Journal: Frontiers in Neural Circuits

Article Title: Divisive Inhibition Prevails During Simultaneous Optogenetic Activation of All Interneuron Subtypes in Mouse Primary Visual Cortex

doi: 10.3389/fncir.2019.00040

Figure Lengend Snippet: Optogenetic modulation of V1 neurons in transgenic mice. (A) Diagram of the proposed wiring of V1 local interneuron circuits described using in vitro methods (Pfeffer et al., ; Crandall and Connors, ; Karnani et al., ). Pyramidal neurons (Pyr; black), and interneurons expressing parvalbumin (Pvalb+; red), somatostatin (SOM+; teal), and vasoactive intestinal peptide (VIP+; purple) are connected with electrical synapses (Gap) as well as GABAergic (GABA) and cholinergic (Ach) chemical synapses. (B) Spike Density Functions (SDFs) and rasters for a putative pyramidal neuron's response to drifting square wave gratings with (azure) or without (black) LED illumination. (C) Two photostimulated Pvalb+ neurons recorded in PvAi32 mice in the same format as (B) . The SDFs and rasters for the top neuron show low intensity photostimulation elevated firing while maintaining important temporal features of visually evoked responses (see Methods), as well as eliciting several low latency spikes. The spike traces and rasters for the bottom neuron illustrate robust and low latency firing evoked by high intensity photostimulation (which was not used in the main dataset). For the example cells in (B) and (C) , the timing of photostimulation (LED; light blue bar) and the visual stimulus (Visual; thick black line depicting the change in luminance of a point on the monitor over time) are shown above the SDFs or spike traces. Shaded regions on the SDFs in (B) and (C) indicate SEM. (D) Scatter graphs showing recording depths for VGAT (blue) and PvAi32 (red) transgenic mice. Approximate layer boundaries are indicated on the right vertical axis (Lein et al., ). Histograms indicating cell count distribution across approximate cortical layers are shown inset.

Article Snippet: The mouse primary visual cortex (V1) has become an important brain area for investigating how local interneuron circuits shape cortical information processing thanks in part to the array of genetic tools available in this species (e.g., Hübener, ; Callaway, ; Luo et al., ; Huberman and Niell, ), and the foundation of knowledge from classic work in cats and primates (e.g., Hubel and Wiesel, ; Movshon et al., , ; Carandini et al., ; Tong, ; Espinosa and Stryker, ).

Techniques: Transgenic Assay, In Vitro, Expressing, Cell Counting

Journal: The Journal of Neuroscience

Article Title: How Attention Enhances Spatial Resolution: Preferential Gain Enhancement of High Spatial Frequency Neurons

doi: 10.1523/JNEUROSCI.2691-16.2016

Figure Lengend Snippet: Spike generation is controlled by a generator potential (x-axis) along a spiking nonlinearity, resulting in mean firing rates being proportional to the gain, which is represented by the slope of the linear fits (solid lines). Low- and high-spatial-frequency neurons (dots) exhibited a similar firing rate increase during locomotion (Δratehigh == Δratelow) but had different operating points (ratehigh ≪ ratelow). Given this difference, a shift in the operating point of V1 neurons along the spiking nonlinearity between rest and locomotion preferentially enhanced the relative gain of high-spatial-frequency neurons, heightening resolution.

Article Snippet: During active locomotion, neurons in the mouse primary visual cortex (V1) show increased firing rates and enhanced gain associated with higher arousal ( Niell and Stryker, 2010 ).

Techniques: