Cortical Dynamics (Australia)

Brain Microphysiological Systems, including neural organoids derived from human induced pluripotent stem cells, offer a unique lens to study the intricate workings of the human brain. This paper investigates the foundational elements of learning and memory in neural organoids by quantifying immediate early gene expression in response to chemical modulation, input-specific short- and long-term synaptic plasticity, neuronal network dynamics, connectivity, and criticality to demonstrate the utility of these organoids in basic science research. Neural organoids showed synapse formation, glutamatergic and GABAergic receptor expression, immediate early gene expression basally and evoked, functional connectivity, criticality, and synaptic plasticity in response to theta-burst stimulation. In addition, pharmacological interventions on GABAergic and glutamatergic receptors and input-specific theta-burst stimulation further shed light on the capacity of neural organoids to mirror synaptic modulation, specificallyshort- and long-term potentiation and depression, demonstrating their potential as tools for studying neurophysiological and neurological processes and informing therapeutic strategies for diseases.

Using the spectral method, we investigate the scalar and axial quasinormal modes (QNMs) of massive static phantom wormholes. Our results reveal the existence of purely imaginary QNMs that were not identified in previous studies, suggesting potential (in)stabilities as the ratio of the Schwarzschild radius to the wormhole throat varies within a specific range. For scalar perturbations, instabilities arise when this ratio exceeds 1.0, with the threshold value of 1.0 itself included. In the case of axial perturbations, the onset of instability occurs at smaller ratios, reflecting the impact of gravitational waves on the wormhole’s stability. The findings suggest that the wormhole remains stable when the throat size significantly exceeds the Schwarzschild radius. Our results align with existing literature but offer new insights into the stability conditions of phantom wormholes.

Recent advances in human stem cell-derived brain organoids promise to replicate critical molecular and cellular aspects of learning and memory and possibly aspects of cognition in vitro . Coining the term “organoid intelligence” (OI) to encompass these developments, we present a collaborative program to implement the vision of a multidisciplinary field of OI. This aims to establish OI as a form of genuine biological computing that harnesses brain organoids using scientific and bioengineering advances in an ethically responsible manner. Standardized, 3D, myelinated brain organoids can now be produced with high cell density and enriched levels of glial cells and gene expression critical for learning. Integrated microfluidic perfusion systems can support scalable and durable culturing, and spatiotemporal chemical signaling. Novel 3D microelectrode arrays permit high-resolution spatiotemporal electrophysiological signaling and recording to explore the capacity of brain organoids to recapitulate the molecular mechanisms of learning and memory formation and, ultimately, their computational potential. Technologies that could enable novel biocomputing models via stimulus-response training and organoid-computer interfaces are in development. We envisage complex, networked interfaces whereby brain organoids are connected with real-world sensors and output devices, and ultimately with each other and with sensory organ organoids (e.g. retinal organoids), and are trained using biofeedback, big-data warehousing, and machine learning methods. In parallel, we emphasize an embedded ethics approach to analyze the ethical aspects raised by OI research in an iterative, collaborative manner involving all relevant stakeholders. The many possible applications of this research urge the strategic development of OI as a scientific discipline. We anticipate OI-based biocomputing systems to allow faster decision-making, continuous learning during tasks, and greater energy and data efficiency. Furthermore, the development of “intelligence-in-a-dish” could help elucidate the pathophysiology of devastating developmental and degenerative diseases (such as dementia), potentially aiding the identification of novel therapeutic approaches to address major global unmet needs.

Abstract Amongst the characteristics about information processing in the brain, observations of dynamic near-critical states have generated significant interest. However, theoretical and experimental limitations have precluded a definite answer about when and why neural criticality arises. To explore this topic, we used anin vitroneural network of cortical neurons that was trained to play a simplified game of ‘Pong’. We demonstrate that critical dynamics emerge when neural networks receive task-related structured sensory input, reorganizing the system to a near-critical state. Additionally, better task performance correlated with proximity to critical dynamics. However, criticality alone is insufficient for a neuronal network to demonstrate learning in the absence of additional information regarding the consequences of previous actions. These findings have compelling implications for the role of neural criticality.

Abstract Here, we examined prey-capture in wild common marmosets (Callithrix jacchus) to explicate the active role of primate vision for high-precision, goal-directed motor actions in challenging natural environments. We observed distinct marmoset hunting strategies that each relied on the close integration of visual processes and dynamic biomechanical motor movements, but differed based on several factors including prey size/speed, substrate, and their relative distance to the prey. Marmoset positional behavior in these complex arboreal settings often involves extending the body, including inversions, while relying on vision to guide prey capture. Applying markerless pose estimation technology, analyses revealed details of how primate vision both guides and corrects rapid motor actions in real-time during prey-capture in the wild. These findings illustrate the significance of active vision during primate ethological behaviors in response to the very challenges the visual system evolved to solve.

Default DATETIME columns to NULL in ClientJobsDAO for compatibility across mysql versions. As of mysql 5.7.8, values of 0 are not allowed for DATETIME columns, and CURRENT_TIMESTAMP is semantically inappropriate for those columns. Suppress this optional dependency on matplotlib without logging, because python logging implicitly adds the StreamHandler to root logger when calling logging.debug, etc., which may undermine an application's logging configuration Bugfix: Write the 'actualValues' to the output, don't reassign the output Fixed Username Regex in ClientJobsDAO cleaned up region a bit to make it compliant with numenta's coding guidelines.

Serotonin is shown to regulate the activity of primary auditory cortex, but little is known about serotonin modulation of other sensory cortices. We investigated somatosensory evoked magnetic fields (SEF) to left median nerve stimulation in eight healthy subjects in a double-blind, controlled, cross-over design study after acute tryptophan depletion (ATD) and control mixture. SEFs were recorded with the whole-head magnetoencephalography 6 h after ingestion of mixtures. The SEF sources and strength were estimated by a least-squares fit of a single equivalent current dipole. ATD decreased the total and free TPR levels by 75 and 48% and control mixture increased them by 98% and 44%. ATD had no effect on the amplitudes or latencies of SEF components. The source locations of the responses were not significantly affected by ATD. Serotonin does not affect stimuli processing in the primary somatosensory cortex.