Sympathetic sprouting and recovery of a spatial behavior

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Neuroplasticity

Background:

• Medial septal lesions induce sympathetic fiber ingrowth into the hippocampus.
• This neuronal rearrangement's functional impact on hippocampal-dependent memory is unclear.

Purpose of the Study:

• To investigate the functional significance of sympathetic ingrowth into the hippocampus following medial septal lesions.
• To assess the effect of this ingrowth on spatial and memory task performance.

Main Methods:

• Rats underwent medial septal lesions and/or superior cervical ganglionectomies.
• Behavioral analysis was performed using a radial eight-arm maze to assess working and reference memory.
• Performance recovery rates were compared between groups with different surgical timings.

Main Results:

• Medial septal lesions impaired performance on the radial eight-arm maze.
• Simultaneous medial septal lesions and ganglionectomies significantly enhanced the rate of performance recovery.
• Delayed ganglionectomy after recovery from septal lesions had no effect on maze performance.

Conclusions:

• Sympathetic fiber ingrowth into the hippocampal formation following medial septal lesions appears to retard behavioral recovery processes.
• The timing of sympathetic denervation influences the recovery trajectory from hippocampal-induced memory deficits.