Splicing processes (2D)

What is the purpose of splicing?

When tracing in serial sections, two processes may appear to exit a section close together. But when tracing in the next section, it becomes apparent that the two processes are actually one continuous process with a short segment in the second section.

 

  • A look at section B only suggests a small process.
  • A look at section A only suggests two different processes rather than one process that crosses sections.

Splicing allows for joining two processes after they have been completely traced in two sections as separate processes.

Procedure

  1. Click Trace>Edit>Select objects and click a branch to select it.
  2. Place the cursor over the end of the branch, right-click and select Splice. A line extends from the end to the cursor.
  3. Move the cursor over the end of the branch you want to join to. A circle appears at the end.
  4. Click to splice the two branches. You are prompted to "adjust the Z values of the spliced branch to match those of the selected neuron."

    Click No to avoid introducing distortion into the Z position of the newly joined branch.

Splicing and directionality

The program marks the first point placed to trace the process as the beginning of the process.

To determine whether a point is a beginning or an ending, click Trace>Edit>Select objects, click the traced process to select it, and hover over the point.

  • The letter E indicates an ending.
  • The letter B indicates a beginning.

To change a point from an ending to a beginning, right-click the ending and select Change Ending Type. Select Origin Ending.

  1. Click Trace>Edit>Select Objects and click process α to select it.
  2. Hover over the ending of process α until the letter E displays (to indicate an ending).
  3. Right-click over the E and select Splice. A line appears, connecting the ending of process α to the cursor.

    Click the beginning of process β to splice the processes. You are prompted to "adjust the Z values of the spliced fragment to match those of the selected neuron."

    • If you are confident that process β was recorded at the correct Z depth, select No. The splicing segment traverses the Z depth between the two fragments. Use the Orthogonal View to check that the jump is not too abrupt.
    • If you have not set the Z depth of process β, select Yes. The beginning of process β is assigned the same Z depth as the ending of process α.

  1. Click Trace>Edit>Select Objects and click process α to select it.
  2. Hover over the ending of process α until the letter E displays (to indicate an ending).
  3. Right-click over the E and select Splice. A line appears, connecting the ending of process α to the cursor.

    Click the ending of process β to splice the processes. The beginning of the more distal segment (β) is automatically changed to a Generated Ending (GE).

The program automatically renumbers the branch order of branches on the processes spliced together.

Attempting to splice a beginning to a beginning results in an error message with instructions to flip the orientation of one of the process fragments.

To flip the orientation:

  1. Click Trace>Edit>Select Objects and click the process to flip to select it.
  2. Right-click and select Change Ending Type.
  3. Select Origin Ending). The branches are automatically renumbered.