the maternal brain[1]
TRANSCRIPT
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The Maternal BrainKashmala Qasim
NROC61
Kinsley, C.H & Lambert, K.G. (2006). The maternal brain. Scientific American(January), 72-79.
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Outline
1. Introduction
2. Structural changes & Significancea) Cortex
b) mPOA
c) Hippocampus
3. Hormonal changes: Oxytocin
4. Cellular changes: Glial cells
5. Changes beyond lactation period
6. Summary
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Mothers are made, not born
Hormonal fluctuations
that occur during
pregnancy may modify
the female brain
Increase in size of
neurons
Structural changes
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Structural Changes: CortexDef. receives and processes sensory information & controls voluntary movements
1) Cortex
Cortices of pregnant rats fromimpoverished environments werecomplex = rats from enriched settings
Significance:
- Faster at catching prey
- Food-deprivation studies: virgin rats
took longer to find the cricket and
eat it (270 sec vs. 50 sec).
http://www.familyhopecenter.org/english/images/cortex_indepth_large.jpg -
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Structural Changes: mPOADef.
2) mPOA
- cell bodies of the neurons increase in
volume- length and number of dendritesincreases as pregnancy progresses
- neuronal alterations accompany a risein protein synthesis
Significance:
- mPOA neurons direct the mothersattention & motivation to offspring
- Maternal behavioural traits: care,
protection and nurture
V
P
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Structural Changes: HippocampusDef. regulates memory, learning & emotions
3) Hippocampus
- Ebb-and-flow variations inthe CA1 region of thehippocampus
- Increase in dendritic spines asthe females levels of estrogenrise
- - Reduction in neuronal activityin the CA3 region &basolateral amygdala ---
regulate stress and emotion
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Hippocampus
Significance
1) Spatial ability
- Pregnant rats better than age-matched
virgin rats at remembering the location
of food in maze tasks
2) Amygdala: Lessened fear & anxiety
- easier to leave the nest & forage faster
- forced swimming, investigate the space
less likely to freeze up
3) Dendritic Spines: input to associated
neurons, leads to enhanced ability of the
mothers to navigate mazes & captureprey
8-arm radial maze
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HormonalChanges
Oxytocin
- triggers birth contractions andmilk release
- effects on hippocampus:improves memory & learning
- production of long-lastingconnections between neurons in
the hippocampus
- Study: Injections of oxytocininto the brains of virgin femalemice improved their long-termmemory
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3) Cellular Changes
Glial cells
- astrocytes, star-shaped glial
cells that provide nutrientsand structural support forneurons
- significantly more complexand numerous in mPOAneurons & hippocampus,than those in virgin rats
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Changes Beyond Lactation Period
Mother rats up to two years oldequivalent to human females olderthan 60learn spatial tasks significantly faster than age-matchedvirgin rats and exhibit less steep memory declines
At every age tested (six, 12, 18 and 24 months), mothers were betterat remembering the locations of food rewards in mazes
Fewer deposits of amyloid precursor proteinswhich seem to play a
role in the degeneration of the aging nervous systemin two parts ofthe hippocampus, the CA1 region and the dentate gyrus
Mother rats spent more time in the fear-evoking open arms of themaze
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Summary- Structural changes are observed in the
cortex, mPOA neurons and hippocampus
- Changes contribute to increased spatial
ability, foraging ability, maternalbehaviour and able to catch prey faster
- An increase in oxytocin = milk release,
contractions
- Glial cells (astrocytes) increase- These effects remain long after the
lactation period has ended & mitigate
effects of aging