The Miller Lab

Limber Neurons for a Nimble Mind
Earl K. Miller and Stefano Fusi
Neuron. 78:211-213, 2013. (Preview)
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For years, researchers have noted that many neurons in the prefontal cortex have “weird” properties.  They respond to a wide range of seemingly unrelated unrelated information.  These kitchen sink, “mixed selectivity” neurons were often ignored or dismissed because they didn’t seem to make sense (well, except to network modelers who knew about hidden units and support vector machines).  Stokes et al recorded from multiple electrodes in the prefrontal cortex.  This revealed shifting patterns of PFC activity that followed a trajectory through multi-dimensional space from signaling sensory events to internal factors like rules and decisions.  Many PFC neurons participated in multiple states.  Thus, mixed selectivity doesn’t result in cortical porridge but rather an orderly progression of mental states, provided you have multiple electrodes and can simultaneously take multiple neurons into account.

Stokes et al. (2013) Neuron, 78: 364-375

Read a Preview of Stokes et al:
Miller, E.K. and Fusi, S. (2013) Limber neurons for a nimble mind. Neuron. 78:211-213. View PDF »

A model that shows how oscillations in different neuron populations can drive each other towards synchrony at different frequencies.  The system can fall into a mode in which it explores synchrony across a range of oscillations.  Among other things, the model shows how oscillations across neurons can be highly dynamic yet their synchroncy can be stable.  The idea that oscillatory synchrony provides communication channels  between neurons has been criticized because  the frequencies bounce around and therefore are not stable enough to support communication .  This model shows that synchrony is stable even if the exact frequency is not.  (BTW, no one complains that the activity of single neurons bounce around).
http://tinyurl.com/b5e4ywc

For a discussion of the role of synchrony in neural communication see:
Miller, E.K. and Buschman, T.J. (2013) Cortical circuits for the control of attention.  Current Opinion in Neurobiology.  23:216–222  View PDF »

Miller, E.K. and Fusi, S. (2013) Limber neurons for a nimble mind. Neuron. 78:211-213.
View PDF

In this issue of Neuron, Stokes et al (2013) demonstrate that cortical neurons that adapt their properties with task demands form patterns reflecting the shifting mental states needed to solve the task.  Adaptive neurons may be critical to hallmarks of cognition: behavioral complexity and flexibility.

Robert Desimone, Director of MIT’s McGovern Institute for Brain Research answers 3 questions about the new federal BRAIN initiative.
http://web.mit.edu/newsoffice/2013/robert-desimone-on-the-federal-brain-initiative-0423.html