3. Stop-and-Go Tract Tracing
Adam R. Aron, Tim E. Behrens, Steve Smith, Michael J. Frank, and Russell A. Poldrack
Aron et al. this week mapped a connection between brain regions that control cognitive "stop" signals. The authors looked for a direct link between inferior frontal cortex (IFC) and subthalamic nucleus (STN) in human subjects using diffusion-weighted imaging tractography, a form of magnetic resonance imaging (MRI). They identified a white matter tract between STN and IFC in the right hemisphere; each of these regions also projected to the presupplementary motor area (preSMA). Next, subjects were instructed to stop a motor task command under some conditions and to ignore a stop signal under others. Functional MRI revealed increased activity in the IFC, STN, and preSMA when a stop signal was delivered under the noncritical condition, similar to outright stop responses. In this network, preSMA may serve a conflict-monitoring function for the stop signals involving IFC and STN.
4. An Old Treatment for Epilepsy and a New Cellular Mechanism
Weiyuan Ma, Jim Berg, and Gary Yellen
A low-carb ketogenic diet, although definitely not delicious, can be therapeutic in intractable epilepsy. However, seizure protection ends abruptly with sugar intake. Ma et al. looked for a cellular mechanism in GABAergic neurons of the substantia nigra pars ret
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Contact: Sara Harris
sharris@sfn.org
202-962-4000
Society for Neuroscience
3-Apr-2007