Neuroteknik

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• The outermost layer of the connective tissue surrounding the peripheral nerve Epineurium
• The smooth membrane on the nerve perineurium
• The layer of connective tissue around the myeline sheat Endoneurium:
• A bundle of skeletal muscles Fascicle
• sköter myaliniseringen på nervcellerna och axon i CNS vilket ökar aktionspotentialen obligodendrocyter
• neurons involved in transmitting sensory information unipolar neuron
• specialized for sensory functions, from peripheral receptors to CNS bipolar neuron
• the most common type. found in CNS multipolar neuron
• carries information from tissue and organs to CNS afferent neurons
• carries information from CNS to effector cells (e.g. muscles) efferent neurons
• communication between other neurons interneurons
• activation of sensory receptor cells at the level of stimulus sensation
• process and organize sensory information perception
• Mechanoreceptors found in sensitive skin areas, like fingertip Meissner corpuscle
• found in skin and deeper tissues like joints. Contribute to grip control Pacinian corpuscle
• Contribute to the detection of fine details Merkels disk
• motor neuron + muscle fibers it innervates motor unit
• bundle of nerve fibers and associated connective tissue that extends from CNS to various part of body peripheral nerve
• the outermost layer of the connective tissue surrounding the peripheral nerve Epineurium
• the smooth membrane on the nerve Perineurium
• the layer of connective tissue around the myelin sheet endoneurium
• a bundle of skeletal muscles fascicle
• electrodes placed outside of the nervous system extraneural electrode
• wraps around the nerve cuff electrode
• squishes the nerve to get flatter to reach stuff in middle, generating better information FINE
• Flat interface nerve electrode FINE
• electrode implanted directly into the nerve or its fascicles Intraneural electrode
• longitudinal intrafascicular electrodes LIFE
• an electrode implanted longitudinally. Designed to interface with single axons or a small group of axons within the nerve LIFE
• thin film LIFE tfLIFE
• specialized implant that helps nerves to heal and integrate with electrode. Improves function and longevity of neural interfaces Regenerative neural electrode
• Cut the nerve and let them grow through these electrodes sieve electrode
• flexible material, when it is stretched out, the nerves go through it microchannel electrode
• incorporates a scaffold like structure to provide support for neural tissue growth and integration scaffold electrode
• minimum amplitude of current required to create an action potential rheobase
• the minimum time required for an electric current to double the strength of the rheobase to stimulate a muscle or a neuron chronaxie
• the outermost layer of connective tissue that surrounds the entire muscle, providing protection and support to the muscle as a whole epimysium
• layer of connective tissue that surrounds a bundle of muscle fibers (fascicles). endomysium
• Surrounds individual muscle fibers within a fascicle. Provides support and protection to each muscle fiber perimysium
• responsible for muscle contraction. sacromere
• the site where the nervous system communicates with the muscular system neuromuscular junction
• Slow-twitch fiber. Don't generate a lot of force. Fatigue resistant Type I fibers
• fast-twitch fatigue resistant fibers type IIA
• fast-twitch, fatigable fibers Type IIX
• describe the order of recruitment of motor units during muscle contraction size principle
• larger motor units fast twitch type II
• smaller motor units slow-twitch type I
• a cranial nerve, creating a pathway for interface with the parasympatic control of heart, lungs etc vagus nerve
• the pyramidal tract and the extra pyramidal tract. Conveying voluntary motor commands from brain to spinal cord to become muscle movement. main motor descending pathway
• The anterolateral system, the dorsal column system and spinocerebellar system. Responsible for transmitting sensory information from PNS to brain, where it's perceived and interpreted main sensory ascending pathway
• pyramidal tract main motor descending pathway
• extrapyramidal tract main motor descending pathway
• anterolateral system main sensory ascending pathway
• dorsal column system main motor ascending pathway
• spinocerebellar system main motor ascending pathway
• a part of the neuron, between the myelin sheath node of ranvier
• given by a stimuli twitch
• repeated stimuli delivered to a neuron/muscle fiber are integrated over time. Leading to a increasing effect on membrane potential or muscle fibers contraction strength wave summation
• Muscle fibers are stimulated at high frequency but contractions don't merge completely. unfused (incomplete) tetanus
• Muscle fibers stimulated at high frequency, contractions become so frequent that they merge into a smooth continuous contraction fused (complete) tetanus
• where does the upper motor neuron synapse with the lower motor neuron in spinal cord or in brainstem
• motor neurons pool their axons together to form nerves that extent to the muscle fibers they control motor neuron pool
• rapid involuntary response to a specific sensory stimulus, mediated entirely within the spinal cords without involvements of higher brain centers spinal reflex mechanism
• muscle contraction, creating a movement concentric contraction
• muscle contraction, flexion/extension eccentric contraction
• muscle contraction, contract muscles but keep still isometric contraction
• prime muscle moving agonist
• muscle that assists the prime moving muscle synergist
• a muscle that performs the opposite action antagonist
• electrical activity produced by skeletal muscles electromyogram EMG
• targeted muscle rein nervation TMR
• moving a nerve from a lost limb to another muscle, creates AP to control prosthesis TMR
• residual nerve that originally innervated the muscle of the amputated limb is identified and dissected surgical procedure
• the nerves are surgically transferred and rerouted to another working muscle nerve transfer
• new established connections created to muscle fibers muscle reinnervation
• electrodes used to detect electric signals by muscle contractions. EMG signals used to control prostheses EMG control
• prosthesis can be programmed to perform various movements and functions prosthetic control
• removes noise and strengthens the small signals amplifier
• filter out everything that doesn't contain interesting information filter
• make it digital A/D
• transfer EMG signal to another domain to extract useful information Feature extraction
• the output from these controls the prostheses classification/regression
• classify input data. Can be used to identify different types of movements or activities, like walking, running classification
• predict values based on input. Used to predict muscle force, joint angles etc regression
• non invasive electrode using HDsEMG or individual electrodes for measurement sEMG
• matrix of electrodes HDsEMG
• type of electrode, Record signals from inside of the muscle iEMG
• intramuscular EMG electrode iEMG
• electrode that gets sutured on to muscle epimysial
• sEMG frequency range 1-300Hz
• Should amplifier impedance be high or low? high
• allows only low frequency components to pass. Can be used to remove aliasing low-pass filter
• allows only high-free signals to pass. Can be used to reduce movement artifacts high-pass filter
• used to extract useful information. Transforming data into a time domain that can be interpreted by humans and machines feature extraction
• provides the magnitude of muscle activity without consideration of direction mean absolute value
• can be useful for analyzing the intensity of muscle activation during different tasks mean absolute value
• quantifies the variability of EMG amplitude values over a specific time window variance
• understand variability in muscle activity, useful for evaluating characteristics of muscle activity, like recruitment patterns variance
• identify the points in EMG signal where it crosses the zero amplitude axis zero crossing
• provide information about the frequency or rate of change in signal, can be indicative of muscle activation patterns zero crossing
• counts how many time the data points in the EMG signal exceeds a certain threshold willison amplitude
• makes it hard to isolate signals from specific muscles or motor units Limited space resolution
• risk of recording of adjacent muscles leading to unintended interference cross talking
• set of parameters from fitting a model to a signal. Used characterize temporal dependencies and predictability of the EMG signal Autoregressive coefficients
• relationships or patterns between data points temporal dependencies
• captures the spectral characteristics of the EMG signal. Highligts the dominant spectral features cepstral coefficients
• the sum of spectral amplitude calculated using FFT total signal energy
• calculated from the windowed EMG power spectrum as the average frequency mean of signal frequencies
• calculated as the power spectrum is divided into two regions with equal power median of signal frequencies
• prosthetic control systems, using electric signals generated by muscle contraction to control prostheses myoelectric control system
• require some sort of classification that controls the controlling machine pattern recognition my-electric control
• based on control systems that are individualized and requires an onset analysis. Threshold based. non pattern based recognition myoelectric control
• when the muscle signal exceeds the threshold, it triggers the activation of a specific function or movement threshold based ON-OFF
• focus on detecting the beginning of muscle contraction, used for detecting the users intention to innate a movement onset analysis
• consists of finding k nearest points with the shortest Euclidean distance, using these k outputs as the prediction k-nearest neighborhood
• classification method used for high-dimensional dataset Linear discriminant analysis
• finds the optimal projection, classification by applying a decision rile to the projected data linear discriminant analysis
• learns statistically patterns of muscle activity associated with different movements Hidden Markov Models
• Finds the optimal decision boundary that separates the feature space into different classes Support Vector machine
• computational network consisting of layers called neurons neural network
• No human in loop, where sensors directly control the prostheses intrinsic feedback
• human in the loop, when sensors in the prosthetic communicates through some human sense sensory substitution
• stimulate skin and the brain translates the feeling to force electrotactile
• stimulate the nerve directly and fool the brain that the stimulation is coming from the prosthetic hand electrotactile
• using a small vibrator placed on skin. Sensors are measuring force and translate it into the vibrator, changing sensory like amplitude, frequency, pulse etc vibrotactile
• push into the skin with a force that is proportional to the measured force in the sensor mechanotactile
• refers to the cortical representation of the missing limb. What the brain remembers of the amputated limb regarding to sensations phantom map
• use methods to acquire signals from the brain, like EEG and MEG signal acquisition
• the goal is to interpret the neural signals and determine the intended action from the observed brain activity classification BCI
• which brain cells contributes the most to measured EEG signal? Pyramidal cells
• executive functions like planning, organizing, thinking, emotions frontal lobe
• movement motor cortex
• sensation sensory cortex
• perception, making sense of the world, spelling parietal lobe
• vision occipital lobe
• breathing, heart, respiration medulla oblangata
• memory, understanding, language temporal lobe
• ElectroEncephalography EEG
• non invasive technique for measuring electrical activity generated by the brain using electrodes placed on the scalp ElectroEncephaloGraphy
• how quick changes in neural activity can be captures signal acquisition speed
• fMRI functional magnetic resonance imaging
• records changes in metabolism of neurons fMRI
• records changes in electrical field EEG
• Records changes in magnetic field MEG
• medium fast acquisition speed EEG
• fast acquisition speed MEG
• slow acquisition speed fMRI
• ECoG ElectroCorticoGraphy
• Electrodes that go inside the brain intracortical electrodes
• electrodes implanted above the brain cortex inside the skull but doesn't penetrate the brain ECoG
• Describes how precisely a technique can localize brain activity in both space and time spatio-temporal resolution
• amplitude and frequency range of EEG <100hz, 5-300mikroV
• reflects the collective activity of large population of neurons in the brain frequency
• reflects the magnitude of electrical potentials generated amplitude
• amplitude and frequency range of ECoG <200hz, 0.01-5mV
• amplitude and frequency range of brain signals recorded with intracortical implants ca 500mV, 0.1-7khz
• amplitude and frequency range of brain signals recorded with subcortical/DBS implants <1mV, <200hz
• 10-20 system EEG electrode placement
• fNIRS functional Near Infrared Spectoscopy
• outputs from brain activity is used to control the device independent from external device active BCI
• outputs from external stimuli used for controlling an application reactive BCI
• biofeedback technique used for training self-regulation of brain activity neurofeedback
• help people with ADHD to focus neurofeedback
• an example where BCI is the only option for communication between a person and the outside world locked-in syndrome
• ERS event related synchronization
• ERD event related desynchronization
• raw EEG frequency bandwidth 0-45 hz awake
• delta frequency bandwith 0.5-3.5 hz deep sleep
• theta 4-7.5 hz drowsy
• alpha 8-12 hz relaxed
• beta 13-35hz engaged
• hilbert envelope envelopes of signal that represents magnitude and strength
• which layers of cerebral cortex are contributing to MEG measurements? 2, 3, 5
• what determines current dipole strength? Q = i * d
• What is the minimal MEG measurable current? 10nAm
• To enable the MEG measurement, how many simultaneous active neurons and synapses are involved at least? 1 million active neurons and synapses
• Due to partial signal cancellation, what is the minimal size of active cortex should be involved? 1-40mm2
• What are the three main aspects affecting the MEG signal strength? neuronal activity, orientation of current dipoles, head geometry and sensor placement
• What is the deviation for MEG signal detection? What results in the deviation? noise, brain activation variability, head movement
• SQUID Superconducting quantum interference device
• SERF spin exchange relaxation-free
• planar gradiometers a sensor to detect the measured magnetic field
• magnetometers measures the strength and directions of magnetic fields
• adv of planar gradiometers spatial localization, noise rejection, cancellation of common mode noise
• adv of magnetometers sensitive to radial sources
• HPI coils Head Position indicator
• What is HPI small coils placed on subjects head to compensate for head movements
• what is spontaneous stimuli in MEG experimental studies ongoing patterns in brain activity without external stimuli
• what is evoked stimuli in MEG experimental studies neutral responses to specific sensory stimulus or tasks

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