Chapter 1 Flashcards
What is the difference between an hormone and a neurotransmitter?
neurotransmitters→ local action only in the synapse
hormone→ can be released in blood stream and carry to another part of the body
What are some examples of hormones affecting behaviour?
Example→ Testosterone and agression
- testosterone influenced brain regions like amygdala and PFC
- heightened aggression, risk taking and competitive behaviours
- heighten sensory sensitivity like visual and auditory processing→ prepare for social dominance interactions
Example→ Oxytocin and bonding
- oxytocin released by posterior pituitary gland and act on hypothalamus and amygdala
- promotes empathy, bonding, trust / reduces stress
- breastfeeding→ release oxytocin to strengthens mother-infant bonding
What are some examples of behaviour affecting hormones?
Example→ Exercise and Endorphins
- physical activity stimulates hypothalamus to release endorphins
- lead to release cortisol and adrenaline
- opiate binds to same receptors
- reduce stress and promote feeling of well-being
—>Proprioceptive input from muscle movement triggers hormonal changes
Example→ Social Stress and Cortisol
- Fear of rejection→ activate hypothalamus and release corticotropin-releasing hormone (CRH)
- increase alertness and prepare body to cope with stress
—>make every stimuli more salient / sensitive state
Example→ Sexual activity and testosterone
SEE TABLE
How to assess the interactions between hormone and behaviour?
- A hormonally dependent behavior should disappear when the source of
the hormone is removed - After the behavior stops, restoration of the missing hormonal source or its
hormone should reinstate the absent behavior - hormone concentrations and the behavior in question should be
covariant→ behavior should be observed only when hormone concentrations are relatively high and never or rarely when hormone
concentrations are low
What is another name for Environmental Chemicals Mimic Hormones and give two examples?
= Endocrine-disrupting chemicals (EDCs)
Example→ Bisphenol A (BPA)
- found in plastic
- mimics estrogen by binding to estrogen receptors
- altered reproductive behaviours and impaired mating preferences
- might affect pheromones
Example→ Polychlorinated Biphenyls (PCBs)
- mimic thyroid hormones
- exposure during development kink to cognitive impairment
Describe Berthold’s experiment
Berthold’s experiment→ first experiment in 1849 on how testes travel through the bloodstream
- Group1→ castrated roosters lead to no crowing, mating or aggression and physical changes
- Group2→ testis reimplanted before puberty lead to normal male development
—>Substances (hormones) can travel through the bloodstream to affect other parts of the body
How do the cell influence by a specific hormone is called?
Target cell
What are the three key components of animal behaviours?
- Input systems→ sensory systems detecting environmental stimuli
- Integrators→ CNS processes
- Output Systems→ effectors producing behavioral responses
Do hormones cause behavioural changes?
Hormones don’t cause behavioural changes but influence likelihood of specific behaviours
What are the different levels of analysis used in behavioural endocrinology?
Immediate causation
- the under lying physiological, or proximate, mechanisms responsible for a given behavior
- most used class in analysis
Development
- interaction between genes and environmental factors over time
Evolution
- ways that specific behaviors change during the course of natural selection
Adaptive function
- role that behavior plays in the adaptation of animals to their environment and with the selective forces that currently maintain behavior
What is the proximate causation and its levels of analysis?
How?
immediate causation + development
What is the ultimate causation and its levels of analysis?
why?
evolution + adaptive function
How does the ablation and replacement techniques determine the function of a hormone?
Def→ Removal of the suspected source of a hormone to determine its function
What are the four steps of the ablation and replacement technique?
- Remove→ gland suspected to be source of hormone affecting a behavior
- Observe→ effects of removing gland
- Replace
- Reimplanting removed gland
- injecting homogenate or extract from gland
- injecting a purified hormone
- Observe/Determine→ after replacement
—>determination based on observed consequences of ablation reversed by replacement
What is the major drawback of the ablation and replacement technique?
- many glands produce more than one hormone
- ex: pituitary gland→ growth hormone, Adrenocorticotropic hormone, thyroid hormone
What are the three related approaches to ablation and replacement techniques?
- drugs to block hormone synthesis or hormone receptor activity
- manipulation of genes to block hormone production
- gland naturally stop functioning and observe
How do the immunoassays study the function of hormones?
broad category of tests using the specific binding between an antigen and an antibody to measure the presence and concentration of hormones in a sample
- principle that hormone binds to specific protein (antibody)
What are an antigen and an antibody?
- Antigen→ Target hormone
- Antibody→ molecule binding to hormone of interest
What are a labelled hormone/ hot hormone and a cold hormone?
- Labelled hormone/ hot hormone→ hormone + antibody
- Cold hormone→ hormone without antibody attached
What are the six different steps of immunoassays?
1.Preparation→ find antibody for the target hormone to bind to
2.Binding Reaction→ create the antigen/antibody complex
3. Detection→ need a way to detect the complex
- RIA→ radioactive label
- ELISA→ antibody with enzyme, colour change
4.Washing/Separation→ excess substances need to be washed away to avoid interference
5.Measurement→ measure signal generated by detection system
- RIA→ measured for level of radioactivity
- ELISA→ colour intensity (darker means more antigen)
6. Interpretation→ analyse data to determine if antigen is present
- RIA→ comparing sample’s radioactivity to a standard curve
- ELISA→ standard curve
Describe the radioimmunoassay (RIA)
- radioactively labeled substances to measure the concentration of a target antigen
- using specific antibody and detect bound thought radioactive marker
Describe the Enzymoimmunoassay (EIA)/Enzyme-Linked Immunosorbent Assay (ELISA)
- enzymes as labels of reaction with a substrate
- result in a colours change that can be quantified
What are the differences between Electrical recording, electrical stimulation and optogenetics?
Electrical recording-> technique used to investigate the activity of neurons during and after exposure to hormone
- by placing small electrodes inserted into the brain to measure the activity of individual neurons
- use living animals
- single unit
Electrical stimulation→ small electrodes are placed in the brain to stimulate neurons
- reveals effects of hormones on neural circuits
- impacts anterograde (away from the cell) and retrograde (towards) connections
Optogenetics→ uses light to control the activity of light-sensitive ion channels, enabling the activation or inhibition of specific neuronal functions with millisecond precision
- Channelrhodopsin ion channel(ChR2)→ light guided ligands with blue lights
- Halorhodopsin→ activated by yellow lights and inhibit action potentials by hyperpolarization
What is gene knockout?
Def->inactivation of specific genes by scrambling the order of the nucleotides
- create mutated version of gene
- mouse embryonic stem collected
- mutated gene is introduced via microinjection
- altered genes incorporated in DNA of stem cells via recombination and then inserted in normal mouse embryos (blastocysts)
—>lead to chimera→ mouse with both normal and and genetically modified cells in its body
