Transcript SEX: Alt - UCSD Cognitive Science

Sex:
The Altered State of
Consciousness
COGS 175, June 5th 2006
Part I:
Cody Frew, Rachel Jaffe, Rajiv Rao
Part II:
Katie Frehafer, Dan Hoag, Josh Kirsch, Brian Waldberg
Topic Outline
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Group I
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Intro - Cody, Rachel, Rajiv
Neurochemicals - Rachel
Arousal Pathways - Rajiv
Hormones / Baseline States - Cody
Group II
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Pheromones / Attraction - Josh
Biological Changes - Katie
Sexual Abnormalities - Brian
Masochism – Dan Hoag
Conclusion – Josh, Katie, Brian, Dan
Warning:
contains explicit material
Introduction
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Is sex an altered state of consciousness?
Yes…
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Many changes take place during sexual arousal
and intercourse that deviate from the normal
waking state of consciousness.
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Neurochemical changes
Hormonal changes
Changes in brain activation
Changes in the biological state of the body
Social behavior and interactions that are limited to
sexual states
Neurochemicals of Sex
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Neurotransmitters and Neuropeptides involved in
sexual function
 Nitric Oxide (NO)
 Serotonin (5-HT)
 Dopamine (DA)
 Epinephrine
 Norepinephrine (NE)
 Opioids
 Acetylcholine (Ach)
 Histamine
 γ-Aminobutyric Acid (GABA)
Nitric Oxide (NO)
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Key factor in production of penile/clitoral vasocongestion
and tumescence.
Sexual stimulation  NO production  Guanylate Cyclase
Guanosine Triphosphitase (via Guanylate Cyclase) 
cGMP
cGMP: relaxation of smooth muscles genital arteries
resulting in increased blood flow to those areas.
cGMP is metabolized by cyclic nucleotide
phosphodiesterase isoenzymes.
As long as stimulation continues, metabolic degradation is
balanced by production and arousal is maintained.
Serotonin (5-HT)
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Selective Serotonin Reuptake Inhibitors (SSRIs) effects 5HT activity and causes sexual side effects.
Increased 5-HT causes decreased libido.
5-HT2 receptor stimulation impairs sexual functioning.
5-HT1a receptor stimulation facilitates sexual functioning.
95% of 5-HT receptors are located in the periphery of the
body.
Peripheral 5-HT acts on:
 smooth muscle vasodilation/vasoconstriction, including the
smooth muscle of the genitals.
 peripheral nerve functions, including those of the sexual
organs.
Dopamine (DA)
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DA facilitates male sexual behavior
D1 and D2 receptor agonists increase sexual
activity and induces erection.
Common DA agonists: Apomorphine and L-Dopa
Moderate doses of cocaine, which blocks the
reuptake of DA, can increase sexual pleasure, but
also inhibit sexual behavior in the withdrawal
phase.
Epinephrine
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Adrenergic activity has a role in maintaining the
penis in a flaccid state and reducing swelling.
Blockade of the α1-adrenergic receptors produces
erection.
Adrenergic agonists, like Ephedrine, increase
vaginal pulse amplitudes in response to erotic
stimuli.
Adrenergic system activates when sexual arousal
begins, and epinephrine increases until its peak at
orgasm.
Norepinephrine (NE)
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Blood plasma levels of NE increase during sexual
activity.
NE levels positively correlate with arousal,
peaking at orgasm and then returning to baseline.
NE levels return to baseline within minutes for
males, while it can take up to 23 hours for
females.
Opioids
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Role in sexual function is studied by looking at:
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Endogenous opioids (endorphins, enkephalins,
dynorphins).
Narcotics (opiates)
Abuse of opiates leads to sexual difficulties.
Opioid anatogonists (naloxone and naltrexone)
used to treat erectile dysfunction.
Exact role of endogenous opioids in normal
sexual functioning is unclear, but levels are
thought to increase during sexual activity.
Acetylcholine (Ach)
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Ach is involved in the sexual function of males
much more than females.
Ach stimulates the cholinergic receptors in the
penile tissue to act as a key factor in producing
erection.
Penile erection is controlled by the Ach levels in
the CNS, regardless of cholinergic receptors in
the periphery.
Histamine
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Histamine antagonists tied to loss in libido.
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Due to decrease in uptake of testosterone.
Administering histamine counters some cases of
impotence.
Possible action on H2 and H3 receptors.
γ-Aminobutyric Acid (GABA)
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Effects only studied in male rats
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Inhibits sexual behavior (mounting, intermitting,
erection, ejaculation)
Possibly correlates to GABA effects in human
sexual function.
Arousal Pathways
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Connectivity in the Brainstem and Spinal
Cord
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Neurological Substrates Involved in
Sexual Activity and Arousal
Arousal Pathways
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Connectivity in the Brainstem and Spinal Cord:
o
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The Nucleus Paragigantocellularis → lumbosacral
spinal cord of both males and females.
lumbosacral spinal cord → ascending reticular
activating system.
The Raphe Nuclei (5-HT) → lumbosacral spinal cord
Magnus and Parapyramidal regions → lumbosacral
spinal cord
Locus Ceruleus (NE) → lumbosacral spinal cord
Arousal Pathways
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Connectivity in the Brainstem and Spinal Cord
(continued):
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Further evidence shows that the Periaqueductal Grey
Area of the midbrain acts as a relay center for sexually
relevant stimuli.
Arousal Pathways
Arousal Pathways
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Neurological Substrates Involved in Sexual
Activity and Arousal
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Hypothalamus
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Lesions to the Medial Preoptic area
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The Paraventricular Nucleus (PVN) of the hypothalamus
shows activation in both sexes during copulation in rats.
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Oxytocin precursors released from PVN
Arousal Pathways
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Neurological Substrates (continued)
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Medial Amygdala
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Bed Nucleus of Stria Terminalis
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EEG studies have shown that right-to-left hemispheric
asymmetry occurs during nocturnal penile tumescence.
Arousal Pathways
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Neurological Substrates (continued)
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Right prefrontal cortex activity during the viewing of sexual
stimuli.
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Bilateral rCBF increases in the inferior temporal cortex, right
insula, right inferior frontal cortex, as well as the left anterior
cingulate cortex.
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Largest rCBF increase occurred in cerebellum
Arousal Pathways
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Neurological Substrates (continued)
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Activation of the mesodiencephalic transition zone, as well as the
ventral tegmental area during ejaculation in males.
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Activation in midbrain lateral central tegmental field
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Zona incerta, subparafascicular nucleus, and the ventroposterior,
midline, and intralaminar thalamic nuclei (all to a lesser extent than
the ventral tegmental area).
Hormones/Baseline states
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“Hormone” – Greek for “to activate”
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What do hormones have to do with sex and
the altered state of consciousness?
Hormones/Baselines
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Endocrine System
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Anatomy:
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Adrenal glands
Pituitary gland
Hypothalamus
Testes (male)
Ovaries (female)
Placenta (pregnancy)
Seen in all mammals- Must be important to
survival.
Hormones/Baselines
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What are some of the hormones related to the ASC
of sex?
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Pituitary hormones
 Gonadotropins
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Prolactin
 Oxytocin
Adrenal hormones
 Androgens
 Estrogens
 Steroids
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Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Hormones/Baselines
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Hormones play a vital role in overall mood,
arousal, desire, coitus, and even post-coital
behavior
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E.g. Oxytocin – the “cuddle” hormone
Hormones/Baselines
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How do hormones play a role in brain
function, sex, and consciousness?
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Constant interaction within endocrine system and
brain
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Hypothalamus Feedback Mechanism
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Gn-RH
Gn-IH
Excessive estrogen ↓ sexual desire (both M & F)
Testosterone ↑ sexual desire (both M & F)
Hormones/Baselines
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Hormone Configurations/Baseline States
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Effect on Cognition
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higher testosterone levels has been correlated with
higher performance on spatial intelligence tasks, but
lower performance on verbal intelligence tasks.
Hormones/Baselines
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Timelines:
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Lifetime (male- testosterone):
Hormones/Baselines
Monthly (female):
Daily (male):
Males seem to have higher
levels of testosterone in the
morning, compared to the rest
of the day.
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Different hormonal states are
constructed that serve as baselines
for motivation, perception, cognition,
and behavior.
Hormones/Baselines
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Gender Differences
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Same chemicals but different:
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Amounts
Proportions
Physical anatomy!
The Female Brain
The Male Brain
Hormones/Baselines
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Questions…
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Who controls sexual behavior? Is it you or your
hormones???
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The hypothalamus monitors and helps maintain
various hormone levels within the body that is deemed
appropriate… but who tells the hypothalamus what is
appropriate?!?
Is it possible to moderate your hormones with
deliberate conscious thought?
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Biofeedback perhaps!
Works Cited (Group I)
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Arnow, Bruce et. al. “Brain activation and sexual arousal in healthy, heterosexual males” Brain.
Vol. 125, No. 5, 1014-1023, May 2002. http://brain.oxfordjournals.org/cgi/content/full/125/5/1014
Holstege, Gert et. al. “Brain Activation During Male Ejaculation.” The Journal of
Neuroscience, October 8, 2003, 23(27):9185-9193
http://www.jneurosci.org/cgi/content/full/23/27/9185
McKenna, K. “The Brain is the master organ in sexual function: CNS control of male and female
sexual function.” Int. J Impot. Res. 1999;11 (suppl 1):S48-S55
Meston, Cindy et. al. “The Neurobiology of Sexual Function” Arch Gen Psychiatry, Vol. 57.
American Medical Association. Nov 2000.
http://www.usfca.edu/fac_staff/dever/neurobiologyofsex2.pdf
Fundamental Neuroscience, 2nd edition. Ch. 35, p. 928-933. Ch. 40, p. 1031-1036. Academic
Press, San Diego, 2003.
Allgeier, ER, Allgeier, AR. Sexual Interactions, 5th Edition. Houghton Mifflin Company, Boston,
New York. 2000.
Gangestad S.W., et al. “Women's Preferences for Male Behavioral Displays Change Across the
Menstrual Cycle.” Psychological Science, Volume 15, Number 3, March 2004, pp. 203-207(5)
Christiansen, K., & Knussmann, R. “Sex hormones and cognitive functioning in men.“
Neuropsychobiology, 18: 27 - 36. 1987
Sanders, R. “Brain hormone puts brakes on reproduction.” February 2006.
http://www.berkeley.edu/news/media/releases/2006/02/06_hormone.shtml