Cosyne 2007 Workshops
February 26-27, 2007
The Canyons, Utah
Workshop Title
How active is the cortex?
Organizer(s)
Tim Blanche (UC Berkeley): timblanche{at}fastmail{dot}fm
Mike Deweese (UC Berkeley): deweese{at}cshl{dot}edu
Abstract
This simple but fundamental question awaits a definitive answer. Yet it's one that has far-reaching implications ranging from the nature of neural coding to the design of effective cortical prostheses. One school of thought says that information processing in the cortex is subserved by a network of highly redundant, broadly tuned, and inherently noisy neurons. Consequently large populations of cortical neurons are active during any given task. The alternate view is that most cortical neurons are silent most of the time, and neural computation involves only a small subset of sparsely active, highly reliable neurons. Physiological evidence and theoretical arguments exist in support of both models.
In recent years large scale neuronal recordings with multielectrode arrays and 2-photon microscopy are beginning to shed light on this important question. The goal of this workshop is to bring together new experimental measures of neural activity from a diversity of cortical areas and species.
This workshop will be of interest to people seeking answers to the following questions: How significant are experimental sampling biases? What is the relative importance of the recording technology, the depth and type of anesthesia in acute recordings, the level of arousal in chronic recordings, and the type of stimulus or behavioral paradigm? Have electrophysiologists been studying the minority of highly active neurons? If so, what is the other largely ignored population doing? Can we reconcile the small number of active neurons typically encountered along a single unit electrode track with recent data from 2-photon imaging that suggest the majority of neurons are active? Do the experimental data support a population coding scheme? Are overall activity levels consistent with the predictions of metabolic and sparse coding models? Or does the answer depend on the cortical area in question? Is there a progression of neural sparsity as one moves from primary sensory cortices to ‘higher’ cortical areas?
Most importantly can we reach a consensus on how active – or inactive – the cortex is?
Speakers
| Tim Blanche (UC Berkeley) | Population sparsity in primary visual cortex. |
| Michael Brecht (Erasmus MC) |
Barrel cortex spikes: quantification and psychophysics. |
| Charles Gray (Montana State University) | Striate neuronal responses to time varying natural scenes are sparse and heterogeneous. |
| Kenneth Harris (Rutgers) | Fine structure of spontaneous and evoked activity in neocortex. |
| Jason Kerr (Max Planck Institute) | Population imaging of spontaneous and sensory-evoked activity in vivo: what's the difference? |
| Bruce McNaughton (University of Arizona) | Sparse vs. distributed coding: economy vs. efficiency, and a lession from the subicular-neocortical projection. |
| Xiaoqin Wang (Johns Hopkins University) | Stimulus selectivity and responsiveness of auditory cortex. |
| Stephen Waydo (Caltech) | Sparse representation in the human medial temporal lobe. |
| Ben Willmore (UC Berkeley) | Definition and measurement of sparseness in extrastriate visual cortex. |
| Tony Zador (Cold Spring Harbor) | Sparse coding in auditory cortex. |
