Chronic electrical stimulation homeostatically decreases spontaneous activity, but paradoxically increases evoked...

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Neural dynamics in cortical networks are crucial for brain function.
• Learning rules governing recurrent network dynamics and their plasticity remain largely unknown.

Purpose of the Study:

• To investigate the plasticity of network dynamics in cortical organotypic slices.
• To understand how chronic activity changes influence these dynamics using a physiological stimulation method.

Main Methods:

• Utilized chronic electrical stimulation via implanted electrodes for 4 days in in vitro cortical circuits.
• Compared effects of electrical stimulation with bicuculline treatment on network activity.
• Analyzed spontaneous and evoked network activity, including monosynaptic and polysynaptic responses.

Main Results:

• Chronic electrical stimulation and bicuculline decreased spontaneous activity, aligning with homeostatic plasticity.
• Paradoxically, chronic stimulation increased polysynaptic evoked activity despite reduced monosynaptic strength.
• An inverse correlation between spontaneous and evoked activity suggested a homeostatic tradeoff.

Conclusions:

• Chronic stimulation alters neural network dynamic regimes.
• Homeostatic learning rules appear to shift networks from spontaneous to evoked activity regimes when external input is present.