Persistent activity is problematic as a working memory (WM) mechanism. When WMs are in a persistent active state, they are easy to disrupt by distractions, additional inputs etc. Using modeling, Freedman and crew show that during simple WM maintenance, neural activity is transient, not persistent. This makes sense because the less often memories are in an active state, the better they are protected from disruption. However, when working memories must be manipulated and changed, the activity is more persistent. This makes sense because you want memories to be in a labile, changeable, state when ..read more

Widge, A.S.,  Zorowitz, S., Basu, I.  Paulk, A., Cash, S., Eskandar, E., Deckersbach, T., Miller, E.K., and Dougherty, D.  (2019) Deep brain stimulation of the internal capsule enhances human cognitive control and prefrontal cortex function. Nature Communications. https://doi.org/10.1038/s41467-019-09557-4  View PDF Summary: Deep brain stimulation (DBS) is a circuit-oriented treatment for mental disorders. Unfortunately, even well-conducted psychiatric DBS clinical trials have yielded inconsistent symptom relief, in part because DBS’ cognitive and physiologic me ..read more

More evidence that cognitive control stems from low-frequency rhythms in deep-layer cortex inhibiting superficial layer cortex. Johnston, K., Ma, L., Schaeffer, L., & Everling, S. (2019). Alpha Oscillations Modulate Preparatory Activity in Marmoset Area 8Ad. Journal of Neuroscience, 39(10), 1855-1866. For further reading see: Miller, E.K., Lundqvist, L., and Bastos, A.M. (2018) Working Memory 2.0  Neuron,  DOI:https://doi.org/10.1016/j.neuron.2018.09.023  View PDF Bastos, A.M., Loonis, R., Kornblith, S., Lundqvist, M., and Miller, E.K. (2018)  Lam ..read more

This paper provides further evidence for different roles for beta vs gamma oscillations in attention. The authors used TMS to provide evidence that beta stimulation affects top-down attention whereas gamma stimulation affects bottom-up attention. This corresponds nicely with recent work in animals. Riddle, J., Hwang, K., Cellier, D., Dhanani, S., & D’Esposito, M. (2019). Causal Evidence for the Role of Neuronal Oscillations in Top–Down and Bottom–Up Attention. Journal of cognitive neuroscience, 1-12. For further info see: Buschman, T.J. and Miller, E.K. (2007) Top-down versus bottom ..read more

Widge, A.S., Boggess, M., Rockhill, A.P., Mullen, A., Sheopory, S., Loonis, R. Freeman, D.K., and Miller, E.K.  (2018)  Altering alpha-frequency brain oscillations with rapid analog feedback-driven neurostimulation. PLOS ONE Abstract Oscillations of the brain’s local field potential (LFP) may coordinate neural ensembles and brain networks. It has been difficult to causally test this model or to translate its implications into treatments because there are few reliable ways to alter LFP oscillations. We developed a closed-loop analog circuit to enhance brain oscillations by feeding the ..read more

An article in Scientific American discusses the debate about whether brain waves have a function or whether they are an epiphenomenon: Do Brain Waves Conduct Neural Activity Like a Symphony?    There are so many things wrong with this debate. We know so little about how the brain functions. To dismiss observable signals as an epiphenomenon assumes a level of knowledge that no one has.  It is merely a defense of the status quo paradigm, straight out of Thomas Kuhn.  The attitude boils down to “they don’t play a role because we kind of already know how the ..read more

Widge AS, Boggess M, Rockhill AP, Mullen A, Sheopory S, Loonis R, Freeman DK, Miller EK  (in press)  Altering alpha-frequency brain oscillations with rapid analog feedback-driven neurostimulation. PLOS ONE Stayed tuned for the exciting details ..read more

Check out this National Public Radio piece on the debate about our new model of working memory: Neuroscientists Debate A Simple Question: How Does The Brain Store A Phone Number?    I have a few follow-up points. 1. In the piece, Christos Constantinidis says: “The problem with the theory is that so far there has been no experimental evidence linking this critical variable with behavior,” This is false.  We have a paper entirely devoted to experimental evidence linking the theory to behavior: Lundqvist, M., Herman, P. Warden, M.R., Brincat, S.L., and Miller, E.K. (2018) Gamm ..read more

Our new paper describing a new model of working memory.  Actually, not so much a new model as an update to the classic model. The classic model posited that we hold thoughts “in mind” (i.e., in working memory) via the persistent spiking of neurons.  That is not wrong.  It is right to a certain level of approximation. There is little doubt that spikes help maintain working memories. However, a closer examination revealed that there is much more going on than persistent spiking. It is important to keep in mind (pun intended) that virtually all evidence for persistent spiking comes ..read more

V1-V4 gamma coherence before stimulus change predicts reaction time to detect the change while deviations from the phase relation increases reaction times.  Nice. Gamma Synchronization between V1 and V4 Improves Behavioral Performance Gustavo Rohenkohl, Conrado Arturo Bosman, Pascal Fries ..read more