Visual Cue Manipulation and Chamber Shape Change Experiment
Objective: To describe the positional firing properties of medial entorhinal cortex (MEC) cells and compare them with hippocampal place cells, specifically testing neuronal firing responses to visual cue rotation and chamber shape changes (cylinder to square) to assess spatial coding strategies.
Gather these items before starting the experiment. Check off items as you prepare.
Equipment3
Materials2
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Software1
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Protocol Steps
Baseline recording in cylindrical chamber
Record MEC cell firing patterns while rats retrieve pellets in cylindrical recording chamber to establish baseline positional firing properties
Note: Behavioral task and data collection procedures were the same as used in previous studies on hippocampal place cells
View evidence from paper
“MEC cells were recorded from rats while they retrieved pellets in simple geometric enclosures. The behavioral task as well as procedures for data collection and analysis were the same used in previous studies”
Visual cue rotation experiment
Rotate the white visual cue card attached to the wall and record changes in MEC cell firing patterns to test cue-dependent firing control
Note: Test whether MEC firing can be controlled by visual cue rotation, similar to hippocampal place cells
View evidence from paper
“their firing can be controlled by the rotation of a visual cue (a white card attached to the wall)”
Visual cue removal experiment
Remove the white visual cue card and record MEC cell firing patterns to test whether firing is disrupted by cue removal
Note: Determine if MEC firing patterns are disrupted or maintained without visual cue
View evidence from paper
“but is not disrupted by removing the cue”
Chamber shape change experiment
Transition recording chamber from cylinder to equal-area square of similar appearance and record MEC cell firing pattern changes
Note: Compare MEC firing pattern transformation to hippocampal place cell responses in same chamber shape change
View evidence from paper
“In the transition from a cylinder to an equal-area square of similar appearance, MEC firing patterns topologically transformed (or 'stretched')”
Long-duration recordings
Conduct extended recording sessions to assess reproducibility and improvement in spatial signal of MEC firing patterns
Note: Long-duration recordings demonstrate that MEC firing patterns are stationary in time and reproducible
View evidence from paper
“MEC firing patterns are stationary in time as evidenced by their reproducibility, and the improvement in spatial signal with long-duration recordings”