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Behavioral analysis
Phenotype
=
Genotype
X Environment
PHENOTYPE – the observable or measurable properties and
characteristics of an individual as produced by its genotype and the
environment
GENOTYPE – the genetic make-up of an individual (the one that you’re born
with and the one that is operating at a particular moment)
ENVIRONMENT – broadly defined: ambient conditions, developmental
conditions, social conditions, internal milieu
GENE-ENVIRONMENT INTERPLAY:
Gene-environment correlation; Gene-environment interaction
DEFINITION OF BEHAVIOR
Behavior seen as a function of an
organism's environment BEHAVIORISM
Behavior seen as a function of an
organism's mental processes –
COGNITIVE SCIENCE
Behavior seen as a function of an
organism's biology –
NEUROSCIENCE,
BEHAVIORAL GENETICS
BEHAVIORAL
GENETICS
GENETIC AND EPIGENETIC THEORIES OF
INFORMATION PROCESSING
DNA
DNA
RNA
RNA
Proteins
Proteins
Epigenetic networks
(open)
FUNCTION
FUNCTION
MOLECULAR NEUROSCIENCE
BEHAVIORAL GENETICS – WHAT IS IT ALL ABOUT?
Research in behavioral genetics examines the effects of
genotype and environment on a range of phenotypic traits
such as anxiety, intelligence, sexual orientation, antisocial
behavior etc.
•Gene for aggression
•Gene for homosexuality
•Gene for memory
•Gene for fear…
WHO ARE THE SUBJECTS OF STUDY?
HUMANS – families; twins: mono-/dizygous, reared
together or apart; isolated populations
ANIMALS – rodents, flies, fish, nematodes
- normal, genetically segregating populations
- selected lines
- inbred strains (incl. recombinant and congenic strains)
- genetically altered animals (gene amplification, knock-out,
mutagenesis)
How to correlate behaviors
with gene functions?
Behavioral analysis of mutants?
GENETIC APPROACHES TO BRAIN-BEHAVIOR
RELATIONSHIPS
REVERSE GENETICS – genotype driven
FORWARD GENETICS – phenotype driven
The ethics of animal use
• Utilitarianism: the view that an action is
right if and only if it produces a better
balance of benefits and harms than
available alternative actions
• Consider the “U.S. Government
Principles for the Utilization and Care of
Vertebrate Animals Used in Testing,
Research, and Training”
U.S Government Principles (summary)
• Procedures involving animals should be designed and performed
with due consideration of their relevance to human or animal
health, the advancement of knowledge, or the good of society.
• The animals selected for a procedure should be of an appropriate
species and quality and the minimum number required to obtain
valid results. [Alternative] methods…should be considered.
• Proper use of animals, including the avoidance or minimization of
discomfort, distress, and pain when consistent with sound
scientific practices, is imperative.
• Procedures with animals that may cause more than momentary or
slight pain or distress should be performed with appropriate
sedation, analgesia, or anesthesia.
• Animals that would otherwise suffer severe or chronic pain or
distress that cannot be relieved should be painless killed at the
end of the procedure or, if appropriate, during the procedure.
U.S Government Principles (continued)
• The living conditions of animals should be
appropriate for their species and contribute to
their health and comfort….veterinary care shall
be provided as indicated.
• Investigators and other personnel shall be
appropriately qualified and experienced for
conducting procedures on living animals.
• …exceptions…should be made by…an
appropriate review group such as an IACUC
The three “R’s”:
a consensus in the research community
•Reduce
•Refine
•Replace
www.jax.org/phenome
Paigen K, Eppig JT. A mouse phenome project.
Mamm Genome. 2000 Sep;11(9):715-7.
Moldin SO et al. Trans-NIH neuroscience
initiatives on mouse phenotyping and
mutagenesis. Mamm Genome. 2001
Aug;12(8):575-81.
Grubb SC et al. A collaborative database of
inbred mouse strain characteristics.
Bioinformatics. 2004 Nov 1;20(16):2857-9.
IACUC
• Must have at least a laboratory animal veterinarian, a
scientist, and a community member not affiliated with the
institution and who does not use animals in research
• Reviews all facilities and programs twice a year;
identifies and ensures correction of any deficiencies
• Reviews “Protocols”, the researcher’s or teacher’s
proposal for animal use
• Monitors animal use; can suspend any animal activity
that does not meet standards
The protocol review
process (simplified)
IACUC Protocol Review
• Does the research address an important
question?
• Does the research require the use of animals?
• Is the research necessary, in that it does not
needlessly repeat previous work?
• Is the experience of each animal in the study
adequately described and justified?
Factors control behaviors
The three “E’s”:
• Epigenetic factors
• Environmental factors
• Experimenter
Epigenetic sources of behavioral differences in mice
(Francis DD et al. Nat Neurosci 6:445-6, 2003)
Crabbe JC and Phillips TJ (Nat Neurosci 6:440-2, 2003) Mother nature meets mother nurture
Intrauterine position in mice according to
number of flanking males (0M to 2M).
In mice, 2M fetuses are exposed to a higher level of
androgens than 1M or 0M. Females adjacent to males
become partially masculinized in their behavior, and 2M
fetuses, both male and female, show increased body
weight, greater aggression and territoriality, and
enhanced male traits including reproductive behavior
(Ryan & Vandenbergh 2002). In rat, overall litter
male/female composition may be more important than
precise intrauterine position (reviewed by Ryan &
Vandenbergh 2002).
Conversely, proximity to female fetuses influences male
physiological development: prostate glands of males
flanked by two females were enlarged compared to
controls (Timms et al. 1999); estradiol is implicated
(vom Saal et al. 1997).
Lathe, R. (2004) The individuality of mice. Genes, Brain & Behavior 3 (6), 317-327.
Environmental factors
• Housing environment
• Enriched environment
• Experimental environment
Experimenter
이건 아니 자나
왜 이리 실험이
안 되는 거야?
Experimental procedures
Experiments without habituation ---- Experiments demanding habituation
This order was chosen in the attempt to go from the least stressful to the most stressful test. Animals were received at least 2 weeks
prior to the beginning of testing and given at least these 2 weeks for acclimation. They were group housed, 3–5/cage, and were at least
8 weeks of age at the start of the experimental series in order to minimize variability due to developmental factors.
In addition, two partners (EMBL and Harwell) tested the influence of cage enrichment on behaviour in this test battery.
Results are currently being analysed and will be compared and evaluated in the next workpackage meeting at the end of April/04. The
“working” SOPs will be audited accordingly.
Hierarchical Strategy
for Phenotypic (Behavioral) Analysis in
Transgenic Mice
Rogers et al., 1997 – SHIRPA
Crawley and Paylor, 1997
Gold LH (1999) Psychopharmacol. 147:2-4
Two words of behavior
• Habituation
• Sensitization
Repeated stimulations make
one boring or sensitive?
Stephen Jay Gould on the evolution of Mickey Mouse
Supernormal stimuli?
vs.
Repeated stimulations
Repeated stimulation
Elicited behavior is not plastic, but can change
with repeated stimulation.
Habituation effect
Decreased response with repeated stimulation.
Sensitization effect
Increased response with repeated stimulation.
Habituation effect
Response
Trials
Dishabituation
Dishabituation effect
Response
Trials
Spontaneous recovery
Retention Interval
Response
Trials
Location of habituation processes
Sensory
adaptation
Habituation
Fatigue
How is habituation different from sensory
adaptation and fatigue?
• Sometimes the habituated response will not
recover after for a long time.
• (Long Term Habituation)
Day
Day 11
Responses
to
Stimulus
Day
Day 21
21
Repeated Trials
of stim
Repeated Trials
of stim A
Habituation will be slower for stimuli
which have a higher salience (i.e., intensity)
Resp
Resp to
to weak
weak
coffee
coffee flavor
flavor
Resp
Resp to
to Strong
Strong
coffee
coffee flavor
flavor
Responses
to
Stimulus
Repeated Trials
Repeated Trials
Dishabituation following the presentation
of a novel stimulus.
Present
Response
Response to
to Present
Stimulus B
B
stimulus
stimulus A
A Stimulus
(light)
(light)
(tone)
(tone)
Responses
to
Stimulus
Response
Response to
to
stimulus
stimulus A
A
(tone)
(tone)
Repeated Trials
Generalization gradient of a habituated
response.
Responses
to
Stimulus
1700
1800 1900
2000 2100 2200 2300
Tone frequency of test stimulus following
habituation at 2000 Hz
Fashion and quality of experiments
Sensitization effect
Response
Trials
Sensitization (Arousal)
In general Sensitization effects can be
influenced by similar parameters as habituation.
However, generalization is greater in Sensitization.
- Following exposure to cutaneous pain, rats’ reactivity to a wide
range of auditory stimuli is increased.
Sensitization can be thought of as “arousal”.
Habituation and Sensitization in
Aplysia
Sensitization Pathway
Increased
serotonin release
Dual-Process theory of
Habituation and Sensitization
2 underlying processes exist
– 1) A Habituation process
– 2) A Sensitization process
The observable behavior is the sum of these two
processes.
The habituation effect is observed when the
habituation process is greater than the
sensitization process.
Dual Process examples
Sensitization effect
Habituation effect
S
S
+
+
NET
-
-
H
NET
H
Trials
Trials
Groves and Thompson (1970)
S-R System: Habituation is thought to occur in the
reflex arc.
State System: Sensitization is thought to occur in
the part of the nervous system that determines
general responsiveness.
Infant attention
Looking
Time
Trials
Opponent Process Theory of Motivation