Use the 'findpeaks' function to get the locations, from there you can find the sum between the indices
[peak_magnitudes,peaks_locs] = findpeaks(your_signal);
If you want the locations in terms of the x-axis variable, use the following:
[peak_magnitudes,peaks_locs_x] = findpeaks(your_signal,your_x_variable);
For finding the sum between the peaks:
% initialize your summation array
signal_peak_sum(numel(peaks_locs)) = 0;
% For the first peak
signal_peak_sum(1) = sum(your_signal(1:peaks_locs(1)));
% For the remaining peaks
for i=2:numel(peaks_locs)
signal_peak_sum(i) = sum(your_signal(peaks_locs(i-1):peaks_locs(i)));
end
Hope this helps.
