Neuroanatomical studies on bipolar disorder

Area of Science:

• Neuroscience
• Psychiatry
• Histopathology

Background:

• Neuroimaging studies indicate structural and functional brain abnormalities in mood disorders.
• These findings suggest underlying neurohistological alterations may explain observed in vivo macropathology.
• This review focuses on post-mortem evidence in affective disorders, particularly bipolar disorder.

Purpose of the Study:

• To summarize recent post-mortem studies on affective disorders.
• To investigate neurohistological findings in mood disorders, with an emphasis on bipolar disorder.
• To correlate histological data with neuroimaging observations.

Main Methods:

• Literature review of post-mortem studies.
• Analysis of volumetric, cyto-architectural, and immunohistochemical data.
• Discussion of findings related to specific brain regions and neurotransmitter systems.

Main Results:

• Smaller basal ganglia volumes observed in depression, regardless of diagnostic polarity.
• Increased neuron numbers in the locus caeruleus reported in bipolar disorder compared to unipolar depression.
• Subtle structural deficits in the dorsal raphe found in both bipolar and unipolar illness.
• Histological data suggest regional reductions in noradrenaline and serotonin synthesis, potentially compensated by antidepressants.

Conclusions:

• Preliminary findings indicate that subtle structural brain abnormalities, beyond functional dysregulation, may play a role in mood disorder pathogenesis.
• Neurohistological changes in specific brain regions are associated with affective disorders.
• Antidepressant effects may involve compensation for reduced neurotransmitter synthesis.