15-09-2016, 04:09 PM
1454677206-BCI.ppt (Size: 5.17 MB / Downloads: 4)
Introduction
Brain-computer interface (BCI) is a fast-growing emergent technology, in which researchers aim to build a direct channel between the human brain and the computer.
A Brain Computer Interface (BCI) is a collaboration in which a brain accepts and controls a mechanical device as a natural part of its representation of the body.
Computer-brain interfaces are designed to restore sensory function, transmit sensory information to the brain, or stimulate the brain through artificially generated electrical signals.
Early work
Algorithms to reconstruct movements from motor cortex neurons, which control movement, were developed in 1970s.
The first Intra-Cortical Brain-Computer Interface was built by implanting electrodes into monkeys.
After conducting initial studies in rats during the 1990s, researchers developed Brain Computer Interfaces that decoded brain activity in monkeys and used the devices to reproduce movements in monkeys and used the devices to reproduce monkey movements in robotic arms.
Invasive
Invasive BCIs are implanted directly into the grey matter of the
brain during neurosurgery.
As they rest in the grey matter, invasive devices produce the
highest quality signals of BCI devices but are prone to scar-
tissue build-up, causing the signal to become weaker or even
lost as the body reacts to a foreign object in the brain.
Semi and Non Invasive
• Electrocorticography (ECoG) measures the electrical activity of the brain taken from beneath the skull in a similar way to non-invasive electroencephalography but the electrodes are embedded in a thin plastic pad that is placed above the cortex, beneath the dura mater.
Electroencephalography In conventional scalp EEG, the recording is obtained by placing electrodes on the scalp with a conductive gel or paste, usually after preparing the scalp area by light abrasion to reduce impedance due to dead skin cells. Many systems typically use electrodes, each of which is attached to an individual wire.
fMRI = Functional Magnetic Resonance Imaging fMRI exploits the changes in the magnetic properties of hemoglobin as it carries oxygen. Activation of a part of the brain increases oxygen levels there increasing the ratio of oxyhemoglobin to deoxyhemoglobin.
Magnetoencephalography (MEG) MEG detects the tiny magnetic fields created as individual neurons "fire" within the brain. It can pinpoint the active region with a millimeter, and can follow the movement of brain activity as it travels from region to region within the brain.