3. The Subdivisions of Visual Working Memory
Harald M. Mohr, Rainer Goebel, and David E. J. Linden
According to the "domain-specific" view, visual working memory tasks are separated in the lateral prefrontal cortex into functional subdivisions: dorsal areas handle the spatial features of a task, and ventral areas take on object and color information. The "process-specific" account, in contrast, argues that the ventral areas maintain information while manipulation occurs in dorsal areas. This week, Mohr et al. attempted to reconcile these two views. Human subjects were shown a colored semicircle and performed either maintenance or manipulation tasks after a delay period. Functional magnetic resonance imaging during the delay showed that cortical activity was segregated based on content. Dorsal premotor activation occurred with maintenance and manipulation of spatial tasks, whereas ventral premotor activation was seen for maintenance and manipulation of color tasks. Manipulation-specific activity involved other areas in a frontal-parietal network, consistent with multiple levels of specialization in frontal cortex.
4. Postseizure Granule Cell Dispersion
Christophe Heinrich, Naoki Nitta, Armin Flubacher, Martin Mller, Alexander Fahrner, Matthias Kirsch, Thomas Freiman, Fumio Suzuki, Antoine Depaulis, Michael Frotscher, and Carola A. Haas
Temporal lobe epilepsy is accompanied by several structural changes in the hippocampus, including widening of the granule cell layer in the dentate gyrus. In this week's Journal, Heinrich et al. examined the causes of this granule cell dispersion (GCD) in mice after intrahippocampal injections of kainic acid (KA). This protocol induced repeated hippocampal seizures (nonconvulsive status epilepti
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Contact: Sara Harris
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Society for Neuroscience
25-Apr-2006