run_searchlight: Run Searchlight Analysis

In bbuchsbaum/rMVPA: Multivoxel Pattern Analysis in R

Run Searchlight Analysis

Description

Execute a searchlight analysis using multivariate pattern analysis.

Usage

run_searchlight(
  model_spec,
  radius,
  method = c("standard", "randomized"),
  niter = NULL,
  ...
)

Arguments

model_spec	A mvpa_model instance containing the model specifications
radius	The searchlight radius in millimeters
method	The type of searchlight, either 'randomized' or 'standard'
niter	The number of searchlight iterations (used only for 'randomized' method)
...	Extra arguments passed to specific searchlight methods

Value

A named list of NeuroVol objects containing performance metrics (e.g., AUC) at each voxel location

Examples

  # Generate sample dataset with categorical response
  dataset <- gen_sample_dataset(
    D = c(8,8,8),           # 8x8x8 volume
    nobs = 100,             # 100 observations
    response_type = "categorical",
    data_mode = "image",
    blocks = 3,             # 3 blocks for cross-validation
    nlevels = 2             # binary classification
  )
  
  # Create cross-validation specification using blocks
  cval <- blocked_cross_validation(dataset$design$block_var)
  
  # Load the SDA classifier (Shrinkage Discriminant Analysis)
  model <- load_model("sda_notune")
  
  # Create MVPA model
  mspec <- mvpa_model(
    model = model,
    dataset = dataset$dataset,
    design = dataset$design,
    model_type = "classification",
    crossval = cval
  )
  
  # Run searchlight analysis
  results <- run_searchlight(
    mspec,
    radius = 8,            # 8mm radius
    method = "standard"    # Use standard searchlight
  )
  
  # Results contain performance metrics
  # Access them with results$performance

bbuchsbaum/rMVPA documentation built on June 10, 2025, 8:23 p.m.