Information from the world around us is first transmitted to our cerebral cortex via the primary sensory, or first-order, thalamic nuclei. Higher-order thalamic nuclei, like the pulvinar and mediodorsal nucleus, receive relatively little input from the sensory periphery and instead form pathways between cortical areas, which can strongly influence cortical activity. These cortico-thalamo-cortical pathways are ideally positioned to regulate communication between cortical neurons.
Our vision is to establish the general principle across sensory, motor and cognitive domains that the higher-order thalamus helps selectively route information across the cortex according to behavioral demands. Current evidence suggests key mechanisms involve the higher-order thalamus controlling the excitability and synchrony of cortical neurons.
To realize this vision, we combine three main methodological approaches:
- Simultaneous multi-site neural recordings from higher-order thalamic and cortical areas of behaving animals as a model for human cognition
- Precise targeting of electrodes to interconnected network sites using neuroimaging techniques, particularly diffusion MRI, necessary because cortical areas project to circumscribed zones of higher-order thalamus
- Perturbations of brain networks, e.g., using microstimulation, to manipulate higher-order thalamus and its effect on the cortex and behavior
Current projects in our lab investigate thalamo-cortical interactions during:
- Cognitive control, e.g., rule-processing, decision-making and selective attention
- Memory processes
- Conscious and anesthetized states
The significance of this research is that it advances our understanding of fundamental cognitive processes, particularly how information is transmitted through large-scale brain networks. Disruption of brain networks lies at the heart of many psychological disorders, e.g., schizophrenia, autism, and depression. Our research is a first essential step towards treating such disorders.