Biology subjects

Paradiso, K. G.

Publications and source records attributed to Paradiso, K. G..

2 recordsLinked to original sources

bioRxiv2018

Opposing Influence of Sensory and Motor Cortex on Striatal Circuitry and Choice Behavior

The striatum is the main input nucleus of the basal ganglia and is a key site of sensorimotor integration. While the striatum receives extensive excitatory afferents from the cerebral cortex, the influence of different cortical areas on striatal circuitry and behavior is unknown. Here we find that corticostriatal inputs from whisker-related primary somatosensory (S1) and motor (M1) cortex differentially innervate projection neurons and interneurons in the dorsal striatum, and exert opposing effects on sensory-guided behavior. Optogenetic stimulation of S1-corticostriatal afferents in ex vivo recordings produced larger postsynaptic potentials in striatal parvalbumin (PV)-expressing interneurons than D1- or D2-expressing spiny projection neurons (SPNs), an effect not observed for M1-corticostriatal afferents. Critically, in vivo optogenetic stimulation of S1-corticostriatal afferents produced task-specific behavioral inhibition, which was bidirectionally modulated by striatal PV interneurons. Optogenetic stimulation of M1 afferents produced the opposite behavioral effect. Thus, our results suggest opposing roles for sensory and motor cortex in behavioral choice via distinct influences on striatal circuitry.

neuroscience↗

bioRxiv2018

Active presynaptic ribosomes in mammalian brain nerve terminals, and increased transmitter release after protein synthesis inhibition

Presynaptic neuronal activity requires the localization of thousands of proteins that are typically synthesized in the soma and transported to nerve terminals. Local translation for some dendritic proteins occurs, but local translation in mammalian presynaptic nerve terminals is difficult to demonstrate. Here, we present evidence for local presynaptic protein synthesis in the mammalian brain at a glutamatergic nerve terminal. We show an essential ribosomal component, 5.8s rRNA, in terminals. We also show active translation in nerve terminals, in situ, in brain slices demonstrating ongoing presynaptic protein synthesis. After inhibiting translation for ~1 hour, the presynaptic terminal exhibits increased spontaneous release, and increased evoked release with an increase in vesicle recycling during stimulation trains. Postsynaptic response, shape and amplitude were not affected. We conclude that ongoing protein synthesis limits vesicle release at the nerve terminal which reduces the need for presynaptic vesicle replenishment, thus conserving energy required for maintaining synaptic transmission.

cell biology↗