Key points• Sensory neurons that detect painful and non-painful stimulation of body tissues have axons that project to the dorsal horn of the spinal cord, where their terminations are partially segregated into superficial (I-II) and deep (III-IV) dorsal horn laminae, respectively.• The dorsal horn contains many excitatory and inhibitory interneurons whose axons synapse on other dorsal horn neurons to enhance or suppress sensory transmission.• This study used a localized stimulation technique (laser scanning photostimulation) for high-resolution mapping of synaptic connections between dorsal horn interneurons, in an in vitro 'slice' preparation of the mouse lumbar spinal cord.• Some neurons in superficial layers of the dorsal horn have long dendrites that extend ventrally into deeper layers of the dorsal horn, and these neurons can receive excitatory or inhibitory synaptic input from neurons in the deeper layers.• These interlaminar connections may be involved in interactions between transmission of signals underlying painful versus non-painful sensations.Abstract The primary goal of this study was to map the transverse distribution of local excitatory and inhibitory synaptic inputs to mouse lamina I spinal dorsal horn neurons, using laser scanning photostimulation. A sample of lamina II neurons was also studied for comparison. Lamina I neurons received excitatory synaptic input from both laminae I-II and the outer part of III-IV, especially the II/III border region, while the inhibitory input zones were mostly confined within I-II. The excitatory synaptic input zones showed a pronounced medial asymmetry, which was correlated with a matching asymmetry in the dendritic fields of the neurons. Inhibitory input from laminae III-IV was found in a subpopulation of neurons occupying a highly restricted zone, essentially one cell layer thick, immediately below the lamina I/II border, with morphological and physiological properties that were distinct from other laminar populations in the superficial dorsal horn, and that suggest a critical role in interlaminar communication. This subpopulation also received excitatory input from laminae III-IV. Within this subpopulation, inhibitory III-IV input was correlated with the presence of long ventral dendrites. Correlations between the distribution of synaptic input zones and dendritic fields support the concept that interlaminar communication is mediated in part via contacts made onto ventrally extending dendrites of superficial laminae neurons. The results point to the presence of cell type specificity in dorsal horn circuitry, and show how the study of connectivity can itself help identify previously unrecognized neuronal populations.

Nanoscale deterministic lateral displacement (nanoDLD) has emerged as an effective method for separating nanoscopic colloids for applications in molecular biology, yet present limits in throughput, purification, on‐chip filtration, and workflow restricting its adoption as a practical separation technology. To overcome these impediments, array scaling and parallelization for integrated nanoDLD (i‐nanoDLD) enrichment devices are developed to achieve a density of ≈83 arrays mm−2 with 31 160 parallel arrays, producing an ≈30‐fold concentration of the target colloid and a record throughput of 17 mL h−1. Purification using a dual‐fluid input embodiment of i‐nanoDLD is demonstrated to successfully remove background contaminants from target colloid samples, including urine. Used serially, high‐throughput enrichment and purification chips achieve >1700 gain in particle over protein concentration compared to input sample. Additionally, integration of upstream filter banks shows improved operation lifetime > 7× for particles with diameters close to the gap size. Finally, the integrated design and associated flow rates allow a straightforward approach to chip‐to‐world interfacing as demonstrated using a prototype system for facile, turn‐key sample processing. Collectively, these developments advance nanoDLD into the range of sample volumes and process times needed for research and clinical samples.

We examined the dynamics of the spectral powers and indices of frequency components of background field electrical activity recorded from tropho-and ergotropic zones of the rat hypothalamus (electrohypothalamogram, EHtG) in the course of long-term (21 weeks) emotional stress induced by a zooconflict situation. Lowfrequency delta-range (0.5 to 3.5 Hz) oscillations dominated in EHtGs recorded from both hypothalamic zones of both control and stressed animals. The integral power of EHtG oscillations underwent significant changes within the observation period; it considerably increased on the 6th to 9th week, dropped within the 12th to 18th week, and, after this (up to the 21st week) again increased, i.e., the dynamics, in general, were threephase. The dynamics of the power of separate frequency components of EHtG showed certain similarities to the dynamics of the integral power. Changes in the EHtG power in stressed animals were characterized by a shorter duration and greater rate; the powers of all EHtG components in these animals were lower than in control ones within a greater part of the observation period. The dynamics of the normalized powers and of the indices of different EHtG rhythms in stressed and control animals, especially the dynamics of dominating oscillations of the delta and theta ranges, were to a certain extent opposite. Our data show that changes in the EHtG can be electrographic correlates of subsequent phases of a long-lasting stress reaction of the organism in the course of the experiment; specific features of manifestation of these modifications in the tropho-and ergotropic hypothalamic zones are related to a certain specificity of the hormonal/transmitter mechanisms in the structures under study.

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