News

Working memory, the ability to maintain a limited amount of information “in mind” to guide everyday thoughts and behaviors, is a core cognitive process. Its function depends on activity in a network of brain areas distributed across the cerebral cortex. Each of these areas display different patterns of activity while information is being maintained. These differences are correlated with, and might depend on, distinctive properties of the neurons located in each area. For example, excitatory pyramidal neurons in cortical layer 3 differ significantly between primary visual and dorsolateral prefrontal (DLPFC) cortices. “However, the extent to which these neurons differ between DLPFC and other brain regions in the working memory network is less clear,” notes Dr. Guillermo González-Burgos, lead author of a study published in the Journal of Neuroscience.

Dr. González-Burgos and his collaborators compared the properties of layer 3 pyramidal neurons in monkey DLPFC versus posterior parietal cortex (PPC), key nodes in the cortical working memory network. Using patch-clamp recordings, they found layer 3 pyramidal neurons could be divided into regular spiking and bursting physiological subtypes, but the proportions of these two types differed substantially between the DLPFC and PPC. In addition, using biocytin cell filling, they found that these neurons had larger and more complex basal dendrites with higher dendritic spine density in DLPFC than in PPC. Finally, using laser microdissection of layer 3 pyramidal neurons, combined with DNA microarray or quantitative PCR, they found differential expression of hundreds of genes, suggesting a transcriptional basis for the differences in the functional and structural phenotypes of layer 3 pyramidal neurons between DLPFC and PPC. These data suggest that the previously observed differences between DLPFC and PPC neuron activity during working memory tasks are associated with diversity in the cellular/molecular properties of layer 3 pyramidal neurons.

“These findings might also provide insight into how alterations of these neurons in schizophrenia could contribute to the working memory impairments that are commonly seen in this illness,” noted co-author Dr. David Lewis. 

Distinct Properties of Layer 3 Pyramidal Neurons from Prefrontal and Parietal Areas of the Monkey Neocortex
González-Burgos G, Miyamae T, Krimer Y, Gulchina Y, Pafundo DE, Krimer O, Bazmi H, Arion D, Enwright JF, Fish KN, Lewis DA
The Journal of Neuroscience 11 September 2019, DOI: https://doi.org/10.1523/JNEUROSCI.1210-19.2019