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O'Toole, S. M.

Publications and source records attributed to O'Toole, S. M..

2 recordsLinked to original sources

Prediction error neurons in mouse cortex are molecularly targetable cell types

Predictive processing postulates the existence of prediction error neurons in cortex. Functionally, both negative and positive prediction error neurons have been identified in layer 2/3 of visual cortex, but whether they correspond to transcriptionally defined subpopulations is unclear. Here we used the activity-dependent, photoconvertible marker CaMPARI2 to tag neurons in layer 2/3 of visual cortex during stimuli and behaviors designed to trigger prediction errors. We performed single-cell RNA-sequencing on these populations and found that previously annotated Adamts2 and Rrad layer 2/3 cell types were enriched when photolabeling for negative or positive prediction error responses respectively. Finally, we validated these results functionally by designing artificial promoters for use in AAV vectors to express genetically encoded calcium indicators. Thus, positive and negative prediction error responses mapped onto transcriptionally distinct cell types in layer 2/3 that can be targeted using AAV vectors.

neuroscience↗

A transcriptional constraint mechanism limits the homeostatic response to activity deprivation in mammalian neocortex

Healthy neuronal networks rely on homeostatic plasticity to maintain stable firing rates despite changing synaptic drive. These mechanisms, however, can themselves be destabilizing if activated inappropriately or excessively. For example, prolonged activity deprivation can lead to rebound hyperactivity and seizures. While many forms of homeostasis have been described, whether and how the magnitude of homeostatic plasticity is constrained remains unknown. Here we uncover negative regulation of cortical network homeostasis by the PARbZIP family of transcription factors. In cortical slice cultures made from knockout mice lacking all three of these factors, the network response to prolonged activity withdrawal measured with calcium imaging is much stronger, while baseline activity is unchanged. Whole cell recordings reveal an exaggerated increase in the frequency of miniature excitatory synaptic currents reflecting enhanced upregulation of recurrent excitatory synaptic transmission. Genetic analyses reveal that two of the factors, Hlf and Tef, are critical for constraining plasticity and for preventing life-threatening seizures. These data indicate that transcriptional activation is not only required for many forms of homeostatic plasticity but is also involved in restraint of the response to activity deprivation.

neuroscience↗