Depression Affects Working Memory Performance: A Functional Near Infrared Spectroscopy (FNIRS) Study

Depression is a complex disorder that can be caused by psychosocial and biological conditions and it not only effects
mood disorders, but also cognitive functions such as memory, decision making, psychomotor speed and attention.
As a result of the studies, some findings indicate that depressed individuals perform worse in neuropsychological
tests than healthy individuals, while other studies indicate there is no difference between the two groups. According
to neuroimaging studies on this subject, functional and anatomical differences were detected at the cortex and
subcortical levels in the prefrontal lobe. This study is consisting of two parts, behavioral and neuroimaging using
FNIRS. BDI was applied to the participants. The average age of the group with lower BDI score is 23, 9 ± 3, 04; the
average age of the higher group with higher BDI score is 22, 2+2, 28. A visuospatial 2-back task, which includes 4
different stimulus types with neutral, emotional, verbal, and non-verbal qualities, was applied to the participants. No
significant differences were observed between the two groups in behavioral data. However, when FNIRS results were
examined, it was found that the group with the high BDI scores showed more activation in the right PFC during the
visuospatial 2-back task compared to the group with low BDI scores. Although the FNIRS results are consistent in
the literature, behavioral findings support some of the findings in literature, while contradicting others. It is thought
that the reason for this may be that participants are young, and the 2-back task is not difficult enough.