title: The temporal impulse response function during smooth pursuit.
abstract: Recent studies indicate that the extent of perceived motion smear is attenuated asymmetrically during smooth pursuit eye movements, based on the relative directions of the target and eye motion. We conducted two experiments to determine if the reduction of perceived smear during pursuit might be associated with an acceleration of the temporal impulse response function (TIRF). In Experiment 1, two-pulse increment sensitivity was determined during fixation and rightward pursuit for sequential flashes of a long horizontal line, presented with stimulus-onset asynchronies between 5.9 and 234 ms. In Experiment 2, temporal contrast sensitivity was measured during fixation and rightward pursuit for a vertical 1 cpd grating with retinal image velocities between 4 and 30 Hz. During pursuit, grating motion was either in the same or the opposite direction as the eye movement. TIRFs were modeled as the impulse responses of a second-order, low-pass linear system, fit to the two-pulse increment sensitivity data by an optimization procedure and to the temporal contrast sensitivity results by iterative Fourier synthesis. The results indicate that the natural temporal frequency of the fitted TIRFs was approximately 10% higher during pursuit than fixation. In Experiment 2, the increased natural frequency of the TIRF was restricted to the condition in which the grating moved spatially in the opposite direction of the pursuit eye movement. The results are consistent with the hypothesis that extra-retinal signals reduce the extent of perceived motion smear during pursuit, in part by increasing the speed of visual processing preferentially for one direction of image motion.
authors.affiliation: College of Optometry, 505 J. Davis Armistead Building, University of Houston, Houston, TX 77204-2020, USA.
authors.forename: Jianliang
authors.initials: J
authors.lastname: Tong
authors.forename: Mahalakshmi
authors.initials: M
authors.lastname: Ramamurthy
authors.forename: Saumil S
authors.initials: SS
authors.lastname: Patel
authors.forename: Lan-Phuong
authors.initials: LP
authors.lastname: Vu-Yu
authors.forename: Harold E
authors.initials: HE
authors.lastname: Bedell
mesh_terms: D015350:Contrast Sensitivity / Q000502:physiology; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology; D011601:Psychophysics; D011698:Pursuit, Smooth / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology
references.citation: J Vis. 2008 Dec 18;8(14):22.1-18
references.pmid: 19146323
references.citation: Vision Res. 1978;18(5):521-30
references.pmid: 664333
references.citation: Vis Neurosci. 1992 May;8(5):483-6
references.pmid: 1586649
references.citation: J Physiol. 1978 Dec;285:275-98
references.pmid: 745079
references.citation: J Vis. 2007 Oct 12;7(13):3.1-15
references.pmid: 17997631
references.citation: Vision Res. 2005 Jul;45(16):2191-200
references.pmid: 15845249
references.citation: J Opt Soc Am. 1965 May;55(5):560-6
references.pmid: 5867974
references.citation: J Vis. 2008 Oct 23;8(14):7.1-6
references.pmid: 19146308
references.citation: Vision Res. 1996 Jul;36(14):2069-78
references.pmid: 8776473
references.citation: Vision Res. 2007 Sep;47(21):2767-77
references.pmid: 17765281
references.citation: Vision Res. 2008 Jul;48(15):1575-83
references.pmid: 18550143
references.citation: J Neurosci. 1997 Nov 1;17(21):8621-44
references.pmid: 9334433
references.citation: J Opt Soc Am A. 1987 Oct;4(10):1992-2005
references.pmid: 3430210
references.citation: J Opt Soc Am. 1979 Oct;69(10):1340-9
references.pmid: 521853
references.citation: Vision Res. 2007 Mar;47(7):1011-9
references.pmid: 17239420
references.citation: Vision Res. 1969 Jan;9(1):195-7
references.pmid: 5778039
references.citation: Nat Neurosci. 2008 Oct;11(10):1211-6
references.pmid: 18806785
references.citation: Vision Res. 2004 Apr;44(9):895-902
references.pmid: 14992833
references.citation: Vision Res. 2009 Jan;49(2):262-7
references.pmid: 19010344
references.citation: Vision Res. 2005 Jun;45(12):1519-24
references.pmid: 15781070
references.citation: Biol Cybern. 1987;56(5-6):329-44
references.pmid: 3620532
references.citation: Vision Res. 1972 Feb;12(2):279-92
references.pmid: 5033690
references.citation: Vision Res. 2001 Feb;41(4):521-8
references.pmid: 11166054
references.citation: Vision Res. 1987;27(5):765-80
references.pmid: 3660638
references.citation: Vision Res. 1988;28(7):819-26
references.pmid: 3227659
references.citation: Vision Res. 2003 Mar;43(6):617-27
references.pmid: 12604098
references.citation: Vision Res. 1992 Jan;32(1):47-59
references.pmid: 1502811
references.citation: J Opt Soc Am. 1971 Apr;61(4):537-46
references.pmid: 4323022
references.citation: Curr Biol. 1996 Aug 1;6(8):1032-4
references.pmid: 8805336
references.citation: Vision Res. 2003 Feb;43(3):285-98
references.pmid: 12535987
references.citation: J Physiol. 1970 Sep;210(1):165-86
references.pmid: 5500775