Papademetras Image-guided Navigation Systems Structural and

Papademetras • Image-guided Navigation Systems – Structural and Functional images registered to patient space • Research workstation is interfaced to commercial surgical workstation for Epilepsy surgery – Allows stable, reliable system for clinical surgery – VVLink now part of Brain. Lab system • Includes ability to track surgical tools • MODELS OF TUMOR GROWTH ARE CLOSEST

Papademetras • Brain Deformation is compensated for by stereo cameras and modeling • In cases where surgical resection is not possible, neurostimulators are used (in functionally sensitive areas) • How does one leverage prior information from normal controls • How do we emphasize robustness over accuracy?

• • • Coulon Cortical localization and inter-subject surface matching For morphometric or functional studies of populations Volume-based and sphere transformations have been used in the past Cortical organization based on “sulcal roots” is an alternative model Sulcal landmarks are (semi-automatically? ) defined for tranform to standard space Application can be for parcellation of brain anatomy and QUESTIONS: How does one deal with anatomical variability. – Can this generalized to maps of brain function (e. g. language defined in surgical stimulation studies • Should multiple atlases be developed? • See: brainvisa. info

Clatz Modeling brain tumors for patient-specific therapy • Tumor growth and mass effects are simulated through computer (linear elastic) models • Goal is to use models for patient-specific treatments

Leiphart Neurosurgery for brain implants • Technology for seizure detection Paradigm shift from exec (localized) center to [network] of anatomically distinct centers Synchrony precedes 70% of seizures Advanced algorithms and computation needed to predict seizures (shift from electrocorticog)

Reisenhuber • How does object (face) recognition work? • Is there an “Alice Cooper neuron” in the brain? • Question: How nonlinear is the f. MRI/EEG brain? Is there a functional role for oscillations…?

Brette • Electrode introduces bias in single neuron recording • Active electrode Compensation is a computer model to remove this bias. • Message: Model based approaches can extend possibilities of standard electrode recording, for example measuring excitatory and inhibitory synaptic conductance.

Schmueli • Physiological noise (nuisance variables) can be removed from f. MRI – Heart rate – Magnetic susceptibility corrections also shown

Marrelec • How do we infer interactions in f. MRI – Motor network is well understood – Information exchange between brain units – definition of functional interactions • Can this be defined mathematically • Can causality be inferred from f. MRI?

Pessiglione functional imaging/pharm challenges • DA involved in reward, validated in monkeys, mimicked by engineered models • Behavioral experiment in choice experiment rewarded by money (or punished by loss) • L-dopa associated with faster learning than Haldol • Model/theory ventral striatum associated with critic. Anterior putamen • Are [decisions] subconscious? • Can brain reading predict decisions?

Gaillard Epilepsy, functional imaging and language • Auditory Description Decision Task (ADDT) f. MRI • Stroke or epilepsy result in relocation of language function in R hemisphere • Exploratory data analysis (no a priori hypothesis) was done in epilepsy pts. • Posterior margin of Wernicke’s is utilized • Anterior only group vs. anterior and posterior moves to contralateral side

Nadja CNMC Neuroradiology Research National Children’s Center, Wash DC • MRI scanners, technologies and neuroradiologists available for collab. • Areas of ongoing research – Craniofacial phenomics, head shape modeling – Molecular imaging of pediatric brain tumors • Superparamagnetic nanoparticles for MRI and optical fluorescence imaging – – – Tumor volumetry Infant MRS and DTI Fetal MRI and 3 D U/S ASL/Susceptibility weighted imaging in stroke (sickle cell) Small animal imaging

Michael Levene • Multiphoton microscopy – Single molecule sensitivity • Sub micron resolution • Two photon excitation, unlike single, has a single focal point of excitation • Near IR light scatters less than blue light • Intrinsic fluorescence of UV is possible too • Hypometabolism measured in epilepsy with neurosurgeon – NADH is fluorescent, NAD is not • Long lens might be used to penetrate 3. 5 mm of tissue for optical biopsy • What are clinical applications for MPM and optical imgs?

Olivier David EEG/f. MRI/Epilepsy • • • Small animal up to 7 T Human 3 T scanner f. MRI studies of unilateral epilepsy Rat model (genetic absence f. MRI of visual stimulation (thalamic relay) Implanted epileptic patients are used in studies of 1 Hz neurostimulation of hippocampus • Antiepileptics studied in animal (rat) models • Microelectronics developed for neural implants and adaptive control of epilepsy • Stimulation of network may be alternative model for TX – Experimental work needed prior to clinical trials – Animal studies are vital

Christian Habeck Multivariate neuroimage analysis • Univariate stats (SPM) are straightforward parametric and use stringent type-I error correction • Multivariate – non-parametric, better suited for distributed analysis – data dredging? • Covariance analysis of ASL MRI in Alzheimer’s appears to discriminate • Multivariate techniques could be used in meta-analyses • Where does Multivariate analysis show new insight over univariate analysis? • Epiphenomena or does Multivariate analysis really provide insights

Thirion Group Analysis of f. MRI • Problems with standard inference – Small samples – Spatial normalization –precision about 1 cm • Critical questions – Which structures should be studied? – How to detect false positives – Which structures are cross-correlated? – Question: Build an anatomo-functional atlas (integrated and fully Bayesian) – Brainvisa software available soon.

Baillet Time resolved imaging MEG/EEG • Atlas of basal ganglia might be used for DBS targeting – plug in for Papademetras? • Inverse problem – go from signal to map of brain (function, anatomy) • What can time perspective bring you for understanding brain function? – 400 ms duration map of tennis ball catch – Similarly conscious perception moves from visual to ventral processing of information – Optical flow (borrowed from weather models) can be used to understand dynamics of brain activity – State 1 flows to state 2 • Challenges: Reduce theory/computational gap • Make tools clinically useful tools • Richard Leahy USC collaborator