The striatum is the primary input to the basal ganglia, a collection of structures involved in initiation of voluntary movements and motor learning. This structure is involved in many movement and cognitive disorders. The principle output of striatum is through the GABAergic medium spiny neurons (MSNs). Cholinergic interneurons (CINs) of the striatum fire tonically and provide the sole source of the neuromodulator acetylcholine (Ach) to the striatum. In vitro, Ach presynaptically inhibits corticostriatal EPSCs in MSNs. This provides a powerful opportunity for regulation of MSN activity. However, it has been difficult to assess the role of CIN firing on this inhibition. Furthermore, CINs are thought to correspond to tonically active neurons (TANs) reported in vivo. These cells briefly cease firing to rewarding stimuli and stimuli that predict reward, suggesting the possibility that this pause reduces Ach relieving this inhibition. In this project we seek to link the activity of CINs to changes in MSN firing and corticostriatal EPSCs both in vitro and in vivo. We selectively control the firing of CINs using virally delivered light activated membrane proteins, channelrhodopsin (ChR2) and halorhodopsin (HR). We have validated that we can control the firing of CINs in vivo and in vitro. We can now investigate how both the timing of CIN action potential and their firing rate affects EPSCs in MSNs in the acute slice. And, with HR we now have the ability to briefly pause CINs in striatum. We will observe any changes to corticostriatal EPSCs, allowing us to make predictions on the function of TAN pauses. Additionally, using implanted fiberoptics and in vivo recording devices we can activate and pause CINs in vivo. By comparing evocable CINs to apparent TANs we can identify if CINs are in fact TANs. And by recording the activity of the surrounding MSNs we can identify the net effect of CIN activity or pause on spontaneous and cortically driven activity. This approach allows the first opportunity to observe the effects of cholinergic interneuron activity, and provides the first insight to a function of the behaviorally important pause in TAN firing.
Acetylcholine in striatum is critically involved in voluntary movement and associative learning. However, the mechanisms of this control are not well understood. The new techniques that we develop in this proposal will help us understand how acetylcholine release controls the behaviors of other cells, aiding in our understanding of normal cognition as well as the pathophysiology of brain disorders such as Parkinson's Disease, Alzheimer's Disease, Huntington's Disease, and Schizophrenia.
|Saunders, Arpiar; Huang, Kee Wui; Sabatini, Bernardo Luis (2016) Globus Pallidus Externus Neurons Expressing parvalbumin Interconnect the Subthalamic Nucleus and Striatal Interneurons. PLoS One 11:e0149798|
|Saunders, Arpiar; Oldenburg, Ian A; Berezovskii, Vladimir K et al. (2015) A direct GABAergic output from the basal ganglia to frontal cortex. Nature 521:85-9|
|Oldenburg, Ian A; Sabatini, Bernardo L (2015) Antagonistic but Not Symmetric Regulation of Primary Motor Cortex by Basal Ganglia Direct and Indirect Pathways. Neuron 86:1174-81|
|Pisanello, Ferruccio; Sileo, Leonardo; Oldenburg, Ian A et al. (2014) Multipoint-emitting optical fibers for spatially addressable in vivo optogenetics. Neuron 82:1245-54|
|Jiang, Han; Wang, Lingyan; Beier, Kevin T et al. (2013) Lineage analysis of the late otocyst stage mouse inner ear by transuterine microinjection of a retroviral vector encoding alkaline phosphatase and an oligonucleotide library. PLoS One 8:e69314|
|Beier, Kevin T; Saunders, Arpiar B; Oldenburg, Ian A et al. (2013) Vesicular stomatitis virus with the rabies virus glycoprotein directs retrograde transsynaptic transport among neurons in vivo. Front Neural Circuits 7:11|
|Higley, Michael J; Gittis, Aryn H; Oldenburg, Ian A et al. (2011) Cholinergic interneurons mediate fast VGluT3-dependent glutamatergic transmission in the striatum. PLoS One 6:e19155|
|Beier, Kevin T; Saunders, Arpiar; Oldenburg, Ian A et al. (2011) Anterograde or retrograde transsynaptic labeling of CNS neurons with vesicular stomatitis virus vectors. Proc Natl Acad Sci U S A 108:15414-9|
|Oldenburg, Ian Antón; Ding, Jun B (2011) Cholinergic modulation of synaptic integration and dendritic excitability in the striatum. Curr Opin Neurobiol 21:425-32|