359 lines
9.8 KiB
Markdown
359 lines
9.8 KiB
Markdown
# Automated Curation Reference
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Guide to automated spike sorting curation using Bombcell, UnitRefine, and other tools.
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## Why Automated Curation?
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Manual curation is:
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- **Slow**: Hours per recording session
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- **Subjective**: Inter-rater variability
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- **Non-reproducible**: Hard to standardize
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Automated tools provide consistent, reproducible quality classification.
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## Available Tools
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| Tool | Classification | Language | Integration |
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|------|---------------|----------|-------------|
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| **Bombcell** | 4-class (single/multi/noise/non-somatic) | Python/MATLAB | SpikeInterface, Phy |
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| **UnitRefine** | Machine learning-based | Python | SpikeInterface |
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| **SpikeInterface QM** | Threshold-based | Python | Native |
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| **UnitMatch** | Cross-session tracking | Python/MATLAB | Kilosort, Bombcell |
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## Bombcell
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### Overview
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Bombcell classifies units into 4 categories:
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1. **Single somatic units** - Well-isolated single neurons
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2. **Multi-unit activity (MUA)** - Mixed neuronal signals
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3. **Noise** - Non-neural artifacts
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4. **Non-somatic** - Axonal or dendritic signals
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### Installation
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```bash
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# Python
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pip install bombcell
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# Or development version
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git clone https://github.com/Julie-Fabre/bombcell.git
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cd bombcell/py_bombcell
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pip install -e .
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```
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### Basic Usage (Python)
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```python
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import bombcell as bc
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# Load sorted data (Kilosort output)
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kilosort_folder = '/path/to/kilosort/output'
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raw_data_path = '/path/to/recording.ap.bin'
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# Run Bombcell
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results = bc.run_bombcell(
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kilosort_folder,
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raw_data_path,
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sample_rate=30000,
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n_channels=384
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)
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# Get classifications
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unit_labels = results['unit_labels']
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# 'good' = single unit, 'mua' = multi-unit, 'noise' = noise
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```
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### Integration with SpikeInterface
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```python
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import spikeinterface.full as si
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# After spike sorting
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sorting = si.run_sorter('kilosort4', recording, output_folder='ks4/')
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# Create analyzer and compute required extensions
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analyzer = si.create_sorting_analyzer(sorting, recording, sparse=True)
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analyzer.compute('waveforms')
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analyzer.compute('templates')
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analyzer.compute('spike_amplitudes')
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# Export to Phy format (Bombcell can read this)
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si.export_to_phy(analyzer, output_folder='phy_export/')
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# Run Bombcell on Phy export
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import bombcell as bc
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results = bc.run_bombcell_phy('phy_export/')
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```
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### Bombcell Metrics
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Bombcell computes specific metrics for classification:
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| Metric | Description | Used For |
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|--------|-------------|----------|
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| `peak_trough_ratio` | Waveform shape | Somatic vs non-somatic |
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| `spatial_decay` | Amplitude across channels | Noise detection |
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| `refractory_period_violations` | ISI violations | Single vs multi |
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| `presence_ratio` | Temporal stability | Unit quality |
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| `waveform_duration` | Peak-to-trough time | Cell type |
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### Custom Thresholds
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```python
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# Customize classification thresholds
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custom_params = {
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'isi_threshold': 0.01, # ISI violation threshold
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'presence_threshold': 0.9, # Minimum presence ratio
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'amplitude_threshold': 20, # Minimum amplitude (μV)
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'spatial_decay_threshold': 40, # Spatial decay (μm)
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}
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results = bc.run_bombcell(
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kilosort_folder,
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raw_data_path,
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**custom_params
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)
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```
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## SpikeInterface Auto-Curation
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### Threshold-Based Curation
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```python
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# Compute quality metrics
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analyzer.compute('quality_metrics')
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qm = analyzer.get_extension('quality_metrics').get_data()
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# Define curation function
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def auto_curate(qm):
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labels = {}
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for unit_id in qm.index:
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row = qm.loc[unit_id]
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# Classification logic
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if row['snr'] < 2 or row['presence_ratio'] < 0.5:
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labels[unit_id] = 'noise'
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elif row['isi_violations_ratio'] > 0.1:
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labels[unit_id] = 'mua'
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elif (row['snr'] > 5 and
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row['isi_violations_ratio'] < 0.01 and
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row['presence_ratio'] > 0.9):
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labels[unit_id] = 'good'
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else:
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labels[unit_id] = 'unsorted'
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return labels
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unit_labels = auto_curate(qm)
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# Filter by label
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good_unit_ids = [u for u, l in unit_labels.items() if l == 'good']
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sorting_curated = sorting.select_units(good_unit_ids)
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```
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### Using SpikeInterface Curation Module
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```python
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from spikeinterface.curation import (
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CurationSorting,
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MergeUnitsSorting,
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SplitUnitSorting
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)
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# Wrap sorting for curation
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curation = CurationSorting(sorting)
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# Remove noise units
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noise_units = qm[qm['snr'] < 2].index.tolist()
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curation.remove_units(noise_units)
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# Merge similar units (based on template similarity)
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analyzer.compute('template_similarity')
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similarity = analyzer.get_extension('template_similarity').get_data()
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# Find highly similar pairs
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import numpy as np
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threshold = 0.9
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similar_pairs = np.argwhere(similarity > threshold)
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# Merge pairs (careful - requires manual review)
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# Get curated sorting
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sorting_curated = curation.to_sorting()
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```
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## UnitMatch: Cross-Session Tracking
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Track the same neurons across recording days.
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### Installation
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```bash
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pip install unitmatch
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# Or from source
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git clone https://github.com/EnnyvanBeest/UnitMatch.git
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```
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### Usage
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```python
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# After running Bombcell on multiple sessions
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session_folders = [
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'/path/to/session1/kilosort/',
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'/path/to/session2/kilosort/',
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'/path/to/session3/kilosort/',
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]
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from unitmatch import UnitMatch
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# Run UnitMatch
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um = UnitMatch(session_folders)
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um.run()
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# Get matching results
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matches = um.get_matches()
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# Returns DataFrame with unit IDs matched across sessions
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# Assign unique IDs
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unique_ids = um.get_unique_ids()
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```
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### Integration with Workflow
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```python
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# Typical workflow:
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# 1. Spike sort each session
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# 2. Run Bombcell for quality control
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# 3. Run UnitMatch for cross-session tracking
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# Session 1
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sorting1 = si.run_sorter('kilosort4', rec1, output_folder='session1/ks4/')
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# Run Bombcell
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labels1 = bc.run_bombcell('session1/ks4/', raw1_path)
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# Session 2
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sorting2 = si.run_sorter('kilosort4', rec2, output_folder='session2/ks4/')
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labels2 = bc.run_bombcell('session2/ks4/', raw2_path)
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# Track units across sessions
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um = UnitMatch(['session1/ks4/', 'session2/ks4/'])
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matches = um.get_matches()
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```
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## Semi-Automated Workflow
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Combine automated and manual curation:
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```python
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# Step 1: Automated classification
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analyzer.compute('quality_metrics')
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qm = analyzer.get_extension('quality_metrics').get_data()
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# Auto-label obvious cases
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auto_labels = {}
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for unit_id in qm.index:
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row = qm.loc[unit_id]
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if row['snr'] < 1.5:
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auto_labels[unit_id] = 'noise'
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elif row['snr'] > 8 and row['isi_violations_ratio'] < 0.005:
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auto_labels[unit_id] = 'good'
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else:
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auto_labels[unit_id] = 'needs_review'
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# Step 2: Export uncertain units for manual review
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needs_review = [u for u, l in auto_labels.items() if l == 'needs_review']
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# Export only uncertain units to Phy
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sorting_review = sorting.select_units(needs_review)
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analyzer_review = si.create_sorting_analyzer(sorting_review, recording)
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analyzer_review.compute('waveforms')
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analyzer_review.compute('templates')
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si.export_to_phy(analyzer_review, output_folder='phy_review/')
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# Manual review in Phy: phy template-gui phy_review/params.py
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# Step 3: Load manual labels and merge
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manual_labels = si.read_phy('phy_review/').get_property('quality')
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# Combine auto + manual labels for final result
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```
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## Comparison of Methods
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| Method | Pros | Cons |
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|--------|------|------|
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| **Manual (Phy)** | Gold standard, flexible | Slow, subjective |
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| **SpikeInterface QM** | Fast, reproducible | Simple thresholds only |
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| **Bombcell** | Multi-class, validated | Requires waveform extraction |
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| **UnitRefine** | ML-based, learns from data | Needs training data |
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## Best Practices
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1. **Always visualize** - Don't blindly trust automated results
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2. **Document thresholds** - Record exact parameters used
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3. **Validate** - Compare automated vs manual on subset
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4. **Be conservative** - When in doubt, exclude the unit
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5. **Report methods** - Include curation criteria in publications
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## Pipeline Example
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```python
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def curate_sorting(sorting, recording, output_dir):
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"""Complete curation pipeline."""
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# Create analyzer
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analyzer = si.create_sorting_analyzer(sorting, recording, sparse=True,
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folder=f'{output_dir}/analyzer')
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# Compute required extensions
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analyzer.compute('random_spikes', max_spikes_per_unit=500)
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analyzer.compute('waveforms')
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analyzer.compute('templates')
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analyzer.compute('noise_levels')
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analyzer.compute('spike_amplitudes')
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analyzer.compute('quality_metrics')
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qm = analyzer.get_extension('quality_metrics').get_data()
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# Auto-classify
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labels = {}
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for unit_id in qm.index:
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row = qm.loc[unit_id]
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if row['snr'] < 2:
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labels[unit_id] = 'noise'
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elif row['isi_violations_ratio'] > 0.1 or row['presence_ratio'] < 0.8:
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labels[unit_id] = 'mua'
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elif (row['snr'] > 5 and
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row['isi_violations_ratio'] < 0.01 and
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row['presence_ratio'] > 0.9 and
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row['amplitude_cutoff'] < 0.1):
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labels[unit_id] = 'good'
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else:
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labels[unit_id] = 'unsorted'
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# Summary
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from collections import Counter
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print("Classification summary:")
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print(Counter(labels.values()))
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# Save labels
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import json
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with open(f'{output_dir}/unit_labels.json', 'w') as f:
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json.dump(labels, f)
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# Return good units
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good_ids = [u for u, l in labels.items() if l == 'good']
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return sorting.select_units(good_ids), labels
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# Usage
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sorting_curated, labels = curate_sorting(sorting, recording, 'output/')
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```
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## References
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- [Bombcell GitHub](https://github.com/Julie-Fabre/bombcell)
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- [UnitMatch GitHub](https://github.com/EnnyvanBeest/UnitMatch)
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- [SpikeInterface Curation](https://spikeinterface.readthedocs.io/en/stable/modules/curation.html)
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- Fabre et al. (2023) "Bombcell: automated curation and cell classification"
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- van Beest et al. (2024) "UnitMatch: tracking neurons across days with high-density probes"
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