Interesting study showing that there are decreases in the frequency of alpha oscillations when a task requires require integration of two inputs that are separated in time.  The slowing fosters integration by making it more likely that two stimuli fall within one alpha cycle and are thus integrated.  Cool.

Wutz, A., Melcher, D., & Samaha, J. (2018). Frequency modulation of neural oscillations according to visual task demandsProceedings of the National Academy of Sciences, 201713318.

Lundqvist, M., Herman, P. Warden, M.R., Brincat, S.L., and Miller, E.K. (2018) Gamma and beta bursts during working memory read-out suggest roles in its volitional control. Nature Communications. 9, Article number: 394 doi:10.1038/s41467-017-02791-8

Abstract:
Working memory (WM) activity is not as stationary or sustained as previously thought. There are brief bursts of gamma (~50–120 Hz) and beta (~20–35 Hz) oscillations, the former linked to stimulus information in spiking. We examined these dynamics in relation to readout and control mechanisms of WM. Monkeys held sequences of two objects in WM to match to subsequent sequences. Changes in beta and gamma bursting suggested their distinct roles. In anticipation of having to use an object for the match decision, there was an increase in gamma and spiking information about that object and reduced beta bursting. This readout signal was only seen before relevant test objects, and was related to premotor activity. When the objects were no longer needed, beta increased and gamma decreased together with object spiking information. Deviations from these dynamics predicted behavioral errors. Thus, beta could regulate gamma and the information in WM.

Wutz, A., Loonis, R., Roy, J.E., Donoghue, J.A., and Miller, E.K. (2018) Different levels of category abstraction by different dynamics in different prefrontal areas. Neuron  published online Jan 25 2018.

SUMMARY

Categories can be grouped by shared sensory attributes (i.e. cats) or by a more abstract rule (i.e. animals). We explored the neural basis of abstraction by recording from multi-electrode arrays in prefrontal cortex (PFC) while monkeys performed a dot-pattern categorization task. Category abstraction was varied by the degree of exemplar distortion from the prototype pattern. Different dynamics in different PFC regions processed different levels of category abstraction. Bottom-up dynamics (stimulus-locked gamma power and spiking) in ventral PFC processed more low-level abstractions whereas top-down dynamics (beta power and beta spike-LFP coherence) in dorsal PFC processed more high-level abstractions. Our results suggest a two-stage, rhythm-based model for abstracting categories.

Andre Bastos was selected at a Rising Star by the Association for Psychological Science.  Indeed, he is.  Congrats, Andre!

http://www.psychologicalscience.org/rising-stars/stars.cfm

Check out Andre’s latest paper:
Bastos, A.M., Loonis, R., Kornblith, S., Lundqvist, M., and Miller, E.K. (2018)  Laminar recordings in frontal cortex suggest distinct layers for maintenance and control of working memory.  Proceedings of the National Academy of Sciencesdoi:10.1073/pnas.1710323115   View PDF

A new addition to the proposed circuitry for top-down control.

White, M. G., Panicker, M., Mu, C., Carter, A. M., Roberts, B. M., Dharmasri, P. A., & Mathur, B. N. (2018). Anterior Cingulate Cortex Input to the Claustrum Is Required for Top-Down Action ControlCell reports22(1), 84-95.

The authors find that dopamine increased power of beta-low gamma oscillations in cortex.  During visual stimulation, dopamine increased information encoding over a wide range of frequencies but most prominently in the feedforward supragranular layers and in the gamma band (50-100 Hz).

Zaldivar, D., Goense, J., Lowe, S. C., Logothetis, N. K., & Panzeri, S. (2018). Dopamine Is Signaled by Mid-frequency Oscillations and Boosts Output Layers Visual Information in Visual CortexCurrent Biology.

This must be correct.  It is very remarkably consistent with our recent study 🙂
Bastos, A.M., Loonis, R., Kornblith, S., Lundqvist, M., and Miller, E.K. (2018)  Laminar recordings in frontal cortex suggest distinct layers for maintenance and control of working memory.  Proceedings of the National Academy of Sciencesdoi:10.1073/pnas.1710323115   View PDF

as well as with our previous work showing that gamma is associated with bottom-up processing:
Buschman, T.J. and Miller, E.K. (2007) Top-down versus bottom-up control of attention in the prefrontal and posterior parietal cortices. Science. 315: 1860-1862  View PDF »

 

High frequency waves (Davis on trumpet) carry sensory inputs from the back of the brain to the front. Low frequency waves (Mingus on bass) carry executive (top-down) information from the front to the back of the brain. The low frequencies control the expression of high frequencies. That’s how you choose what sensory inputs to hold in mind (working memory). (Image: Andre Bastos)

It makes sense because we all know that the bass should guide the lead instruments. Am I right?

Bastos, A.M., Loonis, R., Kornblith, S., Lundqvist, M., and Miller, E.K. (2018) Laminar recordings in frontal cortex suggest distinct layers for maintenance and control of working memory. Proceedings of the National Academy of Sciences. published ahead of print January 16, 2018, doi:10.1073/pnas.1710323115

Read MIT press release here.

 

This is the first of three papers that all lead to the same general conclusion:  Sensory (bottom-up) information is fed forward through cortex by gamma (>50 Hz) waves in superficial cortical layers. Executive (top-down) information is fed back through cortex by alpha/beta waves (4-22 Hz) in deep cortical layers. The beta waves in deep layers regulate superficial layer gamma in a push-pull fashion thereby allowing top-down information to control the flow of bottom-up sensory information. This allows volitional control over what we hold in mind.  Stayed tuned for the other two papers. They will appear in the next few weeks.

Bastos, A.M., Loonis, R., Kornblith, S., Lundqvist, M., and Miller, E.K. (2018) Laminar recordings in frontal cortex suggest distinct layers for maintenance and control of working memory. Proceedings of the National Academy of Sciences. published ahead of print January 16, 2018, doi:10.1073/pnas.1710323115

Read MIT press release here.

Persistent activity (indexed by broadband gamma) across human cortex encodes stimulus features and predicts motor output.

Haller, Matar, John Case, Nathan E. Crone, Edward F. Chang, David King-Stephens, Kenneth D. Laxer, Peter B. Weber, Josef Parvizi, Robert T. Knight, and Avgusta Y. Shestyuk. “Persistent neuronal activity in human prefrontal cortex links perception and action.” Nature Human Behaviour (2017): 1.

But how persistent is it?
Lundqvist, M., Rose, J., Herman, P, Brincat, S.L, Buschman, T.J., and Miller, E.K. (2016) Gamma and beta bursts underlie working memory.  Neuron, published online March 17, 2016. View PDF »

Coarse visuospatial categories are represented in the posterior parietal cortex whereas fine-scale discrimination are in primary visual cortex with the latter depending on feedback from the former.

Li, Y., Hu, X., Yu, Y., Zhao, K., Saalmann, Y. B., & Wang, L. (2017). Feedback from human posterior parietal cortex enables visuospatial category representations as early as primary visual cortexBrain and Behavior.