Original Research ARTICLE
Temporal preparation, impulsivity and short-term memory in depression
- 1Graduate Institute of Mind, Brain and Consciousness, College of Humanities and Social Sciences, Taipei Medical University, Taiwan
- 2Shuang Ho Hospital, Taipei Medical University, Taiwan
- 3Department of Emergency Medicine, School of Medicine, Taipei Medical University, Taiwan
- 4Department of Psychiatry, Shuang Ho Hospital, Taipei Medical University, Taiwan
- 5Research Center of Sleep Medicine, College of Medicine, Taipei Medical University, Taiwan
- 6Graduate Institute of Medical Humanities, College of Humanities and Social Sciences, Taipei Medical University, Taiwan
- 7Division of System and Cognition, Institute of Neurosciences, Catholic University of Louvain, Belgium
Patient suffering of Major Depressive Disorder (MDD) often complain that subjective time seems to ‘drag’ with respect to physical time. This may point towards a generalized dysfunction of temporal processing in MDD. In the present study, we investigated temporal preparation in MDD. “Temporal preparation” refers to an increased readiness to act before an expected event; consequently, reaction time should be reduced. MDD patients and age-matched controls were required to make a saccadic eye movement between a central and an eccentric visual target after a variable duration preparatory period. We found that MDD patients produced a larger number of premature saccades, saccades initiated prior to the appearance of the expected stimulus. These saccades were not temporally controlled; instead, they seemed to reflect reduced inhibitory control causing oculomotor impulsivity. In contrast, the latency of visually-guided saccades was strongly influenced by temporal preparation in controls; significantly less so, in MDD patients. This observed reduced temporal preparation in MDD was associated with a faster decay of short-term temporal memory. Moreover, in patients producing a lot of premature responses, temporal preparation to early imperative stimuli was increased.
In conclusion, reduced temporal preparation and short-term temporal memory in the oculomotor domain supports the hypothesis that temporal processing was altered in MDD patients. Moreover, oculomotor impulsivity interacted with temporal preparation. These observed deficits could reflect other underlying aspects of abnormal time experience in MDD.
Keywords: Memory, Depression, temporal cognition, EYE MOVEMENT, impulsivity
Received: 25 Jul 2019;
Accepted: 31 Oct 2019.
Copyright: © 2019 Hsu, Lee, Lane and Missal. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Marcus Missal, Division of System and Cognition, Institute of Neurosciences, Catholic University of Louvain, Brussels, Belgium, email@example.com