Thyroid hormones maintain parvalbumin neuron functions in the mouse neocortex

Area of Science:

• Neuroscience
• Endocrinology
• Cellular Biology

Background:

• Parvalbumin neurons regulate cortical excitation-inhibition balance.
• Thyroid hormones are critical for parvalbumin neuron maturation.
• The role of thyroid hormones in mature parvalbumin neurons remains unclear.

Purpose of the Study:

• To investigate the function of thyroid hormones in mature parvalbumin neurons.
• To determine the impact of disrupted thyroid hormone signaling on established parvalbumin neuron function.
• To elucidate the consequences of impaired thyroid hormone signaling in adult cortical circuits.

Main Methods:

• Utilized genetically modified mouse models with targeted disruption of thyroid hormone signaling in parvalbumin neurons.
• Conducted genomic, histological, and electrophysiological analyses.
• Performed sleep and behavioral assessments, including seizure susceptibility tests.

Main Results:

• Mutant mice exhibited reduced perineuronal net components and decreased neuronal excitability.
• Observed alterations in gamma oscillations, behavioral hyperactivity, and increased wakefulness.
• Demonstrated delayed sleep onset and heightened susceptibility to seizures in mutant mice.

Conclusions:

• Thyroid hormones are essential for maintaining mature parvalbumin neuron function, not just development.
• Disruption of thyroid hormone signaling in adulthood impairs cortical function and network oscillations.
• Imbalances in thyroid hormone signaling may underlie neurological and psychiatric disorders associated with abnormal brain activity.