SPP 2411:  Sensing LOOPS: cortico-subcortical interactions for adaptive sensing

• Subject Area: Medicine ; Biology ; Social and Behavioural Sciences
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 500900173

Our brain perceives the world dynamically, zooming in into relevant stimuli and fading out irrelevant ones, generating skewed moment-to-moment snapshots of reality. For example, if you are in New York City in need of a cab, you will be susceptible to yellow objects, the colour of cabs in NYC. This “adaptive sensing” of the world is at the essence of the flexibility that has allowed mammals to flourish in varying environmental conditions. Adaptive sensing depends on the interaction between incoming sensory input and the feedback that can modulate it, in other words, it depends on a processing loop. Anatomists have known of feedback projections for decades. These projections often arise in the cortex and innervate numerous subcortical nuclei at various levels of the sensory processing, creating cortico-subcortical loops. Importantly, feedback projections can exceed in number their feedforward counterparts. And yet, we continue to view sensory processing as a feedforward transformation of information. Feedforward networks, however, fail to capture the high proficiency of mammalian brains to flexibly interpret a complex world on a moment-to-moment basis, according to current needs and previous experience. We must venture away from the streetlight to incorporate the role of feedback projections into our understanding of adaptive sensing. While theories on the function of feedback projections have been put forward, their investigation has been limited mostly because existing tools were not sufficiently refined to selectively target these projections. Thanks to recent technical advances, this is now possible. Indeed, we can now use genetic tools to unprecedentedly target and even manipulate both the cortical neurons that send feedback, as well as the subcortical neurons that receive it. Combined with recent advancements in high density electrophysiology and brain-wide imaging, these techniques allow us to sample and manipulate the activity of cortical and subcortical neurons even in alert behaving animals during adaptive sensing. The momentum generated by these technical developments is paralleled at the theoretical level, with the incorporation of feedback projections into current artificial network models.

• DFG Programme: Priority Programmes
• International Connection: Israel, USA

Projects

• A cortico-collicular network for hearing and noise avoidance responses in bats (Applicants Hechavarria, Julio ;  Triesch, Jochen )
• Cortico-subcortical interactions via the thalamic reticular nucleus for visual adaptive sensing (Applicant Busse, Laura )
• Cortico-thalamic feedback loops for representational stabilization of visual sensation (Applicants Rose, Tobias ;  Tchumatchenko, Tatjana )
• Corticofugal mechanisms of naturalistic threat memory (Applicant Letzkus, Ph.D., Johannes )
• Corticofugal regulation of thalamic nuclei by the somatosensory cortex (Applicant Manahan-Vaughan, Denise )
• Fear loops: Adaptive sensory coding in cortico-thalamic circuits upon associative learning. (Applicant Gründemann, Ph.D., Jan )
• Learning-related topographic network activity patterns of auditory corticofugal neurons (Applicant Hirtz, Jan Jasper )
• Neural interaction during context dependent visual processing in the human medial temporal lobe (Applicants Liebe, Ph.D., Stefanie ;  Mormann, Florian )
• Peripheral-to-foveal cortico-collicular processing of visual information across eye movements (Applicant Hafed, Ph.D., Ziad )
• Perturbing human thalamocortical loops to understand their contribution to visual perception (Applicants Jaramillo, Jorge ;  Kaufmann, Elisabeth ;  Staudigl, Tobias ;  Zaehle, Ph.D., Tino )
• Role of cortico-subcortical loops in olfactory stimulus detection and figure background separation (Applicants Rothermel, Markus ;  Schwarz, Martin )
• SPP2411 - Sensing LOOPS: cortico-subcortical interactions for adaptive sensing (Applicant de Hoz, Ph.D., Livia )
• Temporal dynamics of unsupervised contextual learning in cortico-collicular loops (Applicant de Hoz, Ph.D., Livia )
• The control of multi-neuron temporal encoding in the LGN by striate feedback (Applicant Vinck, Ph.D., Martin )
• The mediodorsal thalamus as a central hub in olfactory learning (Applicants Johenning, Friedrich ;  Schiller, Ph.D., Jackie )
• The nature of sensory gating – probing the function of a corticofugal loop. (Applicant Schwarz, Cornelius )
• The pulvinar nuclei as a computational system: Computing and calibrating the organization of 3-D visual space. (Applicant Parker, Ph.D., Andrew )

• Spokesperson: Livia de Hoz, Ph.D.