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analysis:course:week10 [2013/11/18 09:36]
mvdm
analysis:course:week10 [2018/07/07 10:19] (current)
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 </​code>​ </​code>​
  
-Next, we plot the spikes of a single cell (cell 5, which we met in the previous module) where the rat was when each spike was emitted:+Next, we plot the spikes of a single cell (cell 7, which we met in the previous module) where the rat was when each spike was emitted:
  
 <code matlab> <code matlab>
 % get x and y coordinate for times of spike % get x and y coordinate for times of spike
-iC = 5;+iC = 7;
 spk_x = interp1(Range(sd.x),​Data(sd.x),​Data(sd.S{iC}),'​linear'​);​ spk_x = interp1(Range(sd.x),​Data(sd.x),​Data(sd.S{iC}),'​linear'​);​
 spk_y = interp1(Range(sd.y),​Data(sd.y),​Data(sd.S{iC}),'​linear'​);​ spk_y = interp1(Range(sd.y),​Data(sd.y),​Data(sd.S{iC}),'​linear'​);​
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 spk_binned = ndhist(cat(1,​spk_x',​spk_y'​),​[SET_nxBins;​ SET_nyBins],​[SET_xmin;​ SET_ymin],​[SET_xmax;​ SET_ymax]); spk_binned = ndhist(cat(1,​spk_x',​spk_y'​),​[SET_nxBins;​ SET_nyBins],​[SET_xmin;​ SET_ymin],​[SET_xmax;​ SET_ymax]);
  
-imagesc(spk_binned'​) +imagesc(spk_binned'​); 
-axis xy; colorbar+axis xy; colorbar;
 </​code>​ </​code>​
  
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 tc = spk_binned./​(occ_binned .* (1./​VT_Fs));​ % firing rate is spike count divided by time tc = spk_binned./​(occ_binned .* (1./​VT_Fs));​ % firing rate is spike count divided by time
  
-pcolor(tc'​);​ shading flat +pcolor(tc'​);​ shading flat; 
-axis xy; colorbar; axis off+axis xy; colorbar; axis off;
 </​code>​ </​code>​
  
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 figure; figure;
 pcolor(tc'​);​ shading flat; axis off pcolor(tc'​);​ shading flat; axis off
-axis xy; colorbar+axis xy; colorbar;
 </​code>​ </​code>​
  
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 tc(isinf(tc)) = NaN; tc(isinf(tc)) = NaN;
  
-pcolor(tc'​);​ shading flat +pcolor(tc'​);​ shading flat; 
-axis xy; colorbar; axis off+axis xy; colorbar; axis off;
 </​code>​ </​code>​
  
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 Initially, when the rat is moving around at the base of the maze (its actual position is indicated by the white ''​o''​),​ no decoding results will be shown because there are no cells active. However, after a few seconds the rat starts running up the stem of the maze, and some pixels in the plot will change color, indicating $P(\mathbf{x}|\mathbf{n})$,​ the "​posterior probability"​ that is the output of the decoding procedure. As you can see, the decoding seems to track the rat's actual location as it moves. Initially, when the rat is moving around at the base of the maze (its actual position is indicated by the white ''​o''​),​ no decoding results will be shown because there are no cells active. However, after a few seconds the rat starts running up the stem of the maze, and some pixels in the plot will change color, indicating $P(\mathbf{x}|\mathbf{n})$,​ the "​posterior probability"​ that is the output of the decoding procedure. As you can see, the decoding seems to track the rat's actual location as it moves.
  
-☛ No decoding is available for those bins where no neurons are active, because we manually set the posterior to zero. However, there also seem to be some frames in the animation where some neurons are active (as indicated in the title). What is the explanation for this?+☛ No decoding is available for those bins where no neurons are active, because we manually set the posterior to zero. However, there also seem to be some frames in the animation where some neurons are active (as indicated in the title), yet no decoded estimate is visible. What is the explanation for this?
  
 === Exporting the results to a movie file === === Exporting the results to a movie file ===
analysis/course/week10.1384785394.txt.gz · Last modified: 2018/07/07 10:19 (external edit)