Local Integration accounts for weak selectivity of mouse neocortical parvalbumin interneurons
Dissecting the functional roles of excitatory and inhibitory neurons in cortical circuits is a fundamental goal in neuroscience. Of particular interest are their roles in emergent cortical computations such as binocular integration in primary visual cortex (V1). We measured the binocular response selectivity of genetically defined subpopulations of excitatory and inhibitory neurons. Parvalbumin (PV+) interneurons received strong inputs from both eyes but lacked selectivity for binocular disparity. Because broad selectivity could result from heterogeneous synaptic input from neighboring neurons, we examined how individual PV+ interneuron selectivity compared to that of the local neuronal network, which is primarily composed of excitatory neurons. PV+ neurons showed functional similarity to neighboring neuronal populations over spatial distances resembling measurements of synaptic connectivity. On the other hand, excitatory neurons expressing CaMKIIα displayed no such functional similarity with the neighboring population. Our findings suggest that broad selectivity of PV+ interneurons results from nonspecific integration within local networks.
We characterized visual motion dependence of smooth eye movement in marmosets trained to perform fixation tasks. We found that marmosets naturally pursue small moving targets with some degree of diligence without any further demands on their behavioral conditioning other than their initial fixation training. As seen in other primates, we find that initial pursuit is driven by the direction of target motion, with acceleration amplitude related to the target velocity.
Eye-tracking and Intracellular, Whole-Cell, Current-Clamp
Continuous whole cell current clamp record of Vm from a V1 neuron and eye movements in a behaving primate viewing sinusoidal drifting grating visual stimuli over multiple trials and inter-trial periods.
Pole Descent Cliff Task
In the pole descent cliff task (PDCT), a mouse descends a vertical pole to the glass divided into four quadrants. One quadrant is closer, with a 2.5 cm surface below the cone, whereas the other quadrants had surfaces with adjustable deeper depths. A cone 10 cm in diameter rests at the bottom of the pole on thin metal rails 2 cm above a plate of glass and 2.5 cm above the nearest platform