Regional variation in cholinergic terminal activity determines the non-uniform occurrence of cortical slow waves during REM sleep in mice.

Sleep consists of two basic stages: non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM sleep is characterized by slow high-amplitude cortical electroencephalogram (EEG) signals, while REM sleep is characterized by desynchronized cortical rhythms. Despite this, recent electrophysiological studies have suggested the presence of slow waves (SWs) in local cortical areas during REM sleep. Electrophysiological techniques, however, have been unable to resolve the regional structure of these activities because of relatively sparse sampling. Here, we map functional gradients in cortical activity during REM sleep using mesoscale imaging in mice and show local SW patterns occurring mainly in somatomotor and auditory cortical regions with minimum presence within the default mode network. The role of the cholinergic system in local desynchronization during REM sleep is also explored by calcium imaging of cholinergic activity within the cortex and analyzing structural data. We demonstrate weaker cholinergic projections and terminal activity in regions exhibiting frequent SWs during REM sleep.

Mouse Arm and hand movements in grooming are reaching movements: Evolution of reaching, handedness, and the thumbnail.

Grooming in the mouse features hand licking and symmetric and asymmetric arm and hand "strokes" over the face and body to maintain pelage. Grooming is syntactically organized but the structure of individualized movements of the arm, hand, and tongue have not been examined. Here spontaneous and water-induced grooming was video recorded in free-moving and head-fixed mice and subject to frame-by-frame video inspection and kinematic analysis using Physics Tracker. All groom arm and hand movements had a structure similar to that described for reach-to-eat movements. The movement included the hand lifting from the floor to supinate with the digits flexing and closed to a collect position, an aim position directed to a groom target, an advance to the target during which the fingers extend and open and the hand pronates, a grasp of a target on the snout, nose, or vibrissae, and a withdraw to the mouth where licking occurs, or a return to the starting position. This structure was present in individual unilateral forelimb groom strokes, in bilateral symmetric, or asymmetric groom strokes, and comprised the individuated components of a sequence of groom movements. Reach-to-groom movements could feature an ulnar adduction that positions the ulnar portion of the hand including and the thumb across the eye and nose, a movement that aids Hardarian fluid spreading. It is proposed that the mouse thumb nail is an anatomical feature that minimizes damage to the eye or nose that might be incurred by a claw. This analysis of the reach-to-groom movement provides insights into the flexibility of hand use in adaptive behavior, the evolution of skilled reaching movements, the neural control of reaching movements and the presence of the thumb nail in the mouse.

Quaddles: A multidimensional 3-D object set with parametrically controlled and customizable features.

Many studies of vision and cognition require novel three-dimensional object sets defined by a parametric feature space. Creating such sets and verifying that they are suitable for a given task, however, can be time-consuming and effortful. Here we present a new set of multidimensional objects, Quaddles, designed for studies of feature-based learning and attention, but adaptable for many research purposes. Quaddles have features that are all equally visible from any angle around the vertical axis and can be designed to be equally discriminable along feature dimensions; these objects do not show strong or consistent response biases, with a small number of quantified exceptions. They are available as two-dimensional images, rotating videos, and FBX object files suitable for use with any modern video game engine. We also provide scripts that can be used to generate hundreds of thousands of further Quaddles, as well as examples and tutorials for modifying Quaddles or creating completely new object sets from scratch, with the aim to speed up the development time of future novel-object studies.