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Prenatal stress alters dendritic morphology and synaptic connectivity in the prefrontal cortex and hippocampus of
Richelle Mychasiuk1, Robbin Gibb, Bryan Kolb
1Canadian Centre for Behavioural Neuroscience, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, Canada. r.mychasiuk@uleth.ca
Insights
Prenatal stress impacts brain development, causing sex-specific changes in the prefrontal cortex and hippocampus. This early neurodevelopmental disruption affects synaptic connectivity and neuronal organization.
Area of Science:
- Neuroscience
- Developmental Biology
- Neuroanatomy
Background:
- Prenatal stress is a known environmental factor impacting offspring neurodevelopment.
- Understanding the specific neuroanatomical consequences of gestational stress is crucial for identifying early developmental disruptions.
- The prefrontal cortex and hippocampus are key brain regions involved in cognitive and emotional regulation, and are vulnerable to early life stress.
Purpose of the Study:
- To investigate the neuroanatomical alterations in the prefrontal cortex and hippocampus of developing offspring exposed to gestational stress.
- To examine sex-dependent effects of prenatal stress on neuronal morphology and synaptic connectivity.
- To estimate the impact of prenatal stress on synaptic connectivity in specific brain regions.
Main Methods:
- Stereological techniques combined with Golgi-Cox staining were employed.
- Morphological analysis included dendritic branching, length, and spine density.
- Neuron number and estimated synaptic connectivity were quantified at weaning.
Main Results:
- Prenatal stress induced region-specific and sex-dependent neuroanatomical alterations.
- Medial and orbital prefrontal cortices showed sexually dimorphic, opposing changes in synaptic connectivity.
- The hippocampus exhibited reduced neuron and synapse numbers in both sexes, despite increased spine density.
Conclusions:
- Prenatal stress disrupts normal neurodevelopment and neuronal circuit organization in the neocortex and hippocampus.
- These early alterations likely influence subsequent experience-dependent synaptic plasticity.
- Findings highlight the critical impact of the prenatal environment on brain development and function.
Abstract:
The current study used stereological techniques in combination with Golg-Cox methods to examine the neuroanatomical alterations in the prefrontal cortex and hippocampus of developing offspring exposed to gestational stress. Morphological changes in dendritic branching, length, and spine density, were examined at weaning along with changes in actual numbers of neurons. Using this information we generated a gross estimation of synaptic connectivity. The results showed region-specific and sex-dependent alterations to neuroanatomy in response to prenatal stress. The two regions of the prefrontal cortex, medial prefrontal, and orbital prefrontal cortices, exhibited sexually dimorphic, opposite changes, in synaptic connectivity in response to the same experience. Both male and female offspring demonstrated a loss of neuron number and estimated synapse number in the hippocampus despite exhibiting increased spine density. The results from this study suggest that prenatal stress alters normal development and the organization of neuronal circuits in both neocortex and hippocampus early in development and thus likely influences the course of later experience-dependent synaptic changes.
