Inhalt des Dokuments
From optimal control problems to brain stimulation
Friday, 29th November 2019
Location: Technische Universität Berlin
HBS building, Room HBS 005
Straße des 17. Juni 135, 10623 Berlin
Guests are welcome!
Programme
Friday, 29th November 2019
| 15:00 | Sparse Solutions in Optimal Control of Partial Differential Equations Eduardo Casas, University of Cantabria, Santander (Spain) |
| 15:50 | Coffee Break |
| 16:10 | Transcranial stimulation targeting memory-relevant sleep oscillations: A potential therapeutic approach in aging and mild cognitive impairment? Julia Ladenbauer, Kognitive Neurologie, Universitätsmedizin Greifswald |
| 16:35 | Applications of optimal control to the dynamics of a whole brain network Teresa Chouzouris, Neuronale Informationsverarbeitung, Technische Universität Berlin |
| 17:00 | Informal get-together ("Stammtisch") |
Abstracts
Eduardo Casas,University of Cantabria, Santander (Spain)
Transcranial stimulation targeting memory-relevant sleep oscillations:
A potential therapeutic approach in aging and mild cognitive impairment?
Julia Ladenbauer, Kognitive Neurologie, Universitätsmedizin Greifswald
Memory-relevant sleep oscillations, in particular cortical slow oscillations (SO) and thalamo-cortical spindle activity, decrease during aging, which is accompanied by a decline in declarative memory consolidation. These changes are profoundly accelerated in Alzheimer's dementia and its precursor mild cognitive impairment (MCI).
We investigated the potential of slow oscillatory transcranial direct current stimulation, applied during a daytime nap and nighttime sleep in a brain-state-dependent manner, to modulate these activity patterns and sleep-related memory consolidation in healthy elderly and MCI patients.
We consistently found positive immediate effects on SO as well as fast spindle activity. Stimulation further enhanced the functional coupling between SO and spindle activity, a mechanistic component considered crucial for the transfer of memories from hippocampus to cortical long-term storage networks. Regarding memory performance, we observed that stimulation during a daytime nap significantly improved visual recognition performance, while stimulation during nighttime sleep unexpectedly resulted in a negative memory effect.
An explanation for this discrepancy and the relation to other relevant studies will be discussed.
Our findings indicate a well-tolerated therapeutic approach for disordered sleep physiology and memory deficits and advance our understanding of offline memory consolidation.
Applications of optimal control to the dynamics of a whole brain network
Teresa Chouzouris, Neuronale Informationsverarbeitung, Technische Universität Berlin
Modulating and controlling neuronal activity is becoming increasingly important in clinical settings for the treatment of neurological disorders. In this study, we use a model-based approach to investigate the impact of external stimulation on the global dynamics of the brain. We implement a network model simulating spatiotemporal activity in the brain and using methods from nonlinear control theory, we optimize the stimulation effects. The network's structural connectivity is constructed using Diffusion Tensor Imaging (DTI) data from the Human Connectome Project (HCP) divided into 94 cortical and subcortical regions according to the Automated Anatomical Labelling (AAL2) atlas, each region corresponding to a node in the network. The node dynamics are defined by the phenomenological FitzHugh-Nagumo model, simulating the neuronal activity of each brain region. After systematically exploring the network's state space for varying parameters, we add external control to the nodes either synchronizing their dynamics or inducing transitions between the network states. Defining a minimization problem for the above system, we analyse the external stimuli that optimize the input energy and the deviation from the target state. We tune the number of controlled brain regions via applying sparse optimal control. This way, we transition to targeted, local stimulation.