Research articles

Adaptive control to improve performance after making mistakes in a given task is known to involve prediction error signaling in the anterior cingulate cortex (ACC). The current study examines adaptive control in humans and rats by using comparable time-estimation tasks for each organism, and the authors show that low-frequency oscillations within the ACC in humans and the medial frontal cortex (MFC) in rats are correlated with adaptive behavioral control. They also show that these frontal oscillations are phase locked to the oscillation in the motor regions in the brain and that inactivation of the MFC in rats can disrupt both behavioral control and oscillatory coupling.

In this study, the authors show that a subset of cerebellar granule neurons originate not from the granule neuron precursors (GNPs) but from a population of Nestin-expressing progenitors (NEPs) in the deep external germinal layer. In addition, they find that these NEPs are more susceptible to Sonic Hedgehog–induced genomic instability and tumor formation.

The authors study fMRI responses to colors and achromatic images to address the fundamental organizational principles of monkey inferior temporal cortex. They report color-biased regions adjacent and ventral to face patches, at locations predicted by a series of coarse eccentricity maps.

The authors investigated the mechanisms underlying hippocampal sharp waves. They found that CA3 axo-axonic cells (AACs) stopped firing during sharp waves in vivo. They also identified GABAergic cells in the medial septum that are activated during sharp waves and project to CA3; these cells may inhibit AACs during sharp waves.

Diverse species use ineraural time differences to locate the origin of sounds in space. Here the authors show that GABA_B receptor–mediated feedback onto the medial superior olive modulates the gain of auditory space coding, leading to systematic shifts in the percept of sound location.

α7-nicotinic acetylcholine receptors (α7nAChRs) modulate the effects of the main psychoactive ingredient of marijuana, Δ⁹-tetrahydrocannabinol (THC), in the brain. Here the authors show that pharmacologically enhancing kynurenic acid, an endogenous modulator of α7nAChRs, attenuated the rewarding properties of THC and prevented drug relapse in monkeys and rats.

The authors show that type 2 dopamine receptors (D2Rs) negatively regulate spine morphogenesis in the hippocampi of adolescent mice. Spine deficiency resulting from D2R overactivation was associated with dysconnectivity in the entorhinal-hippocampal circuit and working memory deficits. These phenotypes could be rescued by D2R antagonists given during adolescence.

GABAergic cortical interneurons have important roles in the computations of neural circuits, but their developmental origin in primates is controversial. Here the authors characterize neural stem cell and progenitor cell organization in the developing human ganglionic eminences and reveal that, just as in rodents, they give rise to a majority of cortical GABAergic neurons.

The self renewal and long-term maintenance of neural stem cells (NSCs) is related to how quickly they pass through the cell cycle. Here the authors describe a new role for the cyclin-dependent kinase inhibitor p21 and show that it maintains an active NSC pool through repression of Bmp2.

Here the authors demonstrate a causal role for the barrel cortex in the detection of single whisker stimuli. Whisker deflection evoked an early (<50 ms) reliable sensory response that was encoded through cell-specific reversal potentials. A secondary late (50–400 ms) depolarization was enhanced in hit trials compared to misses. Optogenetic inactivation revealed a causal role for late excitation.

The origin and functional importance of noise in mammalian cones is poorly understood. Here, the authors find that channel noise and fluctuations in cGMP dominate cone noise, that adaptation in cones affects signal and noise differently, and that cones generate less noise than previously thought. These results help reconcile cone noise and behavioral sensitivity.

In primates, the developmental origin of neocortical interneurons is controversial. Here the authors map out expression patterns of key transcription factors in the developing human and monkey brain and reveal that, just as in rodents, the majority of cortical GABAergic neurons originate from the ganglionic eminences.

There is a diverse set of cortical interneurons that uniquely participate in the computations of large cell assemblies. Here the authors show that the same type of interneuron within the hippocampus, those projecting to the oriens-lacunosum moleculare, can have distinct developmental origins and different circuit functions.

The authors find that long-range axons from primary motor cortex (vM1) preferentially recruit vasointestinal peptide (VIP)-expressing interneurons in somatosensory cortex (S1). VIP neurons in turn inhibit somatostatin-expressing interneurons that target the distal dendrites of pyramidal cells in S1. This dis-inhibitory circuit is active during voluntary movement, suggesting that it participates in the modulation of primary cortical sensory processing by motor cortex.

It has been suggested that posterior insular regions code lower-level sensory information and anterior regions code higher-level stimulus significance relative to the body's homeostatic needs. However, here the authors report that the caudal, but not rostral, insula response to food images was directly related to the body's homeostatic state.

In this study, the authors generate a new mouse model that allows selective genetic targeting of microglial cells. Using this model, they show that elimination of TGF-β-activated kinase 1 (TAK1) specifically in microglial cells reduces pathology in a mouse model of multiple sclerosis by inhibiting NF-κB, ERK and JNK signaling pathways.

In rats self-administering cocaine, drug seeking behavior induced by a cocaine-paired cue increases progressively during cocaine withdrawal. The authors detected silent synapses in basolateral amygdala–to–nucleus accumbens projections during early withdrawal, but these synapses progressively disappeared during protracted withdrawal. Optogenetic 're-silencing' of these synapses decreased cue-induced cocaine seeking following withdrawal.

In this study, the authors recorded from the cerebellum while monkeys experienced an illusory perception of self-motion, and found that the neurons encoded the erroneous linear acceleration. Their findings provide evidence that the cerebellum might be involved in the implementation of internal models, as previously hypothesized by theorists.

Using optogenetics and other methods in the zebrafish olfactory bulb, the authors explore the role of interneurons that are densely connected to mitral cells (MCs) by both electrical and chemical synapses. These interneurons maintain the mean and distribution of MC population activity within narrow limits as stimulus intensity changes.

The authors show that shortening of the basal process in neural progenitor cells by depletion of TAG-1 results in overcrowding in the periventricular space and, eventually, delamination and aberrant migration. These results suggest that one of the functions of interkinetic nuclear migration is to prevent progenitor congestion and mechanical stress.