Brief Communications

How the cortex processes and transforms sensory input coming from the thalamus is still a matter of debate. Here the authors optogenetically silence local cortical circuits to show that intracortical excitation amplifies and prolongs thalamic inputs to the auditory cortex.

Grid cell activity in the rodent and non-human primate entorhinal cortex is thought to provide spatial location information to the hippocampus for navigation and spatial processing. Here, Jacobs et al. examined single neuron spiking activities from human subjects performing a virtual spatial navigation task and show the presence of grid-like firing activity.

The authors use two-photon Ca²⁺ imaging of axonal boutons in hippocampal CA1 of behaving mice to monitor the activation of septo-hippocampal GABAergic boutons. They report that some sensory inputs are more effective than locomotion in driving firing by these long-range GABAergic projections.

Although oxytocin is generally thought to exert anxiolytic, prosocial and antistress effects, reports of anxiogenic effects in humans have recently emerged. Here the authors show that oxytocin receptors in the lateral septum mediate the stress-induced enhancement of fear conditioning in mice in a process involving MAPK-ERK signaling.

It's unclear how the brain alters sensory processing in response to emotionally laden stimuli. Here the authors show that changes in auditory acuity depend on the auditory cortex and on how specific a cue is in predicting an aversive stimulus.

The authors report that, when subjects are asked to remember visual properties of an object, object identity can be decoded from fMRI measures of activity in extrastriate, but not prefrontal, cortex, whereas the opposite holds when they are asked to remember nonvisual properties. Thus, the ability to maintain information during working memory is a general and flexible cortical property.

In this study, the authors show that information regarding both the identity and the value of a given odor is multiplexed in the anterior piriform cortex. Specifically, they find that value is encoded by changes in firing rate while identity is determined by sniff-locked spiking.

Ependymal cell cilia regulate cerebrospinal fluid flow through the cerebral ventricles. Here the authors show that the metabolic peptide melanin-concentrating hormone (MCH) increases cilia beat frequency in the third ventricle, and a lack of the MCH receptor increases ventricle size.

Genome-wide association studies have identified CD33 as an Alzheimer's disease susceptibility locus. Here, the authors show that the CD33 risk allele is associated with altered myeloid function, microglial activation and in vivo amyloid pathology.

Prior anatomical studies have suggested that intratelencephalic (IT) and pyramidal tract (PT) cortical neurons project to different populations of striatal spiny projection neurons (SPNs). Here, the authors find using optogenetic stimulation that both IT and PT neurons project to both direct and indirect pathway SPNs.

In this study, the authors show that transposable element activity increases in the Drosophila brain with advancing age. Mutating the Drosophila Argonaute 2 (Ago2) gene exacerbated age-related transposable element activity and led to impaired memory and shortened lifespan.

In this study, the authors show that a sodium/solute co-transporter–like protein, SLC5A11, is expressed in a subset of R4 ellipsoid body neurons in Drosophila and is involved in the detection of the nutritive value of sugars. Flies that lack functional SLC5A11 exhibit sugar preference on the basis of concentration.

When sleep followed implicit training on a motor sequence, children showed greater gains in explicit sequence knowledge after sleep than adults. Measurements of slow-wave sleep and hippocampal activation suggest that the children's superior performance could be a result of enhanced reprocessing of hippocampal memory representations during slow-wave sleep.

Here the authors demonstrate that the long-term behavioral expression of fear memory can be predicted from neural patterns at the time of learning by applying multi-voxel pattern analysis to single-trial functional magnetic resonance imaging data.

Patients with obsessive-compulsive disorder (OCD) have attenuated reward anticipatory activity in the nucleus accumbens (NAc), and deep brain stimulation (DBS) of the NAc is used to treat OCD. The authors show that NAc DBS normalizes NAc activity, reduces connectivity between NAc and prefrontal cortex, and decreases frontal low-frequency oscillations in OCD patients.

Stress reduces motivation to work for rewards. The authors show that corticotrophin releasing factor (CRF) acts in the ventral tegmental area (VTA) to reduce the motivation to work for food rewards. CRF in the VTA inhibited dopamine release occurring in response to reward delivery, but not to reward-predictive cues.

The authors use Ca²⁺ imaging in freely behaving mice to look at the long-term dynamics of CA1 hippocampal place codes. They find that, in a familiar environment, there is substantial change in the population of place-coding cells over time, but the ensembles of these cells are sufficiently stable to preserve an accurate spatial representation across weeks.

Despite substantial work highlighting the amygdala's role in fear, the authors provide a surprising finding that carbon dioxide inhalation evokes fear and panic in three patients with bilateral amygdala damage. These results indicate that the amygdala is not required for fear triggered internally rather than by external threats.

In the human brain, the lateral occipital area, which is thought to support object recognition, contains two separate visual field maps, LO1 and LO2. Using transcranial magnetic stimulation, the authors identify the specialized and independent processing of orientation and shape in these two maps.

In this study, the authors show that velocity-dependent lag normalization in the retina is accomplished via a subset of adjacent directionally selective ganglion cells that are electrically coupled, allowing each activated cell to prime its neighbor.