Physiologically driven avian vocal synthesizer

In this work, we build an electronic syrinx, i.e., a programmable electronic device capable of integrating biomechanical model equations for the avian vocal organ in order to synthesize song. This vocal prosthesis is controlled by the bird’s neural instructions to respiratory and the syringeal motor systems, thus opening great potential for studying motor control and its modification by sensory feedback mechanisms. Furthermore, a well-functioning subject-controlled vocal prosthesis can lay the foundation for similar devices in humans and thus provide directly health-related data and procedures.Fil: Sitt, Jacobo Diego. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arneodo, Ezequiel Matías. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goller, Franz. University of Utah; Estados UnidosFil: Mindlin, Bernardo Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The audiovisual structure of onomatopoeias: An intrusion of real-world physics in lexical creation

Sound-symbolic word classes are found in different cultures and languages worldwide. These words are continuously produced to code complex information about events. Here we explore the capacity of creative language to transport complex multisensory information in a controlled experiment, where our participants improvised onomatopoeias from noisy moving objects in audio, visual and audiovisual formats. We found that consonants communicate movement types (slide, hit or ring) mainly through the manner of articulation in the vocal tract. Vowels communicate shapes in visual stimuli (spiky or rounded) and sound frequencies in auditory stimuli through the configuration of the lips and tongue. A machine learning model was trained to classify movement types and used to validate generalizations of our results across formats. We implemented the classifier with a list of cross-linguistic onomatopoeias simple actions were correctly classified, while different aspects were selected to build onomatopoeias of complex actions. These results show how the different aspects of complex sensory information are coded and how they interact in the creation of novel onomatopoeias.Fil: Taitz, Alan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Assaneo, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Elisei, Natalia Gabriela. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tripodi, Monica Noemi. Universidad de Buenos Aires; ArgentinaFil: Cohen, Laurent. Centre National de la Recherche Scientifique; Francia. Universite Pierre et Marie Curie; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Sitt, Jacobo Diego. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Institut National de la Santé et de la Recherche Médicale; Francia. Universite Pierre et Marie Curie; FranciaFil: Trevisan, Marcos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin

Survival and consciousness recovery are better in the minimally conscious state than in the vegetative state

BACKGROUND The prognosis value of early clinical diagnosis of consciousness impairment is documented by an extremely limited number of studies, whereas it may convey important information to guide medical decisions. OBJECTIVE We aimed at determining if patients diagnosed at an early stage (<90 days after brain injury) as being in the minimally conscious state (MCS) have a better prognosis than patients in the vegetative state/Unresponsive Wakefulness syndrome (VS/UWS), independent of care limitations or withdrawal decisions. METHODS Patients hospitalized in ICUs of the Pitié-Salpêtrière Hospital (Paris, France) from November 2008 to January 2011 were included and evaluated behaviourally with standardized assessment and with the Coma Recovery Scale-Revised as being either in the VS/UWS or in the MCS. They were then prospectively followed until 1July 2011 to evaluate their outcome with the GOSE. We compared survival function and outcomes of these two groups. RESULTS Both survival function and outcomes, including consciousness recovery, were significantly better in the MCS group. This difference of outcome still holds when considering only patients still alive at the end of the study. CONCLUSIONS Early accurate clinical diagnosis of VS/UWS or MCS conveys a strong prognostic value of survival and of consciousness recovery

Vocal biomimetic

El canto de las aves es un modelo para comportamiento vocal aprendido con gran similitud al proceso de aprendizaje y producción vocal en humanos. El canto es producido en el órgano vocal, la siringe, mediante la coordinada interacción de dos sistemas motores: los músculos que controlan la siringe y los músculos respiratorios. El canto está compuesto por elementos acústicos llamados sílabas, cada sílaba posee características propias. Mientras que algunas especies presentan únicamente sílabas tonales, otras como el Diamante Mandarín (Taeniopygia guttata) alternan sílabas tonales de alta frecuencia con sílabas de baja frecuencia que poseen gran contenido espectral. En esta tesis estudiamos los mecanismos mediante los cuales la siringe puede contribuir a esa riqueza espectral. Se muestra que en el Diamante Mandarín, el gran contenido espectral presente en las sílabas de baja frecuencia, es una indicación de la dinámica presentada por su aparato vocal. Mediante el modelado teórico, esta dinámica es capturada en un modelo matemático de baja dimensión. La variación de contenido espectral no es el resultado de un control activo central de esta caracter ística acústica, sino que emerge de la dinámica intrínseca de la siringe. A partir de los modelos teóricos desarrollados de la biomecánica de la siringe, se diseñó un dispositivo biomimético, capaz de reemplazar el órgano vocal del ave. Se desarrollo una siringe electrónica capaz de generar canto mediante la transducci ón de instrucciones fisiológicas. La salida del dispositivo respeta las características acústicas del canto natural del ave. Este dispositivo electrónico integra digitalmente las ecuaciones de la dinámica de la siringe, constituyendo una solución robusta para generar vocalizaciones con control fisiológico en tiempo real. Este trabajo ilustra la necesidad de explorar cuantitativamente la interacción entre el sistema nervioso y el sistema periférico que controla, de modo de entender el comportamiento emergente. Por otro lado, con el fin de generar dispositivos biomiméticos, se remarca la importancia de incorporar la física del problema en su desarrollo, logrando así soluciones más eficientes.Birdsong is a model system for learned vocal behaviour with remarkable parallels to human vocal development and sound production mechanisms. Song is generated in the birds vocal organ by the coordinated interaction of two motor systems the syrinx muscles and the respiratory muscles. Birdsong is composed by acoustics elements called syllable, each syllable has different acoustic features. While some species exhibit only tonal sounds, other species, like the Zebra Finch, alternate high frequency tonal notes and low frecuency syllables with high spectral content. In this thesis, we study the mechanisms of how the avian sound source might contribute to spectral richness. Here we show in the zebra finch (Taeniopygia guttata), that the broad range of upper harmonic content in different low frequency song elements is the fingerprint of the dynamics displayed by its vocal apparatus. Using theoretical modelling we captured this dynamic with a low dimensional dynamical model. The varying harmonic content of birdsong is not the result of the active neural control of the acoustic characteristics but emerges of the intrinsic dynamics of the sound source. Using the developed theoretical models of biomechanics of the syrinx we also designed a biomimetical device capable of replacing the organ. We developed an electronic syrinx that generates song by transducing physiological instructions into acoustic output. The synthetic output is highly similar in acoustic features to the natural sounds. This electronic circuit digitally integrate the equations for the dynamics of the syrinx, constituting a robust solution suitable for generating synthetic song in real time. This work illustrates the need to fully explore the deep interaction between a nervous system and the peripheral system it controls in order to understand the emerging behavior. Also, in order to develop biomimetic devices, we indicate the importance of incorporating the physics of the problem to design in order to obtain efficient solutions.Fil:Sitt, Jacobo Diego. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Measuring states of pathological (un)consciousness: research dimensions, clinical applications, and ethics

Consciousness is a multidimensional construct with no widely accepted definition. Especially in pathological conditions, it is less clear what exactly is meant by (un)consciousness, how it can be reliably observed or measured. Here, we aim at (i) bringing together state of the art approaches to classification of single patients suffering from disorders of consciousness by means of motor-independent assessment of consciousness states with electrophysiology and functional neuroimaging, (ii) showing how each proposed metric translates into clinical practice and (iii) raising a discussion on the ethical aspects of consciousness measurements.We realize that when dealing with patients some issues commonly pertain to each method- ology discussed here, such as the overall clinical condition, clinical heterogeneity, and diagnostic uncertainty. When pre- dicting patients’ diagnosis, though, each method adopts a different approach to determine (a) a “gold standard” of the benchmark population upon which the metric is computed and (b) the generalization and replicability in the attempt to avoid overfitting. From an applied ethics perspective, the focus is, hence, on knowing what one is measuring and on the validity of measurements.We conclude that, when searching for consciousness in pathological conditions, confident diag- nosis can be based on the use of probabilistic predictions as well as on accumulative evidence stemming from multiple non-overlapping assessments with different modalities. A framework which will regulate the application order of these techniques (balancing their availability, sensitivity, and specificity, based on underlying clinical assumptions about a patient’s conscious state), is expected to ameliorate clinical management and further inform on the critical patterns of (un)consciousness

A low cost, modular, and physiologically inspired electronic neuron

We describe a low cost design of an electronic neuron, which is designed to represent the dynamical properties of the membrane potential of biological neurons by modeling the states of the membrane channels. This electronic neuron can be used to study the nonlinear properties of the membrane voltage dynamics and to develop and analyze small neuronal circuits using electronic neurons as building blocks.Fil: Sitt, Jacobo Diego. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Campetella Mayoral, Florencia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Aliaga, Jorge Luis. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Probing consciousness in a sensory-disconnected paralyzed patient.

peer reviewedBACKGROUND: Diagnosis of consciousness can be very challenging in some clinical situations such as severe sensory-motor impairments. CASE STUDY: We report the case study of a patient who presented a total "locked-in syndrome" associated with and a multi-sensory deafferentation (visual, auditory and tactile modalities) following a protuberantial infarction. RESULT: In spite of this severe and extreme disconnection from the external world, we could detect reliable evidence of consciousness using a multivariate analysis of his high-density resting state electroencephalogram. This EEG-based diagnosis was eventually confirmed by the clinical evolution of the patient. CONCLUSION: This approach illustrates the potential importance of functional brain-imaging data to improve diagnosis of consciousness and of cognitive abilities in critical situations in which the behavioral channel is compromised such as deafferented locked-in syndrome

Signature of consciousness in the dynamics of resting-state brain activity

At rest, the brain is traversed by spontaneous functional connectivity patterns. Two hypotheses have been proposed for their origins: they may reflect a continuous stream of ongoing cognitive processes as well as random fluctuations shaped by a fixed anatomical connectivity matrix. Here we show that both sources contribute to the shaping of resting-state networks, yet with distinct contributions during consciousness and anesthesia. We measured dynamical functional connectivity with functional MRI during the resting state in awake and anesthetized monkeys. Under anesthesia, the more frequent functional connectivity patterns inherit the structure of anatomical connectivity, exhibit fewer small-world properties, and lack negative correlations. Conversely, wakefulness is characterized by the sequential exploration of a richer repertoire of functional configurations, often dissimilar to anatomical structure, and comprising positive and negative correlations among brain regions. These results reconcile theories of consciousness with observations of long-range correlation in the anesthetized brain and show that a rich functional dynamics might constitute a signature of consciousness, with potential clinical implications for the detection of awareness in anesthesia and brain-lesioned patients.Fil: Barttfeld, Pablo. Commissariat A Energie Atomique; Francia. Institut National de la Santé et de la Recherche Médicale; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Uhrig, Lynn. Commissariat A Energie Atomique; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Sitt, Jacobo Diego. Commissariat A Energie Atomique; Francia. Institut National de la Santé et de la Recherche Médicale; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sigman, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad Torcuato Di Tella; ArgentinaFil: Jarraya, Béchir. Commissariat A Energie Atomique; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Dehaene, Stanislas. Commissariat A Energie Atomique; Francia. Institut National de la Santé et de la Recherche Médicale; Franci

Incongruent interoceptive signals shift our attention to ourselves

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