eNeuro: Featured Research June 2019
Featured Articles
Dynamic Brain Interactions during Picture Naming
Models of brain function often assume that brain areas pass information serially from one brain region to another. Giahi-Saravani et al. test this by measuring directly from the brains of patients undergoing neurosurgery while they name pictures. The activity patterns are described using a stochastic nonlinear dynamical system model that reveals a reliable sequence of brain states defined not by serial activations but rather by changing bidirectional interactions between brain areas. This result reinforces the view that different brain areas work in tandem, suggesting that neuroscience should focus on understanding these interactions as well as activations. Read more...
Prodromes and Preclinical Detection of Brain Diseases: Surveying the Ethical Landscape of Predicting Brain Health
Detecting brain disorders before symptoms arise promises a means of delaying or preventing clinical symptoms, but the science and practice of such disclosures are in their infancy. The unique risks to patient autonomy and identity should be explicitly addressed as preclinical detection of brain disorders enters clinical practice, especially given the societal and self-stigma surrounding disorders of the brain. Patient autonomy and the limits of possible interventions should remain driving factors in the decisions of when and how to disclose current and future preclinical diagnoses of brain disorders. Read more...
Also of Interest
Targeting Microglia Using Cx3cr1-Cre Lines: Revisiting the Specificity
Microglia-specific Cre-lines are essential for studying the role of microglia in the CNS. Several Cx3cr1-Cre lines have been developed and used in a number of landmark studies. However, there is growing concern in the microglia research community regarding potential leakiness of Cre-lines into neurons. The conclusions drawn from previous studies are also being questioned and key ongoing studies have been stalled. We found that a GFP-reporter mouse lines used in a previous study displays spontaneous leakiness into neurons, independent of Cre recombinase. Furthermore, we confirmed that two Cre-lines are microglia-specific and thus can be redeployed without hesitation. Our study also suggests that testing for potential leakiness of GFP-reporter lines should be included as a control in cell-tracing experiments. Read more...
Subthreshold Fear Conditioning Produces a Rapidly Developing Neural Mechanism That Primes Subsequent Learning
Laboratory studies of memory are typically designed to identify mechanisms that allow the brain to represent past experience. The purpose of this ability is likely so that prior learning can direct future behavior, however studies are most often focused on the storage aspects of memory and less on how later experience is altered. We used a fear conditioning paradigm in which a single trial, subthreshold for producing long-term behavioral change, primes future learning when a second trial is later encountered. Neural activity in the amygdala was required for long-term memory (LTM) priming; however, post-training disruption of neural activity or cell signaling events had no effect. These results provide insight into the mechanisms that allow prior aversive experience to modify new learning. Read more...
A Roadmap for Understanding Memory: Decomposing Cognitive Processes into Operations and Representations
Accounts of cognition often assume that the brain is organized along lines of cognitive process, for example, with recollection mediated by one neural structure and familiarity by another. We argue that cognitive processes—introspectively-identifiable mental events like recollection—are inadequate labels for characterizing neural mechanisms, because they conflate lower-level components of the mechanisms we seek to identify. Recollection involves both a neurocomputational operation (pattern completion) and a neural representation (high-dimensional, associative content). To uncover memory’s mechanisms, we must decompose memory processes into their operations and representations, asking how each contributes to mnemonic phenomena. Decomposing recollection suggests that, within the ventral visual pathway and MTL, different brain regions contribute to memory retrieval according to their representational content. Read more...
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