Workshop "Principles and applications of extracellular potentials: experiments and theory"

To be held at the Computational Neuroscience Society (CNS) meeting in Antwerp.
Time: Wednesday, July 19th, 9AM - 6PM.
Location: Room K. 203 (see map; entrance on Kl. Kauwenberg)

Michiel Remme (Humboldt University Berlin)
Torbjørn Ness (Norwegian University of life Sciences)
Gaute Einevoll (Norwegian University of life Sciences - University of Oslo)

Workshop abstract
Electrical signals from the cortical surface of animals were recorded as early as 1875. The high-frequency part (above ~500 Hz) of the recorded potentials provides information about the spiking activity of neurons located around the electrode, whereas the low-frequency part, the ‘local field potential’ (LFP), was found more difficult to interpret. Recently, the interest in LFPs has undergone a resurgence. Key reasons are the growing capacity for streaming continuous data from multiple electrodes and the development of multicontact electrodes for high-density recordings across areas and laminae. Further, the LFP captures key integrative synaptic processes that cannot be measured by observing the spiking activity of a few neurons alone. The LFP is also a promising signal for steering neuroprosthetic devices and for monitoring neural activity in human recordings because they are more easily and stably recorded in chronic settings than are spikes. The goal of the workshop is to provide a resume of the advances in understanding the generation of extracellular potentials through theoretical and experimental approaches as well as on the consequences (e.g., ephaptic interactions) and the applications of such signals (e.g., neuroprosthetic devices).


9:00-9:15            Welcome (Michiel Remme)

9:15-10:00          Gaute Einevoll (Norwegian University of Life Sciences)
What can we learn from local field potentials (LFPs)?

10:00-10:30        Florian Aspart (Technical University of Berlin)
Frequency dependent polarization of pyramidal cells models due to weak extracellular fields
10:30-11:00       Coffee break
11:00-11:30        Joshua Goldwyn 
(Ohio State University)
Generators of field potentials and (possible) ephaptic interactions in the auditory brainstem

11:30-12:00        Paula Kuokkanen (Humboldt University Berlin)
Extracellular ITD potential and spike contributions in barn owl's nucleus laminaris

12:00-12:30        Bartosz Teleńczuk
 (Centre National de la Recherche Scientifique)
Contributions of inhibitory and excitatory neurons to the focal LFP in human and monkey

12:30-14:15        Lunch break 
14:15-15:00        Ad Aertsen (University of Freiburg)
Decoding motor cortex activity at multiple scales

15:00-15:30        Alberto Mazzoni (Scuola Superiore Sant'Anna)
Predicting risk attitude in conflictual economic tasks from subcortical local field potentials

15:30-16:00        Coffee break
16:00-16:30        Sonja Grün 
(Research Centre Jülich, Aachen University)
Spatial and temporal LFP-LFP and spike-LFP relationships

16:30-17:00        Arno Onken (Italian Institute of Technology)
Application of mixed vine copulas to model jointly neural spikes and local field potentials

17:00-17:30        Costas Anastassiou (Allen Institute for Brain Science)
Brain dynamics and associated electric fields during physiological and pathological activity

17:30-18:00        Closing discussion (led by Gaute Einevoll)

Discussion questions
  • What does the LFP tell us as and what does it tell the brain, if anything at all? (Ad Aertsen)
  • What can the LFP tell us about network activity? (Gaute Einevoll)
  • What do we know about LFP origins in subcortical structures? (Alberto Mazzoni)
  • Can the cortical LFP tell us something about motor/behavioral intention that can't be decoded with non-invasive methods or spiking activity? (Alberto Mazzoni)
  • Are there methods/heuristics for knowing when extracellular potentials reflect "outputs" (spikes) of neural activity, and when they are signaling "inputs" (synaptic current flows)? (Joshua Goldwyn)
  • Do we know of instances when LFPs provide information/insights that would not be obtained by spikes (alone)? (Joshua Goldwyn)
  • What are the implications of an ephaptic interaction between neurons on the analysis of spikes and LFP data? Do we need to take this effect into account when e.g. analyzing spike-LFP relationship? (Florian Aspart)
  • What is the most useful representation of the LFP signal? Its oscillatory nature suggests that a representation in frequency space is an appropriate representation. Are there other representations that lend themselves even better to a compact information-theoretic analysis and should this representation be area/modality/task-dependent? (Arno Onken)