Effects of guided exploration on reaching measures of auditory peripersonal space.

Despite the recognized importance of bodily movements in spatial audition, few studies have integrated action-based protocols with spatial hearing in the peripersonal space. Recent work shows that tactile feedback and active exploration allow participants to improve performance in auditory distance perception tasks. However, the role of the different aspects involved in the learning phase, such as voluntary control of movement, proprioceptive cues, and the possibility of self-correcting errors, is still unclear. We study the effect of guided reaching exploration on perceptual learning of auditory distance in peripersonal space. We implemented a pretest-posttest experimental design in which blindfolded participants must reach for a sound source located in this region. They were divided into three groups that were differentiated by the intermediate training phase: Guided, an experimenter guides the participant's arm to contact the sound source; Active, the participant freely explores the space until contacting the source; and Control, without tactile feedback. The effects of exploration feedback on auditory distance perception in the peripersonal space are heterogeneous. Both the Guided and Active groups change their performance. However, participants in the Guided group tended to overestimate distances more than those in the Active group. The response error of the Guided group corresponds to a generalized calibration criterion over the entire range of reachable distances. Whereas the Active group made different adjustments for proximal and distal positions. The results suggest that guided exploration can induce changes on the boundary of the auditory reachable space. We postulate that aspects of agency such as initiation, control, and monitoring of movement, assume different degrees of involvement in both guided and active tasks, reinforcing a non-binary approach to the question of activity-passivity in perceptual learning and supporting a complex view of the phenomena involved in action-based learning.

Recurrence analysis of sensorimotor trajectories in a minimalist perceptual task using sonification.

Active Perception perspectives claim that action is closely related to perception. An empirical approach that supports these theories is the minimalist, in which participants perform a task using an interface that provides minimal information. Their exploratory movements are crucial to generating a meaningful sequence of information. Previous studies analyzed sensorimotor trajectories describing qualitative strategies and linear quantification of participants' movement performance, but that approach struggles to capture the behavior of non-stationary data. In the present study, we applied the recurrence plot (RP) and recurrence quantification analysis (RQA) to study the structure of sensorimotor trajectories developed by participants trying to discriminate between two invisible geometric shapes (Triangle or Rectangle). The exploratory movements were made using a computer mouse and sonification-mediated feedback was provided, which depended exclusively on whether the pointer was inside or outside the shape. We applied RP and RQA to the sensorimotor trajectories, with the aim of studying their fine structure characteristics, focusing on their repetitive patterns. Recurrence analysis proved to be useful for quantifying differences in dynamic behavior that emerge when participants explore invisible virtual geometric shapes. The differences obtained in RQA-based measures associated with the vertical structures allowed to postulate the existence of particular exploration strategies for each figure. It was also possible to determine that the complexity of the dynamics changed according to the shape. We discuss these results in light of antecedents in haptic and visual perceptual exploration.

Rediscovering Richard Held: Activity and Passivity in Perceptual Learning.

Understanding the role of self-generated movements in perceptual learning is central to action-based theories of perception. Pioneering work on sensory adaptation by Richard M. Held during the 1950s and 1960s can still shed light on this question. In a variety of rich experiments Held and his team demonstrated the need for self-generated movements in sensory adaptation and perceptual learning. This body of work received different critical interpretations, was then forgotten for some time, and saw a surge of revived interest within embodied cognitive science. Through a brief review of Held's work and reactions to it, we seek to contribute to discussions on the role of activity and passivity in perceptual learning. We classify different positions according to whether this role is considered to be contextual (facilitatory, but not necessary), enabling (causally necessary), or constitutive (an inextricable part of the learning process itself). We also offer a critique of the notions of activity and passivity and how they are operationalized in experimental studies. The active-passive distinction is not a binary but involves a series of dimensions and relative degrees that can make it difficult to interpret and replicate experimental results. We introduce three of these dimensions drawing on work on the sense of agency: action initiation, control, and monitoring. These refinements in terms of causal relations and dimensions of activity-passivity should help illuminate open questions concerning the role of activity in perception and perceptual learning and clarify the convergences and differences between enaction and ecological psychology.

Reaching measures and feedback effects in auditory peripersonal space.

We analyse the effects of exploration feedback on reaching measures of perceived auditory peripersonal space (APS) boundary and the auditory distance perception (ADP) of sound sources located within it. We conducted an experiment in which the participants had to estimate if a sound source was (or not) reachable and to estimate its distance (40 to 150 cm in 5-cm steps) by reaching to a small loudspeaker. The stimulus consisted of a train of three bursts of Gaussian broadband noise. Participants were randomly assigned to two groups: Experimental (EG) and Control (CG). There were three phases in the following order: Pretest-Test-Posttest. For all phases, the listeners performed the same task except for the EG-Test phase where the participants reach in order to touch the sound source. We applied models to characterise the participants' responses and provide evidence that feedback significantly reduces the response bias of both the perceived boundary of the APS and the ADP of sound sources located within reach. In the CG, the repetition of the task did not affect APS and ADP accuracy, but it improved the performance consistency: the reachable uncertainty zone in APS was reduced and there was a tendency to decrease variability in ADP.

Tinnitus, Medial Olivocochlear System, and Music Exposure in Adolescents.

INTRODUCTION: The most common cause of tinnitus is the exposure to noise; in the case of adolescents, music is the main sound source they are exposed to. Currently, one of the hypotheses about the genesis of tinnitus is related to the deterioration in the functioning of the medial olivocochlear system (MOCS). AIM: The aim of this study was to determine the presence or absence of tinnitus in adolescents with normal hearing and to relate it to: (a) the functioning of the MOCS, by the contralateral suppression of the transient evoked otoacoustic emissions (TEOAEs) and (b) the musical general exposure (MGE). MATERIALS AND METHODS: A cross-sectional descriptive correlational study was conducted. The sample was composed by adolescents with ages between 14 and 15. Two questionnaires were administered, one in relation to the subjective report of tinnitus and the other in relation to recreational activities to know the MGE. RESULTS: The results showed that the amplitude of frequencies (1000, 1500, 2000, and 3000 Hz) and global amplitude of TEOAEs, with and without acoustic contralateral stimulation, were higher in the group without tinnitus, with a statistically significant difference (P < 0.05). The suppressive effect was higher in the group without tinnitus; however, there was no statistically significant difference. Contrastingly, a significant association (P < 0.05) between exposure to music and tinnitus was observed; 72.41% of the adolescents with high exposure to music had tinnitus. DISCUSSION AND CONCLUSION: The results of the present investigation provide a contribution to the hypothesis of "the participation of the MOCS." Furthermore, a high MGE can be considered a risk factor for the onset of tinnitus.

Conductas de riesgo auditivo y acción del mecanismo de protección coclear en adolescentes / Auditory risk behaviors and the action of cochlear protection mechanism in adolescent

La exposición a ruido no ocupacional y a la música a alto nivel sonoro, constituye un creciente factor de riesgo de pérdida auditiva en adolescentes. Estudios internacionales postulan que una función importante del Sistema Eferente Medial (SEM) es proteger el oído interno frente al ruido mediante un mecanismo reflejo y que puede ser evaluado a través de la Supresión Contralateral (SC) de las otoemisiones acústicas transitorias (TEOAEs). El mecanismo subyacente de este fenómeno no se conoce en su totalidad y los antecedentes sobre el tema son escasos. En esta investigación se analizó la relación entre la Exposición General a Música (EGM), el estado de la función auditiva y el mecanismo de protección coclear. Participaron 91 adolescentes con edades entre 14 y 15 años. Se evaluaron dos dimensiones (a) Psicosocial: se examinó la EGM con un cuestionario de actividades extraescolares y (b) auditiva o sea el funcionamiento del SEM mediante SC de las TEOAEs y los perfiles audiométricos con audiometrías. Los resultados mostraron que la SC no influyó estadísticamente en los perfiles audiométricos y categorías de exposición. Sin embargo, los resultados de la SC se orientan hacia la menor magnitud de efecto supresor, disminución en la respuesta total en relación al descenso de los umbrales auditivos y en relación con las categorías alta y baja de EGM. Es necesario promover trabajos destinados al comportamiento de riesgo auditivo conjuntamente con el mecanismo protector del SEM. De esta manera se podrá contribuir en la identificación temprana de la sensibilidad auditiva en adolescentes expuestos a ruido no ocupacional.

Non-occupational exposure to noise, such as loud music sound level is an increasing risk factor for hearing loss in adolescents. International studies propose that an important function of the medial efferent system (MES) is protect the inner ear against noise by a reflex mechanism and can be evaluated through Contralateral Suppression (CS) of transient otoacoustic emissions (TEOAEs) to analyzing the presence or absence of suppressive effect. The absence of suppressive effect is considered a possible alteration of the MES and the role it exerts on the regulation of the outer hair cells. The underlying mechanism of this phenomenon is not known totality and the background about this topic are limited. However, researches suggests that MES would have an important role in protection against acoustic overstimulation under the hypothesis that a hearing with the presence of suppressive effect would tend to be more protected against exposure to high noise levels while ears with no effect suppressor may be more vulnerable to noise exposure. In this research the relationship between the General Exposure to Music (MGE), the state of hearing function and cochlear protection mechanism were analyzed in 91 adolescents with 14/15 years old, with male predominance, of two technical schools of the city of Córdoba (Argentina). Were evaluated the following dimensions: (a) Psychosocial: MGE through an Out of School Activities Questionnaire to know in detail the participation in five recreational activities to finally analyze the MGE and (b) Audiological: assessment of audiometric profiles, as a subjective method, by audiometry in the conventional frequency ranges (250-8000) Hz and an extended high frequency audiometry (8000-16000) Hz; function of MES assessment, objective method, through CS of TEOAEs to determine the presence or absence of suppressive effect. The study CS of TEOAEs consisted of two steps: Step 1, application of TEOAEs of an ear in form ipsilateral without acoustic stimulation in the contralateral ear (CAS) and Step 2, application of TEOAEs in the ear ipsilateral while applying CAS. Was considered presence of suppressive effect when there was a reduction in the response after the CAS that is to say when the difference of values obtained in the total response with and without CAS was positive. At the same time, was considered absence of suppressive effect in cases of maintained or increased the response after the CAS, obtaining a value of zero or negative. The results of the research showed that in the group with presence of suppressive effect the most of ears is among moderate and high categories of MGE with a lower average magnitude of suppressive effect and a decreased amplitude of the total response in the high category of MGE than the media category. Regarding audiometry the ears with presence of suppressive effect showed higher magnitude in the group of normal hearing thresholds compared with the group of descended hearing thresholds. The results related to CS of the TEOAEs statistically did not influence in the audiometric profiles and the exposure categories. However the results of the CS were oriented towards the smaller magnitude of suppressive effect, decreased total response related with the descended hearing thresholds and high and low categories of MGE. It is necessary to promote and intensify researches in relation to the auditory risk behaviors together with the protection mechanism of MES. In this way, more researches can contribute to the early identification of hearing sensitivity in adolescents exposed to non-occupational noise. It is important to implement a Psycho-Auditory Screening to collaborate in the prevention and promotion of hearing health.

Sensorimotor strategies for recognizing geometrical shapes: a comparative study with different sensory substitution devices.

The sensorimotor approach proposes that perception is constituted by the mastery of lawful sensorimotor regularities or sensorimotor contingencies (SMCs), which depend on specific bodily characteristics and on actions possibilities that the environment enables and constrains. Sensory substitution devices (SSDs) provide the user information about the world typically corresponding to one sensory modality through the stimulation of another modality. We investigate how perception emerges in novice adult participants equipped with vision-to-auditory SSDs while solving a simple geometrical shape recognition task. In particular, we examine the distinction between apparatus-related SMCs (those originating mostly in properties of the perceptual system) and object-related SMCs (those mostly connected with the perceptual task). We study the sensorimotor strategies employed by participants in three experiments with three different SSDs: a minimalist head-mounted SSD, a traditional, also head-mounted SSD (the vOICe) and an enhanced, hand-held echolocation device. Motor activity and fist-person data are registered and analyzed. Results show that participants are able to quickly learn the necessary skills to distinguish geometric shapes. Comparing the sensorimotor strategies utilized with each SSD we identify differential features of the sensorimotor patterns attributable mostly to the device, which account for the emergence of apparatus-based SMCs. These relate to differences in sweeping strategies between SSDs. We identify, also, components related to the emergence of object-related SMCs. These relate mostly to exploratory movements around the border of a shape. The study provides empirical support for SMC theory and discusses considerations about the nature of perception in sensory substitution.

Auditory localization and precedence effect: an exploratory study in infants and toddlers with visual impairment and normal vision.

The precedence effect is a spatial hearing phenomenon implicated in sound localization on reverberant environments. It occurs when a pair of sounds, with a brief delay between them, is presented from different directions; listeners give greater perceptual weight to localization cues coming from the first-arriving sound, called lead, and suppress localization cues from the later-arriving reflection, called lag. Developmental studies with sighted infants show that the first responses to precedence effect stimuli are observed at 4-5 months of life. In this exploratory study, we use the minimum audible angle (MAA) paradigm in conjunction with the observer-based psychophysical procedure to test the ability of infants and toddlers, with visual impairment and normal vision, to discriminate changes in the azimuthal position of sounds configured under precedence effect conditions. The results indicated that similar and, in some conditions, higher performances were obtained by blind toddlers when compared to sighted children of similar age, and revealed that the observer-based psychophysical procedure is a valuable method to measure auditory localization acuity in infants and toddlers with visual impairment. The video records showed auditory orienting behaviors specific of the blind children group.

Ecolocación humana: Revisión histórica de un fenómeno particular - Segunda parte / Human echolocation: Historical review of a particular phenomenon - Second part

La ecolocación es una habilidad que usaría inconscientemente la mayoría de las personas. Resulta crucial para la movilidad independiente de la persona ciega e implica utilizar sonidos autoproducidos y sus reflexiones para localizar y reconocer objetos que no se ven. Dos nuevos paradigmas han enriquecido el estudio de esta sorprendente habilidad: el del acoplamiento sensoriomotor y el de la sustitución sensorial. El primero sostiene que los sistemas perceptivo y motor constituyen procesos acoplados que requieren un insoslayable tratamiento unificado. El segundo considera que es posible ver con los oídos o con la piel en virtud de la plasticidad cerebral. En esta segunda parte se presenta la temática en el contexto teórico de la cognición corporizada y de recientes avances en neurociencias; se desarrollan además los estudios realizados en el tercer período. En esta revisión se reflejan cambios paradigmáticos en las ciencias del comportamiento y el valor científico acrecentado de la ecolocación humana.

Echolocation is an ability that can be used daily by human beings, even without being conscious of it. It turns out to be crucial to the efficient independent mobility of the blind person, an aspect that is severely affected by blindness. It implies using the information that emerges from self-produced sounds and their reflexions in order to locate and recognize unseen objects. According to the new cognitive and ecological paradigms in perception, it is believed that the primary function of the auditory system is to determinate, i.e., to localize and recognize, the characteristics of the sound source through the sounds emitted by it. Within this context, it has been very recently argued that echolocation (i.e., the ability to locate and recognize biologically relevant secondary sound sources through the information contained in the direct-reflected couple) is a variant of that general process of primary sound sources determination. Two recently established scientific paradigms have specially enriched the study of this amazing ability: the sensorimotor contingency theory and the sensory substitution perspective. The first approach claims that the perceptual and motor systems are coupling processes that demand a thoroughly unified treatment. The second approach considers that, for example, vision loss does not mean loss of the ability to see since it is possible to see with the ears or the skin. The central idea is that the information usually captured by vision may instead be captured by touch or audition, on account of brain plasticity. In this way, in echolocation (which represents a kind of 'seeing with the ears' natural sensory substitution system that is part of the human endowment) action consists of the exploratory activity that the subject carries out through self-generation of sounds and head and/or cane movements while sensation refers to certain tonal or spatial percepts related to the presence and characteristics of the objects that the subject (implicitly) learns to perceive probably as auditory Gestalts. In the first part of this article the main theoretical aspects and a revision of the studies throughout two of the three delimited periods were developed: FIRST APPROACHES (1700 - 1935) and SIENTIFIC STUDY OF HUMAN ECHOLOCATION (1940 -1980). The questions that researchers formulated during these periods were firstly concerned with discovering if blind persons actually possessed this ability, which of the sense organs was involved and which sensory stimulation was its necessary and sufficient condition. Secondly, they inquired into the scopes of echolocation and its possible underlying psychoacoustic mechanisms. The thorough investigations carried out allowed to unequivocally establishing that audition is the sensory basis of this ability and that changes in pitch are its necessary and sufficient condition. It was also demonstrated that not only blind subjects but also appropriately trained sighted subjects were able to precisely localize and recognize the characteristics of the experimental objects. In this second part, we present the object of study within the context of theories of embodied cognition and recent developments in the field of the neurosciences; we also elaborate upon studies carried out during the third period, named RECENT STUDIES, that extends from 1990 to present days. We show how the blind person with good echolocation ability becomes an excellent experimental model to study behavioral and neurophysiological aspects involved in implicit learning. The article illustrates the paradigm shifts that occurred in recent scientific history through the study of this particular human ability that, within the mentioned recent theoretical context, has acquired a renewed interest.