Setup Recordings

Your First Recording

At this point, you should have completed your initial training with a staff member. Whenever possible, refer to the specific recording strategies discussed during that training.

This tutorial serves as a basic reminder of the core workflow, focusing on an activity scan and a network assay.

Typical Experimental Workflow

flowchart LR
A["Seed Cells"] --> B["Culture & Maintenance"]

subgraph T["Measurements over Time"]
  C["Activity Scan"] --> D["Network Assay"]
end

B --> C
D --> B
style T fill:#ffffff,stroke:#333333,stroke-width:1px

Experimental workflow showing long-term culture maintenance with repeated electrophysiological measurements combining Activity Scans and Network Assays.

Assess Whether You Have Biologically Meaningful Signals

At the beginning of your experimental journey, it might be difficult to evaluate whether you are observing biologically meaningful signals.

Here are some general guidelines to help you assess the quality of your recordings:

  • Activity Level: Look for spontaneous spiking activity patterns. If you see very few or no spikes, your cells may not be healthy or mature enough.

  • Signal in close proximity to electrodes: Check if spikes are detected on multiple neighboring electrodes. This indicates that the signal originates from the same cell, since the electrodes are very close together (17.5 µm pitch). This can be done by:

    • Drawing a high-density region-of-interest around an electrode were you suspect to detect biological meaning signal (Sees selection tools in MaxLab Scope GUI)

    • Click on Route and then Download.

    • Check whether spikes appear around the electrode of interest at the same time.

    • Alternatively use the Footprint tool to check at the waveform and the waveform of the surrounding signals.

The Activity Scan Assay

As a reminder, an activity scan assay is necessary to determine the most active areas of your chip. If your cells are still young or not very active, you may need to perform an activity scan during every session.

In general, it is recommended to sacrifice some spatial resolution in order to gain temporal resolution, especially when working with low-activity cultures.

To set up an Activity Scan:

  • Go to the Assay tab.
  • Change the Project to your specific project (IMPORTANT).
  • Open a new assay and choose Activity Scan.
  • Select the Checkerboard configuration.
  • Scan for at least 90 seconds per configuration.

This setup provides a good compromise between temporal and spatial resolution. You can adjust the settings by increasing or decreasing the spatial resolution (e.g. Full Scan) or the scan duration.

In some cases—especially with highly connected, mature neuronal networks—cells may become active only in infrequent bursts. In these situations, increasing the scan duration to 120–180 seconds can help avoid banding artifacts caused by inactivity.

A full Activity Scan may take up most of your session time. Once your cultures reach a more mature state (typically after bursting begins), you may not need to repeat the Activity Scan every session and can reuse the same activity map for multiple recordings.

The Network Assay

A Network Assay records a specific electrode configuration—typically derived from the results of an Activity Scan—for a predefined period of time. Depending on the activity level of your cells, a recording duration of 5–10 minutes is usually sufficient.

You will typically use the results of an Activity Scan to select areas of interest for the Network Assay. Experiment with different configurations initially, but once you are satisfied, it is recommended to remain consistent across sessions.

We typically use Feature Maximization to include the maximum number of electrodes (approximately 1020 electrodes).

You can queue the Network Assay to start immediately after the Activity Scan. Make sure that the Network Assay is configured to use the newest Activity Scan results, which will appear black while the scan is still running.

Advanced Topic: Repeated Network Assays with Waiting Blocks

For pharmacological treatments, you may want to perform repeated measurements that are evenly spaced in time. MaxWell does not support this functionality directly, but a workaround allows you to perform repeated recordings in an unsupervised manner.

Make sure to book the corresponding time slots to accommodate the full sequence.

Waiting Blocks Using Record Assays

Although these are technically not true waiting blocks, Record Assays can be used to simulate them.

To configure a waiting block:

  • Create a Record Assay.
  • Set a short recording duration (typically 1 minute).
  • Set the in-between cycle time to half of the desired waiting period
    (e.g. 30 minutes for a 1-hour waiting block).
  • Repeat the assay for 3 cycles.
  • Use the Estimate Time button to verify that the waiting block is configured correctly.
Warning

IMPORTANT

You must select a configuration for the Record Assay. If the configuration is left blank, the waiting block will be skipped.

You can simply click “Choose Current Configuration.”

By alternating Network Assays with Waiting Blocks (Record Assays), you can space out recordings and perform repeated measurements. You will need to open and queue the assays in the exact order in which you want them to run.

Frequently Asked Questions

How do I know that my cells are healthy?

This can be difficult to assess, as cells are not visible on the surface of the sensors. We recommend plating sister cultures in parallel on glass coverslips to obtain a general indication of culture health.

In older cultures, you may start to see a matte coating on the sensor surface. A gradual change in media color toward a more orange hue is also an indication that cells are still metabolically active.

Make sure that these changes are not caused by fungal or bacterial contamination, which typically turns the media bright yellow very quickly and produces a cloudy layer on top of the sensor area. If contamination is suspected, terminate the experiment immediately to avoid cross-contamination—especially when using shared cell culture facilities.

When can I expect neuronal activity in my cells?

This depends strongly on the cell type and culturing conditions.

Empirically:

  • iPSC-derived neuronal cultures (forward programming):
    • Initial activity: Day 14–18
    • Onset of bursting: Day 18–35
  • Primary rodent neuronal cultures:
    • Initial activity: ~Day 7
    • Onset of bursting: Day 10–14

These timeframes are approximate, and results may vary depending on experimental conditions.