. Although the neural mechanisms underlying the perception of looming objects have been extensively studied in the visual system, little is known about their auditory counterparts. Echolocating bats use their auditory senses to perceive not only the soundscape, but also the physical environment through active sensing.

Discrimination of object information by bat echolocation deciphered from acoustic simulations.

High-precision visual sensing has been achieved by combining cameras with deep learning. However, an unresolved challenge involves identifying information that remains elusive for optical sensors, such as occlusion spots hidden behind objects. Compared to light, sound waves have longer wavelengths and can, therefore, collect information on occlusion spots.

The distress context of social calls evokes a fear response in the bat Pipistrellus abramus.

Bats primarily use sound information, including echolocation, for social communication. Bats under stressful conditions, for example when confronted by a predator, will emit aggressive social calls. The presentation of aggressive social calls, including distress calls (DCs), is known to increase heart rate (fH), but how this change in fH is related to the bat's sound perception and how this evokes behaviors such as the fear response is unknown.

Subjective Audibility Modulates the Susceptibility to Sound-Induced Flash Illusion: Effect of Loudness and Auditory Masking.

When a brief flash is presented along with two brief sounds, the single flash is often perceived as two flashes. This phenomenon is called a sound-induced flash illusion, in which the auditory sense, with its relatively higher reliability in providing temporal information, modifies the visual perception. Decline of audibility due to hearing impairment is known to make subjects less susceptible to the flash illusion.

Feasibility evaluation of transtympanic laser stimulation of the cochlea from the outer ear.

Infrared laser stimulation has been studied as an alternative approach to auditory prostheses. This study evaluated the feasibility of infrared laser stimulation of the cochlea from the outer ear, bypassing the middle ear function. An optic fiber was inserted into the ear canal, and a laser was used to irradiate the cochlea through the tympanic membrane in Mongolian gerbils.

Vocalization during agonistic encounter in Mongolian gerbils: Impact of sexual experience.

Behaviors and vocalizations associated with aggression are essential for animals to survive, reproduce, and organize social hierarchy. Mongolian gerbils (Meriones unguiculatus) are highly aggressive and frequently emit calls. We took advantage of these features to study the relationship between vocalizations and aggressive behaviors in virgin and sexually experienced male and female Mongolian gerbils through the same-sex resident-intruder test.

Echo reception in group flight by Japanese horseshoe bats, .

The ability to detect behaviourally relevant sensory information is crucial for survival. Especially when active-sensing animals behave in proximity, mutual interferences may occur. The aim of this study was to examine how active-sensing animals deal with mutual interferences.

Music in Noise: Neural Correlates Underlying Noise Tolerance in Music-Induced Emotion.

Music can be experienced in various acoustic qualities. In this study, we investigated how the acoustic quality of the music can influence strong emotional experiences, such as musical chills, and the neural activity. The music's acoustic quality was controlled by adding noise to musical pieces.

Two-dimensional shape discrimination by sighted people using simulated virtual echoes.

In this study, a new research method using psychoacoustic experiments and acoustic simulations is proposed for human echolocation research. A shape discrimination experiment was conducted for sighted people using pitch-converted virtual echoes from targets of dissimilar two-dimensional (2D) shapes. These echoes were simulated using a three-dimensional acoustic simulation based on a finite-difference time-domain method from Bossy, Talmat, and Laugier [(2004).

Auditory cortical activity elicited by infrared laser irradiation from the outer ear in Mongolian gerbils.

Infrared neural stimulation has been studied for its potential to replace an electrical stimulation of a cochlear implant. No studies, however, revealed how the technic reliably evoke auditory cortical activities. This research investigated the effects of cochlear laser stimulation from the outer ear on auditory cortex using brain imaging of activity-dependent changes in mitochondrial flavoprotein fluorescence signal.

USVSEG: A robust method for segmentation of ultrasonic vocalizations in rodents.

Rodents' ultrasonic vocalizations (USVs) provide useful information for assessing their social behaviors. Despite previous efforts in classifying subcategories of time-frequency patterns of USV syllables to study their functional relevance, methods for detecting vocal elements from continuously recorded data have remained sub-optimal. Here, we propose a novel procedure for detecting USV segments in continuous sound data containing background noise recorded during the observation of social behavior.

Auditory-induced visual illusions in rodents measured by spontaneous behavioural response.

When two brief sounds are presented with a short flash of light, we often perceive that the flash blinks twice. This phenomenon, called the "sound-induced flash illusion", has been investigated as an example of how humans finely integrate multisensory information, more specifically, the temporal content of perception. However, it is unclear whether nonhuman animals experience the illusion.

Three forebrain structures directly inform the auditory midbrain of echolocating bats.

Echolocating bats emit various types of vocalizations for navigation and communication, and need to pay attention to vocal sounds. Projections from forebrain centers to auditory centers are involved in the attention to vocalizations, with the inferior colliculus (IC) being the main target of the projections. Here, using a retrograde tracer, we demonstrate that three forebrain structures, namely, the medial prefrontal cortex (mPFC), amygdala, and auditory cortex (AC), send direct descending projections to the central nucleus of IC.

Brain Activity Related to Sound Symbolism: Cross-modal Effect of an Aurally Presented Phoneme on Judgment of Size.

Sound symbolism is the idea that a sound makes a certain impression (e.g., phoneme "p" is associated with an impression of smallness) and could be the psychological basis of the word-meaning association.

Bat-inspired signal design for target discrimination in human echolocation.

Echolocating bats exhibit sophisticated sonar behaviors using ultrasounds with actively adjusted acoustic characteristics (e.g., frequency and time-frequency structure) depending on the situation.

Hearing sensitivity evaluated by the auditory brainstem response in .

This study evaluated the hearing sensitivity of , a frequency-modulating (FM) bat species, by measuring the auditory brainstem responses in the inferior colliculus. The average audiogram was U-shaped. The mean threshold decreased gradually as the frequency increased from 16 to 40 kHz and then decreased rapidly as the frequency reached 46 kHz, with the peak sensitivity occurring at the terminal portion of the echolocation pulse between frequencies of 44 and 56 kHz.

Adaptive frequency shifts of echolocation sounds in according to the frequency-modulated pattern of jamming sounds.

When flying in a group, echolocating bats have to separate their own echoes from pulses and echoes belonging to other individuals to extract only the information necessary for their own navigation. Previous studies have demonstrated that frequency-modulated (FM) bats change the terminal frequencies (TFs) of downward FM pulses under acoustic interference. However, it is not yet clear which acoustic characteristics of the jamming signals induce the TF shift according to the degree of acoustic interference.

Bats enhance their call identities to solve the cocktail party problem.

Echolocating bats need to solve the problem of signal jamming by conspecifics when they are in a group. However, while several mechanisms have been suggested, it remains unclear how bats avoid confusion between their own echoes and interfering sounds in a complex acoustic environment. Here, we fixed on-board microphones onto individual frequency-modulating bats flying in groups.

Organization of subcortical auditory nuclei of Japanese house bat (Pipistrellus abramus) identified with cytoarchitecture and molecular expression.

The auditory system of echolocating bats shows remarkable specialization likely related to analyzing echoes of sonar pulses. However, significant interspecies differences have been observed in the organization of auditory pathways among echolocating bats, and the homology of auditory nuclei with those of non-echolocating species has not been established. Here, in order to establish the homology and specialization of auditory pathways in echolocating bats, the expression of markers for glutamatergic, GABAergic, and glycinergic phenotypes in the subcortical auditory nuclei of Japanese house bat (Pipistrellus abramus) was evaluated.

Organization of projection from brainstem auditory nuclei to the inferior colliculus of Japanese house bat (Pipistrellus abramus).

Objectives: Echolocating bats show remarkable specialization which is related to analysis of echoes of biosonars in subcortical auditory brainstem pathways. The inferior colliculus (IC) receives inputs from all lower brainstem auditory nuclei, i.e.

Acoustic characteristics used by Japanese macaques for individual discrimination.

The vocalizations of primates contain information about speaker individuality. Many primates, including humans, are able to distinguish conspecifics based solely on vocalizations. The purpose of this study was to investigate the acoustic characteristics used by Japanese macaques in individual vocal discrimination.

Role of vocal tract characteristics in individual discrimination by Japanese macaques (Macaca fuscata).

The Japanese macaque (Macaca fuscata) exhibits a species-specific communication sound called the "coo call" to locate group members and maintain within-group contact. Monkeys have been demonstrated to be capable of discriminating between individuals based only on their voices, but there is still debate regarding how the fundamental frequencies (F0) and filter properties of the vocal tract characteristics (VTC) contribute to individual discrimination in nonhuman primates. This study was performed to investigate the acoustic keys used by Japanese macaques in individual discrimination.