Primary Sensory Representations Modulated by Brain State
Abstract
Our research addresses the interactions between neural activity, perception and learning. We use a combination of techniques (in vivo electrophysiology, viral targeting, optogenetic manipulation and two-photon imaging, computational modeling and behavioral analysis) to investigate how features of the outside world are represented in the brain and how they are influenced by internal states. Prior research has shown that primary sensory representations can depend strongly on cortical state; indeed it has been argued that this should be included explicitly as a variable in the analysis of sensory processing. Specific timing relationships between activity in sensory areas and local field potential oscillations have been described for species ranging from insects to humans, and their precise timing has been shown to depend also on brain state and context. In some cases, top-down effects such as attention and context are apparent at the single cell level, whereas in others, including primary auditory cortex, such effects seem to be particularly notable at the level of population codes. While previous work has pointed to the influence exerted by brain state on responses in primary sensory areas, there has been as yet no systematic study of the modulation of neural codes across a wide range of brain states. In the first phase of the project, we will measure auditory tuning in primary auditory cortex using two-photon calcium imaging while capturing a wide range of different brain states. This will be done by analyzing local field potentials recorded across cortical layers and hippocampus, and by tracking several behavioral metrics. We will quantitatively characterize cells’ responses to allow fine-grained analysis of the influence of brain state on neural coding. In the second phase of the project, we will carry out patch clamp recordings to obtain more detailed single-cell sensory responses, using the same simultaneous brain state measurements. The whole-cell recordings provide access to sub-threshold membrane potential and spiking activity at maximal temporal resolution. Sub-threshold measurements will connect this new work to the mechanistic investigations of our previous research, while the high temporal resolution spiking information will be used to assess precise timing relationships with brain state associated oscillations, as well as auditory stimuli.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 08, 2021
- Source ID
- N000142112872
Entities
People
- S. Cassenaer
Organizations
- California Institute of Technology
- Office of Naval Research
- United States Navy