Articles in 2012

The authors studied how neurons in three frontal cortical areas encode the outcomes of social decisions as monkeys performed a social reward allocation task. Orbitofrontal cortex (OFC) neurons signaled received rewards, anterior cingulate (ACCs) neurons signaled forgone rewards, and the ACCg emerged as a key nexus for the computation of shared experience and social reward.

Dorsal root ganglion neurons respond to both painful and itchy stimuli, but whether itch-specific neurons exist was, up until now, unknown. Here the authors describe a group of MrgprA3-expressing neurons that innervate the superficial layers of the skin and selectively sense itch.

In this study, the authors show that self-administration of cocaine by males resulted in an increase in BDNF expression in the mPFC and reduced drug-seeking behavior by their male offspring. This change in BDNF expression was associated with an increase in acetylated histone H3 at the Bdnf promoter IV.

The authors utilize optical occlusion of penetrating blood vessels to induce cortical microinfarcts. Occlusion of even a single such vessel leads to behavioral dysfunction, whereas multiple, yet sparse, occlusions can induce substantial tissue damage. Excitotoxicity blockers ameliorate both effects.

Here the authors show that the suppression of salient, but task-irrelevant, distractors is much stronger in the dorsolateral prefrontal cortex (dlPFC) than in the lateral intraparietal area (LIP). Their results suggest that, although both areas can contribute to perceptual selection, the dlPFC has a decisive influence on whether a salient stimulus influences actions.

The authors show that nerve injury induces expression of NRG1 type I in Schwann cells and that this expression is necessary for efficient remyelination. In addition, axonally expressed NRG1 type III can negatively regulate the expression of NRG1 type I in Schwann cells.

This study examines the neural coding of decision confidence when human subjects make value-based economic choices, and finds that signals of explicit confidence are encoded in the activity of ventromedial prefrontal cortex and its interaction with the rostrolateral prefrontal cortex.

Midbrain dopaminergic neurons show phasic elevations of firing in response to reward-predicting stimuli during learning. Here the authors provide data from in vivo recordings and optogenetic stimulation to support a role for monosynaptic inhibition of dopamine neurons from projection neurons in the substantia nigra in extinction of learned behaviors.

Gene-environment interactions of FKBP5 and early trauma predict adult stress-related psychiatric disorders. In this study, the authors reveal the molecular mechanism of how transcriptionally active variants interact with early trauma leading to long-term allele-specific changes in DNA methylation in glucocorticoid response elements of FKBP5.

The authors examined the differential roles of GluN2A and GluN2B in modulating synaptic plasticity and behavior. This study provides insight into how gene duplication events during evolution can produce new functional consequences.

In this paper, the authors show that mice lacking Dlg genes each show distinct deficits in various learning paradigms. In addition, they find that humans with DLG2 mutations show similar cognitive deficits to their murine counterparts, suggesting an evolutionary conservation of function.

By pairing acoustic stimuli and electrical stimulation of the nucleus basalis neuromodulatory system in rats, the authors show an induction of long-lasting synaptic modifications of the auditory cortex that conserved excitation across the auditory receptive fields. This type of modification also improved auditory sensory detection and behavioral performance in tone perception.

Functional links between neuronal activity and perception are studied by examining trial-by-trial correlations (choice probabilities) between neural responses and perceptual decisions. Here the authors report that subcortical vestibular neurons show robust choice probabilities if they selectively represent self-translation, suggesting that choice-related activity emerges from a critical transformation of vestibular signals.

Here the authors investigate the neural basis of coherence and contrast detection in the somatosensory system. Model-based analysis of the responses of neurons in the barrel cortex reveal different coding schemes according to the level of correlation in the spatiotemporal patterns of whisker stimulation. The cell populations they find in the primary somatosensory cortex are analogous to cell classes previously reported in two separate cortical areas of the visual system.

The authors show that the oncogene Bcl6 is necessary for proper cortical neurogenesis in vivo and from embryonic stem cells. BCL6 alters the composition of Notch-dependent transcriptional complexes at the Hes5 promoter, including the recruitment of Sirt1, to promote transition to a neurogenic fate despite active Notch signaling.

The positive effect of stress on memory formation involves glucocorticoid receptors, but is otherwise not well understood. This article reports that stressful memory consolidation in rats involves the activation of a nongenomic molecular cascade downstream of hippocampal glucocorticoid receptors that overlaps with the BDNF-TrkB signaling pathway.

Brain-machine interfaces (BMIs) have typically focused on performing single-targeted movements. Here the authors report the presence of two subpopulations of neurons in the monkey premotor cortex that allow two planned targets to be simultaneously held in working memory without degradation. They use this finding to develop a BMI that concurrently decodes a full motor sequence in advance of movement and then accurately executes it.

The function of neuroligins in regulating synapse formation remains controversial. Here, the authors show that neuroligin-1 (NL1) regulates activity-dependent synaptogenesis and mature synapse number on cortical layer 2/3 pyramidal neurons in vivo. They find that relative differences in transcellular expression of NL1, rather than absolute expression levels, regulate synapse number.

Newly generated dentate granule cells in the hippocampus at 4 weeks after their 'birth' are more plastic than existing neurons. The authors use a combined retroviral and optogenetic approach to show that silencing these 4-week-old cells, but not cells of other ages, impaired retrieval of hippocampal memory.

The EphB family of receptor tyrosine kinases can signal bidirectionally and functions in a kinase-dependent and kinase-independent manner. To determine the importance of the kinase activity of EphBs for axonal guidance and synaptogenesis, the authors used a chemical genetic method and generated knock-in mice that allow the kinase activity of EphBs to be inhibited without altering kinase-independent functions of EphBs. They find that specific inhibition of EphB kinase activity had no effect on synaptogenesis, but impaired axonal guidance, thereby implicating the kinase function of EphB in one neuronal process, but not other processes that are nevertheless dependent on EphBs.