Hormones and Behavior Flashcards
Behavioral Neuroendocrinology
“the study of the interaction between hormones and behavior”
why is there an endo emphasis on behavioral neuroendocrinology?
historical accident - the behaviors that were once considered “motivated” are those that are concerned with homeostasis - sex, feeding, drinking, aggression and so on
- hormones are the common thread in these behaviors
define hormone
Chemicals secreted by specialized cells and conveyed to other parts of the body, where they act on specific target tissues to produce specific physiological effects
what do hormones coordinate and how
the physiology and behavior of an animal by regulating, integrating, and controlling bodily functions
gray area in neuroendo
distinction between neurotransmitters and hormones. Some things do both.
4 bodily factors/humors (overall concept?)
phlegm, blood, yellow bile, black bile
- medial concept of what balances to regulate our personality
phlegm
sluggishness (modern use: “phlegmatic = unemotional, calm)
- person is relaxed and thoughtful
blood
sanguinity = social temperament (hot-blooded)
- person is pleasure seeking and sociable
yellow bile
choler = aggressive nervousness (choleric = irritable, cranky)
- anxious and vigilant
- person is ambitious and leader like
black bile
melancholia (biliousness = peevishness or wrathfulness)
- person is analytical and literal
what did aristotle write developmental effects about
of applying hot pokers to testes
capons vs geldings
castrated male chicken vs castrated male horse
eunuchs
castrated males
hijra
AMB that dont identify with any gender
castrati
males castrated pre-puberty to retain an opera like voice: their voice did not drop
pangenesis
concept that bits and pieces of various organs were secreted into the blood and congregated in the gonads to assemble into tiny humans
3 ideas berthold 1849 had as a result of pangenesis
- various bodily sites release agents into the blood
- these agents travel through the blood to particular targets
- the testes were an important part of the process
4 conditions of bertholds experiment
no op, remove both testes, remove 1 teste and implant other in abdomen (disconnect from nerve/blood supply), remove 1 teste and cross implant the other from a stranger
findings of condition 1
normal rooster behavior: aggressive and crow
findings of condition 2
not normal size, crow eventually, TASTY, dont chase hens
findings of condition 3 & 4
normal rooster behavior
why did all of this conditions kind of all work out?
testosterone was the critical need here and it was still secreted in all conditions
brown sequard 1890
a self experiment with testicle extract: rejuvenating elixir
- the contents of a testicle were not isolated for many more decades… 40kg of pig testes gave 20mg T
bayliss and starling 1905
Credited as first to isolate and describe an endocrine factor
- these 2 were the first people to use the name hormone
- described how pancreas works and what is secreted
- started w homeostasis
which endocrine factor did bayliss and starling isolate
Secretin, a gut hormone related to pancreatic secretion
walter cannon 1920s
main homeostasis guy!
- Originator of the notion of an “internal milieu”, regulated by factors now known to be hormones.
- Led to the notion of homeostasis - precise regulation of bodily state, and
integration of internal state with manifest behavior
frank beach 1911
first to realize that hormones contribute
directly to the generation of behavior, not just to structure, or some basic physiological role in homeostasis
- performed many landmark studies of hormones and sexual behavior
which relationship did beach realize was reciprocal
behavior can alter endocrine function
what was beachs book that revolutionized endo
“Hormones & Behavior” (1948)
7 experimental issues in BNE experiments
- objectivity and anthropomorphism
- ecological validity
- behavioral grammar
- field vs lab
- experimental design
- objective measurement
- levels of analysis
- hormone–behavior transactions
- criteria for determining causality
objectivity and anthropomorphism
the way we apply human motives to animals
- hungry, lonely, horny, angry etc
Ecological validity
need to assess the hormone-behavior relationship with reference to the purpose it serves in order to identify all related behaviors and physiological mechanisms
- what is the actual natural response of animals if we are just putting them in labs and running lab experiments
Behavioral Grammar
Need methods for precisely describing the induced behavior, in terms of both the
specific actions that occur AND the consequences of those actions
- E.g. a hormone may cause an animal to drink, but may also cause it to travel (in order to drink) AND may be involved in limiting the
intake of water around a homeostatic set point
field vs lab
field shows validity (complex situation)
- animal tends to show normal behavior in natural settings
lab shows reliability (simple situation)
- you get to control to see exactly what is needed
experimental design
between subjects: fast, no order effects, good in the field
- capture and release
within subjects: statistical power, precision, good in the lab
- compare individuals before and after
treatments: physiological or supraphysiological
- phys = remove testes and give T replacement
- supra = increased effect: give 2-3x the normal dose
objective measurement
a blind observer is required since behavior analysis needs subtle judgements from experimenter; its easy to bias your results
- ex: lordosis ratings
levels of analysis
proximate causation:
- the how questions
- deals w mechanisms & developmental issues
- most common approach in BNE
ultimate/distal causation:
- the why questions
- deals with evolution and adaptive significance of behaviors
- often studied phylogenetically; i.e. comparing closely related species
- If a species is short-lived, can also induce evolution experimentally.
- Examples: bacteria, drosophila, C. elegans
P voles vs M voles
example of phylogenetically study of closely related species
- P voles = monogamous males and females look and behave similar - M voles = polygamous have large ranges that encompass females
how does a short lived species induce evolution
short life span = generative bc hormones are easy to manipulate and its easy to induce mutations
hormone–behavior transactions AND 4 examples
this relationship is bidirectional
- change in energy leads to estrus
- change in oxytocin leads to milk production
- losing a fight leads to decreased T
- nipple stimulation leads to increased oxytocin
3 criteria for determining causality
- removal of hormone leads to target behavior ceasing or reducing greatly
- restoration of hormone leads to behavior resuming
- hormone levels and target behavior should be found to covary
problems with criteria 1
- redundancy: remove 1/3 and others have to make up for it.. redundant
- mediation/moderation: hormone may work indirectly by mediating some other effect in body / might need a 2nd hormone to work
- joint causality: 2 hormones have to be present jointly in order for effect to happen – 2 sex hormones needed in partners for sexual behavior to happen
problem with criteria 2
critical period problem
- hormones might only act on critical periods. casteration early in life can result in no display of sexual behavior ever, despite # of T shots
- puberty = critical period
problem with criteria 3
time course problem
- T and aggression covary: if one goes up so should the other
- dont know the time course of hormones: steroids take time to work because of the process of gene expression
- how long are you meant to wait?
the main action of hormone
alter gene expression
gene
a length of DNA (on
chromosomes) that codes for a particular
protein
protein
is a chain of amino acids, a peptide is a short chain; code for specific proteins
steroid
has 4 rings (3 6-carbon rings, and a 5-carbon ring) and is constructed from cholesterol by enzymes.
