PMC

A, Conceptual model of dynamic elasticity with competing mechanisms for regulating detrusor wall tension. Passive mechanisms (stretch due to filling or geometry changes) cause strain softening by breaking actin-myosin cross bridges leading to lower wall tension during the next fill. Active contractions (voiding or nonvoiding detrusor overactivity) reverse strain softening by re-establishing actin-myosin cross bridges leading to increase wall tension during subsequent filling. B, Comparative-fill urodynamics protocol. Following a setup fill and active void (solid arrow), fill 1 was to 40% capacity and emptied by syringe aspiration (dashed black arrow). Fill 2 was to ~100% capacity and followed by an active void. Fill 3 was to 40% capacity. Vesical pressures (P_ves) were measured between 0% and 40% capacity for fill 1 (blue line—before strain softening—SS]), fill 2 (red line—after strain softening due to fill 1), and fill 3 (green line —after active void—AV])

Schematic representations of contrasting preservational styles for sand-filled open burrows constructed in a muddy/silty sediment. (A) Passive fill of an open burrow in which burrow fill is continuos with source of casting sediment. (B) Passive fill in which there is a distinct break between the burrow fill and overlying sediment (adhering preservation of ref. ). (C) Passively filled burrow that is surrounded by silty sediment (floating preservation of ref. ).

Example vesical pressure data for a volume range of 0–30% of cystometric capacity from a comparative-fill urodynamics protocol (). The “control” fill was completed following a fill to capacity and an active void. The subsequent “softened” fill was completed following a fill to 60% of capacity and passive emptying via syringe aspiration. The subsequent “reversed” fill was completed following a fill to capacity and an active void. These data demonstrate dynamic elasticity characterized by decreased filling pressure following a fill-passive emptying cycle to soften the bladder and increased filling pressure following a fill-active void cycle to reverse strain-induced stress softening.

Comparison of sensory and attempted movement responses. PSTH and rasters were calculated from passive joint manipulations (green) and attempted movement (black outline with no fill) of the same joint and same direction of the passive manipulation. The movement direction is indicated above each raster and PSTH. A: responses of a unit in session 2 (C42U1) that was unresponsive during passive manipulation but responded strongly to attempted movement. Each subpanel shows the result of 10 trials of each attempted and passive movement. B: responses from a unit (C75U1) in session 1 showing differential responses to passive and attempted movement. In this session only 5 movements were attempted, and there were only 5 trials of each passive movement and 8 trials of each attempted movements. C: responses of a unit in session 2 (C13U2). D: responses from a unit in session 1 (C83U2). Both the units in C and D show very similar responses to passive and attempted movement.