Behavioural and neuronal correlates of sensory prioritization in the rat whisker system [article]

Conrad Lee, University, The Australian National, University, The Australian National
2017
Animals need to assess when to initiate actions based on uncertain sensory evidence. To formulate a response, decision making systems must prioritize extraction of neuronal signals that represent ecologically relevant events from signals that are behaviorally less relevant. This is commonly known as selective attention. The current thesis aims to investigate two simple forms of attention in rodents: sensory prioritization to a specific modality and temporal cueing. The rat whisker system is
more » ... isker system is functionally efficient, and anatomically well characterized. We therefore utilize the whisker touch as a model sensory system to investigate the neuronal and behavioral correlates of attention in rats. We begin this thesis by designing a novel simple detection task that investigated whether rats dedicate attentional resources to the sensory modality in which a near-threshold event is more likely to occur. Detection of low-amplitude events is critical to survival, and to formulate a response, animals must extract minute neuronal signals from the sensory modality that is more likely to provide key information. We manipulated attention by controlling the likelihood with which a stimulus was presented from one of two modalities. In a whisker session, 80% of trials contained a brief vibration stimulus applied to whiskers and the remaining 20% of trials contained a brief change of luminance. These likelihoods were reversed in a visual session. When a stimulus was presented in the high-likelihood context, detection performance increased and was faster compared with the same stimulus presented in the low-likelihood context. Sensory prioritization was also reflected in neuronal activity in the vibrissal area of primary somatosensory cortex: single units responded differentially to a whisker vibration stimulus when presented with higher probability compared to the same stimulus when presented with lower probability. Neuronal activity in the vibrissal cortex displayed signatures of multiplicative gain control and enhanced response to vib [...]
doi:10.25911/5d70f13c0c526 fatcat:t5s46mejjjdn5jpztqglvg3yle