AUTOMATIZED BRAIN COMPUTER INTERFACE : AUTOMATIZED BRAIN COMPUTER INTERFACE INTRODUCTION : INTRODUCTION BRAIN-COMPUTER INTERFACE ,is a direct communication pathway between a brain and an external device
The specimen brain is able to motor memory for controlling a virtual device in a manner similar to the way it creates such memory for the specimens body.
Here the specimen with electrodes implanted in their brains used their thoughts to control a computer cursor.
Multiple electrodes spreads over a greater area of the brain to obtain neuronal signals to drive a BCI. ANALYSIS MADE WITH A SPECIMEN : ANALYSIS MADE WITH A SPECIMEN The analysis involve arrays of microelectrodes implanted on the primary motor cortex of a monkey .
The microelectrodes are implanted to about 2 to 3 millimeters deep into the brain ,tapping 75 to 100 neurons.
The activities of the neurons are carefully monitored using software which analyze the waveform and timing of the signals. MONKEY OPERATING A ROBOTIC ARM WITH BRAIN COMPUTER INTERFACING MANUAL CONTROL Vs BRAIN CONTROL : MANUAL CONTROL Vs BRAIN CONTROL During manual control the specimen maneuvers the computer cursor while the analysis records the neuronal activity ,used to create a decoder.
Under brain control ,the analysis feed the neuronal signals into the decoder ,which then controls the cursor.
The decoder is basically a set of equations that multiply the firing rates of the neurons by certain numbers ,or weights. continues…. : continues…. When the weights have the right values ,the neuronal data can be plugged into the equations and they will spill out the cursor position.
Next the scientists immobilized the specimen arm and fed the neuronal signals measured in real time into the decoder.
Initially ,the cursor moved spastically. Continues… : Continues… But over a week of practice the performance climbed to nearly 100 percent.
For those later session , the specimen didn’t have to undergo any retraining it promptly recalled how to skillfully maneuver the cursor.
In predicting the kinetic parameters of limb movements , BCIs predict electrical activity of muscles are being developed which could used to restore mobility in paralyzed limbs by electrically stimulating muscles.
When the BMI session began , the neurons quickly locked into a pattern of activity-known as a cortical map-for controlling the cursor. CORTICAL MAP : CORTICAL MAP Cortical map can be stable over time and readily recalled . But they also demonstrated a third characteristics.
These cortical maps are robust , resistant to interference . DEMONSTRATION OF CORTICAL MAPPING : DEMONSTRATION OF CORTICAL MAPPING This technique taught the specimen how to use a second decoder.
To create the new decoder , they again recorded the neuronal activity while the specimen manually moved the cursor using the exoskeleton arm .
The new data sets contained small fluctuations compared with the original one’s, resulting in different weights for the equations. Continues… : Continues… As expected the performance was poor at first , but after just a few days it reached nearly 100 percent .
After about just three days , the specimen learned the new decoder.
Just as before , practice allowed the neurons to develop a cortical map for the new task. INVASIVE BCI’s : INVASIVE BCI’s The research has targeted repairing damaged sight and providing new functionality to persons with paralysis.
Invasive BCI’s 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’s. OSERVATION MADE ON THE SPECIMEN : OSERVATION MADE ON THE SPECIMEN A single array BCI containing 68 electrodes was implanted onto specimens visual cortex and succeeded in producing phosphenes , the sensation of seeing light.
The system included cameras mounted on glasses to send signals to the implant. ELECTROCORTICOGRAPHY : ELECTROCORTICOGRAPHY ECoG measures the electrical activity of the brain taken from beneath the skull .
The electrodes are embedded in a thin plastic pad that is placed above the cortex , beneath the durra mater.
This research indicates that control is rapid , requires minimal training.
Thus we conclude by saying that this technique is more useful for physically challenged people. Slide 13: QUERIES..? THANK YOU. : THANK YOU.