Sensory-guided decision making
The transformation of complex sensory information into behavioral decisions requires the coordinated activity of many brain regions. We want to understand how these regions process sensory inputs and interact with each other to create a unified behavioral response. We therefore study the brain activity of awake mice while they perform a well-controlled perceptual task. This allows us to precisely control the available sensory inputs and then closely watch the activity in the brain as it transforms sensory information into behavior. In many of our experiments we focus on regions in the cortex (the outer shell of the brain) but we also study deeper brain structures, such as the striatum and the superior colliculus. To obtain a detailed view of brain-wide neural activity, we combine a large array of methods such as cortical widefield and 2-photon microscopy and high-density electrophysiology.
Pathway-specific information transfer
Different brain areas are heavily interconnected and constantly send information back and forth to create the brain-wide neural dynamics that give rise to behavior. What information is transmitted is hereby often custom-tailored to the recipient. For example, a cortical area will send different information to another cortical area compared to what is sent to deeper brain areas, such as the basal ganglia or the brainstem. The neurons that form connections between brain areas are therefore functionally distinct ‘output channels’ that are crucial for the communication within large-scale neural networks.
Using pathway-specific 2-photon imaging, we study the function of specific projection neurons in the cortex to reveal what information they sent to other brain areas and how distinct cortical projection pathways shape sensory perception and behavior.
Neuromodulation of cortical circuits and behavior
Behavioral decisions and their underlying neural dynamics vary widely across different behavioral states. Whether we are focused on a challenging task or thinking about past experiences determines how we interpret and respond to external stimuli. The basal forebrain (BF) is a major driver of such state-dependent fluctuations and releases the neuromodulator acetylcholine throughout the brain. We want to understand the function of different nuclei in the BF and how they affect cortical areas to enhance sensory perception. To achieve this goal, we simultaneously record the activity of different BF nuclei and cortical circuits and also use optogenetic manipulation to selectively change the activity of cholinergic projection neurons.
Better understanding BF function could also be important for clinical applications since degradation of cholinergic circuits leads to a significant loss of cognitive functions in many neurodegenerative disorders, such as Alzheimer’s or Schizophrenia.
Single-Trial Neural Dynamics Are Dominated by Richly Varied Movements, S. Musall et al., Nature Neuroscience 22, 1677-1686, October 2019
Harnessing behavioral diversity to understand neural computations for cognition, S. Musall et al., COIN, 58, 229-238, October 2019
Deviant processing in the primary somatosensory cortex, S. Musall et al., Cerebral Cortex 27, 863-876, January 2017