Articles in 2011

The authors find that the principal hippocampal neurons consist of distinct subpopulations that show distinct neurogenesis and synaptogenesis time windows and that these neurons interconnect selectively at dentate gyrus–to-CA3 and CA3-to-CA1 synapses.

TDP-43 is a RNA-binding protein that forms inclusion bodies in ALS. The authors show that TDP-43 preferentially binds long clusters of UG-rich sequences and that TDP-43 binding on pre-mRNAs influences alternative splicing. Many alternative mRNA isoforms regulated by TDP-43 encode proteins that regulate neuronal development or are implicated in neurological diseases.

According to reinforcement learning theory, reward expectation reflects an integration of past rewards over a fixed time scale. Here the authors extract signals about reward memory from neurons in the prefrontal, cingulate and parietal cortex, finding a wide range of time constants across the neuronal population, with a power-law distribution.

In Drosophila, R7 and R8 photoreceptors, which detect different wavelengths, form synapses in distinct medulla layers. The authors report that Golden Goal and Flamingo, two cell-surface proteins involved in photoreceptor targeting, functionally interact in R8 cells and that their interaction specifies synaptic-layer selection of photoreceptors.

Westerlund and colleagues show that c-Jun N-terminal protein kinase 1 (JNK1), via phosphorylation of SCG10/Stathmin-2, acts as a negative regulator of the rate of neuronal migration and transition through the multipolar stage during cortical development in rodents.

Larsen et al. find that presynaptic NMDA receptors at neocortical synapses are heteromeric receptors containing the developmentally expressed NR3A subunit. Their data also indicate that NR3A-containing presynaptic NMDARs mediate tonic presynaptic activity, synaptic transmission and spike timing–dependent plasticity.

Although the olfactory receptor neurons converging onto the same glomeruli in the olfactory bulb are known, evidence for an olfactory map at cortical level is lacking. The current study finds that mitral cells that are born later during embryogenesis preferentially project to the olfactory tubercles as the late-born mitral cells tangentially migrate further on the axons of earlier born cells, forming an organization of neuronal projection into the olfactory cortex based on the timing of cell birth.

The authors use a mouse model of rapid-onset dystonia-Parkinsonism to show that an adverse interaction between the cerebellum and basal ganglia can account for the symptoms in this condition. Aberrant cerebellar activity alters basal ganglia function via a di-synaptic thalamic pathway, causing dystonia.

Lafourcade et al. find that a lifelong insufficiency in dietary n-3 polyunsaturated fatty acids leads to a specific loss of long-term synaptic depression mediated by endocannabinoids in the prelimbic prefrontal cortex and accumbens in mice. This was associated with impaired emotional behavior.

Reinforcement signals indicating success or failure are known to alter the probability of selecting between distinct actions. Here the authors examine the structure of learning at a millisecond timescale, suggesting that reinforcement can also guide learning of continuous action trajectories.

Acetylcholine (Ach) and agrin are opposing signals that regulate NMJ development. The authors report that the intermediate filament protein nestin interacts with Cdk5 and is required for Ach-induced p35 association with the muscle membrane. Blocking this signaling inhibits Ach-induced AchR cluster dispersion during NMJ development.

Memory reactivation underlying consolidation can occur during periods of sleep or in waking where wakeful memory reactivation is susceptible to disruption. Contrary to prior predictions, the authors find that memory reactivation during slow-wave sleep immediately stabilizes memories in the absence of REM sleep.

The authors report that the rate at which calmodulin binds calcium is faster than that of other calcium binding proteins, and that calmodulin directly intercepts incoming calcium and sets [Ca²⁺]_free rather than responding to the lower [Ca²⁺]_free set by other buffers.

Ephaptic coupling is the feedback of extracellular fields onto the electrical potential across the neuronal membrane, independent of synapses. Here, the authors report that, under physiological conditions, endogenous brain activity can affect neural function through field effects.

Combining positron emission tomography and functional magnetic resonance imaging, the authors investigate the effects of emotionally arousing music on the dopamine system. They find that the anticipation of this abstract reward can result in dopamine release in an anatomical pathway that is distinct from that associated with the peak pleasure itself.

Using genetics and pharmacology, the authors find that the dynamics of olfactory receptor neurons can be separated into two sequential steps: transduction and spike generation. They then characterize these two components.

Here the authors demonstrate that the orientation preference of a cortical column is closely related to the population receptive field of the ON and OFF thalamic inputs. These results support models suggesting that orientation maps develop on the basis of the receptive field arrangement of ON and OFF visual inputs to the cortex.

Graf et al. examine how information can be decoded from the pattern of population activity in primary visual cortex neurons. They find that the structure of neuronal response distributions, including their correlated variability, contains critical information for sensory decoding.

Aponte et al. show that optogenetic activation of a population of hypothalamic neurons expressing agouti-related peptide (AGRP) is sufficient to evoke voracious feeding behavior in mice. This feeding was not dependent on suppressing the activity of anorexigenic pro-opiomelanocortin–expressing neurons, suggesting that AGRP neurons directly engage feeding circuits.