bipolar disorder

Specific Types of Genes and Mutations

• Types of Mutated Genes:

  • Genes that regulate carcinoid signaling, monomies, and mitochondrial functions are implicated in bipolar disorder.

  • These mutations contribute to the likelihood of developing bipolar disease rather than directly causing it.

  • Suggested that these genetic pathways mediate the pathology associated with bipolar disorder.

Pathologies in Bipolar Disease

• Brain Symmetry Modification:

  • Recent studies indicate modifications in the brain’s symmetry may be a factor in bipolar disorder.

  • Ongoing research aims to deepen understanding of these mechanisms.

• Dopamine Neurotransmission Changes:

  • Hypothesis suggests changes in dopamine neurotransmission might play a role in bipolar disorder.

  • Dopamine Functions:

  • Key neurotransmitter involved in the brain's reward system.

  • Influences various neural pathways.

  • Imbalance in dopamine circuits:

  • Some dopamine-using circuits are upregulated, while others are downregulated.

  • Associated with receptor inhibition and potentiation.

Specific Types of Genes and Mutations

• Types of Mutated Genes:

  • Genes that regulate calcium signaling (such as $CACNA1C$), cell signaling, and mitochondrial functions are heavily implicated in bipolar disorder.

  • These mutations contribute to a "polygenic risk," meaning many small genetic variations combine to increase susceptibility rather than a single gene causing the disorder.

  • Mutations in mitochondrial DNA can lead to cellular energy deficits and increased oxidative stress in neurons, affecting overall brain health.

  • Suggested that these genetic pathways mediate the pathology associated with bipolar disorder by altering neurotransmitter release and neuronal excitability.

Pathologies in Bipolar Disease

• Brain Symmetry and Structural Modifications:

  • Recent studies indicate modifications in the brain’s symmetry may be a factor, specifically in the prefrontal cortex ($PFC$) and temporal regions.

  • Neuroimaging often shows reduced gray matter volume in areas like the anterior cingulate cortex ($ACC$) and the hippocampus, which govern emotion and memory.

  • Ongoing research aims to deepen understanding of how these structural changes correlate with the frequency of mood cycles.

• Dopamine Neurotransmission Changes:

  • The Dopamine Hypothesis: Mania is frequently linked to high dopamine activity or oversensitive receptors, whereas depression is linked to low dopamine states.

  • Dopamine Functions:

  • Key neurotransmitter involved in the brain's reward system, motivation, and motor coordination.

  • Influences various neural pathways including the mesolimbic and mesocortical systems.

  • Imbalance in Dopamine Circuits:

  • Some dopamine-using circuits, particularly in the reward centers (ventral striatum), are upregulated during manic episodes, leading to impulsivity.

  • Other circuits may be downregulated during depressive episodes, contributing to a lack of motivation (anhedonia).

  • Associated with receptor inhibition, potentiation, and changes in synapse density.

• Neurochemical and Biological Factors:

  • Neuroplasticity: Reduced levels of Brain-Derived Neurotrophic Factor ($BDNF$) are observed during mood episodes, which may impair the brain's ability to maintain healthy neuronal connections.

  • Circadian Rhythms: Dysregulation of "clock" genes often leads to the sleep-wake cycle disturbances that are a hallmark of the disorder.