Figure 4
Summary heat maps illustrating micturition changes due to spinal cord epidural stimulation (scES). Heat maps showing void volumes (ml) from all intact female (IF, A), T9 transected female (STxF, B), intact male (IM, C), and T9 transected male (STxM, D) groups of Wistar rats. Void volume data with scES (Stim ON, left column) and without scES (Stim OFF, right column) at L5-S1 are provided. Each map is subdivided into low/high frequency and intensity quadrants (Q1-4) with micturition volume ranges indicated to the far right (dark blue—low; dark red- high). Intact female rats (A) have a reduced volume due to suppression of the bladder to contract with Stim ON (left Q3; higher intensities and frequencies), although some volume is still generated due to overflow incontinence. A bladder contraction and void occur upon offset of scES (right side of A, Q3), reflected by the larger volumes. At lower intensities but higher frequencies (Q2), significantly higher volumes are generated, relative to Stim OFF, other Stim ON parameters (Q1,3,4), and the transected female group (Q2, B). Unlike the IF group, STxF animals void immediately at the onset of higher intensity and frequency scES (Q3 in B). Note that the higher micturition volumes post-transection (B, Q3) reflect over-distended bladders. The same general patterns were seen for males and the low micturition volumes in male rat’s post-transection reflects the acontractile condition (presence of overflow incontinence; see “Discussion”). Overall group void volume differences, regardless of frequency/intensity, were IF > STxF (for both Stim ON and OFF), IM > STxM (for both Stim ON and OFF), IF > IM (Stim ON only) and STxF > STxM (Stim ON and OFF). These differences reflect larger volumes for intact relative to injured animals regardless of sex, and greater void volumes in females. Between quadrant group statistical differences demarcated by placement of a black or white lowercase letter in the greater area are (a) IF > STxF; (b) STxF > IF; (c) IM > STxM; (d) IF > IM; and (e) STxF > STxM. Within group differences are (f) Q2 > Q1,3 and Q2 On > Off; (g) Q3 > Q1,2,4 and Q3 On > Off.
