Article Figures & Data
Figures
- Figure 1.
Protocol for the ejaculation condition. The bold black line shows a typical time-activity curve. Vertical lines indicate time frames of 10 sec. Ejaculation took place within the early phase of the time-activity curve, as indicated by gray shading. kcps, Kilocounts per second.
- Figure 2.
So-called glass brains for ejaculation minus stimulation. Activations are shown in a sagittal, coronal, and horizontal orientation.
- Figure 3.
Strong activation in the mesodiencephalic transition zone. Increased rCBF is represented in coronal sections (a-h) through the brain. The red lines on the glass brain on the left indicate the orientation and location of the sections. Activations are superimposed on the averaged MRI of the volunteers. The activated cluster contains the VTA (sections a-d). The midline thalamic nuclei are located slightly more caudally (sections d-f). The lateral central tegmental field (lctf; sections c-f) and the zona incerta are located lateral to this area. The activated region extends dorsally into the intralaminar nuclei (intralam. nucl.; sections d-h) and the ventroposterior thalamus. Note also the activation in the medial pontine tegmentum (pt; sections g and h). y = -14 (means 14 mm posterior to the anterior commissure). r, Right side.
- Figure 4.
Increased rCBF is represented in oblique (45°) sections (a-d) through the brain, to enable comparisons with sections obtained in experimental animals. The red lines on the glass brain on the left indicate the orientation and location of the sections. Activations are superimposed on the averaged MRI of the volunteers. The activated cluster contains the VTA (sections a-d). r, Right side.
- Figure 5.
Activations in the basal ganglia and the anterior nucleus of the thalamus and absence of activation in the hypothalamus. Increases in rCBF are superimposed on the averaged MRI of the volunteers and are depicted in coronal sections (see the red lines on the glass brain on the left). Activations are found in the lateral putamen and perhaps the laterally adjoining claustrum and insula (cp; sections a-c). Note that in sections c and d, the anterior nucleus (na) of the thalamus is on the right side. Sections (b-d) demonstrate that in the hypothalamus (hyp) no activation is found. y = -6 (means 6 mm posterior to the anterior commissure). r, Right side.
- Figure 6.
Activations in the cerebral cortex rendered onto a standard anatomical template (SPM99). Note that the cortical activations are almost exclusively on the right side.
- Figure 7.
Sagittal view of the activations in midline cortical structures, the mesodiencephalic transition zone, and the cerebellum. Increased rCBF is represented in sagittal sections, of which the location is indicated by the red lines on the glass brain on the left. Activations are superimposed on the averaged MRI of the volunteers. In b and c, activation in the secondary visual cortex (BA 18) and posterior cingulate/precuneus (BA 23/31), respectively, can be found. Note in sections a-c that the activation in the mesodiencephalic transition zone (mes-di) extends from the rostral midbrain into the ventral parts of the caudal thalamus. x = -12 (means 12 mm left to the intercommissural line).
- Figure 8.
Activations in the cerebellum, brainstem, and occipital cerebral cortex. Increases in rCBF are superimposed on the averaged MRI of the volunteers and are depicted in oblique (45°) sections (see the red lines on the glass brain on the left). Cerebellar activations can be observed in the vermis (v; sections b-h), the cerebellar hemispheres (ch; sections d-h), and the deep cerebellar nuclei (dcn; sections b-d). Note that activation in the cerebellar hemisphere is more pronounced on the left than on the right side. Brainstem activation is present in the medial pontine tegmentum (section a), the lateral pontine tegmentum (sections b and c), and in a region possibly involving the dorsal vagal nuclei and the solitary complex (sections f and g). pt, Pontine tegmentum; r, right side.
- Figure 9.
Deactivation in the anterior part of the left medial temporal lobe, comprising parts of the amygdala and entorhinal cortex (entorhin.). Decreases in rCBF are superimposed on the averaged MRI of the volunteers and are depicted in coronal sections (see the red lines on the glass brain on the left). The significance threshold was p < 0.001 (uncorrected for multiple comparisons). y = -2 (means 2 mm caudal to the anterior commissure).
Tables
Ejaculation 1 Ejaculation 2 Volunteer Seconds after T0 Frames Seconds after T0 Frames 1 51 5 + 6 2 3 73 4 71 5 35 3 + 4 32 3 + 4 6 74 48 4 + 5 7 55 5 + 6 60 6 + 7 8 60 6 + 7 9 10 34 3 + 4 11 Each volunteer tried to ejaculate twice (left and right column). The moment of ejaculation is measured in seconds after tracer injection (T0), and the selected time frames are shown. When volunteers ejaculated >70 sec after T0, the corresponding time frames were not included in the present study.
- Table 2.
Stereotaxic (Montreal Neurological Institute) coordinates of increases and decreases in rCBF during ejaculation compared with penile stimulation
Coordinates Side Brain region x y z z-score Activations Brainstem Right Medial pontomesencephalic tegmentum 2 −28 −22 5.80 Left Lateral pontine tegmentum −18 −14 −34 6.69 Right Lateral pontine tegmentum 14 −28 −30 5.28 Midline Dorsal medulla (solitary complex) 0 −46 −50 5.48 Thalamus/midbrain Left Mesodiencephalic junction −8 −24 0 7.75 Right Mesodiencephalic junction 12 −24 0 6.53 Right Anterior thalamus 12 −4 6 6.03 Basal ganglia Right Claustrum/insula 34 14 −8 6.21 Left Claustrum/putamen −32 6 4 6.28 Right Claustrum/putamen 32 6 0 6.50 Right Putamen 20 4 8 5.38 Cortical areas Left Inferior occipital gyrus (BA 18) −2 −100 −4 5.20 Right Lingual gyrus (BA 18) 4 −86 −12 6.22 Midline Lingual gyrus (BA 18) 0 −92 −6 5.74 Right Precuneus/post. cingulate (BA 31/23) 16 −62 24 6.38 Right Precuneus (BA 7) 8 −54 50 6.05 Right Supramarginal gyrus (BA 40) 52 −48 28 7.70 Right Inferior parietal lobule (BA 40) 28 −38 50 5.39 Right Paracentral lobule (BA 5) 18 −26 58 5.93 Right Frontal dorsal gyrus (BA 6) 16 4 60 5.88 Left Superior/medial frontal gyrus (BA 6) −30 −4 64 5.61 Right Superior temporal gyrus (BA 39) 54 −60 36 7.05 Right Temporal operculum (BA 42) 52 −28 12 6.20 Right Inferior temporal gyrus (BA 20/21) 64 −6 −32 6.33 Right Insula 44 14 12 5.54 Right Inferior frontal gyrus (BA 47) 54 44 −12 7.03 Right Inferior frontal gyrus (BA 47) 56 38 −6 6.71 Cerebellum Left Deep cerebellar nuclei −6 −44 −24 5.88 Left Deep cerebellar nuclei −8 −52 −30 5.31 Left Vermis −4 −88 −28 5.33 Right Vermis 2 −58 −4 6.61 Right Vermis 2 −66 −32 6.47 Left Hemisphere −34 −58 −40 7.38 Left Hemisphere −30 −84 −34 7.19 Right Hemisphere 32 −68 −46 6.55 Deactivations Left Entorhinal cortex −16 0 −38 4.34 Left Entorhinal cortex −18 10 −32 3.91 Left Amygdala −18 2 −24 3.34 The height threshold for activations was t = 6.09 (p < 0.01; corrected for multiple comparisons) and for deactivations t = 3.21 (p <0.001; uncorrected for multiple comparisons; extent threshold 8 voxels). Activations and deactivations are reported in the table as z-scores (conversion of t statistics to normal distribution). After transformation to Talairach coordinates, the cortical regions were identified using the Talairach atlas (Talairach and Tournoux, 1988). The thalamic and rostral midbrain structures were identified according to the stereotactic atlas of the human brain by Mai et al. (1997).
