The Format of MTC Files
A MTC file contains the functional data (time series) of one experimental run (one functional scan) in surface space, typically in cortex space. It is important to realize that the order of vertex time series in a MTC file follows the order of vertices in a corresponding mesh (SRF) file. When the mesh file links the MTC file, proper correspondence between the two files is established since the first time course is attached to the first vertex of the SRF file, the second time course in the MTC file is attached to the second vertex and so on. As with VTC data, the whole time series for a single vertex is stored contiguously, followed by the time course of the next vertex. This speeds up file access of the data. The binary MTC file contains a variable-length header followed by the actual vertices x time data.
MTC Header
BYTES | DATA TYPE | DEFAULT | DESCRIPTION |
4 | int | 1 | version number |
4 | int | number of vertices | |
4 | int |
| number of time points |
N * 1 | char | name of source VTC file' (ends with '0') | |
M * 1 | char |
| name of linked protocol file; if not available: '<none>; (ends with '0') |
4 | int |
| hemodynamic delay (*1) |
4 | float |
| TR - Repetition Time (*1) |
4 | float |
| delta parameter for hemodynamic response function (*1) |
4 | float |
| tau parameter for hemodynamic response function (*1) |
4 | int |
| segment size (intervals per stimulus block/event) (*1) |
4 | int |
| segment offset - first datapoint after first rest period (*1) |
1 | char | 1 | datatype of MTC data; 1 = 'float' |
(*1) These values are not important anymore and might be dropped in future versions (they can be ignored).
MTC Data
The data is organized in a vertices x time matrix: all data points per vertex are saved together, so time runs as the inner loop:
DimVertices
DimT