Gamma knife radiosurgery targeting protocols for the experiments with small animals.

Area of Science:

• Neuroscience
• Stereotactic Surgery
• Behavioral Neuroscience

Background:

• Gamma Knife (GK) irradiation offers potential for manipulating brain functions in clinical and experimental neurology.
• Understanding the precise effects of targeted irradiation is crucial for its effective application.

Purpose of the Study:

• To investigate the behavioral consequences of precisely localized Gamma Knife (GK) irradiation in the rat striatum.
• To establish a protocol for accurate targeting in experimental GK irradiation using stereotactic frames and MRI.

Main Methods:

• Monitoring freely moving rat behaviors, including spontaneous activity and rotations on the apomorphine test, to assess dopaminergic function.
• Analyzing the spatial distribution of necrotic lesions using serial sections to determine the actual irradiation foci.
• Utilizing a behavior tracking system for precise quantification of behavioral changes.

Main Results:

• Specific behavioral alterations were observed corresponding to the exact locations of irradiation lesions within the basal ganglia.
• Anteromedial displacement of irradiation sites led to increased spontaneous activity.
• Posterolateral shifts in irradiation sites resulted in circling behavior during the apomorphine test.

Conclusions:

• Accurate target positioning is critical for experimental GK irradiation, especially in small brains like the rat's.
• A protocol for converting brain map coordinates to an MR imaging coordinate system using the Régis-Valliccioni stereotactic frame is proposed for precise targeting.