PMID- 24586474
OWN - NLM
STAT- MEDLINE
DCOM- 20150102
LR  - 20211021
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 9
IP  - 2
DP  - 2014
TI  - A unified comparison of stimulus-driven, endogenous mandatory and 'free choice' 
      saccades.
PG  - e88990
LID - 10.1371/journal.pone.0088990 [doi]
LID - e88990
AB  - It has been claimed that saccades arising from the three saccade triggering 
      modes-stimulus-driven, endogenous mandatory and 'free choice'-are driven by 
      distinct mechanisms. We tested this claim by instructing observers to saccade 
      from a white or black fixation disc to a same polarity (white or black) disc 
      flashed for 100 or 200 ms presented either alone (Exo), or together with an 
      opposite (Endo) or same (EndoFC) polarity disc (blocked and mixed sessions). 
      Target(s) and distractor were presented at three inter-stimulus intervals (ISIs) 
      relative to the fixation offset (ISI: -200, 0, +200 ms) and were displayed at 
      random locations within a 4 degrees -to-6 degrees  eccentricity range. The statistical analysis 
      showed a global saccade triggering mode effect on saccade reaction times (SRTs) 
      with Endo and EndoFC SRTs longer by about 27 ms than Exo-triggered ones but no 
      effect for the Endo-EndoFC comparison. SRTs depended on both ISI (the 
      "gap-effect"), and target duration. Bimodal best fits of the SRT-distributions 
      were found in 65% of cases with their count not different across the three 
      triggering modes. Percentages of saccades in the 'fast' and 'slow' ranges of 
      bimodal fits did not depend on the triggering modes either. Bimodality tests 
      failed to assert a significant difference between these modes. An analysis of the 
      timing of a putative inhibition by the distractor (Endo) or by the duplicated 
      target (EndoFC) yielded no significant difference between Endo and EndoFC 
      saccades but showed a significant shortening with ISI similar to the SRT 
      shortening suggesting that the distractor-target mutual inhibition is itself 
      inhibited by 'fixation' neurons. While other experimental paradigms may well 
      sustain claims of distinct mechanisms subtending the three saccade triggering 
      modes, as here defined reflexive and voluntary saccades appear to differ 
      primarily in the effectiveness with which inhibitory processes slow down the 
      initial fast rise of the saccade triggering signal.
FAU - Gorea, Andrei
AU  - Gorea A
AD  - Laboratoire Psychologie de la Perception, Universite Paris Descartes & CNRS, 
      Paris, France.
FAU - Rider, Delphine
AU  - Rider D
AD  - Laboratoire Psychologie de la Perception, Universite Paris Descartes & CNRS, 
      Paris, France.
FAU - Yang, Qing
AU  - Yang Q
AD  - Laboratoire Psychologie de la Perception, Universite Paris Descartes & CNRS, 
      Paris, France.
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20140220
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
SB  - IM
MH  - Adult
MH  - Female
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - *Models, Biological
MH  - Normal Distribution
MH  - Photic Stimulation
MH  - Reaction Time/*physiology
MH  - Saccades/*physiology
PMC - PMC3930601
COIS- Competing Interests: The authors have declared that no competing interests exist.
EDAT- 2014/03/04 06:00
MHDA- 2015/01/03 06:00
PMCR- 2014/02/20
CRDT- 2014/03/04 06:00
PHST- 2013/09/30 00:00 [received]
PHST- 2014/01/13 00:00 [accepted]
PHST- 2014/03/04 06:00 [entrez]
PHST- 2014/03/04 06:00 [pubmed]
PHST- 2015/01/03 06:00 [medline]
PHST- 2014/02/20 00:00 [pmc-release]
AID - PONE-D-13-40071 [pii]
AID - 10.1371/journal.pone.0088990 [doi]
PST - epublish
SO  - PLoS One. 2014 Feb 20;9(2):e88990. doi: 10.1371/journal.pone.0088990. eCollection 
      2014.