Acquired olfactory loss alters functional connectivity and morphology.

Area of Science:

• Neuroscience
• Neuroplasticity
• Sensory Processing

Background:

• Sensory system deafferentation impacts brain morphology and connectivity.
• Most studies focus on long-term or early-onset sensory loss, leaving recent sensory loss effects understudied.

Purpose of the Study:

• To investigate the effects of recent olfactory loss on cerebral morphology and functional connectivity.
• To compare individuals with acquired olfactory loss to healthy controls.

Main Methods:

• Multivariate pattern analyses to assess grey matter volume.
• Dynamic connectivity analyses to examine functional connectivity within and from the olfactory cortex.
• Comparison between individuals with acquired olfactory loss (7-36 months duration) and matched controls.

Main Results:

• Acquired olfactory loss correlated with altered grey matter volume in olfactory processing areas (e.g., posterior piriform cortex) and other regions (inferior frontal gyrus, angular gyrus).
• Individuals with anosmia showed stronger dynamic functional connectivity from the posterior piriform cortex to the angular gyrus (a multisensory integration area).
• Anosmia also led to stronger connectivity from the angular gyrus to visual processing areas.

Conclusions:

• Recent sensory loss, specifically olfactory loss, induces changes in brain morphology within primary olfactory areas.
• Acquired anosmia increases dynamic functional connectivity from the olfactory cortex to brain regions involved in multisensory integration and basic visual processing.