# Simulation for a mixed model

**URL:** <https://mne.discourse.group/t/simulation-for-a-mixed-model/10967>\
**Category:** Support & Discussions\
**Tags:** source-localization\
**Created:** [March 17, 2025, 3:41pm UTC](https://mne.discourse.group/t/simulation-for-a-mixed-model/10967 "2025-03-17T15:41:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![luvebian](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/luvebian/32/4222_2.png) [@luvebian](https://mne.discourse.group/u/luvebian)\
**Post date:** [March 17, 2025, 3:41pm UTC](https://mne.discourse.group/t/simulation-for-a-mixed-model/10967/1 "2025-03-17T15:41:29Z")

</div>

- MNE version: 1.8.0
- operating system: macOS Sequoia

Hello MNE community,

I’m trying to create a simulation using a mixed source model and am having trouble adding subcortical data.

For example:

1. I define a subcortical label (e.g., `Left-Hippocampus`).
2. I successfully add cortical data to my simulation.
3. I attempt to add subcortical data using:

```python
subcort_label = mne.get_volume_labels_from_src(fwd["src"], subject, subjects_dir)[0] 
source_simulator.add_data(subcort_label, source_time_series, events)

```

1. I try simulating raw data using `mne.simulation.simulate_raw(info, source_simulator, forward=fwd)` and encounter the following error:

```python
RuntimeError: Mismatch between number of source spaces (3) and STC vertices (2)  

```

There was a [related thread](https://mne.discourse.group/t/subcortical-source-simulation/7128) two years ago. Have there been updates or solutions since then?