Advanced Science (Oct 2024)

Motor versus Psychomotor? Deciphering the Neural Source of Psychomotor Retardation in Depression

  • Xue Mei Song,
  • Dong‐Yu Liu,
  • Dusan Hirjak,
  • Xi‐Wen Hu,
  • Jin‐Fang Han,
  • Anna Wang Roe,
  • De‐Zhong Yao,
  • Zhong‐Lin Tan,
  • Georg Northoff

DOI
https://doi.org/10.1002/advs.202403063
Journal volume & issue
Vol. 11, no. 40
pp. n/a – n/a

Abstract

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Abstract Major depressive disorder (MDD) is characterized by psychomotor retardation whose underlying neural source remains unclear. Psychomotor retardation may either be related to a motor source like the motor cortex or, alternatively, to a psychomotor source with neural changes outside motor regions, like input regions such as visual cortex. These two alternative hypotheses in main (n = 41) and replication (n = 18) MDD samples using 7 Tesla MRI are investigated. Analyzing both global and local connectivity in primary motor cortex (BA4), motor network and middle temporal visual cortex complex (MT+), the main findings in MDD are: 1) Reduced local and global synchronization and increased local‐to‐global output in motor regions, which do not correlate with psychomotor retardation, though. 2) Reduced local‐to‐local BA4 – MT+ functional connectivity (FC) which correlates with psychomotor retardation. 3) Reduced global synchronization and increased local‐to‐global output in MT+ which relate to psychomotor retardation. 4) Reduced variability in the psychophysical measures of MT+ based motion perception which relates to psychomotor retardation. Together, it is shown that visual cortex MT+ and its relation to motor cortex play a key role in mediating psychomotor retardation. This supports psychomotor over motor hypothesis about the neural source of psychomotor retardation in MDD.

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