3. Neurotechnology Research Systems
iii
The diagram shows how neural
signals are processed and
visualized online via Plexon
hardware and software.
Corporate Overview
Plexon is a leading provider of innovative data-acquisition
hardware and software for recording and analyzing signals
from the brain and peripheral nervous system. Based
in Dallas, Texas, Plexon provides tools for basic brain
and nervous system communication research, brain-
machine interfaces, and neuroprosthetics for the growing
neurotechnology industry.
Who We Are
Founded in 1983 by Harvey Wiggins, Plexon has grown from
a one-person company to a team of engineers, biophysicists,
and neuroscientists with expertise in research, product
development, and advanced neurotechnology research
systems. Plexon’s customers include over 400 domestic and
international academic research labs, research hospitals,
pharmaceutical companies, and military labs. For example,
Plexon’s Multichannel Acquisition Processor is being used
in groundbreaking neural research by customers such as
the East China Normal University in Shanghai, where it is
used to study the role of genes in Alzheimer’s Disease, and
at Duke University’s Center for Neuroengineering, where
neuroscientists are conducting experiments linking the
brain to robotic devices. In recognition of the organization's
accomplishments, Plexon was named to the North America
Fast 500 and the Texas Crescent Technology Fast 50 by
Deloitte & Touche USA LLP in both 2004 and 2005.
What We Do
Plexon designs, builds, and markets advanced hardware and
software that is used to acquire, amplify, record, and analyze
action potential signals (spikes) from individual brain cells
(neurons), as well as lower frequency field potential (EEG)
signals and behavioral and stimulus events. These signals
are typically recorded from live
animal or human brains, brain-slice
cultures, or chambers.
Plexon’s products enable online, real-time visualization of
neural signals relative to external events and stimuli. This
data is used for a wide variety of purposes, such as:
• studying basic information processing in
the brain relating to visual, auditory, motor,
memory, and other neural functions
• studying the effects of drugs and toxins
on brain information processing
• controlling external devices such as prosthetic
limbs or machine hardware systems
Typically researchers implant electrodes in the brain or
mount them in a brain-slice culture. The diagram below
illustrates how the electrical signals from these electrodes
are processed. Each neuron generates a distinct waveform.
Plexon’s solutions use advanced pattern recognition and
cluster analysis algorithms to discriminate and assign
individual waveforms to specific neurons.
The result is the timing of the individual spikes that represent a
neural code, which can be used to determine communication
pathways and map the functional operation of the nervous
system. In addition to providing insight into basic brain function,
this technology has broad implications in the development of
interfaces for direct brain-machine communication and for
prosthetic devices for nervous-system impaired individuals.
For additional information on our neurotechnology
research systems, contact Plexon at 214-369-4957 or at
info@plexoninc.com.
4. Neurotechnology Research Systems
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Multichannel Acquisition Processor
Features
• Powerful, large-scale neuronal waveform
recording and real-time spike sorting using
digital signal processing (DSP) hardware
• Supports stereotrode and tetrode data acquisition
• Easily scalable from 16 to 128 channels
• Independent programmable referencing
for spikes and field potentials
• Provides a clock capable of synchronizing all of
the components in the data acquisition system
• Simultaneous 40 kHz (25-μsec) analog-to-digital
(A/D) conversion on each channel at 12-bit resolution
• Multiple digital inputs for external synchronization
and experiment-state of variables from
behavioral equipment, such as individual
TTL lines of multi-bit strobed word data
• Optional analog signal acquisition for
continuous recording of spike, field potential,
physiological, and behavioral signals
Description
The Plexon Multichannel Acquisition Processor (MAP) sets
the standard for programmable amplification, filtering, and
real-time spike sorting of multi-electrode signals acquired in
neurophysiological research. The MAP is a modular system
of plug-in circuit boards that are mounted in a stand-alone
box. This unique architecture results in a robust and reliable
system that is easily scalable from 16 to 128 channels.
The MAP system can also record up to 64 continuous
analog signals at 40 kHz using National Instruments™ Data
Acquisition (NI DAQ) devices. For example these signals
Multichannel Acquisition Processor™
Neuronal Waveform Recording and Real Time Spike Sorting
can be field potentials, eye position, or blood pressure. The
analog channel count is dependent upon the acquisition
speed. Decreasing the acquisition speed to 10 KHz increases
the channel count to 256 channels.
A powerful component of the MAP system is the Plexon MAP
Control Software, or Real-Time Acquisition System Programs for
Unit Timing in Neuroscience (RASPUTIN), a suite of client/server
programs that control spike sorting in the MAP and provide
real-time data visualization and analysis. The RASPUTIN
program records spike, digital-event data, and analog signals in
to a single data file.
Behavioral Control,
Video Capture, and Tracking
Camera
Multichannel Acquisition Processor (MAP)
Preamp
A/D
LINK
Headstage
PC with Data
Acquisition Capability Low-Frequency
Analog
Spike
Waveforms
Spike Timestamps,
Events, and Tracking Data
Timing and Synchronization
Preamp
Headstage
SIG
HLK2
TIMDSPOUTSIG
1-16
17-32
SIGSIG
MultichannelAcquisitionProcessor
(MAP)TypicalApplication
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Sort Client (main window)
MAP Control Software - RASPUTIN™
RASPUTIN™
isasuiteofapplicationsforcontrol,visualization,
and data analysis.
RASPUTIN's primary application/user interface is Sort
Client™
. Sort Client visualizes, analyzes, and records
spike waveforms that have been filtered and sorted by
the MAP. The main window of Sort Client, shown at the
right, displays the waveforms in several different views to
facilitate detection and classification of spikes.
One method the MAP uses to identify neurons is displaying
waveforms as data points in three-dimensional principal
component analysis (PCA) space. As shown in the close
up view of the 3-D Cluster Display at the lower right, a
cluster of points, which represents an individual spike, can
be easily selected by drawing a boundary around it, which
then establishes a template that is sent back to the MAP
for real-time sorting.
Sort Client Features
• Real-time spike waveform detection and
classification via template matching or
time-voltage window discrimination
• Programmable gain and spike detection thresholds
• Online viewing of continuous signals,
thresholded spikes, activity rasters,
and 2-D and 3-D cluster displays
• Multi-channel waveform display
• Open file format allows recorded spikes or
continuous real-time signals to be accessed
via NeuroExplorer®
, MATLAB®
, or C/C++®
Additional RASPUTIN Applications
In addition to Sort Client, RASPUTIN includes the following clients, all of
which provide on-line functionality:
• REF2 - Tool for configuring MAP and preamplifiers
• Graphical Activity Client - Strip-chart display for
monitoring spike activity or continuous waveforms
• Grid Monitor Client - Display of spike-rate
activity as an animated color grid
• PeriEvent Client - Display of histograms and perievent rasters
• PlexNet - Real-time broadcast of MAP data to other computers within a TCP/IP (Ethernet) network
• Tuning Curve Client - Real-time tuning curve plots firing rates around user-identified events
• Client Development Kit - API and sample code for developing custom applications in C/C++ or MATLAB.
Principal Component Analysis
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Recorder/16™
and Recorder/64™
Neural Data Acquisition System
Features
• Available in 16 or 64 channel
configurations
• Digital filtering for flexible separation
of spikes and field potentials
• Digital event recording (individual TTL
or multi-bit strobed word format) of
experimental and behavioral data
• Independently selectable digitizing
rates for spikes and field potentials
• Programmable referencing
(differencing) for artifact removal
• Output monitor channel for viewing
raw signals on oscilloscope
• Multichannel display of spike
waveforms and firing rates
• Wavestrip scrolling display of continuous
wide-band or filtered signals
• Real-time FFT display of raw
and filtered signals
• Remote start/stop capability for
efficient trial-based recording
Description
Recorder/16 and Recorder/64 are Windows®
-based neural
data acquisition systems for continuous digitization of up to
16 channels (Recorder/16) or 64 channels (Recorder/64) of
spike signals, thresholded spike segments, field potentials,
and external digital events.
Data recorded from either system can be read by Plexon’s
Offline Sorter (OFS) for spike classification, and can then
be imported into NeuroExplorer®
or MATLAB®
for analysis.
7. Neurotechnology Research Systems
Recorder system signal flow diagram
Specifications
Technical Specifications - Recorder/16
A/D Channels 16
A/D Resolution 16 bit or 12 bit
Sampling Frequency per Channel Up to 50 kHz
Digital Filtering Filter types: Butterworth, Bessel, Elliptic (1-pole, 2-pole, 4-pole)
Bandpass, lowpass, highpass, notch
Digital Event Channels 16 TTL or up to 15 multi-bit strobed word
Bandwidth 1 Hz-6 kHz or as requested
Gain Steps 1000, 2000, 5000, 10000, 20000, 50000, 100000
Technical Specifications - Recorder/64
A/D Channels 64
A/D Resolution 16 bits
Sampling Frequency per Channel Up to 40 kHz
Digital Filtering Filter types: Butterworth, Bessel, Elliptic (1-pole, 2-pole, 4-pole)
Bandpass, lowpass, highpass, notch
Digital Event Channels 16 TTL or up to 15 multi-bit strobed word
Bandwidth 1 Hz-6 kHz or as requested
Gain Steps 500, 1000, 1500, 2000, 2500, 3000, 3500
8. Neurotechnology Research Systems
Features
• Online spike sorting via template sorting
or time-voltage discriminator windows
• Several methods of automatic spike
waveform identification
• Automatic thresholding and automatic
template adaptation
• Online viewing of continuous signals,
thresholded spikes, activity rasters,
and 2-D and 3-D cluster displays
• Multi-channel waveform display configured
for standard MEA electrode layouts
• Open file format; recorded spikes
and/or continuous signals can be
accessed via NeuroExplorer®,
MATLAB® or C/C++® programs
MEA™
Workstation
System for Recording and Analyzing Microelectrode Arrays
Description
MEA Workstation (MEA WS) is
a complete system for recording
and analyzing up to 64 channels of
microelectrode arrays (MEAs). The
MEAWorkstationusestheMEAWSsuite
of software programs, which computes
and displays real-time statistical features of the
spike waveforms in three-dimensional Principal
Component Analysis (PCA) space.
The recorded signals are amplified and filtered by
the Plexon Preamplifier, and then sent to the ADS64
acquisition device, which provides simultaneous 16-
bit sampling at 40 kHz per channel. MEAWS software
then displays the spike waveforms and separates
them into units that represent individual neurons.
Typical MEA workstation with
PC, data acquisition cards,
preamp, and headstage.
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An illustration of a typical Plexon/TBSI wireless application
using the 12-gram headstage with integrated battery.
An illustration of a typical Plexon/TBSI wireless application
using the 12-gram headstage with integrated battery.
MEA Workstation Software
The MEA workstation ships with all of the software required
to acquire and analyze data including MEA Sort Client, the
system's primary control program.
MEA Sort Client, the primary user interface for MEA
Workstation, provides a complete environment for
visualizing, analyzing, and recording spike waveforms.
The main window of Sort Client displays the waveforms in
various views to facilitate detection and classification of the
spikes. As shown in the close up view of the 3D Cluster
Display (below), a cluster of points, which represents
an individual spike, can easily be selected by drawing a
boundary around it, which then establishes a template for
sorting.
In addition to MEA Sort Client, the MEA Workstation
software suite includes these other programs:
• Graphical Activity Client - Real-time display for
monitoring spike activity or continuous waveforms
• Grid Monitor Client - Real-time display of
spike-rate activity as an animated color grid
• PeriEvent Client - Real-time display of
histograms and perievent rasters
• PlexNet - Real-time broadcast of MEA
Workstation data to other computers
within a TCP/IP (Ethernet) network
• Client Development Kit - Sample code for
developing custom applications in C/C++ or MATLAB
• MEA Server - Interface for transferring commands
and data to and from the MEA acquisition hardware
MEA Workstation Technical Specifications
System Requirements Windows® operating system
A/D Conversion Rate Simultaneous 40 kHz (25 microseconds) on each channel at a
16-bit resolution
Digital Inputs Up to 2, for external synchronization and experiment-state
variables from experimental equipment, such at TTL lines
Compatibility University of North Texas micro-electrode arrays and the Multi
Channel Systems MEA preamplifier
Preamplifiers
• Software programmable gain from 2500 to 17500
• Zero-latency analog monitoring output
• Connections for TTL event inputs
• Used with Plexon Headstage Preamplifier for
UNT MMEP arrays only (MCS systems come with their own
headstage amplifier)
MEA Preamp
Headstage Preamp
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CinePlex arena with camera and
screen capture of the markup software.
Features
CinePlex Capture Features
• Video capture that can be synchronized with
neural recordings from the Plexon Multichannel
Acquisition Processor (MAP) or Plexon Recorder
• Standard video .avi files in Motion JPEG format
• Selectable image quality setting
• Flexible input and output (I/O) options
• All-digital imaging with Imaging
Source™ camera (640 x 480
resolution, 30 frames per second)
• Optional tracking feature that provides
three methods for real-time animal position
tracking: body contour using image contrast,
colored LED lights on headset (up to three
colors), and reflective color swatches
• Recording of contour motion across
adjacent video frames to detect freezing
behavior in fear-conditioning experiments
• Encoded position data is available
to online user-written programs
CinePlex Markup Features
• Integrated viewing of neural data files
(Plexon .plx, NeuroExplorer .nex) and .avi files
• Full digital video recorder (DVR) playback capabilities
• Display of tracking position data overlaid on video
• Video-aided insertion of event markers and intervals
• Removal of temporal segments of
neural data during artifact-generating
behaviors (chewing, grooming, etc.)
• Ability to edit position data from CinePlex
Capture, and manually enter new coordinates
• Seek and search based on event markers
• Save neural data to Plexon (.plx) and NeuroExplorer®
(.nex) files, or export to Excel®
, MATLAB®
, or text files
Description
CinePlex is a digital video recording and tracking tool that
enables the synchronization of video (.avi files) with neural
data files. The synchronized video, tracking coordinates, and
neural data can then be played back offline, where behavioral
event markers and time-interval variables can be inserted.
The marked-up data can be exported for further analysis.
CinePlex™
Digital Video Recording and Tracking System
CinePlex consists of CinePlex Capture and CinePlex Markup.
CinePlex Capture. CinePlex Capture is a hardware and
software solution that enables the simultaneous capture and
recording of synchronized video and generates real-time
tracking coordinates.
CinePlex Markup. CinePlex Markup is an offline software
tool that enables the viewing and editing of the neural and
tracking data simultaneously with the video.
11. Neurotechnology Research Systems
Typically the CinePlex unit is used in conjunction with the
Multichannel Acquisition Processor (MAP). The CinePlex
Capture processor receives and processes raw video from
a Firewire camera. CinePlex compresses and stores the
captured video on the hard drive, as an .avi file. The MAP
signals the CinePlex processor unit to start, stop, pause, and
resume recording video to the .avi file. The MAP system also
provides a clock signal that enables CinePlex Capture to
time stamp each video frame.
Tracking Option. The available tracking option enables
CinePlex Capture to analyze each frame of video data to
determine the positions of the objects being tracked. The
processor unit encodes this position information digitally
and sends it back to the MAP system through the capture
cable where it is saved directly into the neural data file. This
position data information is also available to online user-
written programs
The video, tracking, and neural data can then be imported into
the CinePlex Markup software to visualize the data and define
new event markers and time intervals.
CinePlex Technical Specifications
Hardware (Included)
CinePlex Capture Processor Unit; video camera, lens, mouse, monitor, software keys,
connecting cables, camera mounting equipment to suit environment; for the Recorder
version, it also includes a modified C-HUB or a modified SCB-68 breakout box
Hardware (Not Included) A suitable arena for your experiment
System Requirements Windows® operating system
Video Resolution Capabilities
CinePlex Capture records video into MJPEG .avi files at a resolution of 640x480 pixels at
30 frames per second
Typical CinePlex Setup with the Plexon
Multichannel Acquisition Processor (MAP) System
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Offline Sorter Screen Capture
Features
• Automatic cluster selection in feature
space using valley seeking or T-Distribution
E-M (Expectation Maximization)
• Manual cluster selection in 3-D feature
space using principal component
projections, voltage slices in time, or
more than 20 other waveform features
• Semi-automatic cluster selection in feature
space using K-means or Standard E-M
• Waveform selection in time-voltage space
• Template matching algorithm
• Stereotrode and tetrode and waveform
extraction and sorting using any method
• Unit cross-correlograms and ISI plots
• Waveform density plots in 2-D
or 3-D in any feature space
• Waveform alignment
• Interval invalidation and artifact removal
• Raster displays of spikes
and continuous data
• Printable sorting summary view
with export to PowerPoint®
• Sort summary statistics
• Waveform features and statistics that can be easily
exported to MATLAB®
, Excel®
or text file
• Export of sorted data to Neuroexplorer™ or
optimized binary format (for fast loading)
Description
Offline Sorter (OFS) speeds up the process of selecting
and classifying action potential waveforms (spikes)
collected from single electrodes or stereotrodes/
tetrodes. Spikes can be displayed as points in either 2-D
or 3-D feature space, where a variety of manual, semi-
automated, or fully automated clustering techniques
can be applied in order to classify (sort) the spikes.
OFS can also perform spike extraction on continuously-
recordedneuraldatausingseveraldifferentthresholding
methods. OFS allows verification of sorting through a
variety of displays, and can calculate statistics and sort
quality metrics. The sorted spikes can be exported in
several formats for subsequent analysis.
Offline Sorter™
Offline Spike Extraction and Sorting Software
Offline Sorter Screen Capture
Tetrode and Stereotrode Sorting
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Multiple methods for spike detection in continuously digitized
data files can be used, including:
• Voltage threshold
• Signal energy (~ voltage2
)
• Nonlinear energy
Stereotrode and tetrode spike detection is supported. A
low-cut filter may be applied to the continuous data prior to
spike extraction.
The typical analysis pathways and files related to OFS are shown
in the diagram below.
Offline Sorter (OFS) can be used to sort or re-sort data
files containing either thresholded waveform segments or
continuously digitized data. File types supported include:
• Plexon
• NeuroExplorer
• Cyberkinetics
• CED Spike-2
• DataWave
• Neuralynx, Inc.
• Multi Channel Systems
• Panasonic MED
• Neuroshare
• Generic binary continuous data
Requirements:
• PC with Windows 2000 or XP (with
1 GB RAM recommended)
• Plexon hardware license key
• Modern graphics subsystem with OpenGL support
For ordering information contact Plexon Sales at (214) 369-4957 or
info@plexoninc.com. You may also download a fully functional demo
version from http://www.plexoninc.com/software_downloads.htm.
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Plexon Motorized Commutator
Features
Non-Motorized
• Manages twisted cables
• Unique slip ring design ensures signal integrity
from headstage to data-acquisition system
• Low torque design for small animals
Motorized
• Manages twisted cables
• Unique slip ring design ensures signal integrity
from headstage to data-acquisition system
• Low torque design for small animals
• No need for stiff headstage cables to transmit torque
• Up to 96-data channels for
high-channel count recording
• Extremely low torque of less than 300 µNm needed
for the motor to engage and track rotation
• Motorized commutator utilizes a magnetic Hall-
effect sensor, which detects angular displacement
of the input connector block and signals the motor
to rotate, preventing the wires from twisting
• Infinitely adjustable tracking/rotation speed from 1
⁄6
revolution per second to over 1 revolution per second
• Contactless actuation, which eliminates
switching noise on data channels
Description
Neurological research involving behavioral tests using small
animals requires the animals to be able to move freely within
the confines of the experiment. Acommutator allows the animal
to move freely while the wires associated with the experiment
accurately relay the signals from the headstage to the preamp
via the commutators wires.
Plexon offers several commutators that are differentiated
from each other by motorized versus non-motorized and
channel count.
Plexon commutators are available in the following
configurations.
Motorized Commutators. The Plexon Motorized Commutator
is a highly sensitive electromechanical device designed for
animal experiments requiring rotating electrical contacts.
A magnetic Hall-effect sensor in the commutator base
recognizes any movement of the connector block. This is
a result of the subject's movement, which transmits torque
through the input wires. The sensor then signals the stepper
motor to rotate the commutator slip ring assembly so that
Commutator System
For Headstage Cable Management
it realigns itself to the same angular position as the input
connector block.
In practice this action occurs in response to movements so
small (depending on the setting of the ADJ RESPONSE
control) that the headstage cables never become twisted. The
commutator continuously tracks and adjusts to compensate
for any movement.
The commutator’s precision stepper motor has three step
sizes (1
⁄2, 1
⁄4, or 1
⁄8) with adjustable response and variable
speed controls. These controls allow tuning of the commutator
operation to more closely match the animal’s behavior. The
optimum settings can also reduce noise produced acoustically
by the motor vibrating the experimental enclosure as well
as electrically by mechanical vibration of the commutator’s
components.
Plexon Non-motorized Commutator
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Specifications
Non-Motorized Commutator
• Channels:
16 data channels
32 data channels
• Required headstage gain: 20x or 1x may be used
• Dimensions: Rotational assembly (includes
commutator), 330 mm x 76 mm diameter plus the
mounting plate; Electronic Drive, 203 mm x 77 mm x
203 mm; Power module, 95 mm x 70 mm x 160 mm
• Weight: Commutator, 4.0 lbs
Motorized Commutator
• Maximum speed: 60 Revolutions per
minute; three step sizes with adjustable
response and variable speed controls
• Channels:
32 data channels
64 data channels
96 data channels
• Power: 110v to 125v and 210v to 230v
operation automatically selectable
• Connector block torque: 300 µNm
• Required headstage gain: 20x or 1x may be used
• Position accuracy: Maximum positional
angular accuracy better than
+
⁄- 0.5 degrees
• Dimensions: Rotational assembly (includes
commutator), 330 mm x 76 mm diameter plus the
mounting plate; Electronic Drive, 203 mm x 77 mm x
203 mm; Power module, 95 mm x 70 mm x 160 mm
• Weight: Commutator, 5.7 lbs; Control box, 2.6 lbs
Individual Component Information
Commutators:
• COM/16 16-channel commutator
with Harwin connectors
• COM/32 32-channel commutator
with Harwin connectors
• COM/32m-H 32-channel commutator with Hall
effect sensor, stepper motor, and Harwin connectors
(for passing 32-signal channels plus headstage
reference, ground and, power channels)
• COM/64m-H 64-channel commutator with Hall
effect sensor, stepper motor, and Harwin connectors
(for passing 64-signal channels plus headstage
reference, ground and, power channels)
• COM/96m-H 96-channel commutator with Hall-effect
sensor, stepper motor, and Harwin connectors (for
passing 96-signal channels plus headstage reference,
ground and, power channels)
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NAN drive with laptop control computer
Features
• Modular - from 1 to 16 electrodes
• Stable recording site for hours
• Quiet during electrode movement - allows
recording during advancement
• Flexible positioning - Users can position each
electrode/tetrode independently in the XY plane
• Accurate positioning due to direct coupling
between the motor and electrode
• One micron resolution
• Flexible range - Users can position each
electrode/tetrode in the Z direction. Working
range up to 150 mm. Standard range of 55 mm
• Less than one minute per tower to replace electrodes
• Coarse movement system, XY table and sphere axis
• Lightweight: 25g per tower, 35g for a 4-channel base
• Sophisticated control software - The user can select
a subset of channels using a variety of controls
• Cost-effective system - A single drive accommodates
16 towers -- add towers as your needs increase
• Uses standard electrodes - Almost any stiff-
wire electrode can be used with the drive
Description
The NAN Electrode Drive is a modular, lightweight
extracellular microelectrode drive that uses individual towers
to independently position each electrode in the XY plane
grid. Brushless motors and a computer-controlled electrode
advancement system ensure accurate electrode positioning
of up to 16 single-site electrodes.
The NAN control mechanism and the power supply for the
drive's motors are consolidated in one component. The
included Windows®
-based control software allows the user to
select a subset of electrode channels to advance using the
following screen elements.
NAN Electrode Drive
Lightweight, Extracellular Microelectrode Drive
Components
NAN Instruments offers a
wide array of components for
accurate electrode positioning.
These include:
Four-ChannelBase-Thebase
may be round, rectangular, or
any other suitable geometry.
The base includes grooves in
which movable holders (tower
holders) are freely positioned in
the XY plane. It can be mounted
on a chamber, frame, robot's arm, or
any other suitable frame.
Tower - The tower includes a
miniature motor that is coupled
to a driving screw that moves
an electrode holder. The holder
can be customized to hold a
microelectrode, probe, needle,
dagger electrode, tetrode, or group
of electrodes.
Guide-Tube Holder -
This holder, attached to
the tower, allows probes
to get near each other.
Chamber System - The base
is attached to the chamber. The
standard grid fits a 23 gauge
tube with one mm spacing.
ElectrodeHolder
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Plexon/TBSI Wireless System
Wireless Neural Headstage System DSP-based
signal processor
(baseband demodulator)
RF Receiver and
System Diagram
Wireless
Headstage
wireless
transmission
Cable to
Plexon Preamplifier
An illustration of a typical Plexon/TBSI wireless application
using the 9.6-gram headstage with integrated battery.
Features
• Wireless range up to 1.5 meters
• Rechargeable battery delivers up
to 2-hours of operation
• Available in 4 or 15 channels
• Operates in unlicensed radio band below FCC Limits
• Lightweight headstages weigh less than 3 grams
• Selectable bandpass filtering per-channel
Description
The Plexon/TBSI wireless headstage system provides a
wireless connection between implanted neural electrodes
and Plexon's MAP®
or Recorder™
data-acquisition system.
This system enables untethered neural recording from freely-
behaving animals via a high-channel-count wireless device
that is small and lightweight.
The system consists of a wireless transmitter, a rechargeable
battery integrated directly into the headstage, and a signal
receiver/DSP-based signal-processing system.
The rechargeable integrated battery powers the headstage
transmitter for up to 2 hours. An optional battery pack delivers
up to 24 hours.
The receiver system consists of a radio-frequency (RF)
receiver/baseband demodulator that is powered by an
included AC to DC power adapter.
Headstage
The headstage transmitter is a wireless neural device that
enables researchers to continuously and simultaneously
monitor electrical activity from up to 4 or 15 neural electrodes,
depending on model.
Experiments are no longer constrained by the need to wire a
test subject to the recording system.
The headstage uses unique wireless ASIC technology and
proprietary radio design techniques to provide high-channel
count functionality in a wireless headstage that is both small
and lightweight. The design incorporates neural preamplifier
circuitry to create an extremely compact and powerful device that
transmits neural activity from the test
subject to the recording system.
Signal-Processing Unit
The RF receiver signal is
demodulatedbyaproprietarysignal-
processing system that uses a high-
speed analog to digital converter.
The demodulated signal is then conditioned by a digital signal
processor (DSP) and converted back to an analog signal for
output via a DB37 female connector.
Deployments of this system include studies involving rats,
rabbits, and monkeys. The system ships with several alternate
mounting mechanisms and cables that are terminated for the
user’s specific laboratory recording system.
Specifications
Specification Value
Frequency 3.4 GHz center transmit
frequency with +
/-100
MHz FM bandwidth
Maximum range 1.5 meters between
headstage transmitter
and receiver
System gain 500x
Input impedance 22 MΩ @ 1 kHz
Bandwidth 1 Hz – 8 kHz
Input referred noise, typical 10 µV rms
Input voltage range 1.25 V
Sampling rates 50 kHz
Phase delay, typical 30 µsec at 10 kHz
Battery life with integrated battery 2 hours
RF Receiver
Filter
Antenna
Ribbon
cable to
Plexon
preamp
DSP Processor
(Baseband Demodulation)
Analog
De multiplexer
Output
Bandpass
Filter
PLL
and
Clk Recovery
RF/FM
Demodulator
Power supply
Neural Headstage Wireless Transmitter
Bandpass
Filter
High
Bandwidth
AmplifierElectrode
Inputs
RF modulator
Time Division
Multiplexer
Antenna
Preamplifers
Power and
control
RF output
noissimsnartsseleriw
19. Neurotechnology Research Systems
16
Plextrode®
Series of Electrodes
Plexon now offers electrodes in the Plextrode Series of Electrodes. Plextrodes are available in stainless steel, platinum/iridium, pure
iridium, and tungsten. The Plextrode series of electrodes is backed by the same high level of support as any other Plexon product.
The following types of electrodes are available:
U-Probe with optional fluid delivery channels
• 16 or 24 electrode contacts embedded in
350 micron OD stainless steel needle
• 25 or 40 micron platinum/iridium electrode diameter
• 50, 100, 150, or 200 micron interelectrode spacing
• Available in tetrode configuration
• Up to 4 optional fluid channels for drug delivery
Floating Microelectrode Arrays
• For long-term chronic recording
• User defined electrode length (to 10 mm), inter-electrode
spacing, impedance (10 kΩ to 2.5 MΩ), and number of electrodes (up to 36)
• Helical spring tether eliminates stress forces and keeps the array buoyant on the brain
• Available in stainless steel, platinum/iridium, tungsten, and
pure iridium for activation and long-term stimulation
Microwire arrays
• Custom array configurations (3x3, 4x4, 4x8, etc.) available for
single electrodes, stereotrodes, and tetrodes
• Available in 25 micron and 50 micron diameter stainless
steel, platinum/iridium, and tungsten wire
• Polyethylene Glycol (carbo wax) molds to fix electrode positions that
can be melted away with application of saline solution
Microelectrode Arrays
• Four different tip profiles available
• User-defined impedances
• Custom array configurations available
• Staggered inter-electrode lengths available
• Available in stainless steel, platinum/iridium, tungsten, and pure
iridium for activation and long-term stimulation
Individual Metal Microelectrodes and Stereotrodes
• Four different tip profiles available
• User-defined impedances
• Available in stainless steel, platinum/iridium, tungsten,
and pure iridium for activation and long-term stimulation
350 µm c4 c3 c2 c1
electrode contacts
c1
c4c3
c2
20-100 mm
fluid
channels
Single Electrode Config:
350µm
c4 c3 c2 c1
(N = 4, 6)
25 µmd
N . . . 3, 2, 1
d
n . . . 3, 2, 1
Tetrode Config:
(n = 16, 24)
(d = 100, 150, 200, 300 µm)
