A non-reward attractor theory of depression

Area of Science:

• Neuroscience
• Cognitive Science
• Psychiatry

Background:

• Depression is linked to altered brain function, particularly in reward and non-reward pathways.
• The lateral orbitofrontal cortex (lOFC) plays a role in processing non-reward and error signals.
• Existing theories lack a comprehensive explanation for the persistent negative states in depression.

Purpose of the Study:

• To propose a novel non-reward attractor theory of depression.
• To elucidate the role of the lateral orbitofrontal cortex (lOFC) and supracallosal cingulate cortex in depression.
• To explore potential mechanisms of action for depression treatments.

Main Methods:

• Theoretical framework development based on existing neuroscience literature.
• Analysis of the function of error neurons and attractor states in the lOFC.
• Hypothesizing the neural underpinnings of depression and mania.

Main Results:

• The lateral orbitofrontal cortex (lOFC) contains error neurons that enter an attractor state upon non-reward, maintaining a memory of it.
• This non-reward system is hypothesized to be hyperactive and more easily triggered in depression, leading to prolonged negative cognitive states.
• Treatments like ketamine may work by disrupting these attractors.

Conclusions:

• Depression may arise from a hyperactive non-reward attractor system in the lateral orbitofrontal cortex (lOFC).
• This system's prolonged activation creates negative cognitive feedback loops.
• Mania in bipolar disorder might involve overactivity in the related medial orbitofrontal cortex reward system.