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Clampfit is a powerful data analysis program with a wide variety of
statistics, analyses, transforms and layout tools for electrophysiological data.
Data Preparation
Compile data sets using the Data File Index (DFI) file manager.
Clean up your data with an excellent set of filtering options,
including electrical cycle noise. For further noise reduction, average
together traces or files. Prepare data by subtracting control files
or adjusting traces for baseline drift. Gather data for analysis by
concatenating gap-free or episodic files with compatible protocols.
Data Analyses
Clampfit is superior at curve fitting. Choose from 24 pre-defined
functions, such as Boltzmann, Exponential, Gaussian, Goldman-Hodgkin-Katz, Hill,
or define your own. Customize your fits by selecting fitting methods, apply
fitting seeds, compare models with different tems, and extrapolate the fits.
View curves, components, residuals, taus, etc.
Analyses such as Variance-Mean (VM) analysis compares postsynaptic
transmitter release under different conditions; Perievent analysis
measures events in relation to a central neurological event; and Normalize
adjusts traces and graphs such as power spectrums and histograms.
Peak statistics fine-tune the percentile settings for Rise
and Decay times and slopes (now based on linear regression) to examine fast phases,
APDs and other components of your action potentials. Autocorrelation
and Cross Correlation analyze repetitive features within a trace or
between traces. The Kolmogorov-Smirnov statistic tests whether two
data sets belong to the same population. Other statistics on secondary spreadsheet
data include Variance, Chi Square, F-test, t-Test, and Pearson and Spearman
Rank Correlations, along with the ability to extract conditional data subsets.
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Click on image to see the full-size screen
Automatic Analysis
As easy as 1-2-3, cut down on keystrokes during live experiments. Have Clampfit
automatically open the last recorded data file and optionally: subtract a
control file from it, open the Arithmetic dialog for your command, generate an
I-V graph, rename and save the modified file, and wait again for
the next recorded file from Clampex.
Cursor Measurements
Clampfit measures up, with up to 9 cursor pairs for statistical
measurements in the Analysis window. Each cursor pair can flexibly measure its own
set of peak statistics independently of the others, just as with the
Clampex online statistics.
Cursors can display the differences (deltas) between cursor pairs.
"Lock" cursor pairs together to preserve their same relative distance when you
reposition them.
Graphing & Layout
Graphing is as simple as selecting a data column and clicking on the Create Graph
button. Or, select from a variety of graphing options among Line, Scatter
and Histogram plots. Histograms offer extra plot options such as
Normalization, Frequency, Sq. Root, Cumulative. Event Detection
scatter plots offer linked views to data and results. Any Clampfit window can
be highly customized, such as with log axes and graph legends, and sent to the
Layout Window for arrangement, annotation and printing.
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Detects Many Types of Events
Clampfit's extremely flexible Event Detection analyzes any kind of spikes or
postsynaptic currents and potentials from continuous or sweep data. Action
potentials, spontaneous and evoked events can be extracted one by one, or nonstop
by the click of a button, and then measured, analyzed and plotted.
Finding Spontaneous Events
Clampfit's flexible Template Searches are ideal for analyzing spontaneous
events such as miniature synaptic EPSPs and IPSPs, etc. These
complex events can vary in amplitude, while their basic shapes remains unchanged -
perfect for detection by a scalable shape-based algorithm. A further benefit is
that this pattern matching is independent of baseline drift.
Template files allow you
to easily setup multiple categories of events based on different shapes, and
variable or fixed sizes. Control the stringency of the matching by adjusting a
template matching threshold.
Data Templates
Use your data to find the events in your data! Events in the actual data are used
to create templates. Visually select and Add or skip to the Next event, via
a special window, to buildup a representative averaged event. These can be saved
at any time as a template file.
Accept or Reject?
As each event is found, use buttons to Accept it, Reject it, mark
it but Suppress its statistics, accept and Tag it for special notice,
Undo your last action, or process non-stop.
The Event Monitor window aids you in deciding in whether to accept or reject
an event, by displaying a few key properties of the currently found event, along
with the averages of previously accepted events.
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Linked Data Views
How do you manage all of your different data views? From raw data in the
Analysis window, to captured events in the Event Viewer window, to
statistics in the Results window, to scatter plots in the Graph window,
that's a lot of information to keep track of! But all of the above data views
are integrated and linked together during Event Detection. This means that
selecting an event in any view, also highlights and displays that same event in
all other views.
Standard Threshold Detection
Amplitude threshold levels provide a simple way to collect and sort events such as
Action Potentials. When the size of the event is your main concern, and you
are not concerned about drifting baselines, this is the standard way to do it.
A fixed Baseline is used for calculating statistics. Data that exceeds a
Trigger threshold level defines an event, although a different Re-arm
level can be set to end the event. Create a window discriminator by setting a
Rejection level, so upper and lower levels bound your event. In addition,
specify minimum and maximum Event Durations for temporal control of detected
events. Multiple categories of events can be enabled with independent sets of
these parameters.
Event Graphing
Graphs can be quickly plotted by selecting X and Y settings from automatically
measured event statistics such as peaks, half-widths, slopes, rise/decay times,
and more.
See interesting groupings in your scatter plots? Just draw a box around a group
of events to instantly select them in all other views, and to process the group
of events.
Where Do Events Go?
As each event is detected, it is automatically transferred to and displayed in an
Event Viewer window. Several display controls help to manage these events, which
are displayed overlaid upon each other. This window can also accumulate events
from multiple searches across different data files. At any time, the detected
events can be optionally saved to ABF data files for later analysis.
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Now in Windows
pCLAMP Single-Channel Analysis is elegantly implemented in Windows. It contains updated analyses and
full processing of up to 1 million events on continuous and episodic data. These are just
some of the benefits provided along with the many innovations found in Clampfit Event Detection.
Event Detection
Detect ion-channel open and closed levels and sub-conductance levels by setting
up to eight levels in the data. For careful inspection of the data,
manually accept and reject each color-coded transition, but then for fast
"hands free" automatic processing, switch to non-stop mode. Baseline drift
is automatically adjusted for in either case.
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Analyses
Flexibly create amplitude and dwell-time histogram plots, utilitizing
conditions, state filters and multiple sources of data. Easily fit any histogram
using Clampfit's large stable of powerful fitting routines. All-points amplitude
histograms are also easily constructed.
Measure open probabilities P(open) from both continuous and episodic data,
adjusting for multiple levels and/or channels in the patch. Statistics include
interval information, along with NP(open) - used for an unknown number of channels.
Other specialized analyses such as Burst Analysis and Latency Analysis
(time to first event) have many options. Use Nonstationary Fluctuation Analysis
to extract single-channel conductance information from sweep data.
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