The purpose of this research is to measure brain activity in individuals with mood disorders and memory problems using a simple, safe, and noninvasive method called functional near-infrared spectroscopy (fNIRS). By comparing brain activity across different groups and relating it to symptom severity, this study aims to improve our understanding of how these conditions affect the brain.

This study will examine cerebral hemodynamic patterns in individuals with mood disorders (major depressive disorder and bipolar disorder) and cognitive disorders (mild cognitive impairment) using functional near-infrared spectroscopy (fNIRS). The primary goal is to compare hemodynamic patterns between these groups, while the secondary goal is to explore correlations between these patterns and symptom severity based on standardized clinical assessments. Additionally, electrophysiological data, including photoplethysmography (PPG) and electrocardiogram (ECG), will be analyzed to investigate autonomic nervous system activity and its relationship with cerebral hemodynamics.

Inclusion Criteria

General Inclusion Criteria (across all diagnostic groups):

• 18 years and older
• Ability to provide written informed consent
• Adequate cognitive and language abilities to understand and complete study tasks, including clinical assessments and fNIRS procedures
• Confirmed clinical diagnosis of major depressive disorder, bipolar disorder, or mild cognitive impairment (MCI)
• Stable psychiatric or cognitive condition, without acute episodes requiring immediate intervention

Specific Inclusion Criteria (for diagnostic groups):

• Healthy control

  o No past or current psychiatric or cognitive disorder

• Major depressive disorder (MDD):

  • Diagnosis of major depressive disorder, confirmed through clinical evaluation.
  • No history of bipolar disorder or psychotic symptoms.

• Bipolar disorder:

  o Diagnosis of bipolar disorder I or II, confirmed through clinical evaluation.

• Mild Cognitive Impairment (MCI):

  • Pre-existing clinical diagnosis of mild cognitive impairment, supported by neuropsychological testing and/or MRI, PET scan data.
  • No history of major psychiatric disorders, such as major depression, bipolar disorder or schizophrenia.

Exclusion Criteria

General Exclusion Criteria (across all diagnostic groups):

• Active primary psychotic or substance use disorders (except nicotine dependence) within the past year
• Any severe or unstable medical condition that could interfere with participation or data collection
• Any active neurological condition (including seizure disorder, traumatic brain injury, stroke) that could affect cognitive functioning or brain imaging results
• Inability to comply with study procedures, including cognitive testing, fNIRS assessment, or other assessments required by the protocol
• Pregnant women will be excluded due to potential physiological changes that could affect study outcomes

Specific Exclusion Criteria (for diagnostic groups):

• Healthy control

  o Any past or current psychiatric or cognitive disorder

• Major depressive disorder (MDD):

  • Diagnosis of bipolar disorder or schizophrenia.
  • Brain stimulation therapy within the past 3 months.

• Bipolar disorder:

  o Diagnosis of schizophrenia or schizoaffective disorder.

• Mild Cognitive Impairment (MCI):

  • Diagnosis of dementia.
  • Significant cognitive impairment preventing understanding or completion of study tasks.

Potential participants will be identified from the Mayo Clinic outpatient clinics in the Departments of Psychiatry, Psychology, Neurology, and Primary Care.