Ranson, A. | bioRxiv Science

bioRxiv2017

NMDAR hypofunction increases top-down influence on sensory processing

Converging evidence implicates NMDAR disruption in the pathogenesis of schizophrenia, a condition in which perceptual disturbances are prominent. To explore how NMDAR hypofunction causes perceptual symptoms we investigated activity in cortical sensory circuits in awake behaving mice during pharmacologically induced NMDAR hypofunction. We observed a reduction in sensory-driven activity in V1 while input from the anterior cingulate cortex simultaneously increased, suggesting NMDAR hypofunction may lead to altered perception by modifying the balance of top-down and bottom-up processing.

neuroscience↗

bioRxiv2016

Stability and plasticity of contextual modulation in the mouse visual cortex

Activity of neurons in primary sensory cortex is shaped by visual and behavioural context. However the long-term stability of the influence of contextual factors in the mature cortex remains poorly understood. To investigate this we used 2-photon calcium imaging to track the influence of surround suppression and locomotion on individual neurons over 14 days. We found that highly active excitatory neurons and PV+ interneurons exhibited relatively stable modulation by visual context. Similarly most neurons exhibited a stable yet distinct degree modulation by locomotion. In contrast less active excitatory neurons exhibited plasticity in visual context influence resulting in increased suppression. These findings suggest that the mature visual cortex possesses stable subnetworks of neurons, differentiated by cell-type and activity level, which have distinctive and stable interactions with sensory and behavioural context, as well as other less active and more labile neurons which are sensitive to visual experience.

neuroscience↗