Pinto and Dan use Ca2+ imaging to identify different subtypes of inhibitory neurons in the mouse prefrontal cortex. They found that different subtypes encode different aspects of the task. By contrast, excitatory neurons are diverse and their task-related activity by cortical layer.
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Kozma et al report brief periods of de-synchronization followed by intense synchronization. They speculate that this may correspond to an “aha!” moment when things “fall into place”. Interesting.
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The limited capacity of working memory has sometimes been explained as a limited number of memory “slots”. Paul Bays argues that working memory capacity is due to sharing of a continuous resource, namely a fixed amount of neural activity. Noise in this activity is the limiting factor.
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The neuron doctrine – that individual neurons are the functional unit of the nervous system – has been the conceptual framework for modern neuroscience for over a century. However, that doctrine has been dissolving under new evidence from multi-electrode recording. Observations of multi-functional “mixed selectivity” neurons, ensembles forming from synchronized rhythmic activity between neurons, etc. is suggesting that ensembles of neurons, not individual neurons, are the functional units. Rafel Yuste walks us through some of the evidence.
Yuste, Rafael. “From the neuron doctrine to neural networks.” Nature Reviews Neuroscience (2015).
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Mirpour and Bisley provide new insights into how saccadic remapping produces perceptual stability during eye movements.
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Decision-making due to a gradual ramp of neural firing rates? Nope. There are discrete state changes that are more informative that spike counts.
Single-trial spike trains in parietal cortex reveal discrete steps during decision-making
Kenneth W. Latimer, Jacob L. Yates, Miriam L. R. Meister, Alexander C. Huk, and Jonathan W. Pillow
Science 10 July 2015: 349 (6244), 184–187. [DOI:10.1126/science.aaa4056] -
Matt Wilson and colleagues describe how oscillatory cycles can be viewed as functional units, how different oscillation phases can represent distinct computations, and how all this can be organized across cycles. Phew!
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Craig and McBain review the role of oscillations in understanding the functional circuitry of the hippocampus with an eye toward bridging in vitro and in vivo studies.
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As the authors pun, the claustrum is worthy of attention given its extensive connections with the cortex. Goll, Atlan, and Citri propose a new hypothesis for the role of inputs from the prefrontal cortex to the claustrum in top-down attentional selection. The claustrum acts to control the output of selected cortical representations at the expense of others.
Goll, Yael, Gal Atlan, and Ami Citri. “Attention: the claustrum.” Trends in Neurosciences (2015).
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Bonnefond and Jenson used MEG in humans to find coupling between alpha and gamma rhythms during an attention-demanding task. High alpha power was associated with weak gamma power at the trough of the alpha cycle. This may provide a mechanism for top-down control of attention.