Papers for the month of August 2015


Navlakha, S. and Bar-Joseph, Z.

"Decreasing-Rate Pruning Optimizes the Construction of Efficient and Robust Distributed Networks"
PLoS Computational Biology, 11(7):e1004347

Mouse over here for a brief summary or click to open article in a new tab.During brain development, synapses are massively over-produced and then pruned-back over time, a strategy that is not commonly used when designing engineered networks since adding connections that will soon be removed is considered wasteful. Here, we show that for large distributed routing networks, network function is markedly enhanced by hyper-connectivity followed by aggressive pruning.


Zachariou, V., Nikas, C. V., Klatzky, R. and Ungerleider, L. G.

"Common Neural Mechanisms for Between-object and Within-object Location Processing"
Journal of Cognitive Neuroscience, in press:unknown

Mouse over here for a brief summary or click to open article in a new tab.http://The neural mechanisms by which surface features are bound to different object parts remain to be determined. To explore this issue, we collected fMRI data while human participants performed a difference detection task on two objects with textured parts. We conclude that both the binding of texture features to object parts and the representation of object spatial position are mediated by common neural mechanisms within the dorsal visual pathway.


Perel S., Sadtler P.T., Oby E.R., Ryu S.I., Tyler-Kabara E.C., Batista A.P.

"ingle-unit activity, threshold crossings, and local field potentials in motor cortex differentially encode reach kinematics"
Journal of Neurophysiology, 114:1500-1512

Mouse over here for a brief summary or click to open article in a new tab.A diversity of signals can be recorded with extracellular electrodes. It remains unclear whether different signal types convey similar or different information and whether they capture the same or different underlying neural phenomena. We examined the similarities and differences in the information contained in four signal types recorded simultaneously from multielectrode arrays implanted in primary motor cortex: well-isolated action potentials from putative single units, multiunit threshold crossings, and local field potentials (LFPs) at two distinct frequency bands. Our findings indicate that the diverse signals recorded from extracellular electrodes provide somewhat distinct and complementary information. It may be that these signal types arise from biological phenomena that are partially distinct.


Ocker GK, Litwin-Kumar A

"Self-Organization of Microcircuits in Networks of Spiking Neurons with Plastic Synapses"
PLoS Computational Biology, 11:1004458

Mouse over here for a brief summary or click to open article in a new tab.Modeling paper that shows how spike timing dependent plasticity can drive microcircuit structure in recurrent networks of neurons.


Heitmann, S., Boonstra, T., Gong, P., Breakspear, M.

"The rhythms of steady posture: Motor commands as spatially organized oscillation patterns"
Neurocomputing, 170:3-14

Mouse over here for a brief summary or click to open article in a new tab.Presents a model of the descending motor system whereby muscle commands are represented in primary motor cortex by the spatial pattern of beta-band (15-30 Hz) neural oscillations therein. It is proposed that neurons of the descending motor pathway act as spatial filters of those oscillation patterns to selectively shape the drive to the muscles. The model demonstrates how oscillatory neural activity in cortex can be translated into steady muscle postures in a biomechanical joint.


Liu, Ran

"Dimension-based statistical learning of vowels"
Journal of Experimental Psychology: Human Perception and Performance, Advance Online Publication:xx

Mouse over here for a brief summary or click to open article in a new tab.Speech perception depends on long-term representations that reflect regularities of the native language. However, listeners rapidly adapt when speech acoustics deviate from these regularities due to talker idiosyncrasies such as foreign accents and dialects. Upon encountering an "artificial accent" in which the spectral-duration correlation is perturbed relative to English language norms, listeners rapidly down-weight reliance on duration. We demonstrate that listeners exhibit short-term statistical learning even in the context of nonwords, confirming that lexical information is not necessary to this form of adaptive plasticity in speech perception. Moreover, learning generalizes to both novel lexical contexts and acoustically distinct altered voices. These findings are discussed in the context of a mechanistic proposal for how supervised learning may contribute to this type of adaptive plasticity in speech perception.


"Microglial activation in the rat brain following chronic antipsychotic treatment at clinically relevant doses."
European Neuropsychopharmacology, 8:4

Mouse over here for a brief summary or click to open article in a new tab.Neuroinflammation is increasingly implicated in the pathogenesis of Schizophrenia (SCZ). In addition, there is increasing evidence for a relationship between the dose and duration of antipsychotic drug (APD) treatment and reductions in grey matter volume. The potential contribution of microglia to these phenomena is however not yet defined. These data provide the first in vivo evidence that chronic APD treatment at clinically relevant doses leads to microglial proliferation and morphological changes indicative of activated microglia in the naïve rat brain.


Stafura, Joseph A., & Rickels, Benjamin

" ERP evidence for memory and predictive mechanisms in word-to-text integration"
Language, Cognition and Neuroscience., 30:1-17

Mouse over here for a brief summary or click to open article in a new tab.During reading, word-to-text integration (WTI) proceeds quickly and incrementally through both prediction and memory processes. We tested predictive and memory mechanisms with event-related potentials (ERPs) recorded on critical words that were across a sentence boundary from co-referential words that differed in dominant direction of lexical association. For comparison of text comprehension, participants performed meaning judgements on a matched set of word pairs. In both tasks, reduced N400 amplitudes were elicited over central scalp electrodes by words associated in either direction relative to task-specific baseline conditions. A temporal principal component analysis of the ERP data extracted a component reflecting this central N400. Additionally, for the text comprehension task early (N200) and late (parietal N400 and P600) discriminated between forward associated and backward associated conditions. The results demonstrate that, beyond N400 indicators of prediction, ERPs reflect the role of memory processes in WTI across sentences.


He, J., Wang, Y., Barth, A. L., Bruchez, M. P.

"Fluorogenic Green-Inside Red-Outside (GIRO) Labeling Approach Reveals Adenylyl Cyclase-Dependent Control of BKα Surface Expression"
Bioconjugate Chemistry, 26:0

Mouse over here for a brief summary or click to open article in a new tab.We developed a method to differentially label surface and internalized BK channels. In doing so, we identified adenlylyl cyclase as a suppressor of BK surface levels. This could have future implications in epileptogenesis.


"Broken Cables: High-definition Imaging Helps Researchers Map the Damage from Traumatic Brain Injury with Unprecedented Accuracy"
Discover Magazine, 36:53-59

Mouse over here for a brief summary or click to open article in a new tab.The September 2015 issue of Discover magazine features Walter Schneider’s High Definition Fiber Tracking (HDFT), in “Broken Cables: High-definition Imaging Helps Researchers Map the Damage from Traumatic Brain Injury with Unprecedented Accuracy (September 2015, pp. 53-59). http://discovermagazine.com/2015/sept/16-broken-cables


332. Mesiwala NK, Shemonski N, Sandrian MG, Shelton R, Ishikawa H, Tawbi HA, Schuman JS, Boppart SA, Labriola LT

"Retinal imaging with en face and cross-sectional optical coherence tomography delineates outer retinal changes in cancer-associated retinopathy secondary to Merkel cell carcinoma."
J Ophthalmic Inflamm Infect, 53:25

Mouse over here for a brief summary or click to open article in a new tab.The study aims to correlate Fourier-domain optical coherence tomography (FD-OCT) with Goldmann visual field (GVF) to show the photoreceptor (PR) structure and function relationship in the first described case of cancer-associated retinopathy (CAR) from Merkel cell carcinoma.


Peirs C., Williams S.P., Zhao X., Walsh C., Gedeon J., Cagle N., Goldring A., Hioki H., Liu Z., Marell P., Seal R.

"Dorsal Horn Circuits for Persistent Mechanical Pain"
Neuron, 87:797-812

Mouse over here for a brief summary or click to open article in a new tab.http://Peirs et al. identified deep dorsal horn neurons that transiently express VGLUT3 and are required for mechanical allodynia. The neurons transmit innocuous input to dorsally directed pain microcircuits that are differentially engaged depending on the type of injury.


Beukema P., Yeh F-C.

"“In vivo characterization of the connectivity and subcomponents of the human globus pallidus.”"
NeuroImage, 120:382–393

Mouse over here for a brief summary or click to open article in a new tab.Using diffusion MRI we show how it is possible to detect the presence of nested efferent pathways within the pallidum and use the diffusion MRI signal to parse the internal and external segments of the globus pallidus.


Lakshmanan K., Sadtler P., Tyler-Kabara E., Batista A.

"Extracting low-dimensional latent structure from time series in the presence of delays"
Neural Computation, 27:1825-1856

Mouse over here for a brief summary or click to open article in a new tab.Noisy, high-dimensional time series observations can often be described by a set of low-dimensional latent variables. Commonly used methods to extract these latent variables typically assume instantaneous relationships between the latent and observed variables. In many physical systems, changes in the latent variables manifest as changes in the observed variables after time delays. Techniques that do not account for these delays can recover a larger number of latent variables than are present in the system, thereby making the latent representation more difficult to interpret. In this work, we introduce a novel probabilistic technique, time-delay gaussian-process factor analysis (TD-GPFA), that performs dimensionality reduction in the presence of a different time delay between each pair of latent and observed variables.

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