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

Pacemaker Artifacts

Image
Dr. Rishabh Pathak

Pacemaker artifacts are a type of electrical cardiac artifact that can be observed in EEG recordings. 

1.     Pacemaker Artifacts:

o Description: Pacemaker artifacts result from the electrical signals generated by cardiac pacemakers and can be picked up by EEG electrodes.

o    Characteristics:

§  High-Frequency Polyphasic Potentials: Pacemaker artifacts typically exhibit high-frequency polyphasic potentials with a shorter duration compared to ECG artifacts.

§  Distribution: These artifacts may have a broader field of distribution across the head compared to other types of cardiac artifacts.

o    Identification:

§ Appearance: Pacemaker artifacts can appear as very brief transients with higher amplitudes in channels including specific electrodes (e.g., A1 and A2), and may be evident diffusely in some occurrences.

§ Synchronization: Simultaneous occurrences of pacemaker artifacts with similarly appearing discharges in the ECG channel can indicate a permanent pacemaker source.

Understanding the characteristics and distinctive features of pacemaker artifacts in EEG recordings is essential for accurate interpretation and differentiation from other types of artifacts or genuine brain activity. Proper identification and differentiation of pacemaker artifacts can help ensure the quality and reliability of EEG data for clinical analysis and diagnosis.

Pulse Artifacts

Pulse artifacts are a type of mechanical cardiac artifact that can be observed in EEG recordings. 

1.     Pulse Artifacts:

o Description: Pulse artifacts result from the mechanical effects of the circulatory pulse on EEG electrodes, leading to waveform distortions in the recorded signals.

o    Characteristics:

§  Source: Associated with the pulsatile force of the circulatory pulse on the electrodes resting over scalp blood vessels.

§  Appearance: Pulse artifacts manifest as slow waves following the ECG peak, often exhibiting periodicity and a regular interval related to the cardiac cycle.

o    Identification:

§  Location: Pulse artifacts commonly occur over frontal and temporal regions but can be present anywhere on the scalp.

§  Alteration: Applying pressure to the electrode producing the artifact can alter its appearance on the EEG recording, aiding in identification.

o    Differentiation:

§ From ECG Artifacts: Pulse artifacts can be distinguished from ECG artifacts by their waveform characteristics and source related to the circulatory pulse.

§ From Other Artifacts: Understanding the unique waveform and periodicity of pulse artifacts helps differentiate them from other types of artifacts in EEG recordings.

Proper identification and differentiation of pulse artifacts in EEG recordings are crucial for accurate interpretation and analysis. Recognizing the distinctive features of pulse artifacts can help researchers and clinicians distinguish them from genuine brain activity and other types of artifacts, ensuring the quality and reliability of EEG data for clinical assessments and research purposes.

 

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