# Chakra Meditation fMRI Dataset

Block-design task-fMRI of expert kundalini-yoga chakra meditation, acquired at
the PRSM lab, Leiden University. This is a small-N (N = 2 practitioners)
proof-of-concept / calibration dataset; it is released raw for reuse.

## Participants and sessions

- **sub-01** (Yogi 1) — three sessions (ses-01, ses-02, ses-03), acquired as
  pilots 1, 2 and 3 respectively. Acquisition differs across sessions:
  - ses-01: single-echo BOLD, B0 fieldmap.
  - ses-02: mixed single-/multi-echo BOLD, **no fieldmap** (synthetic
    distortion correction was used downstream).
  - ses-03: three-echo BOLD, B0 fieldmap.
- **sub-02** (Yogi 2) — one session (ses-01), acquired as pilot 4; three-echo
  BOLD with per-run B0 fieldmaps.

The two subjects are two different people. Within-subject acquisition
differences across sub-01's sessions are real and intentional (pilot
iterations), not errors.

## Tasks

Each functional run is a block design. Most runs contain a Yogic Resting State
(YRS) baseline block followed by one chakra-meditation block; the run is named
for that chakra. Block onsets and durations are in each run's `events.tsv`.

- `task-yrs` — baseline run (Yogic Resting State, sometimes preceded by a
  Spontaneous Resting State (SRS) block; see `events.tsv`).
- `task-manipura`, `task-anahata`, `task-ajna`, `task-sahasrara` — the four
  chakra meditations (YRS baseline block + chakra block).
- `task-ycs` — a single exploratory run sweeping all seven chakras then
  oscillating between Anāhata and Ājñā.
- `task-movie` — two Pilot-2 movie-watching control runs. The BOLD is shared;
  the film stimulus itself is not included.

`sub-01/ses-03` contains two Sahasrara runs (`run-01`, `run-02`). The second
(originally "S7", informally the "secret" meditation) is also a Sahasrara
practice.

## Multi-echo

sub-01/ses-02, sub-01/ses-03 and sub-02 are multi-echo (`echo-1/2/3`). The
multi-echo-combined / TEDANA-denoised (“MEICA”) images are a *derivative* and
are **not** part of this raw release.

## Trial-type labels (events.tsv)

- `YRS` — Yogic Resting State (trained baseline)
- `SRS` — Spontaneous Resting State (untrained baseline)
- `YCS` — Yoga Chakra Sequence (seven-chakra sweep)
- `Manipura` / `Anahata` / `Ajna` / `Sahasrara` — chakra meditation blocks
- `moviesx` / `moviesy` — movie-watching blocks

## De-identification

Anatomical images (T1w/T2w) have been defaced. Identifying fields have been
removed from JSON sidecars. Raw scanner physiological logs (SCANPHYSLOG) are
not included.