Marching for science - p523

doi:10.1038/nn0509-523

The UCLA community, together with the UK-based Pro-test movement and the US campaign group Speaking of Research, is organizing a demonstration in support of animal research. The experience of scientists in the UK suggests that this approach can help stem the tide of rising violence against researchers.

Full Text - Marching for science | PDF (136 KB) - Marching for science

Kuru, moral peril and the creation of value in science - p525

Adriano Aguzzi reviews The Collectors of Lost Souls: Turning Kuru Scientists into Whitemen by Warwick Anderson

doi:10.1038/nn0509-525

Full Text - Kuru, moral peril and the creation of value in science | PDF (131 KB) - Kuru, moral peril and the creation of value in science

Carrot sticks or joysticks: video games improve vision - pp527 - 528

Gideon P Caplovitz & Sabine Kastner

doi:10.1038/nn0509-527

Playing action-based video games has been shown to improve attentional processing. A study now finds that it also induces long-lasting improvements in contrast sensitivity, a basic visual function that commonly deteriorates with age. These improvements do not happen for an equivalent group who played a non-action video game.

Full Text - Carrot sticks or joysticks: video games improve vision | PDF (285 KB) - Carrot sticks or joysticks: video games improve vision

See also: Brief Communication by Li et al.

Bottoms up: transduction channels at tip link bases - pp529 - 530

Kateri J Spinelli & Peter G Gillespie

doi:10.1038/nn0509-529

A study now demonstrates that the transduction channel responsible for converting sound to neural signals in the mammalian cochlea is excluded from the tallest row of stereocilia and is instead more likely in the bottom row.

Full Text - Bottoms up: transduction channels at tip link bases | PDF (842 KB) - Bottoms up: transduction channels at tip link bases

See also: Article by Beurg et al.

Inhibition by an excitatory conductance: a paradox explained - pp530 - 532

Bruce P Bean

doi:10.1038/nn0509-530

I_h is an excitatory inward current at subthreshold voltages, but enhancing I_h in CA1 pyramidal neurons leads to inhibition of action potential firing. A report in this issue suggests activation of the potassium current I_M underlies this paradox.

Full Text - Inhibition by an excitatory conductance: a paradox explained | PDF (851 KB) - Inhibition by an excitatory conductance: a paradox explained

See also: Article by George et al.

The secret language of siblings - pp532 - 534

Tom Binzegger

doi:10.1038/nn0509-532

A recent study in Nature shows that sister neurons of the same lineage are preferentially interconnected to each other, thereby suggesting a local guidance mechanism using chemospecific markers.

Full Text - The secret language of siblings | PDF (325 KB) - The secret language of siblings

Motoneurons buckling under stress - p534

Annette Markus

doi:10.1038/nn0509-534

Full Text - Motoneurons buckling under stress | PDF (135 KB) - Motoneurons buckling under stress

See also: Article by Saxena et al.

Circular analysis in systems neuroscience: the dangers of double dipping - pp535 - 540

Nikolaus Kriegeskorte, W Kyle Simmons, Patrick S F Bellgowan & Chris I Baker

doi:10.1038/nn.2303

This perspective illustrates some of the problems involved in analyzing the complex data yielded by systems neuroscience techniques, such as brain imaging and electrophysiology. Specifically, when test statistics are not independent of the selection criteria, common analyses can produce spurious results. The authors suggest ways to avoid such errors.

Abstract - | Full Text - Circular analysis in systems neuroscience: the dangers of double dipping | PDF (419 KB) - Circular analysis in systems neuroscience: the dangers of double dipping | Supplementary information

Small voltage changes at nerve terminals travel up axons to affect action potential initiation - pp541 - 543

Kenneth Paradiso & Ling-Gang Wu

doi:10.1038/nn.2301

At the calyx of Held nerve terminal, Wu and Paradiso show that small hyperpolarizations or depolarizations can travel back up the axon and influence the threshold for action potential initiation.

Abstract - | Full Text - Small voltage changes at nerve terminals travel up axons to affect action potential initiation | PDF (315 KB) - Small voltage changes at nerve terminals travel up axons to affect action potential initiation | Supplementary information

Relief of itch by scratching: state-dependent inhibition of primate spinothalamic tract neurons - pp544 - 546

Steve Davidson, Xijing Zhang, Sergey G Khasabov, Donald A Simone & Glenn J Giesler Jr

doi:10.1038/nn.2292

Here, the authors show that scratching the cutaneous receptive field of primate spinothalamic neurons produces inhibition during histamine-evoked itchiness, but not during spontaneous activity or activity evoked by pain. This suggests that the inhibition of itch by scratching is state-dependent in the spinal cord.

Abstract - | Full Text - Relief of itch by scratching: state-dependent inhibition of primate spinothalamic tract neurons | PDF (281 KB) - Relief of itch by scratching: state-dependent inhibition of primate spinothalamic tract neurons | Supplementary information

Coding of pleasant touch by unmyelinated afferents in humans - pp547 - 548

Line S Löken, Johan Wessberg, India Morrison, Francis McGlone & Håkan Olausson

doi:10.1038/nn.2312

Much work has been devoted to the elucidation of pain signaling, whereas the transduction of pleasant touch has garnered less attention. In this study, the authors present data suggesting that pleasant touch is mediated by a particular dedicated type of peripheral nerve fibers, the low-threshold, unmyelinated mechanoreceptive C-tactile afferents.

Abstract - | Full Text - Coding of pleasant touch by unmyelinated afferents in humans | PDF (224 KB) - Coding of pleasant touch by unmyelinated afferents in humans | Supplementary information

Enhancing the contrast sensitivity function through action video game training - pp549 - 551

Renjie Li, Uri Polat, Walter Makous & Daphne Bavelier

doi:10.1038/nn.2296

This study finds that playing an action video game results in improvements in visual contrast sensitivity. These improvements do not happen for an equivalent group who played a non-action video game.

Abstract - | Full Text - Enhancing the contrast sensitivity function through action video game training | PDF (170 KB) - Enhancing the contrast sensitivity function through action video game training | Supplementary information

See also: News and Views by Caplovitz & Kastner

Localization of inner hair cell mechanotransducer channels using high-speed calcium imaging - pp553 - 558

Maryline Beurg, Robert Fettiplace, Jong-Hoon Nam & Anthony J Ricci

doi:10.1038/nn.2295

Mechanically sensitive transducer channels are responsible for the detection of sound-induced hair cell vibrations. However, the location of these channels in the stereociliary bundle has been unclear. Using high-speed calcium imaging, this study demonstrates that there are no transduction channels in the tallest row of stereocilia in the mammalian cochlea. Instead, these channels are more likely to be present in the bottom stereociliary rows.

Abstract - | Full Text - Localization of inner hair cell mechanotransducer channels using high-speed calcium imaging | PDF (449 KB) - Localization of inner hair cell mechanotransducer channels using high-speed calcium imaging | Supplementary information

See also: News and Views by Spinelli & Gillespie

Tubulin tyrosination navigates the kinesin-1 motor domain to axons - pp559 - 567

Yoshiyuki Konishi & Mitsutoshi Setou

doi:10.1038/nn.2314

The authors study the molecular mechanisms that discriminate axonal microtubules from somatodendritic microtubules. They report that amino acid substitutions in the beta loop region of kinsin-1 can change the compartmentalization of kinesin-1 from axons to axons and dendrites. Moreover, tyrosinated tubulins normally prevent kinesin-1 from binding to microtubules, but do not similarly inhibit kinesin-1 that is changed to allow localization to both axons and dendrites.

Abstract - | Full Text - Tubulin tyrosination navigates the kinesin-1 motor domain to axons | PDF (900 KB) - Tubulin tyrosination navigates the kinesin-1 motor domain to axons | Supplementary information

Myosin-dependent targeting of transmembrane proteins to neuronal dendrites - pp568 - 576

Tommy L Lewis Jr, Tianyi Mao, Karel Svoboda & Don B Arnold

doi:10.1038/nn.2318

How proteins are targeted for dendrites versus axons remains unclear. Lewis et al. show that the dendritic localization of several transmembrane proteins is dependent on specific myosin motors and an intact actin network. They also target Channelrhodopsin-2 specifically to dendrites, demonstrating a potentially important tool for probing neuronal circuits.

Abstract - | Full Text - Myosin-dependent targeting of transmembrane proteins to neuronal dendrites | PDF (796 KB) - Myosin-dependent targeting of transmembrane proteins to neuronal dendrites | Supplementary information

HCN hyperpolarization-activated cation channels inhibit EPSPs by interactions with M-type K⁺ channels - pp577 - 584

Meena S George, L F Abbott & Steven A Siegelbaum

doi:10.1038/nn.2307

Voltage-gated channels influence processing of synaptic potentials in dendrites. George et al. report the hyperpolarization-activated cation current (I_h) exerts both direct depolarizing and net inhibitory hyperpolarizing effects on subthreshold excitatory postsynaptic potentials, as a function of synaptic strength. Interaction of I_h with an M-type potassium current (I_m) underlies the inhibition.

Abstract - | Full Text - HCN hyperpolarization-activated cation channels inhibit EPSPs by interactions with M-type K+ channels | PDF (952 KB) - HCN hyperpolarization-activated cation channels inhibit EPSPs by interactions with M-type K+ channels | Supplementary information

See also: News and Views by Bean

BK channels modulate pre- and postsynaptic signaling at reciprocal synapses in retina - pp585 - 592

William N Grimes, Wei Li, Andrés E Chávez & Jeffrey S Diamond

doi:10.1038/nn.2302

The authors combine electrophysiology, calcium imaging and immunohistochemistry to show that L-type Ca_v channels in rat A17 amacrine cells are well placed to mediate reciprocal inhibitory feedback to rod bipolar cells. However, they find that the contribution of these channels to GABA release is diminished by large-conductance Ca²⁺-activated potassium (BK) channels, which suppress postsynaptic depolarization in A17s and limit Ca_v channel activation.

Abstract - | Full Text - BK channels modulate pre- and postsynaptic signaling at reciprocal synapses in retina | PDF (611 KB) - BK channels modulate pre- and postsynaptic signaling at reciprocal synapses in retina | Supplementary information

Synaptic mGluR activation drives plasticity of calcium-permeable AMPA receptors - pp593 - 601

Leah Kelly, Mark Farrant & Stuart G Cull-Candy

doi:10.1038/nn.2309

Calcium influx through AMPA receptors can trigger a switch in AMPA receptor subunit composition and cause a loss of Ca²⁺ permeability at the parallel fiber–stellate cell synapse in the cerebellum. Cull-Candy and colleagues now report that mGluRs and GABAB receptors both modulate this plasticity as well.

Abstract - | Full Text - Synaptic mGluR activation drives plasticity of calcium-permeable AMPA receptors | PDF (575 KB) - Synaptic mGluR activation drives plasticity of calcium-permeable AMPA receptors | Supplementary information

Stability of surface NMDA receptors controls synaptic and behavioral adaptations to amphetamine - pp602 - 610

Li-Min Mao, Wei Wang, Xiang-Ping Chu, Guo-Chi Zhang, Xian-Yu Liu, Yuan-Jian Yang, Michelle Haines, Christopher J Papasian, Eugene E Fibuch, Shilpa Buch, Jian-Guo Chen & John Q Wang

doi:10.1038/nn.2300

This study shows that chronic amphetamine exposure in rats downregulates the NMDA receptor NR2B subunit on striatal neurons. This loss of NR2B has consequences for synaptic transmission and for behavior, sensitizing the rats to the stimulant.

Abstract - | Full Text - Stability of surface NMDA receptors controls synaptic and behavioral adaptations to amphetamine | PDF (617 KB) - Stability of surface NMDA receptors controls synaptic and behavioral adaptations to amphetamine | Supplementary information

Oxidation of a potassium channel causes progressive sensory function loss during aging - pp611 - 617

Shi-Qing Cai & Federico Sesti

doi:10.1038/nn.2291

Oxidative damage contributes to loss of nervous system function in age as well as a result of degenerative disease. But how exactly can oxidation impair neuronal function? In the worm C. elegans, this study shows that the potassium channel KVS-1 is subject to oxidation at a particular cysteine residue. Mutation of this residue led to preservation of chemosensation in aging worms.

Abstract - | Full Text - Oxidation of a potassium channel causes progressive sensory function loss during aging | PDF (485 KB) - Oxidation of a potassium channel causes progressive sensory function loss during aging | Supplementary information

The endogenous inhibitor of Akt, CTMP, is critical to ischemia-induced neuronal death - pp618 - 626

Takahiro Miyawaki, Dimitry Ofengeim, Kyung-Min Noh, Adrianna Latuszek-Barrantes, Brian A Hemmings, Antonia Follenzi & R Suzanne Zukin

doi:10.1038/nn.2299

Akt signaling has been implicated in a number of diseases, but its role in brain disorders is less clear. Here, the authors report that CTMP, an endogenous inhibitor of Akt, is critical in the neurodegeneration that is associated with stroke. Blockade of CTMP in a stroke model rescues hippocampal neurons.

Abstract - | Full Text - The endogenous inhibitor of Akt, CTMP, is critical to ischemia-induced neuronal death | PDF (601 KB) - The endogenous inhibitor of Akt, CTMP, is critical to ischemia-induced neuronal death | Supplementary information

A role for motoneuron subtype–selective ER stress in disease manifestations of FALS mice - pp627 - 636

Smita Saxena, Erik Cabuy & Pico Caroni

doi:10.1038/nn.2297

The authors identify motoneurons selectively vulnerable and resistant to motorneuron disease longitudinally in vivo. Their data suggests that subtype-selective ER stress responses influence disease pathology and the progressive manifestations of weakening and paralysis.

Abstract - | Full Text - A role for motoneuron subtype–selective ER stress in disease manifestations of FALS mice | PDF (920 KB) - A role for motoneuron subtype–selective ER stress in disease manifestations of FALS mice | Supplementary information

See also: News and Views by Markus

A precise form of divisive suppression supports population coding in the primary visual cortex - pp637 - 645

Sean P MacEvoy, Thomas R Tucker & David Fitzpatrick

doi:10.1038/nn.2310

Responses of primary visual cortex neurons to optimal gratings are suppressed when a non-optimal grating is superimposed. Using intrinsic optical imaging and intracellular recordings, the authors report that this effect is mediated by divisive suppression in independent population codes for stimulus orientation and strength.

Abstract - | Full Text - A precise form of divisive suppression supports population coding in the primary visual cortex | PDF (975 KB) - A precise form of divisive suppression supports population coding in the primary visual cortex | Supplementary information

Engaging in an auditory task suppresses responses in auditory cortex - pp646 - 654

Gonzalo H Otazu, Lung-Hao Tai, Yang Yang & Anthony M Zador

doi:10.1038/nn.2306

Selective attention is proposed to enhance relevant responses. Here the authors report that, paradoxically, responses in auditory cortex are suppressed when rats are engaged in a task, relative to responses that occurred while the animals were awake, but not performing any task.

Abstract - | Full Text - Engaging in an auditory task suppresses responses in auditory cortex | PDF (532 KB) - Engaging in an auditory task suppresses responses in auditory cortex | Supplementary information

Reinforcement learning can account for associative and perceptual learning on a visual-decision task - pp655 - 663

Chi-Tat Law & Joshua I Gold

doi:10.1038/nn.2304

Using computational methods to model neural recordings and behavioral data, the authors find that reinforcement learning rules, combined with a standard model of decision-making, can explain a range of experimentally observed phenomena in perceptual learning.

Abstract - | Full Text - Reinforcement learning can account for associative and perceptual learning on a visual-decision task | PDF (753 KB) - Reinforcement learning can account for associative and perceptual learning on a visual-decision task | Supplementary information