Reviews & Analysis

Glial cells that express NG2 and platelet-derived growth factor receptor α are found throughout the mature CNS. These cells are mitotically active, but their functions remain enigmatic. A genetic fate-mapping study in this issue shows that these abundant glial cells can generate both oligodendrocytes and some cortical projection neurons in the adult brain.

A study in this issue shows that zebrafish larvae deploy different groups of excitatory spinal interneurons to drive slow, fast and top speed swimming. As one set is gradually activated, the others are partially or fully inhibited.

Correlations in firing rate between pairs of neurons can change depending on task and attentional demands. This new finding suggests that measuring correlations can help to reveal how neural circuits process information.

Demonstrating how specific motor signals modulate sensory processing in the rat vibrissal system, a new study in this issue shows that motor signals first attenuate and then amplify afferent sensory signals.

This review discusses new work that explores how Eph/ephrin forward and reverse signaling affect spine maturation, synaptogenesis and synaptic long-term potentiation.

Oldham et al. present a systematic analysis of gene coexpression relationships in specific human brain regions with the goal of identifying groups of genes with common coexpression patterns. The study used the inherent structure of the brain's transcriptome to find data-driven organizational patterns rather than rely on external classification systems.

A paper in this issue reports that the core mechanisms that strengthen memories have more in common with the mechanisms that support reconsolidation than those that participate in their initial storage.

A recent paper reported the in vitro generation of new prion strains, supporting the idea that 'strain-ness' is encoded in the protein structure itself. This lays the groundwork for a reinvigorated study of prion structure–pathology relationships.

Previous work has focused on neuronal encoding of two-dimensional shapes. Using a new search algorithm and three-dimensional object primitives, a study in this issue identifies potential subunits of complex object recognition.

Combined population activity is usually used to control neural prosthetics. A recent study in Nature finds that a single primary motor cortex neuron can control the artificial stimulation of paralyzed wrist muscles to move a computer cursor.

In a process termed lateral inhibition, nascent neurons via expression of Notch ligands are thought to suppress neuronal development of adjacent cells. It has recently been shown, however, that expression of the Notch ligands, as well as the proneural transcription factors that induce them, and the Notch effector Hes1 oscillate with a period of a few hours. This dynamic expression pattern is incompatible with the notion of lateral inhibition and demands a new understanding of how all-over oscillatory expression patterns are converted to localized and persistent signaling.

The visual and vestibular systems encode different, but complementary, aspects of self motion. A study in this issue sheds light on how the brain combines cues from these disparate sources, which are encoded by single neurons in the monkey extrastriate visual cortex, to support the perception of heading direction.

The transcription factor FoxP1 is important for the establishment of motor neuron diversification and connectivity. New studies indicate that it acts as an accessory factor for the transcriptional output of the Hox transcription factor network.

The adult mouse brain continuously supplies new neurons to the olfactory bulb and hippocampus. A new study in this issue shows that ongoing neurogenesis is essential for maintenance of the olfactory bulb and for spatial memory.

Spike-timing dependent plasticity is a favored synaptic mechanism for learning. However, a surprising new study by Ito and colleagues in the insect mushroom body suggests that it cannot account for a paradigmatic form of learning.

This perspective article proposes a general law (Bouma law), which states that a visual object is crowded (and therefore cannot be perceived) when spacing between multiple objects is less than a critical spacing value. Crucially, this value is independent of the object.

Although the CNS has a robust innate ability to repair demyelinated axons, this capacity appears to dissipate with age. A study in this issue suggests that epigenetic processes participate in myelin repair and that the epigenetic response is less dynamic in older individuals.

Spontaneous ultra-slow oscillations in brain signals are ubiquitous, although their source and function remain unknown. A new study now reports that this activity is correlated between functionally related areas across hemispheres in humans.