Formation and Reverberation of Sequential Neural Activity Patterns Evoked by Sensory Stimulation Are Enhanced during Cortical Desynchronization

Abstract

Memory formation is hypothesized to involve the generation of event-specific neural activity patterns during learning and the subsequent spontaneous reactivation of these patterns. Here, we present evidence that these processes can also be observed in urethane-anesthetized rats and are enhanced by desynchronized brain state evoked by tail pinch, subcortical carbachol infusion, or systemic amphetamine administration. During desynchronization, we found that repeated tactile or auditory stimulation evoked unique sequential patterns of neural firing in somatosensory and auditory cortex and that these patterns then reoccurred during subsequent spontaneous activity, similar to what we have observed in awake animals. Furthermore, the formation of these patterns was blocked by an NMDA receptor antagonist, suggesting that the phenomenon depends on synaptic plasticity. These results suggest that anesthetized animals with a desynchronized brain state could serve as a convenient model for studying stimulus-induced plasticity to improve our understanding of memory formation and replay in the brain.

Activity-induced manganese-dependent MRI (AIM-MRI) and functional MRI in awake rabbits during somatosensory stimulation

“…In macaques, significant reactivation of somatosensory cortex neural ensemble activity was observed after a sequential reaching behavior (Hoffman and McNaughton, 2002). Also, repeated tactile stimulation in rats evokes unique sequential patterns of neural firing in the somatosensory cortex that reoccur during subsequent spontaneous activity (Bermudez Contreras et al, 2013). By comparing the left and right hemispheres of the SS cortex and VPM thalamus, we delineated specific and nonspecific accumulation of Mn 2+ .…”

Effect of methylphenidate on visual responses in the superior colliculus in the anaesthetised rat: Role of cortical activation

“…Bermudez Contreras et al, 2013), yet in the case of amphetamine, visual responses in the superficial layers are depressed by the drug. The reason for this may lie in the proximal effect of the two drugs.…”

The log-dynamic brain: how skewed distributions affect network operations

“…It is experience that attaches ‘meaning’ to the firing patterns in a preconfigured brain 12,19,22,45,48,80,119,137–139 . Even a non-experienced brain can have numerous high-probability states (often referred to as attractors 140 ) that can give rise to distinct constellations of neuronal firing (so-called ‘trajectories’ (REFS 121,141)), each of which is available to represent a unique event or situation 119 .…”