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Institute of Medical Psychology and Behavioral Neurobiology (Germany)
Wadsworth Center (USA)
BCI2000:
A General-Purpose
Software Platform for
BCI
Acknowledgement
I would like to thank all the
providing their material which I
this presentation and at the
would also apologize for
copyrights violations.
author(s) for
have used in
same time I
unintentional
Asad
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Motivation
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Outlines
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•
•
•
•
•
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Introduction & Methodology
Technical Details
System Working (Applications)
Experimental Results
Conclusions
References
Open Questions for Discussion
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Introduction (BCI)
• Uses brain signals to convey intent
• Does not use peripheral nerves or muscles
• Can provide communication and control to people
who are totally paralyzed
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Motivation to BCI2000
• Most of the Brain signals processing systems do not
readily
support
systematic
research
and
development, like
• Evaluating and comparing alternative signals and
combinations of signals, alternative feature extraction
methods, alternative translation algorithms, and control
mechanism for different users.
• In recognition to this situation, BCI2000 was
developed to provide and facilitate the systematic
studies.
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BCI2000 (1/4)
• Factors determine BCI System performance
• Brain signals measured, the signal processing to extract
features, the algorithms to translate features into device
commands, the output devices to execute commands, the
feedback to the user, and user characteristics.
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BCI2000 (2/4)
• Essential Features
• Common Model: Using TCP/IP, so modules can be
developed in any programming language.
• Interchangeability and Independence: Good flexibility, low
coupling and high cohesion.
• Scalability: No constraints on the no of signal channels or
their sampling rate, no of system parameters, and etc.
• Real-Time Capability: To achieve minimum latency jitter,
BCI2000 is designed in a way to minimize the response
time of RT-OS, HD, and other
sources of interruptions.
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BCI2000 (3/4)
• System Variables
• System Parameters: SP are those variables that do not
change throughout a data file i.e. during a specified
period of online operation.
• Event Markers: EM record events that occur during
operation and can change from one data sample to the
next. EM’s allows full reconstruction of a session.
• System Signals: SS’s are functions of user’s brain signals
that are received and modified by the modules.
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Defines system parameters; trial length in a specific application,
Converts
signals
from the
into
signals that
or specific signal processing
variable.
Also signals
defines
thebrain
onset
and
It
receives
control
from
Signal
processing
and
Stores and passes it to signal processing module.
control these
an output
device are made by
offset of operation. Where
definition
uses
them to derive
application
It have data acquisition and storage components
Thebyconversion
is inantwo
steps; display
1) feature extraction
automated algorithms or
the
investigator.
Can
User
applications
are
presented
visually
on computer
File contains ASCII header followed bylikebinary
firing
rate allow
of a cortical
neuron, amplitude
of an
information from any module,
which
the
investigator
to
and
consists
of
selection
of
targets,
letters,
signal samples and then an event marker screen
evoked
potential,
and information
etc 2) translation
control the experiment and
receive
real time
about algorithms
icons
and
etc.
the brain
signalsignals)
features into control signals that
online events (display oftranslates
unprocessed
are sent to user application module
Sys Para
Sig Proc
BCI2000 (3/4)
• Modules
Display
and
control
Info
Display
and
control
Info
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Technical Details
Initial Implementations of BCI2000
• Platform
• Language and Development Environment : BCI2000
system model accommodates any programming
language and any development environment for
implementation. C++ with development environment of
Borland C++ Builder is used for BCI2000 implementation.
• Operating System: MS WindowsTM 2000/XP are used for
the BCI2000 development.
• Device drivers facility
• Real time processing requirements
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Initial Implementations of BCI2000
• Source Module
• Five source module implementations created to date.
Three of them control A/D converter boards, one for EEG
recoding system, and the fifth one is for signal generator
for use in system development and testing.
• In the case of A/D converter boards, brain signals must
first be conditioned i.e. band-pass filtered and amplified,
so that they can be detected by the A/D hardware.
• The data storage component incorporated in these source
implementation is highly optimized so that many data
channels and /or high digitization rates can be used with
minimal effects on the latency of real-time operation.
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Initial Implementations of BCI2000
• Signal Processing Module
• The first stage is feature extraction from the digitized
brain signals. Three signal operators are applied here; 1)
linear transformation of the input matrix i.e. sample block,
2) Linear spatial filters (Laplacian derivation or common
average, IC, and Common Spatial Patterns), 3) Temporal
Filters (slow wave filter, autoregressive spectral
estimation, finite impulse response filter and a peak
detection routine) are applied here.
• In second stage, the translation algorithms translates the
signal features to control signals to be used by user
application.
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Initial Implementations of BCI2000
• User Application Module
• Seven different application are implemented
• Four cursor movement, one evaluating prospective
user, present user selectable auditory and visual
stimuli, and a spelling application based on evoked
potentials.
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Initial Implementations of BCI2000
• Operator Module
• Provides a graphical interface that displays current
system parameters and real-time analysis results (e.g.,
frequency spectra) communicated by other modules. It
allows the investigator to start, stop, suspend, resume,
or reconfigure system operation. In a typical BCI2000
configuration, user feedback is displayed on one monitor
and the operator module’s graphical interface is
displayed on a second monitor.
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User Interface of BCI2000
A Typical BCI2000 System
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BCI2000 Features
• Supported Hardware
•Guarantee support for all devices from g.tec;
•Data Translations, National Instruments, Measurement Computing,
Modular-EEG,
•Neuroscan, Brain Products, and Micromed
• Supported Brain Signals
•Evoked Potentials, EEG mu/beta Rhythms (ERD/ERS), ECoG
Oscillations, Slow Cortical Potentials, Single-Neuron Action Potentials
• Supported Feedback Protocols
•Auditory & Visual Stimulus Presentation, 1D/2D/3D Cursor Movement,
n-Choice Speller, P300 Matrix Speller
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BCI2000
Applications
BCI2000 Application Demonstration
BCI2000 Applications
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Two-Dimensional Control of a Robotic Arm
Spelling using EEG and Dasher
Four-Target Selection Using Tactile Feedback
BCI Control of a Domotic Assistive System
Rapid Identification of Motor Cortex
Overall View
BCI2000
Evaluation
BCI2000 Performance
1.
2.
1.4 GHz, 256 Mb RAM, IDE I/O, DT3003, Windows 2000
2.53 GHz, 1 Gb RAM, SCSI I/O, NI 6024E, Windows XP
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BCI2000 Performance
1.
2.
Topographical distribution of P3000 potential at 340 ms after stimuli
Solid line for desired char and dashed line for un-desired char
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BCI2000
Benefits
Benefits of BCI2000
• To The Investigator
Availability of a complete economical system
already allows for a range of studies
that
• To The Software Engineer
Concentration on the aspects that are unique to
the new BCI method that is to be developed
•
To End User
Large community which helped achieving a
stable release made custom solutions available.
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Future Development of BCI2000
• Platform
• Modules
• Source Module: Currently support data acquisition
hardware from four different vendors
• Signal Processing: Currently, it extract features from
scalp-recorded sensori-motor cortex rhythms, cortical
surface rhythms, slow cortical potentials, cortical single
neurons, and P300 evoked potentials. Other brain signals,
such as the error potential, cortical field potentials, or
intra-cortical neuronal activity are not implemented.
• User Application Module: Auditory plus visual feedback
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Conclusions
Bad decisions are tomorrow’s
constraints.
BCI (with BCI2000) is an
Good
decisions
tomorrow’s
oPEN
dOOR to are
the Future.….
opportunities.
BCI2000 with executables and source code, and documentation is available for
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free for research and educational purposes at http://www.bci2000.org
References
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Schalk, G., McFarland, D., Hinterberger, T., Birbaumer N., Wolpaw J. "BCI2000:
A General-Purpose Brain-computer Interface (BCI) System." IEEE Trans.
Biomed. Eng. , vol. 51, pp. 1034-1043 (2004)
http://bci2000.org/BCI2000/Home.html.
http://www.bciresearch.org/BCI2000/download.html
http://www.bci2000.org/wiki/index.php/User_Tutorial:BCI2000_Tour
http://bci2000.org/BCI2000/Videos/Videos.html
Towards Brain-Computer Interface, Edited by: Guido Dornhege, Jose del R.
Millan, Thilo Hinterberger, Dennis J. McFarland, and Klaus-Robert Muller, The
MIT Press
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Questions????
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Open Discussion Questions
• Experiments
• Music
Future
BCI2000 Architecture
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