Research articles

By optogenetically silencing thalamus, the authors show that visual cortex does not sustain a response without thalamus for more than a few tens of milliseconds. This rapid cortical activity decay predicts the temporal dynamics of sensory activity transmission between thalamus and cortex in awake animals, whereas under anesthesia, the fidelity of thalamo-cortical connection is dominated by the effect of synaptic depression.

Stroke is the leading cause of adult disability. This study shows that the secreted factor GDF10 is a signal for the formation of new brain connections that lead to recovery after stroke and can be manipulated to enhance recovery and movement control in this disease.

Using functional MRI and a novel model-based analysis, the authors find that the uncertainty in sensory representations can reliably be estimated from trial-by-trial activity in human visual cortex. Moreover, this uncertainty represented in cortical activity affects the way people make decisions.

PSD-95 is one of the most abundant proteins at synapses and underlies synapse development and function. Hruska and colleagues show that the synaptic localization and turnover of PSD-95 relies on a direct interaction with the trans-synaptic organizer ephrin-B3, which is negatively regulated by neuronal activity through MAPK-dependent phosphorylation of ephrin-B3.

The authors show that episodic-memory representations progressively increase in scale along the hippocampal long axis, akin to the gradient of encoded space in the rodent hippocampus. They propose that this coding mechanism may enable the formation of memory hierarchies.

Increased signal-to-noise in neural representations of sensory stimuli is thought to underlie the perceptual benefits of attention. Manipulating reward contingencies across two locations dissociates visual cortical activity from attentional behavior. These data argue that attention works by selecting and filtering the relevant and irrelevant information represented in visual cortex.

The amygdala is known to process information about faces, but it has remained unclear whether eye gaze is also encoded. Recording single neurons in the amygdalae of neurosurgical patients, the authors found responses to identity of the faces, but not to gaze direction.

Anorexia nervosa provides a compelling example of persistent maladaptive behavior: the severe restriction of caloric intake. Activity in the dorsal striatum was greater in patients than in controls during food choice and correlated with subsequent caloric intake, suggesting that dorsal fronto-striatal circuits are involved in this disorder.

The authors used trans-synaptic tracing to examine and compare circuit anatomy in mouse barrel and medial prefrontal cortex, revealing novel organizational features and contrasts between the two areas. Notably, medial prefrontal layer 5 neurons receive more long-distance inputs and more local inhibitory inputs than layer 5 neurons in barrel cortex.

This study shows that every individual has a unique pattern of functional connections between brain regions. This functional connectivity profile acts as a ‘fingerprint’ that can accurately identify the individual from a large group. Furthermore, an individual's connectivity profile can predict his or her level of fluid intelligence.

Sleeping mammalian brains show high coherence of slow-wave activity. In mouse models of Alzheimer's disease, which have abnormal levels of amyloid-β, amyloid plaques and associated memory deficits, these waves are massively impaired. This impairment is related to the previously demonstrated neuronal hyperactivity. Pharmacological manipulations that reduce hyperactivity result in the reinstatement of slow-wave coherence and in memory improvement.

The basal forebrain (BF) is important for sleep-wake control. In this study, the authors performed cell type–specific recording and manipulation of four genetically defined BF cell types in freely moving mice and mapped their synaptic connections in slices, providing a BF circuit diagram for sleep-wake control.

People with autism are known for their inflexible behavior. Using a perceptual learning protocol, the authors demonstrate initially efficient learning in observers with autism, followed by anomalously poor learning when the target location is changed (over-specificity). Furthermore, over-specificity can be circumvented by a specifically designed protocol that reduces stimulus repetitions.

The human ability to choose relies considerably on frontoparietal association cortex. Constructing unified perception from inconclusive sensory input also requires selection among alternatives. Combining fMRI with a novel visual stimulus, Brascamp and colleagues find evidence against frontoparietal involvement in such perceptual selection, instead suggesting choice capability in the visual system itself.

Contextual modulation is ubiquitous in sensory processing. This study shows that, in visual cortex, spatial contextual modulation for natural inputs is not well described by existing models. Instead, it can be explained by inference about statistical structure in images, with modulation evident only when images contain spatial redundancies.

In this study, the authors show that microglia play an important role in the propagation of pathogenic tau protein. In addition, the authors find that spread of the tau protein occurs via exosome secretion from these microglial cells.

The study of speech or vocal disorder resulting from neurological diseases lacks a model capable of recapitulating vocal learning. This study suggests that the vocal disorder associated with Huntington's disease is observed in transgenic zebra finches carrying the full-length human mutant huntingtin gene.

This protein quantitative trait analysis in monocytes evaluates cross-talk between Alzheimer risk loci and finds that the NME8 locus influences PTK2B, the CD33 risk allele leads to greater TREM2 expression, and the TREM1 risk allele is associated with a decreased TREM1/TREM2 ratio.

Optogenetic suppression of layer 4 in the sensory cortex reveals a surprising role for its activity in the cortical microcircuit: layer 4 suppresses the main cortical output layer—layer 5—through a direct translaminar inhibitory circuit. This translaminar inhibition sharpens spatial representations in the somatosensory cortex.

Using data from the Human Connectome Project, a single holistic multivariate analysis identified one strong mode of population co-variation: subjects were predominantly spread along a single ‘positive-negative’ axis linking lifestyle, demographic and psychometric measures to each other and to a specific pattern of functional brain connectivity.