Mixed Signals

Individual neurons in the dorsomedial striatum integrate responses to sight and touch.

Molly Sharlach
Oct 31, 2014

VITAL NETWORK: Neurons in the mouse striatum expressing dopamine receptors (green) integrate sensory information from touch and vision.RAMON REIG AND GILAD SILBERBERG


The paper
R. Reig, G. Silberberg, “Multisensory integration in the mouse striatum,” Neuron, 83:1200-12, 2014.

Central station
The striatum, part of the basal ganglia that sit at the base of the forebrain, receives input from the surrounding cerebral cortex to coordinate environmental signals with motor responses. Although it’s known that striatal neurons process different types of sensory stimuli, the temporal and spatial organization of this processing is not well understood. Ramon Reig and Gilad Silberberg of the Karolinska Institute in Stockholm measured responses to visual and tactile cues in individual striatal neurons of living mice.

Delicate work
To prevent interference from motor activity, Reig and Silberberg anesthetized the mice, leaving their sensory abilities intact. The researchers delivered a puff of air to the whiskers or a flash of light to the eye and used an intracellular patch-clamp technique to record voltage changes in the striatal neurons.

Unexpected overlap
Ruffling the whiskers activated a broad swath of neurons in the striatum, while a subset of cells in the striatum’s midsection responded to both tactile and visual signals. “We thought that a small region of neurons would respond to visual stimulation [alone], but the surprise was that [visual neurons] all responded to tactile as well,” Silberberg says. “They integrate sensory input from completely different modalities—light and touch.”

Under the radar
Paul Bolam of the University of Oxford points out that because the mice were knocked out, the researchers could observe “subthreshold” levels of neuronal activity—those not causing action potentials or motor responses. “It may be different in the behaving animal,” says Bolam, who was not involved in the study. “But that’s extremely difficult to test.”