{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Decline in testosterone explains drop in male potency

Info iconThis preview shows pages 31–37. Sign up to view the full content.

View Full Document Right Arrow Icon
Decline in testosterone explains drop in male potency. However, there is huge variation and effects of experience appears to be almost as important as hormones.
Background image of page 31

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Fig.?1 Quartiles of testosterone, from lowest (1) to highest (4), and number of female sex partners (raw data ceiled to a 100; 98% of the male sample). Error bars represent 95% confidence intervals. Thomas V. Pollet , Leander van der Meij , Kelly D. Cobey , Abraham P. Buunk Testosterone levels and their associations with lifetime number of opposite sex partners and remarriage in a large sample of American elderly men and women Hormones and Behavior Volume 60, Issue 1 2011 72 - 77 http://dx.doi.org/10.1016/j.yhbeh.2011.03.005
Background image of page 32
Sex and the Brain Males Medial nucleus of amygdala receives important sensory information and sends info to the MPA large olfactory component Lesions reduce sexual behavior Medial preoptic area of the hypothalamus (MPA) is essential for sexual behavior lesions—no sex Specialized region Sexually Dimorphic Nuclei (SDN) Glutamate measured during sexual behavior Receives input from medial amygdala, BNST, & CeTA MPA is connected to the ejaculation generator via the PAG then to the nPGi in the medulla Ejaculation can happen at the level of the spinal cord Neurons that control it are called Lumbar spinothalamic (Lst) cells—called ejaculation generator
Background image of page 33

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Areas of significant BOLD signal increases in male subjects during (brain activation associated with) viewing the erotic film excerpts via subtraction procedure compared emotionally neutral film excerpts. A: Medial prefrontal cortex, anterior cingulate cortex, thalamus and hypothalamus. B: Orbitofrontal cortex. C: Insular cortex. D: Amygdala. E: Ventral striatum and hypothalamus. F: Occipitotemporal cortex. Karama et al 2002 Hum Brain Mapp. 16(1):1-13 FMRI and Sexual imagery: Men
Background image of page 34
Regression map showing significant positive correlation between individual BOLD signal increases in the hypothalamus and individual reported sexual arousal in male subjects. Height threshold is set at P < 0.004 (z = 2.65). Karama et al 2002 Hum Brain Mapp. 16(1):1-13 Male Sexual Arousal and hypothalamic activation
Background image of page 35

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Ejaculation & fMRI Lack of activation in mPOA??? Several discrete cortical structures in frontal, temporal, and parietal, as well as cerebellum are activated during ejaculation. Mesodiencephalic transition zone (mes- di) extends from the rostral midbrain into the ventral parts of the caudal thalamus are activated during ejaculation. Holstege et al 2003 The Journal of Neuroscience, 23(27):9185-9193
Background image of page 36
Male Sexual Behavior Sexual activity increases T in men Beard study Exposure to erotic stimuli increases male T levels
Background image of page 37
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}