Great strides have been made recently in understanding cerebral cortical microcircuits. The introduction of transgenics and optogenetics together with advances in patch clamp techniques, have been instrumental in the rapid rate of discovery. For example, we now know there are at least three types of inhibitory interneurons in the cerebral cortex: those that express the Ca++ binding protein parvalbumin (PV), and those that use either the peptide neuromodulator vasoactive intestinal peptide (VIP) or somatostatin (SOM). Uniquely labeling these neurons reveals that these inhibitory interneurons exist in most areas of cerebral cortex. They have different morphologies, terminate on different parts of output neurons, have differing synaptic strengths and they play different roles in information processing. In this application, we propose to capitalize on the recent advances in transgenics and optogenetics to reveal the structure and function of inhibitory microcircuits within the superior colliculus and the role external inputs play in modulating these circuits. We have three aims. First, determine the physiology and targets of the local parvalbumin (PV) expressing neurons in the visuosensory layer of the collicular microcircuit. These experiments will test the hypothesis that PV neurons provide the dominant source of inhibition on sensory neurons that give rise to the colliculo-pulvinar-cortical pathway and to the descending intralaminar pathway to the motor layer. Second, determine the physiology and targets of extrinsic GABAergic inputs from the substantia nigra pars reticulata (nigra) to the motor layer collicular microcircuit. These experiments will test the hypothesis that external inhibition from the nigra is the dominant source of inhibition on motor output neurons in the superior colliculus microcircuit. Third, determine the function of the PV and nigral GABAergic inputs to collicular microcircuits. We will test the hypothesis that inhibition from PV neurons and inhibition from the nigra play different roles in determining response gain of collicular neurons in sensory and motor neurons. Because PV neurons have been implicated in neuropsychiatric disease processes the results of our experiments should clarify how these neurons contribute to higher mental function.

Public Health Relevance

A sine qua non of higher mental function is our ability to make decisions. Extreme fluctuations in choice behavior may underlie certain neurological and psychiatric diseases such as schizophrenia, attention deficit disorder, Tourette Syndrome and obsessive compulsive disorder. A deeper understanding of the microcircuits underlying higher mental function such as choice and decision-making may lead to better diagnostics, better ways to assess therapies and should provide important insights into the mechanisms of symptomology in these disease states.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Araj, Houmam H
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California Los Angeles
Schools of Medicine
Los Angeles
United States
Zip Code
May, Paul J; Basso, Michele A (2018) Connections between the zona incerta and superior colliculus in the monkey and squirrel. Brain Struct Funct 223:371-390
Villalobos, Claudio A; Wu, Qiong; Lee, Psyche H et al. (2018) Parvalbumin and GABA Microcircuits in the Mouse Superior Colliculus. Front Neural Circuits 12:35
Perugini, Alessandra; Ditterich, Jochen; Shaikh, Aasef G et al. (2018) Paradoxical Decision-Making: A Framework for Understanding Cognition in Parkinson's Disease. Trends Neurosci 41:512-525
Basso, Michele A; May, Paul J (2017) Circuits for Action and Cognition: A View from the Superior Colliculus. Annu Rev Vis Sci 3:197-226
Ghitani, Nima; Bayguinov, Peter O; Basso, Michele A et al. (2016) A sodium afterdepolarization in rat superior colliculus neurons and its contribution to population activity. J Neurophysiol 116:191-200
Basso, Michele A (2016) Monkey neurophysiology to clinical neuroscience and back again. Proc Natl Acad Sci U S A 113:6591-3
Bayguinov, Peter O; Ghitani, Nima; Jackson, Meyer B et al. (2015) A hard-wired priority map in the superior colliculus shaped by asymmetric inhibitory circuitry. J Neurophysiol 114:662-76
Grimaldi, Piercesare; Lau, Hakwan; Basso, Michele A (2015) There are things that we know that we know, and there are things that we do not know we do not know: Confidence in decision-making. Neurosci Biobehav Rev 55:88-97
Crapse, Trinity B; Basso, Michele A (2015) Insights into decision making using choice probability. J Neurophysiol 114:3039-49
Vokoun, Corinne R; Jackson, Meyer B; Basso, Michele A (2011) Circuit dynamics of the superior colliculus revealed by in vitro voltage imaging. Ann N Y Acad Sci 1233:41-7

Showing the most recent 10 out of 12 publications