Hi,
I am doing action potential analysis and at the moment I am defining my threshold value manually using ginput for analysing width, however I would like to set identical y values for analysis of width of the curve. Right now, I zoom into the figure to try and set the x and y points to get the width of the AP.

My code for producing the figure and setting ginput values manually for the defined variables:
% Roksana’s script to plot .smr AP data
% 20210127

% For troubleshooting analysis – cleans the workspace
clear
close all

%Import data
load(‘C:xyz.mat’)

%Define channel to plot
data = xyz;
vm = data.values;

%scale x-axis by interval
t = linspace(0, length(vm)*data.interval,length(vm));

plot(t,vm)
xlabel(‘Time (s)’)
ylabel(‘Voltage (mV)’)
title(‘Membrane potential’)

%find max Vm value between 2 points selected on the figure
[x, y] = ginput(2);

%Report values towards AP width
xfirst = x(1,1)
xsecond = x(2,1)

%Round values for calculations of parameters
xpt1 = round(x(1));
xpt2 = round(x(2));
ypt1 = round(y(1));
ypt2 = round(y(2));

%Find a point between the first and second points on x-axis
isin = (t >= xpt1 & t <= xpt2);

%Identify the peak between the two points on the x-axis
%peak = max(vm(isin))

peak = max(vm)

%Display trough (mV); from baseline
APtrough = min(vm(isin))

%%Display AP amplitude (mV)
APamp = (peak + (ypt1*(-1)))

%%Display half-amplitude(mV)
APhalfamp = ((peak-APtrough)*0.5)

%%%Area under the curve and width values from threshold value – require zoom%%%
%pause script until button press for zooming in
zoom on;
pause ();
zoom off;

%find max Vm value between 2 points selected on the figure
[a, b] = ginput(2);

%Report values towards AP width
thresholdt1 = a(1,1)
thresholdt2 = a(2,1)
thresholdValue1 = b(1)
thresholdValue2 = b(2)

%%Display width(ms)
width = (thresholdt2 – thresholdt1)*1000 %%%%needs to be defined by threshold

%%Display half-width(ms)
APhalfwidth = (width/2)Hi,
I am doing action potential analysis and at the moment I am defining my threshold value manually using ginput for analysing width, however I would like to set identical y values for analysis of width of the curve. Right now, I zoom into the figure to try and set the x and y points to get the width of the AP.

My code for producing the figure and setting ginput values manually for the defined variables:
% Roksana’s script to plot .smr AP data
% 20210127

% For troubleshooting analysis – cleans the workspace
clear
close all

%Import data
load(‘C:xyz.mat’)

%Define channel to plot
data = xyz;
vm = data.values;

%scale x-axis by interval
t = linspace(0, length(vm)*data.interval,length(vm));

plot(t,vm)
xlabel(‘Time (s)’)
ylabel(‘Voltage (mV)’)
title(‘Membrane potential’)

%find max Vm value between 2 points selected on the figure
[x, y] = ginput(2);

%Report values towards AP width
xfirst = x(1,1)
xsecond = x(2,1)

%Round values for calculations of parameters
xpt1 = round(x(1));
xpt2 = round(x(2));
ypt1 = round(y(1));
ypt2 = round(y(2));

%Find a point between the first and second points on x-axis
isin = (t >= xpt1 & t <= xpt2);

%Identify the peak between the two points on the x-axis
%peak = max(vm(isin))

peak = max(vm)

%Display trough (mV); from baseline
APtrough = min(vm(isin))

%%Display AP amplitude (mV)
APamp = (peak + (ypt1*(-1)))

%%Display half-amplitude(mV)
APhalfamp = ((peak-APtrough)*0.5)

%%%Area under the curve and width values from threshold value – require zoom%%%
%pause script until button press for zooming in
zoom on;
pause ();
zoom off;

%find max Vm value between 2 points selected on the figure
[a, b] = ginput(2);

%Report values towards AP width
thresholdt1 = a(1,1)
thresholdt2 = a(2,1)
thresholdValue1 = b(1)
thresholdValue2 = b(2)

%%Display width(ms)
width = (thresholdt2 – thresholdt1)*1000 %%%%needs to be defined by threshold

%%Display half-width(ms)
APhalfwidth = (width/2) Hi,
I am doing action potential analysis and at the moment I am defining my threshold value manually using ginput for analysing width, however I would like to set identical y values for analysis of width of the curve. Right now, I zoom into the figure to try and set the x and y points to get the width of the AP.

My code for producing the figure and setting ginput values manually for the defined variables:
% Roksana’s script to plot .smr AP data
% 20210127

% For troubleshooting analysis – cleans the workspace
clear
close all

%Import data
load(‘C:xyz.mat’)

%Define channel to plot
data = xyz;
vm = data.values;

%scale x-axis by interval
t = linspace(0, length(vm)*data.interval,length(vm));

plot(t,vm)
xlabel(‘Time (s)’)
ylabel(‘Voltage (mV)’)
title(‘Membrane potential’)

%find max Vm value between 2 points selected on the figure
[x, y] = ginput(2);

%Report values towards AP width
xfirst = x(1,1)
xsecond = x(2,1)

%Round values for calculations of parameters
xpt1 = round(x(1));
xpt2 = round(x(2));
ypt1 = round(y(1));
ypt2 = round(y(2));

%Find a point between the first and second points on x-axis
isin = (t >= xpt1 & t <= xpt2);

%Identify the peak between the two points on the x-axis
%peak = max(vm(isin))

peak = max(vm)

%Display trough (mV); from baseline
APtrough = min(vm(isin))

%%Display AP amplitude (mV)
APamp = (peak + (ypt1*(-1)))

%%Display half-amplitude(mV)
APhalfamp = ((peak-APtrough)*0.5)

%%%Area under the curve and width values from threshold value – require zoom%%%
%pause script until button press for zooming in
zoom on;
pause ();
zoom off;

%find max Vm value between 2 points selected on the figure
[a, b] = ginput(2);

%Report values towards AP width
thresholdt1 = a(1,1)
thresholdt2 = a(2,1)
thresholdValue1 = b(1)
thresholdValue2 = b(2)

%%Display width(ms)
width = (thresholdt2 – thresholdt1)*1000 %%%%needs to be defined by threshold

%%Display half-width(ms)
APhalfwidth = (width/2) action potential analysis, threshold value MATLAB Answers — New Questions

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