Artículos científicos

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12466/19

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Prediction of Estimated VO2max in Active University Students Using Field Tests: RockportWalk Test Versus 20-m Shuttle Run
(2026-04-14) Martín Ruiz, Julio
Background/Objectives: To develop and internally validate multiple linear regression models to predict estimated VO2max from anthropometric variables and easily obtainable physical fitness tests in active university students and to compare model performance when estimated VO2max was derived from the RockportWalk Test versus the 20-m Shuttle Run (Course Navette). Methods: Anthropometric variables and physical fitness indicators, including body mass index (BMI), Ruffier index, and burpee repetitions, as well as sex and age, were evaluated. Estimated VO2max was obtained separately from the Rockport Walk Test and the 20-m Shuttle Run using their respective field test equations. For each test, a multiple linear regression model was fitted using the same set of predictors. Model performance was assessed using apparent metrics and internal validation with optimism correction based on repeated cross-validation. Results: The Rockport walk test model showed better predictive performance, explaining 55.2% of the variability in estimated VO2max (R2 = 0.552; adjusted R2 = 0.498) with a lower prediction error (RMSE = 3.54 mL·kg−1·min−1). In contrast, the 20-m shuttle run model showed lower explanatory capacity (R2 = 0.319; adjusted R2 = 0.256) and a substantially higher prediction error (RMSE = 11.93 mL·kg−1·min−1). Internal validation reduced performance in both models, more markedly in the 20-m shuttle run, where the corrected R2 fell to 0.163 and the corrected RMSE increased to 13.18 mL·kg−1·min−1, compared with 0.338 and 4.37 mL·kg−1·min−1 in the Rockport walk test. Conclusions: Estimated VO2max can be predicted pragmatically using low-cost models based on simple variables in a university setting; however, model performance depends on the field test used. The Rockport walk test appears more suitable for prediction using general-purpose predictors, whereas the 20-m shuttle run may require more test-specific predictors and external validation before application beyond the development sample.
AI-Enhanced CLIL for Embodied Learning: Applying the CLPS Framework in Secondary Physical Education
(2026-01-02) Ramírez-Aroca, Cristina; Javadinejad, Arash
This study examines how Artificial Intelligence (AI) can enhance Content and Language Integrated Learning (CLIL) through embodied, multimodal instruction in secondary Physical Education (PE). Drawing on Fernández Fontecha’s Content and Language Processing Sequence (CLPS) model, four AI-supported CLIL modules were designed and partially implemented in a Spanish secondary school. The exploratory, design-based study involved 25 students (aged 13–14) enrolled in second-year secondary education (2° ESO). Data were collected through a student perception survey and structured teacher observations to examine learners’ perceived content understanding, language use, engagement, and embodied participation in AI-supported CLIL tasks. Results indicate high levels of student engagement and positive perceptions of learning, particularly regarding vocabulary use, task comprehension, and the integration of physical movement with language use. Students reported that AI tools such as NaturalReader and Gliglish supported pronunciation practice, comprehension, and interactive language use when embedded within guided CLIL tasks. The findings highlight the pedagogical potential of AI as a mediating scaffold in embodied CLIL contexts, while underscoring the importance of teacher guidance and task design. The study contributes to emerging research on AI-enhanced CLIL by offering empirically grounded insights into the affordances and limitations of integrating AI in Physical Education.
Open field and vitro-derived plants of ‘Cascade’ hop: a comparison through total polyphenol content and antioxidant activity of vegetative biomass
(2025) Leto, L.; Agosti, A.; Nazeer, S.; Vecchio, L. Del; Fazio1, A. Di; Guarrasi, V.; Ganino, T.; Juan Vicedo, Jorge; Rolli, E.; Cirlini, M.; Chiancone1, B.
Hop (Humulus lupulus L.) stores (both in cones and in the whole vegetative body) valuable bioactive metabolites such as terpenoids, phenolic compounds (i.e. xanthohumol), alkaloids and bitter acids (humulone and lupulone) with antioxidant, antimicrobial and antiviral properties. Characterizing hop vegetative biomass, considered a waste, is the first step for its exploitation as source of bioactive compounds, every day more requested by various industrial sectors (pharmaceutical, cosmetic, agri-food, etc.), thus turning a burden into an additional income for growers. Moreover, to guarantee a continuous supply of hop plant materials for stakeholders, in vitro-derived plantlets could be an important solution. With these premises, this study aims at comparing the chemical composition of open field- and vitro-derived hop vegetative biomass, since they synthetize the same bioactive compounds. Specifically, total polyphenol content (TPC) and antioxidant activity (AO) of leaves and stems (LS) and only leaves (OL) of hop, ‘Cascade', were measured. Moreover, water alone was tested as only solvent to test the sustainability of the process, in comparison to conventional extractions made with ethanol/water (80/20 v/v). Results showed that the open-field plants have significantly higher TPC and AO (measured by DPPH and FRAP tests) when compared to those from in vitro-derived plants. However, when the LS are taken in consideration, in vitro-derived plants showed statistically higher TPC than those from open field (6.20±0.91 vs 5.74±1.52 mg GAE g-1). Regarding the extraction method, ethanol remains the most efficient solvent, but promising results were obtained also using water, both for the TPC (8.32±1.57 vs 5.73±1.10 mg GAE g-1 respectively) and antioxidant activity. Results reported in this study, although preliminary, are very interesting as they highlight how vitro-derived hop plantlets are a wealth source of bioactive compounds; moreover, to make the extraction process more sustainable, further research are worth to be done to increase the efficiency of water as green solvent
The temporary immersion system as an efficient technique for in vitro propagation of ‘Cascade’ hop
(2025) Gianguzzi, V.; Leto, L.; Agosti, A.; Nazeer, S.; Vecchio, L. Del; Fazio, A. Di; Sottile, F.; Juan Vicedo, Jorge; Rolli, E.; Cirlini, M.; Chiancone, B.
Humulus lupulus L. (hop) is an economically important species whose mass propagation has recently increased, due to the multiple interests that its cultivars present in several fields of application. The in vitro propagation techniques can represent a valid alternative to propagate hop plants on a large scale, and to supply a standard biomass for bioactive compound extraction. In fact, extracts obtained from hop vitro-derived plantlets have antioxidant, antimicrobial and antiviral properties. Temporary immersion system (TIS) allow the plant propagation by alternating immersions of microcuttings in liquid culture medium with dry periods, thus avoiding gas accumulation, through forced ventilation. In this study, the use of TIS (Plantform™ bioreactor) as alternative to solid medium, both in presence or absence of sucrose, was evaluated for in vitro propagation of hop ‘Cascade’, considering its effect on morpho-physiological parameters, on total phenolic content and antioxidant activity. At the end of the experiment, results obtained evidenced that microcuttings cultured in Plantform™ bioreactor produced a significantly higher number of shoots (+25.3%), roots (+77.4%), shoot and root elongation (respectively, +26.1 and +58.4%), and relative growth rate index (+2.6 times), when compared to those plants grown in solid medium. The presence of sucrose did not seem to have significantly influenced neither the number of shoots or roots, but it increased the length of both organs (respectively, +45.7 and +33.4%). Different results were obtained regarding the polyphenol content and antioxidant activity; in fact, it seems that plantlets grown in solid medium with sucrose contained significantly higher content of polyphenols and manifested a higher antioxidant activity. The temporary immersion technique has many positive potentials for in vitro propagation; this paper presents preliminary aspects on hops with development prospects for strengthening the production sector.
The Invisible Workout in Sport: A Narrative Review from an Interdisciplinary Perspective
(2025-12-19) Esteve Ibáñez, Héctor; Carrera Juliá, Sandra; Pazos Siri, Rodrigo Martín; Bonora-Lahiguera, Alexandre; Navarro Moreno, María Ángeles; Moreno Sancho, María de la Luz; Drehmer Rieger, Eraci
Several factors-social, academic, occupational, family, and sports-related-shape an athlete’s context and influence performance. These elements, not directly linked to physical training, form what is known as the Invisible Workout or Invisible Training. Although its dimensions have been studied ndividually, there is a lack of comprehensive research addressing this concept as a distinct and actionable space. This narrative review introduces, defines, and positions the Invisible Workout based on scientific evidence, focusing on three key areas: training, psychology, and nutrition. The psychological dimension is especially relevant, as it includes emotional and cognitive aspects of the athlete’s experience. However, the social dimension—encompassing relationships, support ne- tworks, and socio-environmental influences—is more broadly represented in the athlete’s overall context, which serves as the foundation where all dimensions of the Invisible Workout interact. Proper training, assessment, nutrition, hydration, hygiene, and sleep are critical to improving performance and preventing injuries. The review presents a figure illustrating the dimensions of the Invisible Workout, all situated within the athlete’s broader context—since, as demonstrated in our manuscript, this context may hold the key to success. A table of related terms used in recent literature is also included. This work offers practical implications for optimizing training and reducing injury risk through coordinated, context-aware strategies.
Educar jugando y dialogando. Derechos de la infancia, intencionalidad, familia y lenguaje
(2019-10-30) Saneleuterio, Elia; Alonso-Stuyck, Paloma; García-Ramos Gallego, David
El artículo revisa los derechos que contribuyen al alcance de una vida feliz desde la infancia, y se detiene en los elementos clave que procuran la dignidad necesaria para que la felicidad pueda desarrollarse. En primer lugar, la función de la familia en la creación de la identidad y seguridad personales, y también en el establecimiento de las relaciones personales. En segundo lugar, la formación integral de la persona y la educación en el desarrollo del sentido crítico y de la libertad en ejercicio responsable, así como de la capacidad de entender, expresarse y comunicarse para mejorar o superar situaciones problemáticas. Finalmente, el juego, como herramienta básica de disfrute en la infancia, y, al mismo tiempo, de aprendizaje en los dos ámbitos anteriores, en ocasiones complemento único o piedra angular que completa el proceso. El hecho de que los derechos de la infancia estén expresados mediante una convención es un paso fundamental, dado que ello implica la obligatoriedad de su cumplimiento por parte de las entidades responsables, principalmente la familia, ámbito ideal para el desarrollo de los niños y niñas. El acceso al disfrute lúdico, desarrollado en ambientes educativos adecuados, es un derecho inalienable e irrenunciable para aprender el lenguaje de la felicidad, que ninguna persona puede vulnerar y nadie debería desconocer. Promover estilos educativos familiares saludables, sería una manera sencilla de extender al resto de ámbitos sociales escenarios protegidos, donde la infancia creciera con todas las garantías en sana armonía.
A wireless and artefact-free 128-channel neuromodulation device for closed-loop stimulation and recording in non-human primates
(2018-12-31) Zhou, Andy; Santacruz, Samantha R.; Johnson, Benjamin C.; Alexandrov, George; Moin, Ali; Burghardt, Fred L.; Rabaey, Jan M.; Carmena Ramón, José Miguel; Muller, Rikky
Closed-loop neuromodulation systems aim to treat a variety of neurological conditions by delivering and adjusting therapeutic electrical stimulation in response to a patient's neural state, recorded in real time. Existing systems are limited by low channel counts, lack of algorithmic flexibility, and the distortion of recorded signals by large and persistent stimulation artefacts. Here, we describe an artefact-free wireless neuromodulation device that enables research applications requiring high-throughput data streaming, low-latency biosignal processing, and simultaneous sensing and stimulation. The device is a miniaturized neural interface capable of closed-loop recording and stimulation on 128 channels, with on-board processing to fully cancel stimulation artefacts. In addition, it can detect neural biomarkers and automatically adjust stimulation parameters in closed-loop mode. In a behaving non-human primate, the device enabled long-term recordings of local field potentials and the real-time cancellation of stimulation artefacts, as well as closed-loop stimulation to disrupt movement preparatory activity during a delayed-reach task. The neuromodulation device may help advance neuroscientific discovery and preclinical investigations of stimulation-based therapeutic interventions.
Maternal Physical Activity During Pregnancy and the Effect on the Mother and Newborn: A Systematic Review
(2020-12-22) Morales-Suárez-Varela, María; Clemente-Bosch, Eva; Peraita Costa, Isabel Victoria; Llopis-Morales, Agustín; Martínez, Isabel; Llopis-González, , Agustín
Background: The practice of physical exercise during pregnancy has benefits for both the mother and baby. Currently, there is scientific evidence that supports the inclusion of a monitored physical activity program in the daily activities of pregnant women. The objective of this study is to provide an overview of the current status of the association between physical activity during pregnancy and the effects on the mother and the newborn. Methods: A systematic review of the literature, assessing each study using the Scottish Intercollegiate Guidelines Network, from different databases PubMed, Embase, or ScienceDirect, on the association between maternal physical activity and its effects on the mother and the newborn published from 2010 until 2018 was conducted. Results: About 25 studies were identified and divided into categories according to the health problems affecting the mother or newborn. It was found that 8% of all the studies received a grade B, 68% obtained a grade C, and the remaining 24% obtained less than a grade C. Improved cardiovascular function, decreased risk of gestational diabetes mellitus, hypertension, and the limitation of weight gain are among the benefits to the mother with lower percentage of body fat, increased gestational age, and potentially improved neurodevelopment as benefits for the child. Conclusions: The realization of physical activity during pregnancy is supported by most of the studies reviewed. However, given the vulnerability of the studied populations, more studies on the association between physical activity and pregnancy are necessary.
A wireless millimetre-scale implantable neural stimulator with ultrasonically powered bidirectional communication
(2020-02-19) Piech, David K.; Johnson, Benjamin C.; Shen, Konlin; Ghanbari, M. Meraj; Li, Ka Yiu; Neely, Ryan M.; Kay, Joshua E.; Carmena Ramón, José Miguel; Maharbiz, Michel M.; Muller, Rikky
Clinically approved neural stimulators are limited by battery requirements, as well as by their large size compared with the stimulation targets. Here, we describe a wireless, leadless and battery-free implantable neural stimulator that is 1.7 mm3 and that incorporates a piezoceramic transducer, an energy-storage capacitor and an integrated circuit. An ultrasonic link and a hand-held external transceiver provide the stimulator with power and bidirectional communication. The stimulation protocols were wirelessly encoded on the fly, reducing power consumption and on-chip memory, and enabling protocol complexity with a high temporal resolution and low-latency feedback. Uplink data indicating whether stimulation occurs are encoded by the stimulator through backscatter modulation and are demodulated at the external transceiver. When embedded in ex vivo porcine tissue, the integrated circuit efficiently harvested ultrasonic power, decoded downlink data for the stimulation parameters and generated current-controlled stimulation pulses. When cuff-mounted and acutely implanted onto the sciatic nerve of anaesthetized rats, the device conferred repeatable stimulation across a range of physiological responses. The miniaturized neural stimulator may facilitate closed-loop neurostimulation for therapeutic interventions.
Neural reinforcement: re-entering and refining neural dynamics leading to desirable outcomes
(2020-02) Athalye, Vivek R.; Carmena Ramón, José Miguel; Cost, Rui M.
How do organisms learn to do again, on-demand, a behavior that led to a desirable outcome? Dopamine-dependent cortico-striatal plasticity provides a framework for learning behavior’s value, but it is less clear how it enables the brain to re-enter desired behaviors and refine them over time. Reinforcing behavior is achieved by re-entering and refining the neural patterns that produce it. We review studies using brain-machine interfaces which reveal that reinforcing cortical population activity requires cortico-basal ganglia circuits. Then, we propose a formal framework for how reinforcement in cortico-basal ganglia circuits acts on the neural dynamics of cortical populations. We propose two parallel mechanisms: i) fast reinforcement which selects the inputs that permit the re-entrance of the particular cortical population dynamics which naturally produced the desired behavior, and ii) slower reinforcement which leads to refinement of cortical population dynamics and more reliable production of neural trajectories driving skillful behavior on-demand.
Continuous shared control for stabilizing reaching and grasping with brain-machine interfaces
(2006-06) Kim, H. K.; Biggs, J.; Schloerb, W.; Carmena Ramón, José Miguel; Lebedev, M. A.; Nicolelis, M. A. L.
Research on brain-machine interfaces (BMI's) is directed toward enabling paralyzed individuals to manipulate their environment through slave robots. Even for able-bodied individuals, using a robot to reach and grasp objects in unstructured environments can be a difficult telemanipulation task. Controlling the slave directly with neural signals instead of a hand-master adds further challenges, such as uncertainty about the intended trajectory coupled with a low update rate for the command signal. To address these challenges, a continuous shared control (CSC) paradigm is introduced for BMI where robot sensors produce reflex-like reactions to augment brain-controlled trajectories. To test the merits of this approach, CSC was implemented on a 3-degree-of-freedom robot with a gripper bearing three co-located range sensors. The robot was commanded to follow eighty-three reach-and-grasp trajectories estimated previously from the outputs of a population of neurons recorded from the brain of a monkey. Five different levels of sensor-based reflexes were tested. Weighting brain commands 70% and sensor commands 30% produced the best task performance, better than brain signals alone by more than seven-fold. Such a marked performance improvement in this test case suggests that some level of machine autonomy will be an important component of successful BMI systems in general.
A Minimally Invasive 64-Channel Wireless μECoG Implant
(2015-01) Muller, Rikky; Le, Hanh-Phuc; Li, Wen; Ledochowitsch, Peter; Gambini, Simone; Bjorninen, Toni; Koralek, Aaron; Carmena Ramón, José Miguel; Maharbiz, Michel M.; Alon, Elad; Rabaey, Jan M.
Emerging applications in brain–machine interface systems require high-resolution, chronic multisite cortical recordings, which cannot be obtained with existing technologies due to high power consumption, high invasiveness, or inability to transmit data wirelessly. In this paper, we describe a microsystem based on electrocorticography (ECoG) that overcomes these dif- ficulties, enabling chronic recording and wireless transmission of neural signals from the surface of the cerebral cortex. The device is comprised of a highly flexible, high-density, polymer-based 64-channel electrode array and a flexible antenna, bonded to 2.4 mm × 2.4 mm CMOS integrated circuit (IC) that performs 64-channel acquisition, wireless power and data transmission. The IC digitizes the signal from each electrode at 1 kS/s with 1.2 μV input referred noise, and transmits the serialized data using a 1 Mb/s backscattering modulator. A dual-mode power-receiving rectifier reduces data-dependent supply ripple, enabling the integration of small decoupling capacitors on chip and eliminating the need for external components. Design techniques in the wireless and baseband circuits result in over 16× reduction in die area with a simultaneous 3× improvement in power efficiency over the state of the art. The IC consumes 225 μW and can be powered by an external reader transmitting 12 mW at 300 MHz, which is over 3× lower than IEEE and FCC regulations.
Brujas y familiares. La imagen de la bruja por Eva Lara Alberola
(2025-02) Lara Alberola, Eva
Las brujas, arquetipo imprescindible del ideario colectivo, representan todo lo terrible tanto en su aspecto como a través de sus actos. Suponen una amenaza para la comunidad y, cuando se encarnan en personas concretas, serán el perfecto chivo expiatorio. Aunque no existieran como tales hasta los siglos XIV-XV, sus antecedentes habitan las pesadillas humanas desde tiempos inmemoriales.
Leandro Fernández de Moratín y su reedición (1811) de la Relación de las personas que salieron al Auto de la Fe... publicada por Juan de Mongastón (1611): el retorno de las brujas de zugarramurdi
(2026-01-26) Lara Alberola, Eva
El presente trabajo pretende demostrar que las brujas de Zugarramurdi vuelven a la vida en 1811 gracias a la reedición que realiza Leandro Fernández de Moratín del panfleto publicado por Juan de Mongastón en 1611. Más allá del aparato de sesenta notas que el ilustrado añade al texto original, con la finalidad de criticar duramente la superstición y la actuación de la Inquisición, resulta determinante sobre todo la recuperación del opúsculo, lo cual supone una reactivación del interés en el caso brujesco de 1610, que había caído en un cierto olvido tras el edicto de silencio de 1614. Combinando la crítica literaria con disciplinas como la historia y la antropología, se mostrarán las consecuencias del retorno de estas brujas, puesto que saltarán de las páginas de la relación a las de la prensa y a las de múltiples obras literarias, instaurándose en el imaginario colectivo y materializándose también como representación estética.
Control of Redundant Kinematic Degrees of Freedom in a Closed-Loop Brain-Machine Interface
(2016-07-21) Moorman, Helene G.; Gowda, Suraj; Carmena Ramón, José Miguel
Brain-machine interface (BMI) systems use signals acquired from the brain to directly control the movement of an actuator, such as a computer cursor or a robotic arm, with the goal of restoring motor function lost due to injury or disease of the nervous system. In BMIs with kinematically redundant actuators, the combination of the task goals and the system under neural control can allow for many equally optimal task solutions. The extent to which kinematically redundant degrees of freedom (DOFs) in a BMI system may be under direct neural control is unknown. To address this question, a Kalman filter was used to decode single- and multi-unit cortical neural activity of two macaque monkeys into the joint velocities of a virtual four-link kinematic chain. Subjects completed movements of the chain's endpoint to instructed target locations within a two-dimensional plane. This system was kinematically redundant for an endpoint movement task, as four DOFs were used to manipulate the 2-D endpoint position. Both subjects successfully performed the task and improved with practice by producing faster endpoint velocity control signals. Kinematic redundancy allowed null movements whereby the individual links of the chain could move in a way that cancels out and does not result in endpoint movement. As the subjects became more proficient at controlling the chain, the amount of null movement also increased. Task performance suffered when the links of the kinematic chain were hidden and only the endpoint was visible. Furthermore, all four DOFs of the joint-velocity control space exhibited task-relevant modulation. The relative usage of each DOF depended on the configuration of the chain, and trials in which the less-prominent DOFs were utilized also had better task performance. Overall, these results indicate that the subjects incorporated the redundant components of the control space into their control strategy. Future BMI systems with kinematic redundancy, such as exoskeletal systems or anthropomorphic robotic arms, may benefit from allowing neural control over redundant configuration dimensions as well as the end-effector.
Closed-Loop Decoder Adaptation on Intermediate Time-Scales Facilitates Rapid BMI Performance Improvements Independent of Decoder Initialization Conditions
(2012-02-01) Orsborn, Amy L.; Dangi, Siddharth; Moorman, Helene G.; Carmen Ramón, José Miguel
Closed-loop decoder adaptation (CLDA) shows great promise to improve closed-loop brain-machine interface (BMI) performance. Developing adaptation algorithms capable of rapidly improving performance, independent of initial performance, may be crucial for clinical applications where patients have limited movement and sensory abilities due to motor deficits. Given the subject-decoder interactions inherent in closed-loop BMIs, the decoder adaptation time-scale may be of particular importance when initial performance is limited. Here, we present SmoothBatch, a CLDA algorithm which updates decoder parameters on a 1-2 min time-scale using an exponentially weighted sliding average. The algorithm was experimentally tested with one nonhuman primate performing a center-out reaching BMI task. SmoothBatch was seeded four ways with varying offline decoding power: 1) visual observation of a cursor (n = 20), 2) ipsilateral arm movements (n = 8), 3) baseline neural activity ( n = 17), and 4) arbitrary weights (n = 11). SmoothBatch rapidly improved performance regardless of seeding, with performance improvements from 0.018 0.133 successes/min to >;8 successes/min within 13.1 5.5 min (n = 56). After decoder adaptation ceased, the subject maintained high performance. Moreover, performance improvements were paralleled by SmoothBatch convergence, suggesting that CLDA involves a co-adaptation process between the subject and the decoder.
Evidence for a neural law of effect
(2018-03-02) Athalye, Vivek R.; Santos, Fernando J.; Carmena Ramón, José Miguel; Costa, Rui M.
Thorndike's law of effect states that actions that lead to reinforcements tend to be repeated more often. Accordingly, neural activity patterns leading to reinforcement are also reentered more frequently. Reinforcement relies on dopaminergic activity in the ventral tegmental area (VTA), and animals shape their behavior to receive dopaminergic stimulation. Seeking evidence for a neural law of effect, we found that mice learn to reenter more frequently motor cortical activity patterns that trigger optogenetic VTA self-stimulation. Learning was accompanied by gradual shaping of these patterns, with participating neurons progressively increasing and aligning their covariance to that of the target pattern. Motor cortex patterns that lead to phasic dopaminergic VTA activity are progressively reinforced and shaped, suggesting a mechanism by which animals select and shape actions to reliably achieve reinforcement.
Redundant information encoding in primary motor cortex during natural and prosthetic motor control
(2011-11-01) So, Kelvin; Ganguly, Karunesh; Jimenez, Jessica; Gastpar, Michael C.; Carmena Ramón, José Miguel
Redundant encoding of information facilitates reliable distributed information processing. To explore this hypothesis in the motor system, we applied concepts from information theory to quantify the redundancy of movement-related information encoded in the macaque primary motor cortex (M1) during natural and neuroprosthetic control. Two macaque monkeys were trained to perform a delay center-out reaching task controlling a computer cursor under natural arm movement (manual control, ‘MC’), and using a brain-machine interface (BMI) via volitional control of neural ensemble activity (brain control, ‘BC’). During MC, we found neurons in contralateral M1 to contain higher and more redundant information about target direction than ipsilateral M1 neurons, consistent with the laterality of movement control. During BC, we found that the M1 neurons directly incorporated into the BMI (‘direct’ neurons) contained the highest and most redundant target information compared to neurons that were not incorporated into the BMI (‘indirect’ neurons). This effect was even more significant when comparing to M1 neurons of the opposite hemisphere. Interestingly, when we retrained the BMI to use ipsilateral M1 activity, we found that these neurons were more redundant and contained higher information than contralateral M1 neurons, even though ensembles from this hemisphere were previously less redundant during natural arm movement. These results indicate that ensembles most associated to movement contain highest redundancy and information encoding, which suggests a role for redundancy in proficient natural and prosthetic motor control.
Assessing functional connectivity of neural ensembles using directed information
(2012-02-13) So, Kelvin; Koralek, Aaron C.; Ganguly, Karunesh; Gastpar, Michael C.; Carmen Ramón, José Miguel
Neurons in the brain form highly complex networks through synaptic connections. Traditionally, functional connectivity between neurons has been explored using methods such as correlations, which do not contain any notion of directionality. Recently, an information-theoretic approach based on directed information theory has been proposed as a way to infer the direction of influence. However, it is still unclear whether this new approach provides any additional insight beyond conventional correlation analyses. In this paper, we present a modified procedure for estimating directed information and provide a comparison of results obtained using correlation analyses on both simulated and experimental data. Using physiologically realistic simulations, we demonstrate that directed information can outperform correlation in determining connections between neural spike trains while also providing directionality of the relationship, which cannot be assessed using correlation. Secondly, applying our method to rodent and primate data sets, we demonstrate that directed information can accurately estimate the conduction delay in connections between different brain structures. Moreover, directed information reveals connectivity structures that are not captured by correlations. Hence, directed information provides accurate and novel insights into the functional connectivity of neural ensembles that are applicable to data from neurophysiological studies in awake behaving animals.
Recent advances in neural dust: towards a neural interface platform
(2018-06) Neely, Ryan M.; Piech, David K.; Santacruz, Samantha R.; Maharbiz, Michel M.; Carmena Ramón, José Miguel
The neural dust platform uses ultrasonic power and communication to enable a scalable, wireless, and batteryless system for interfacing with the nervous system. Ultrasound offers several advantages over alternative wireless approaches, including a safe method for powering and communicating with sub mm-sized devices implanted deep in tissue. Early studies demonstrated that neural dust motes could wirelessly transmit high-fidelity electrophysiological data in vivo, and that theoretically, this system could be miniaturized well below the mm-scale. Future developments are focused on further minimization of the platform, better encapsulation methods as a path towards truly chronic neural interfaces, improved delivery mechanisms, stimulation capabilities, and finally refinements to enable deployment of neural dust in the central nervous system.

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