Cortically projecting nucleus basalis neurons in rat are physiologically heterogeneous

Area of Science:

• Neuroscience
• Neurophysiology

Background:

• The basal forebrain contains cholinergic neurons projecting to the cortex.
• The nucleus basalis is a key area for these projections.

Purpose of the Study:

• To identify and characterize cortically projecting neurons in the globus pallidus (nucleus basalis) in rats.
• To investigate the physiological properties and cortical connectivity of these neurons.

Main Methods:

• Antidromic activation from the frontal cortex in anesthetized rats.
• Recording of spontaneous discharge rates, impulse amplitudes, and waveforms.
• Measurement of conduction latencies from the frontal cortex.
• Testing antidromic activation from neighboring cortical sites.

Main Results:

• Cortically projecting neurons in the nucleus basalis were successfully identified.
• These neurons displayed heterogeneous physiological properties, including varied discharge rates (0-40 Hz), impulse amplitudes, and waveforms.
• Conduction latencies from the frontal cortex ranged from 1-13 ms.
• Many identified neurons could also be antidromically activated from adjacent cortical areas.

Conclusions:

• Neurons in the globus pallidus projecting to the cortex exhibit diverse physiological characteristics.
• These neurons possess widespread cortical connections, potentially influencing various cortical functions.