Fast read-out of object identity from macaque inferior temporal cortex                  
Supplementary Web Material   
     
Chou P. Hung*, Gabriel Kreiman*, Tomaso Poggio, James J. DiCarlo  
     
Center for Biological and Computational Learning and Computation and Systems Biology Initiative  
McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences  
   
Massachusetts Institute of Technology  
     
*These two authors contributed equally to this work  
   
1 Sample of spiking activity and local field potentials in macaque inferior temporal cortex    
  Sample of spiking responses    
  Sampel of LFP responses    
2 Unsupervised clustering of neuronal responses yields similar categories    
  Correlation coefficient matrix for population responses to two pictures    
  Clustering of correlation coefficient matrix    
  Clustering of correlation coefficient matrix with different numbers of clusters (n=2, 3, …, 10)  
3 What is a category?    
  Random group assignment    
  Classifier performance versus similarity    
  Confusion matrix    
  Extrapolation to other pictures within a category    
4 Read out of scale and position    
  Classifier performance for reading out scale and position    
  Latency of scale and position read-out    
  Overlap in high SNR sites for group read-out, scale read-out and location read-out    
5 Categorization and identification    
  Read out performance for categorization and identification    
  Latency of categorization and identification    
  Latency of categorization and identification, invariance    
  There was a strong overlap between the best neurons for the categorization and identification tasks    
  There was a strong correlation in the categorization SNR and the identification SNR    
6 Spike sorting  
  Spike sorting and classifier performance  
  Separation of single units and multi-units  
7 Codes  
  A family of codes parametrized by the spike count window  
  Single bins  
  Bursts of spikes  
8 Robustness  
  Robustness to neuronal drop-out during testing  
  Robustness to failures in information transmission  
9 Wiring specificity  
  Wiring specificity  
11 Neuronally plausible decoding  
  Neuronally plausible statistical classifier and comparison of different statistical classifiers  
12 Invariance to scale and location  
  Robustness of the classifier to scale and location changes  
  Invariance for novel images  
  Novel objects images  
  Invariance performance as a function of the number of sites  
  Invariance for C2 units of the standard model  
13 Detection of stimulus onset  
  Detection of stimulus onset  
14 Classification from simple image properties  
  Stimulus categorization from simple image properties  
15 Dependence on the number of sites  
  Classifier performance versus number of sites with fits  
  Number of neurons required to discriminate a number of objects at a fixed performance  
16 Active versus passive viewing  
     
  Discriminability for active versus passive viewing  
     
 
     
gk, last updated  
11/9/05    
 
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