Distinct balance of excitation and inhibition in an interareal feedforward and feedback circuit of mouse visual cortex

Mouse visual cortex is subdivided into multiple distinct, hierarchically organized areas that are interconnected through feedforward (FF) and feedback (FB) pathways. The principal synaptic targets of FF and FB axons that reciprocally interconnect primary visual cortex (V1) with the higher lateromedial extrastriate area (LM) are pyramidal cells (Pyr) and parvalbumin (PV)-expressing GABAergic interneurons. Recordings in slices of mouse visual cortex have shown that layer 2/3 Pyr cells receive excitatory monosynaptic FF and FB inputs, which are opposed by disynaptic inhibition. Most notably, inhibition is stronger in the FF than FB pathway, suggesting pathway-specific organization of feedforward inhibition (FFI). To explore the hypothesis that this difference is due to diverse pathway-specific strengths of the inputs to PV neurons we have performed subcellular Channelrhodopsin-2-assisted circuit mapping in slices of mouse visual cortex. Whole-cell patch-clamp recordings were obtained from retrobead-labeled FF(V1→LM)- and FB(LM→V1)-projecting Pyr cells, as well as from tdTomato-expressing PV neurons. The results show that the FF(V1→LM) pathway provides on average 3.7-fold stronger depolarizing input to layer 2/3 inhibitory PV neurons than to neighboring excitatory Pyr cells. In the FB(LM→V1) pathway, depolarizing inputs to layer 2/3 PV neurons and Pyr cells were balanced. Balanced inputs were also found in the FF(V1→LM) pathway to layer 5 PV neurons and Pyr cells, whereas FB(LM→V1) inputs to layer 5 were biased toward Pyr cells. The findings indicate that FFI in FF(V1→LM) and FB(LM→V1) circuits are organized in a pathway- and lamina-specific fashion

Ephus: Multipurpose Data Acquisition Software for Neuroscience Experiments

Physiological measurements in neuroscience experiments often involve complex stimulus paradigms and multiple data channels. Ephus (http://www.ephus.org) is an open-source software package designed for general-purpose data acquisition and instrument control. Ephus operates as a collection of modular programs, including an ephys program for standard whole-cell recording with single or multiple electrodes in typical electrophysiological experiments, and a mapper program for synaptic circuit mapping experiments involving laser scanning photostimulation based on glutamate uncaging or channelrhodopsin-2 excitation. Custom user functions allow user-extensibility at multiple levels, including on-line analysis and closed-loop experiments, where experimental parameters can be changed based on recently acquired data, such as during in vivo behavioral experiments. Ephus is compatible with a variety of data acquisition and imaging hardware. This paper describes the main features and modules of Ephus and their use in representative experimental applications

A toolbox of Cre-dependent optogenetic transgenic mice for light-induced activation and silencing

We report on wide-field optically detected magnetic resonance imaging of nitrogen-vacancy centers (NVs) in type IIa polycrystalline diamond. These studies reveal a heterogeneous crystalline environment that produces a varied density of NV centers, including preferential orientation within some individual crystal grains, but preserves long spin coherence times. Using the native NVs as nanoscale sensors, we introduce a three-dimensional strain imaging technique with high sensitivity (<10[superscript -5] Hz[superscript –1/2]) and diffraction-limited resolution across a wide field of view.Allen Institute for Brain ScienceHoward Hughes Medical Institut

Eating Paradise: Food as Coloniality and Leisure

Sandals Resorts’ Gourmet Discovery Dining programme continues the company’s practice of marketing difference by combining tourism with the commodification of food from non-Western cultures (Dodman and Rhiney 2008). The article draws on bell hooks’ (1992) concept of ‘eating the other’ and the analysis undertakes an interdisciplinary approach that combines visual analysis with Anibal Quijano’s (2007) concept of modernity/coloniality. The discussion explores the trends of global multiculturalism that have been adopted by Sandals in a hybridized cut and mix approach to selling a packaged ideal of the Caribbean. The visual techniques devised to create a culinary holiday package are overlaid onto a manufactured and homogenised or McDonaldized (Ritzer and Liska 1997) Caribbean that provides insight into the way in which global neoliberal multiculturalism is framed by ongoing colonial relations after formal colonial rule has ended in the Caribbean region

Introduction: Toward an Engaged Feminist Heritage Praxis

We advocate a feminist approach to archaeological heritage work in order to transform heritage practice and the production of archaeological knowledge. We use an engaged feminist standpoint and situate intersubjectivity and intersectionality as critical components of this practice. An engaged feminist approach to heritage work allows the discipline to consider women’s, men’s, and gender non-conforming persons’ positions in the field, to reveal their contributions, to develop critical pedagogical approaches, and to rethink forms of representation. Throughout, we emphasize the intellectual labor of women of color, queer and gender non-conforming persons, and early white feminists in archaeology

Long-Range Neuronal Circuits Underlying the Interaction between Sensory and Motor Cortex

SummaryIn the rodent vibrissal system, active sensation and sensorimotor integration are mediated in part by connections between barrel cortex and vibrissal motor cortex. Little is known about how these structures interact at the level of neurons. We used Channelrhodopsin-2 (ChR2) expression, combined with anterograde and retrograde labeling, to map connections between barrel cortex and pyramidal neurons in mouse motor cortex. Barrel cortex axons preferentially targeted upper layer (L2/3, L5A) neurons in motor cortex; input to neurons projecting back to barrel cortex was particularly strong. Barrel cortex input to deeper layers (L5B, L6) of motor cortex, including neurons projecting to the brainstem, was weak, despite pronounced geometric overlap of dendrites with axons from barrel cortex. Neurons in different layers received barrel cortex input within stereotyped dendritic domains. The cortico-cortical neurons in superficial layers of motor cortex thus couple motor and sensory signals and might mediate sensorimotor integration and motor learning

A role for stargazin in experience-dependent plasticity

During development, neurons are constantly refining their connections in response to changes in activity. Experience-dependent plasticity is a key form of synaptic plasticity, involving changes in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) accumulation at synapses. Here, we report a critical role for the AMPAR auxiliary subunit stargazin in this plasticity. We show that stargazin is functional at the retinogeniculate synapse and that in the absence of stargazin, the refinement of the retinogeniculate synapse is specifically disrupted during the experience-dependent phase. Importantly, we found that stargazin expression and phosphorylation increased with visual deprivation and led to reduced AMPAR rectification at the retinogeniculate synapse. To test whether stargazin plays a role in homeostatic plasticity, we turned to cultured neurons and found that stargazin phosphorylation is essential for synaptic scaling. Overall, our data reveal an important role for stargazin in regulating AMPAR abundance and composition at glutamatergic synapses during homeostatic and experience-dependent plasticity