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Launching Your First Experiment

The quickest way to start collecting data with Synapse is to use a template. After initial system set-up, you can use these ready-to-go experiments to collect data on day one or use them as a starting point for a more customized experiment. This section covers:

  • Editing your Rig
  • Creating an Experiment from a Template
  • Using the Runtime Interface

Editing the Rig

Before you can run an experiment you must allow Synapse to gather information about the System 3 hardware components in your system. TDT processors come in many configurations that have different capabilities. Once Synapse knows which devices you're using, it will keep track of the device details for you.

Key Concept

In Synapse, your hardware system is referred to as the 'rig' and it is remembered each time you open the software. The first time you launch the software, the Rig Editor is displayed automatically.

Configuring the rig starts with letting Synapse detect your system devices.

Technical Detail

Make sure your TDT hardware is set-up, connected, and powered on before using the Detect button to begin configuring the rig.

Rig Editor: RZ2 Selected

Detected devices in your hardware configuration are displayed in a hierarchical diagram. Configuration settings for the selected (highlighted) device are displayed in the area to the right.

Rig Editor: SIM IZV Selected

Enabling Devices

There are some device and configuration information that Synapse can't automatically detect. In the illustration above, based on the equipment detected, such as the RZ2 and DSP-I, an IZ2 stimulator is likely to be a part of the attached system. Synapse added the IZ2 to the diagram, but it hasn't been enabled. You would need to click the check box to enable it.

You can also enable or disable devices to control whether they are automatically added to the Processing Tree in new experiments. Only enabled devices are added by default. Disabled devices can still be added later and enabled manually in the Processing Tree. See Disabled Devices and the Processing Tree for more information.

Adding a Device

The UDP interface, a USB Camera, and RA (Medusa) amplifiers are examples of devices that might be part of your system, but can't be detected by Synapse. These devices can be added to the rig manually using the RZ shortcut menu. Right-click your system's processor device (such as RZ2 or RX8) and select the device from the menu.

Hardware Item Right-click Option
Medusa PreAmp Add RAn
USB Camera Add CAM
UDP Interface Add UDPRecv & Add UDPSend

Configuring a Device

Some devices require that you configure some aspect of the device, even if it is automatically enabled.

Selected Amplifier Icon with Channels Drop-Down Menu

The most common item you will need to configure is your PZ amplifier. You'll need to select the number of channels available in your amplifier. In the rig, your device settings should exactly match your hardware. You'll be able to reduce the number of channels actually used or make other experiment-specific changes to settings in individual experiments.

When everything is configured, you can update the rig by clicking OK to commit the changes and return to the Processing Tree.

Processing Tree with UDP Added

In the illustration above, the UDP device icon has been added but is displayed with a warning indicator. The UDP requires an input source. It can be set now or it can be set later when the desired input is available.

After the rig is initially configured, you won't need to repeat this process in future sessions unless your hardware changes. If you do need to make changes, you can return to the Rig Editor, using the Edit Rig command in the main menu.

Main Menu

For more information on working with the rig, see The Rig.

Creating an Experiment from a Template

Templates are pre-built experiments created by TDT to speed up experiment creation. Each Synapse template is a basic working experiment that can be run as configured or modified to meet your needs.

You can access any saved experiments by clicking the Experiment button on the command bar, then clicking More Templates are stored in special category folders within the Templates folder.

Current Experiment Window

The Current Experiment or Experiment Selection window is similar to a standard Windows Explorer window with folders, or categories, on the left and experiments in the category on the right.

Technical Detail

The rest of this section will take a look at the following template:
Templates | Single Units | With LFP Streaming | PCAsort_LFP

Template files are locked to ensure you will always have an unaltered set in their original state. Select the desired experiment template and click the Build From Selected button, to create an editable copy.

The Rig and the HAL

Synapse has two ways of remembering information about your hardware.

The Rig HAL

The Rig Hardware Abstraction Layer (HAL) is the collection of hardware information that stays with your copy of Synapse. It's used to execute your experiments.

The Experiment HAL

The Experiment Hardware Abstraction Layer (HAL) is a collection of hardware information that is stored with the experiment. It remembers the hardware used to create the experiment.

Each template contains HAL information about the system used to design it. When the template is launched, Synapse tries to adapt it to run on your rig. If it's unable to do so, alert symbols are added to the problem elements in the Processing Tree.

Processing Tree with Error Alerts

In the illustration above, the necessary PZn wasn't enabled in the rig where the template was opened. The problem is easily corrected by enabling the PZn.

Viewing the New Experiment

PCA Spike Sorting Gizmo Options in Synapse Window

In the new experiment, two task blocks called 'gizmos' are added to the Processing Tree beneath the PZ amplifier: one for LFP filtering (Lfp1) and another for PCA spike sorting (Neu1). The Processing Tree represents the path of data flow and in the example above the hierarchy shows that the LFPs and Single Units are being acquired in parallel from the same signal source (PZ5). When a gizmo is selected in the tree, its configuration options are displayed in the Options area to the far right. For information on modifying gizmo options, see the corresponding reference in the Gizmo Reference.

Naming the Experiment

Before you name the experiment, take a quick look at the Synapse interface.

Synapse Designtime Interface

Notice the large buttons at the top of the command bar, seen on the left side in the illustration above. The buttons that are initially displayed in red and are switched to black as each area is configured. Until configuration is complete the experiment Record button is unavailable.

Before you can begin collecting data, the new experiment needs to be named and saved. Click the Experiment (From PCASort LFP) button and click Save as.

Current Experiment Window and New Experiment Dialog

In the dialog box you can enter an experiment name, description, or add notes. The experiment is saved under the Root directory. You can add and move categories and experiments using right-click menus.

When you return to the main designtime interface, the experiment has been saved, a new tank name is displayed under the tank icon, and the Record button is available.

Key Concept

The experiment name is one of three special categories of information that Synapse tags and uses in its relational database to index and track designtime and runtime settings and any modification made to parameters during each experiment run. The other two categories are users and subjects. Which of these buttons is displayed is controlled by Synapse preferences. In the default configuration only the experiment and subject are displayed and both must be configured before recording.

To add a subject, click the Subject button in the command bar, then click New.

Subject Menu

You'll need to enter a name in the Subject Name field. You can also enter a description, password, or notes and choose an icon. When you're done adding information, click Save.

The steps to add users and subjects are much the same. For more information about the user, subject, and experiment features, see Managing Users and Subjects.

Using the Runtime Interface

When an experiment is fully configured and saved, the Preview and Record buttons are enabled. In preview mode you can display data, adjust plots, and change runtime settings without any of the data being permanently stored to the data tank. This is particularly useful for tasks like spike sorting, where you might want to establish the sorting parameters before collecting data. For more straightforward tasks, like recording streamed data, you might choose to skip preview and go straight to record mode.

Mode Buttons


Mode Description
Idle Devices are not loaded and are not running
Preview Data is acquired, but deleted after the recording ends
Record Data is acquired and stored to the data tank permanently


The Runtime Window

The runtime window includes tabs with the main data plot and runtime controls for each gizmo. The data displayed is pulled directly from the hardware and sent to the display in parallel with data storage (rather than after).

The basic window includes a plot for each type of data being stored and each plot is automatically configured according to the type of data, for example: snippet, streamed waveforms, or epoch events. You might need to scale the plots to display the waveforms appropriately. This window is explained in more detail in Runtime.

Main Plot at Runtime - Streamed LFPs, Plot Decimated Waveforms, and Snippets

The second tab in the template is derived from the PCSort gizmo and is an interactive display with plots for cluster cutting and provides runtime access to many of the configuration setting, such as filter values, display options and even the sorting algorithm. You can find more information on this interface in PCA Spike Sorting.

To make sure you don't lose your cluster definitions and other settings between runs, Synapse will remember them according to your persistence setting.

Persistence

Key Concept

By default, Synapse saves the state of all experiment variables, including filter settings, threshold values, and cluster definitions in its relational database during each recording sessions. Any changes made to a setting is logged in the database as well as the user and/or subject information. All of these values are retained and saved as part of a history of the experiment. This database of experiments and history of it's past states (collection of settings for a user and/or subject at a given time) support several useful features including persistence and history browsing, filtering, and export features.

In the runtime window, 'persistence' refers specifically to how past experiment states are applied the next time the experiment is run. You can choose this behavior using the Persistence choices on the command bar.

Mode Description
Lock Locks selected persistence
Best Uses the last settings of any runtime controls
for the current experiment and user/subject
Last Uses the last settings of any runtime controls
for the current experiment (regardless of subject or user)
Fresh Uses the settings in the designtime Options area
and clears any past runtime settings
User Choose settings from a previous recording to apply
to next recording. More on that below

Unless you lock the choice, persistence returns to the Best default behavior after each recording session.

User History

History Window

This window includes a variety of filtering mechanisms to help you quickly find the data, experiment state, or specific setting value you are looking for. Using shortcut (right-click) menus you can select and return to start and end states for each session or any change state during the session. The top section of the window also displays the path and location for the data recorded during that session. You can begin working with the data set immediately from this window, using the same shortcut (right-click) menus.

Window Layout

Synapse can also remember information about tab layout. You can drag tabs to float them in new windows or right-click the tab to control placement inside the main window. Information about the window layout is specific to the user and is separate from persistence information. When you return to Idle, you can return to the default layout using the Reset Layout button on the command bar.

The Data Tank

TDT's TTank data server indexes and stores recorded data then makes the data available for post hoc visualization and analysis. By default, Synapse names data tanks (a grouping of recordings) automatically based on the experiment's name. Blocks (single recordings) are automatically named based on the subject ID for that recording session. These default preferences are ideal for labs that run an experiment on multiple subjects then move on to another experiment. If your lab does things differently, such as running experiments on the same subject to compare results over time you can change the Synapse preferences to organize the data is different ways. For more information, see Managing Data for Your Lab.