Brain Computer Interface

    Brain lies in the cranium of skull. The human brain has wrinkled surface and appears as a large, soggy, pinkish grey walnut. Adult brain, on average, weights two per cent of their body weight, growing from the quarter of its size at the time of birth.  the reaches between 75 and 80 percent of adult size at the size of 6 years. Human brain composed of about 30 billion neurons. It weights about 15- 17% of cardiac output. It also receives about 20% of the oxygen consumed by the body. The left hemisphere of the brain controls the right side of the body and vice-versa. Regions of the brain:  Fore-brain: It  consist of three parts Olfactory lobe, Cerebrum, Hypothalamus The cerebrum is the largest part of the human brain. the cerebral cortex is roughly 80% of total brain mass. the Cerebrum is the most complex and specialized  part of the brain. It consists of two cerebral hemispheres. The  cerebr...

The human nervous system consist of three functional subsystems, the central nervous system, functional nervous, system, and autonomous nervous system. brain and  spinal cord make Central Nervous System(CNS). The Peripheral Nervous System includes all the nerve pathways of the body outside the brain and spinal cord. These pathways are divided into two parts. These are the sensory pathways and motor pathways . Sensory pathways transmit information to CNS(Central Nervous System) . the motor pathways transmit commands from the CNS.   The motor pathways are partitioned into  somatic nervous system which relay to commands to skeletal muscles and Automatic nervous that stimulates the glads and other muscles of the body. In addition there is a neuroendocrine  system which is a network of endocrine glands  whose hormone production controlled by  CNS.   Neuron is the structural and fictional part of the  nervous system . It is the largest ...

  Bellow graphs taken for selecting which time is better for the study PSD of EEG signal.   In the Fig 4.17 EEG data of channel taken for 1s. This data pass through the band pass filter for separating different frequency bands. For calculating the power spectrum density of each band we need to calculate the mean of all amplitudes present in the frequency band. In the delta band,  from the observations data it is seen that the amplitude of channel 6 is high as comparing the other channel. This channel present on the frontal lobe of the brain. For the channel seven amplitude man of frequency band suddenly deceasing. The position of this electrode is the right hemisphere of the brain. For this observation frontal part of right hemisphere is dominant, however it is seen that the subject doing the left side work. Generally the right hemisphere of the brain sees the work of the left side and vice versa. Next channel 8 amplitude mean is high which is placed on central l...

It is designed by giving higher cut of frequency and lower cut of frequencies. We record EEG signal externally by using Electrodes. Because of that Skin noise, skull noise, disturbance noise, power line noise etc noise present in EEG signal. For removing the higher cut off and lower cut of frequency from the signal band pass filter is used. We want the signal frequency up to 30 Hz because the beta band frequencies is up to that frequency. Design the Band pass Butterworth filter in the matlab by using the code Algorithm: i) First take eeg input data ii) Pot that data iii) Mention the sampling frequency iv) Calculate the normalize frequency by using formula fnormal = cut of frequency (Fs/2) v) Then design the butter of the filter in that we put the order of filter, normalize frequency , curve type, for this we take two vectors. vi) Then filter the data using Filtfilt . it performs zero-phase digital filtering by processing t...

For study the FFT of periodic and EEG signal program is written in the matlab by using the signal processing function FFT. The FFT of periodic signal shows the different for the sine, square, triangular, swatooth signals. FFT of EEG signal shows that the frequency components present in that signal. The algorithm of this periodic signal program is given bellow. Algorithm For the periodic signal i) Create a periodic signal using signal processing functions. ii) Mention the sampling frequency iii) Give the amplitude and frequency of the periodic signal iv) Pot that signal v) Take the FFT of the input signal vi) Plot the half of the sampling frequency components for the x axis. vii) Plot the FFT of the signal frequency verses amplitude. For the EEG signal i) First read EEG input data from the .xls file. ii) Give the sampling frequency given when recording the EEG signal. iii) Plot the EEG signal. iv) Take the FFT of the EEG signal. v) Plot the half of the sampling ...

Study of brain computer interfacing using fourier transform starting from the study FFT of Periodic signal such as sine, square, triangular, swatooth. For the study FFT start from the basic periodic signal is good work. When study of periodic signal is understood completely then start the Fourier transform of the EEG signal. The Fourier transform of EEG signal is important for the detecting the actual frequency components from the signal. After that the separating frequency spectrum bands from EEG signal design the band pass filters for each band. Next step of the study is calculate the amplitude mean of the each frequency spectrum band of the EEG signal, from that we can detect which channel of the brain in dominant. However we can detect which part of the brain is in currently working state. To prove this result analyses the EEG signal of different task given for the subject using the different electrode montage.

Many researchers are working on the Brain computer interfacing. They work on different methods of BCI. The analysis of EEG signal is doing by using Fourier transform, Wavelet transform. FFT is good method of analyzing the EEG signal. For the studying FFT of signal firstly study of periodic signal is important because the knowing the actual Theme of FFT. Periodic signals means the period is given to the signal. These signals are sine wave, square wave, triangular and swatooth waves. After that by using FFT study the EEG signal. FFT of EEG signal shows the number of frequency components present in the signal. In the different frequency bands are present such that delta, theta, alpha, beta. For separating these frequency bands band pass filters are designed. Power spectrum density has calculated by taking mean amplitudes present in the frequency bands for each channel. Calculate the frequency spectrum density for all bands, from that PSD showing the dominant part on the brain is possib...