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NROC34 Lec 6.docx

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Karen Williams

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NROC34 Lec 6 Last lec: birds - Zebra finch pairs - Giving oxytocin antagonist, might change what is happening - Zebra Finch pair preening picture o Have pair bonded and have pair bonding behaviour o Sensory cues are what we look at o With bird songs – can see that birds pair o Males sing, females do not - Infusion of antagonist of oxytocin o Has NO effect on male song o Reduces pair bonding behaviours of females o Happens in other organisms also - In humans, oxytocin is for maternal behaviour, etc - Voles and vasopressin - Mostly based on readings in text - In prairie voles – known to huddle together o The pair are sitting together with the babies under o Female voles rarely re-mate o Males aggressively defend territory and protect the female - Sensory cues that might be important for behaviour depicted in the picture: o Olfaction – can smell mate o Tactile/touch cues – are huddling - Are there any compounds we might know are important for pair touch behaviour The scientific method - Very important for review – look at article and look at these areas o Hypothesis, predictions o Methods o Results o Discussion - For scientific method, have an idea from other organisms (sheep and lambs) that oxytocin might be important for lambs and sheep for when the sheep have just given birth - In pair bonding, something about touch, etc. are important Vole behaviour: monogamy - Prairie voles are monogamous - Montane and others are polygynous - When mammals exhibit close bonds  correlated with elevated brain levels of OXYTOCIN and VASOPRESSIN Social behaviour of voles - Look at all aspects of behaviour that we can describe - Chart o Look at prairie voles vs. montane voles - All these behaviours for monogamous prairie voles, can ask if they are the same for the montane voles o Many are different - Prairie voles are biparental, while montane are maternal What affects bonding behaviours in other animals? - What makes bonding behaviours? o Sheep and lambs – mothers bond with offspring - Do oxytocin and vasopressin change among the voles with the different mating systems? - In other animals – mammals, mice – can use to get a hypothesis Vasopressin and oxytocin: neuroanatomy - More vasopressin binding in the ventral pallidum of the prairie voles than montane voles - Oxytocin R bind in the Nacc in prairie voles but not so much in montane voles - Just looking at neuroanatomy, can already see differences in behaviour - Look at contact time: o Those cohabiting together  Contact time increases than with a stranger  Most when arginine vasopressin or oxytocin o Mated condition  Mating is higher with partner than with stranger in control (CSF)  When given antagonist for vasopressin R – the difference disappears  stay beside partner and stranger same amount of time  When giving antagonist for oxytocin R – it completely reverses  Contact time with a stranger is much higher - From the different levels in anatomy, can ask physiologically what will happen if we pharmacologically change levels - Partner preference behaviour o Differs in prairie voles and montane voles - Can plot the relationship - Most voles are polygamous, some have variable, few are monogamous - Looking at prairie vole vs montane partner preference Scientific Method - Hypothesis: o Do voles with different mating systems show differences in these hormones? - Prediction: if vasopressin is involved in the pair-bonding behaviour of voles, then changing the level of vasopressin would change the behaviour o Start with ones that are promiscuous and see if we can change pair-bonding behaviour - Methods: Does vasopressin receptor gene influence pair bonding behaviour? - Measure time in contact of stranger, partner - Control: lac-Z - Methods: o Measure time in contact  Of lac-Z vs V1aR in ventral pallidum (VP) or caudate putamen (CP) - V1ar in caudate putamen – contact with a stranger is higher - V1ar put in ventral pallidum – contact with partner is much higher – significantly higher o Large difference - Can conclude: o Talk about VP and CP results Partner Preference Test - Recorded the behaviour of the voles and measured time vole spent in contact with the partner - How close does animal have to be with partner for contact Does this genetic factor change the proportion of animals displaying the behaviour? - Can also ask about voles with different mating systems - Could we change a polygamous vole into a monogamous vole by increasing vasopressin receptor? o Is the difference between partner preference behaviour between monogamous Prairie voles and promiscuous Montane voles affected by v1ar?  Can genetic factor change proportion of animals? - Results: time spent huddling in the prairie voles is higher and in montane – is the same as time spent near stranger o NEED TO KNOW BASIS FIRST - Hypothesis: monogamy (time spent huddling) is not different between genetically modified v1ar bearing male voles and control unaltered male voles - Results: o Expression of v1ar in VP increased pair bond formation for ordinarily promiscuous voles o Know VP is the only place that changes this behaviour - Possible that the time spent huddling is much greater when they are genetically modified with vasopressin R - Conclusion: o Gives us an idea of another question to ask o Monogamous behaviour can be described in a variety of ways o Biparental care could be increased o Vasopressin R = v1ar or avpr1a Biparental care - Hypothesis: overexpression of avpr1a in VP increases the parental care behaviour in prairie voles - Methods: parental care behaviours o Latency to retrieve pups  Different times in prairie vs montane - Results: o In prairie voles, found NO significant difference in parental care – different from other results o Would normally expect major differences when we express in montane voles o Increasing avpr1a in montane voles – don’t increase parental care either - Conclusion: mechanisms by which expression of v1ar influences pair-bond formation is different from those that affect biparental care o Increased avpr1a in VP does NOT increase the parental care behaviour o Both, though, are behaviours to describe monogamy Neuropeptide R plasticity associated with pair-bonding experience - V1ar in sexually naïve voles vs. voles that mated from pair bonding o The ones that pair bonded had more vasopressin expressed in certain areas o Anterior hypothalamus – naïve have less expression than pair bonded - Behaviour changes expression of behaviour - There is some plasticity in specific parts of the brain but not all Selective Aggression - The aggression naïve male voles direct to unfamiliar females is increased by adding vasopressin R to the anterior hypothalamus (AH) but NOT to the lateral septum o More aggressive towards random females when adding vasopressin R to AH - VP important for partner preference. No difference for parental care - Looked at anterior hypothalamus and lateral septum. Note: they are areas that would change with pair bonding - Measured aggression of naïve voles to novel females when expressing vasopressin R in the AH vs. expressing lac-Z - Results: o Typical low aggression with lac-Z – vasopressin caused high aggression  Increased aggression by adding v1ar in AH o Affiliation  Control = higher o V1ar binding  When giving vasopressin – much higher in AH than control  In lateral septum – v1ar binding is the same as control group - Aggression was higher in monogamous roles 1.6 - Proximate and internal mechanisms - Arginine vasopressin gene – important to specific areas of the brain What physiological mechanisms are involved? - Because of pair-bonding behaviour changing expression, expect reward circuit will be involved - Physiological methods that might be involved: o Olfaction  Could give some reward - Dopaminergic signalling o Give DA R antagonist – haloperidol o DA R agonist – apomorphine o (see pg.43) - Hypothesis about reward circuit: - Prediction: if you were to give antagonist vs agonist - Methods: measure huddling in voles using contact times. Measured this by using partner preference test - Results: o Describe EVERY part of the graph - Conclude: - If we were going to repeat experiment again, what dosage of apo would be used? What further experiments would be done? o Tried different doses to see the range of behaviours o With organisms – not sure which dosage to give. Want to check dose response o Might have to do other experiments if going to use high dose of apo. See if it has different effects – makes animal sick, etc How does dopamine affect behaviour? - Mating induces a change o Contact time is much higher with CSF - If mating gives a reward, can block that reward change by giving the D2 antagonist o Does it block that reward and reduce contact time? o We can block pathway and
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