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In Vivo 2-Photon imaging in Synapses of Mobile Mice D. Leinweber, M. Reagan, J. Seaton, J. Sekhon Advisor: Dr. Mitch Tyler Client: Dr. Giulio Tononi and Dr. Ugo Faraguna. Final Prototype. Abstract. Dr. Tononi’s Hypothesis.
D. Leinweber, M. Reagan, J. Seaton, J. Sekhon
Advisor: Dr. Mitch Tyler Client: Dr. Giulio Tononi and Dr. Ugo Faraguna
Dr. Tononi’s Hypothesis
The following pictures show the final prototype as it was installed on the microscope table:
A hypothesis has been proposed by Dr. Giulio Tononi that sleep is used for synaptic downsizing. Specifically, he states that “The synaptic homeostasis hypothesis claims that plastic processes during wakefulness result in a net increase in synaptic strength in many brain circuits; during sleep, synaptic strength is globally downscaled to a baseline level that is energetically sustainable and beneficial for memory and performance”.
A hypothesis has been proposed by Dr. Giulio Tononi that sleep is used for synaptic downsizing. An experiment to test this hypothesis has been proposed using 2-photon microscopy to image synaptic activity in the brain in awake and sleeping mice. In order to successfully test the hypothesis of synaptic downscaling as a neurological function of sleep, a device capable of holding a mouse’s head in a fixed position for 2-photon microscopy is necessary. The device will be broken into two parts—a stereotaxic frame for keeping the mouse’s head in a rigid position, and a stage upon which the mouse can have freedom of movement.
Figure 1: Global view of microscope including head restraint, linear actuator track, and treadmill ball.
Figure 2: Construction!
Treadmill: A Closer Look
The following pictures show the treadmill design in more detail:
The treadmill was made from a replaceable Styrofoam ball placed on an axel. The axel spins using a bearing bolted on to the side of a linear actuator track. The linear actuator track is used for fine adjustments to allow for different objective lengths.
Figure 3: Close up view of linear actuator track.
Figure 4: Close up view of treadmill ball on axel.
Head Restraint: A Closer Look
The following pictures show the Head Restraint design in more detail:
The head restraint was made from a steel bar spanning the gap in the stage. It was essential that the bar be adjustable, so plastic slots on the sides were used to allow for proper adjustability. Plexiglass was used to attach the plastic slots to the bar as well as to attach the entire device to the stage.
Figure 6: Close up view of
adjustability of head restraint.
Figure 5: Close up view of head restraint.