Skip to main content

Energy Manifold Natural Gradient Descent: From Riemannian Optimization to Modern Neuroscience, NeuroAI and Quantum Physics

Dr. Rishabh Pathak
When Geometry, Energy, Artificial Intelligence and Neuroscience Converge Modern Artificial Intelligence is rapidly moving beyond the idea that learning simply means minimizing an error function. Increasingly, researchers are asking a deeper question: what is the structure of the space in which learning takes place? This question becomes particularly important when the system being modelled is constrained, nonlinear, dynamic, or governed by physical principles. A recent work titled “Energy Manifold Natural Gradient Descent: Riemannian Optimization for Neural PDE Solvers” , by Zhangyong Liang and Huanhuan Gao, introduces Energy Manifold Natural Gradient Descent (EMNGD) , a mathematical framework that extends energy-based natural-gradient optimization from unconstrained Euclidean parameter spaces to constrained Riemannian parameter manifolds . At its core, the framework proposes a simple but powerful principle: An optimization algorithm should not only determine how to reduce error; it sh...
Post a Comment

How force is generated in the muscles

Image
Dr. Rishabh Pathak

The generation of force in muscles is a complex physiological process involving intricate interactions at the molecular, cellular, and tissue levels. Muscle contraction, which leads to force production, is primarily driven by the sliding filament theory and the cross-bridge cycle within muscle fibers. Here is a discussion on how force is generated in muscles:

Mechanisms of Force Generation in Muscles:

1.    Sliding Filament Theory:

o    Actin and Myosin Interaction:

§  Muscle contraction is based on the sliding filament theory, where actin and myosin filaments within muscle fibers slide past each other to generate force.

§  Myosin heads on the thick filaments interact with actin filaments on the thin filaments, forming cross-bridges that undergo cyclic interactions to produce force.

2.    Cross-Bridge Cycle:

o    Cross-Bridge Formation:

§  The cross-bridge cycle involves the binding of myosin heads to actin filaments, forming cross-bridges that generate force during muscle contraction.

§  ATP hydrolysis provides the energy for myosin heads to pivot and generate force, leading to the sliding of actin filaments along myosin filaments.

3.    Excitation-Contraction Coupling:

o    Neuromuscular Transmission:

§  The process of force generation in muscles begins with neuromuscular transmission, where motor neurons stimulate muscle fibers at the neuromuscular junction.

§  Action potentials propagate along the sarcolemma and into the transverse tubules, triggering the release of calcium ions from the sarcoplasmic reticulum.

4.    Calcium Regulation:

o    Calcium Binding:

§  Calcium ions released into the muscle cell bind to troponin, causing a conformational change in the troponin-tropomyosin complex.

§  This change exposes the myosin-binding sites on actin, allowing myosin heads to interact with actin and initiate the cross-bridge cycle.

5.    Force-Length Relationship:

o    Optimal Length:

§  The force-generating capacity of a muscle is influenced by its length, with an optimal length for maximal force production.

§  The overlap between actin and myosin filaments affects the number of cross-bridges formed and the force generated during contraction.

6.    Motor Unit Recruitment:

o    Motor Unit Activation:

§  Force generation in muscles is also regulated by the recruitment of motor units, where motor neurons activate muscle fibers based on the required force output.

§  As the demand for force increases, additional motor units are recruited to generate more force through synchronous muscle contractions.

7.    Energy Metabolism:

o    ATP Utilization:

§  Muscle force generation relies on ATP hydrolysis to power the cross-bridge cycle and maintain muscle contraction.

§  ATP is continuously regenerated through various metabolic pathways to sustain muscle activity and force production.

Understanding the mechanisms of force generation in muscles is essential for athletes, clinicians, and researchers to optimize training programs, diagnose muscle disorders, and enhance performance outcomes. The coordinated interactions between actin, myosin, calcium ions, and neural control systems play a critical role in the generation of force during muscle contractions.

 

Categories:

Comments

Post a Comment

Popular posts from this blog

Cancellous Bone

Dr. Rishabh Pathak
Cancellous bone, also known as trabecular or spongy bone, is the other main type of bone tissue found in the human skeleton alongside cortical bone. Cancellous bone has a porous and lattice-like structure, providing flexibility, shock absorption, and a site for hematopoiesis (blood cell formation). Here are key features and characteristics of cancellous bone: 1.     Structure : o     Trabeculae : Cancellous bone is composed of a network of thin, bony trabeculae that form an interconnected lattice structure. o     Bone Marrow : The spaces between trabeculae contain red bone marrow, which is involved in the production of blood cells (hematopoiesis). o     Less Compact : Cancellous bone is less dense and compact than cortical bone, with a higher surface area-to-volume ratio. 2.     Composition : o     Trabecular Bone : The trabeculae are made up of lamellae, osteocytes, and canaliculi similar to corti...
Post a Comment
Read more

Review Settings of EEG

Dr. Rishabh Pathak
The review settings of an EEG recording refer to the parameters that can be adjusted to optimize the visualization and interpretation of electrical brain activity. Here is an overview of the key review settings in EEG analysis: 1.       Amplification (Gain/Sensitivity) : o Definition : Amplification, also known as gain or sensitivity, determines how much the electrical signals from the brain are amplified before being displayed on the EEG recording. o Measurement : Typically measured in microvolts per millimeter (μV/mm). o Impact : Adjusting the amplification setting can affect the visibility of high-amplitude and low-amplitude activity. High-amplitude activity may require vertical compression to fit within the display range, while low-amplitude activity may require lower sensitivity settings for better visualization. 2.      Frequency Filtering : o Bandpass : The frequency range within which EEG signals are analyzed. Common settings include ...
Post a Comment
Read more

Amphiarthrodial or Cartilaginous Joints

Dr. Rishabh Pathak
Amphiarthrodial joints, also known as cartilaginous joints, are joints where the adjacent bones are connected by cartilage. These joints allow for limited movement and provide both stability and flexibility to the skeletal system. Here is an overview of amphiarthrodial or cartilaginous joints: Amphiarthrodial or Cartilaginous Joints: 1.     Structure : o     Cartilage : §   Amphiarthrodial joints are characterized by the presence of cartilage between the articulating surfaces of the bones. §   The cartilage can be hyaline cartilage or fibrocartilage, depending on the specific joint and its function. o     Lack of Joint Cavity : §   Similar to fibrous joints, cartilaginous joints do not have a synovial cavity, and the bones are held together by the cartilaginous tissue. 2.     Types : o     Synchondroses : §   Synchondroses are cartilaginous joints where the connecting material is hyaline carti...
Post a Comment
Read more

Cell Maturation (Dendrite and Axon Growth)

Dr. Rishabh Pathak
Cell maturation, encompassing dendrite and axon growth, is a crucial stage of brain development where neurons undergo structural changes to establish connections and form functional neural circuits. Here is an overview of cell maturation in the context of dendrite and axon growth: 1.      Dendrite Growth : o     Definition : Dendrites are branched extensions of a neuron that receive signals from other neurons and transmit these signals to the cell body. o     Dendritic Arborization : During maturation, neurons extend and elaborate their dendritic arbors, increasing the surface area available for synaptic connections. o     Synaptic Integration : Dendritic growth is essential for forming synapses with other neurons, allowing for the integration of incoming signals and information processing. o     Activity-Dependent Plasticity : Dendritic growth can be influenced by neural activity and sensory experiences, sh...
Post a Comment
Read more

Elements Selection Techniques

Dr. Rishabh Pathak
Element selection techniques play a crucial role in determining how individual elements or units are chosen from the population to form a sample. Here are some common element selection techniques used in sampling: 1.     Unrestricted Sampling : §   In unrestricted sampling, each element in the population has an equal chance of being selected for the sample. This approach is commonly used in simple random sampling, where every element is selected independently of other elements. 2.     Restricted Sampling : §   Restricted sampling involves imposing certain restrictions or conditions on the selection of sample elements. This can include stratification, clustering, or other criteria that guide the selection process. Restricted sampling techniques include: §   Stratified Sampling: The population is divided into homogeneous subgroups (strata), and samples are selected from each stratum to ensure representation of different characteristics. § ...
Post a Comment
Read more