Brief Communications in 2011

Harmonin was previously identified as a scaffolding protein that is important for the localization of cadherin in the upper tip-link density of the stereociliary membrane and for the initial mechanotransduction event in inner hair cells. Here the authors find that harmonin is involved in regulating the voltage-gated calcium channel for synaptic transmission in inner hair cell ribbon synapses.

Using optogenetics and multi-electrode recording in behaving mice, the authors find that briefly driving the thalamic reticular nucleus (TRN) switches thalamocortical firing mode and generates neocortical spindles, which have been implicated in memory and disease. These findings provide causal support for the idea that the TRN is involved in state regulation and introduce a new model for addressing the role of spindles in behavior.

Following eye opening, fast-spiking, parvalbumin-positive GABAergic interneurons in mice have well-defined orientation-tuning preferences. However, the authors find that subsequent visual experience actually broadens this tuning. The authors suggest that experience-dependent broadening of inhibition could be a candidate for initiating the critical period.

Learning both a word list and a motor memory task in a short interval usually leads to interference between the two tasks, resulting in poorer performance. Depending on the order of the tasks, the authors were able to directly prevent interference by applying transcranial magnetic stimulation to disrupt processing in either the prefrontal or the motor cortex, which suggests that distinct mechanisms underlie memory interference.

It is thought that retinal bipolar cells do not fire action potentials, but calcium imaging in live zebrafish now reveals that in bipolar cells there are 'all or none' calcium transients that are modulated by visual stimulation.

In Drosophila, larval neural circuits are remodeled during metamorphosis by both pruning and neurite remodeling, which requires TGF-β signaling. Here, Awasaki and colleagues find that glia secrete myoglianin, a TGF-β ligand, which upregulates neuronal expression of an ecdysone nuclear receptor that triggers neurite remodeling following the late-larval ecdysone peak.

The authors report that light prolongs spiking during retinal waves of correlated activity that occur during mouse development by activating melanopsin-expressing intrinsically photosensitive retinal ganglion cells.

This study uses fMRI to find that visual cortical areas involved in processing task-relevant information are functionally connected with the frontal-parietal network, but those processing task-irrelevant information are simultaneously coupled with the default network. The strength of visual cortex/default network functional connectivity was predictive of subjects' abilities to suppress irrelevant information.

Here the authors find that the kinetics of synaptic vesicle endocytosis are widely variable across different neurons and is stochastic regardless of neuronal firing histories or number of presynaptic boutons.

This paper describes the homeodomain transcription factor Skn-1a as a specification factor for a subset of taste receptor cells (TRCs). Mice lacking functional Skn-1a did not have TRCs or behavioral response to sweet, umami and bitter tastes, but instead had more TRCs that detect sour taste.

Idiopathic basal ganglia calcification (IBGC) is a rare neurodegenerative disease that manifests during midlife, causing Parkinsonian movement disorder and cognitive impairment. This study describes a mouse model of IBGC stemming from perinatal interferon-γ expression.

The presynaptic and postsynaptic compartments of neurons are structurally correlated from initial synaptogenesis. Here the authors show that functional matching is gradually shaped by ongoing electrical activity during maturation.

Although they contain NMDA receptors, hippocampal mossy fiber synapses onto CA3 pyramidal cells have been reported to lack conventional NMDA receptor–dependent LTP of AMPA EPSCs. Here, the authors find that LTP of NMDA receptors serves as a metaplastic switch, making mossy fiber synapses competent to express NMDA receptor–dependent LTP of AMPA EPSCs.

This study uses subjects with newly removed congenital occlusions to demonstrate that object matching between touch and vision is not innate. Formerly blind subjects, when they had their sight restored, were initially unable to visually match an object to a sample they had previously touched, but rapidly developed such cross-modal matching.

Amyloid-β is known to inhibit hippocampal long-term potentiation (LTP), but the underlying molecular mechanisms are only partially understood. In this capacity, Jo and colleagues report the involvement of a signaling pathway comprised of caspase-3, Akt1 and glycogen synthase kinase-3β.

Homeostatic plasticity is mostly thought be a global event that affects all synapses of the same neuron. Here, Deeg and Aizenman finds sensory pathway–specific homeostatic plasticity in the Xenopus optic tectum.

Using high-resolution fMRI in macaque monkeys, the authors demonstrate the existence of a topographic representation for temporal sound properties, which runs from dorsomedial to the ventralateral in the inferior colliculus. This is in addition to a previously reported representation of sound spectral properties (also found here), running approximately perpendicular to the temporal map.

In addition to the morphological difference, inner hair cell (IHC) synapses do not have the full complement of neuronal SNARE proteins found in other types of synapses. Here, Nouvian et al. provide a series of empirical evidence that shows that exocytosis in IHCs occurs independently of neuronal SNARE proteins.

Individual tailored health interventions can be more effective than generic interventions in eliciting behavior change. Here, the authors find that increases in activations in self-related processing regions (including dorsomedial prefrontal cortex) predicted smoking cessation during a follow-up interval.

Using a pharmacogenetic method of Daun02 to selectively inhibit activated neurons, Bossert et al. find that neurons in the ventral medial prefrontal cortex mediate context-induced drug relapse in a rat model of drug reinstatement.