Indirect pathway from caudate tail mediates rejection of bad objects in periphery

Area of Science:

• Neuroscience
• Decision-making
• Behavioral science

Background:

• Appropriate choice-making is essential for everyday functioning.
• The basal ganglia primarily control decision-making processes.
• Selecting "good" options and rejecting "bad" ones are key components of choice behavior.

Purpose of the Study:

• To investigate the neural mechanisms underlying the rejection of "bad" choices.
• To elucidate the role of the indirect pathway, specifically the connection from the tail of the caudate nucleus (CDt) to the caudal-ventral globus pallidus externus (cvGPe), in suppressing undesirable selections.

Main Methods:

• Developed a sequential saccade choice task for monkeys.
• Recorded neuronal activity in the cvGPe.
• Disrupted the inhibitory influence of CDt on cvGPe using bicuculline, a GABA_A receptor antagonist.

Main Results:

• Neurons in cvGPe typically showed inhibition upon the appearance of "bad" objects.
• This inhibitory response in cvGPe was diminished when monkeys incorrectly chose "bad" objects.
• Pharmacological disruption of the CDt-to-cvGPe pathway impaired the monkeys' ability to avoid "bad" choices.

Conclusions:

• The indirect pathway, involving CDt and cvGPe, plays a critical role in mediating the rejection of "bad" choices.
• This rejection mechanism is a fundamental aspect of goal-directed behavior.
• Understanding this pathway offers insights into the neural basis of decision-making and behavioral control.