Whole-Brain Neural Connectivity to Cholinergic Neurons in the Lower Thoracic Intermediolateral Column

Area of Science:

• Neuroscience
• Autonomic Nervous System Research
• Spinal Cord Physiology

Background:

• The intermediolateral column (IML) is vital for sympathetic nervous system (SNS) function.
• Cholinergic neurons expressing choline acetyltransferase (ChAT) define the IML.
• Lower thoracic IML neurons regulate abdominal viscera, but their brain connectivity is poorly understood.

Purpose of the Study:

• To comprehensively map the whole-brain neural inputs targeting lower thoracic IML cholinergic neurons.
• To investigate the anatomical basis for central control of sympathetic functions related to abdominal viscera.

Main Methods:

• Utilized retrograde tracing virus injection into the lower thoracic IML of ChAT-Cre transgenic mice.
• Performed whole-brain fluorescence imaging and quantitative analysis of viral labeling.
• Identified afferent projections from various brain regions.

Main Results:

• Identified labeled neurons in 40 brain regions across the telencephalon, diencephalon, and brainstem.
• Found predominant afferent concentration in 25 brainstem regions, with the pons and medulla showing highest input.
• Observed projections from sympathetic, homeostatic, and motor-related brain regions, including the PVN, LH, RVLM, M1, M2, RN, and Gi.

Conclusions:

• Provided a comprehensive whole-brain anatomical map of inputs to lower thoracic IML cholinergic neurons.
• Revealed an extensive supraspinal network integrating sympathetic, homeostatic, and motor control centers.
• Suggests a potential anatomical basis for the central coordination of somatic motor and autonomic functions.