title: Reach adaptation to explicit vs. implicit target error.
abstract: The adaptation of reaching movements has typically been investigated by either distorting visual feedback of the reaching limb or by distorting the forces acting upon the reaching limb. Here, we investigate reach adaptation when error is created by systematically perturbing the target of the reach rather than the limb itself (Magescas and Prablanc in J Cogn Neurosci 18: 75-83, 2006). Specifically, we investigate how adaptation is affected by (1) the timing of the perturbation with respect to the movement of the eye and the hand and (2) participant awareness of the perturbation. In Experiment 1, participants looked and pointed to a target that disappeared either at the onset of their eye movement or shortly after their eye movement and then reappeared, displaced to the right, at the completion of the reach. In Experiment 2, we made the target displacement more explicit by leaving the target at its initial location until the end of the reach, at which point it was displaced to the right. In Experiment 3, we extinguished the target at the onset of the eye movement but also informed participants about the presence and magnitude of the perturbation. In the no-feedback post-test phase, participants for whom the target disappeared during the reach demonstrated much stronger aftereffects of the perturbation, misreaching to the right, whereas participants for whom the target stayed on until reach completion demonstrated rapid extinction of rightward misreaching. Furthermore, participants who were informed about the target perturbation exhibited faster de-adaptation than those who were not. Our results suggest that adaptation to a target displacement is contingent on the explicitness of the target perturbation, whether this is achieved by manipulating stimulus timing or instruction.
authors.affiliation: School of Human Kinetics, University of British Columbia, 6081 University Blvd., Vancouver, BC, V6T 1Z1, Canada.
authors.forename: Brendan D
authors.initials: BD
authors.lastname: Cameron
authors.forename: Ian M
authors.initials: IM
authors.lastname: Franks
authors.forename: J Timothy
authors.initials: JT
authors.lastname: Inglis
authors.forename: Romeo
authors.initials: R
authors.lastname: Chua
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001364:Awareness / Q000502:physiology; D005133:Eye Movements / Q000502:physiology; D056228:Feedback, Sensory / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology
references.citation: J Cogn Neurosci. 2007 Feb;19(2):341-50
references.pmid: 17280521
references.citation: Exp Brain Res. 2008 Sep;190(3):251-64
references.pmid: 18629484
references.citation: Neural Netw. 1996 Nov;9(8):1265-1279
references.pmid: 12662535
references.citation: Vision Res. 1996 Apr;36(7):985-96
references.pmid: 8736258
references.citation: Nat Neurosci. 1999 Jun;2(6):563-7
references.pmid: 10448222
references.citation: Neurology. 1983 Jun;33(6):766-72
references.pmid: 6682520
references.citation: Nature. 1996 Oct 17;383(6601):618-21
references.pmid: 8857536
references.citation: PLoS Biol. 2006 Jun;4(6):e179
references.pmid: 16700627
references.citation: Nature. 1986 Apr 24-30;320(6064):748-50
references.pmid: 3703000
references.citation: J Cogn Neurosci. 2006 Jan;18(1):75-83
references.pmid: 16417684
references.citation: J Neurophysiol. 2007 Jul;98(1):54-62
references.pmid: 17507504
references.citation: Exp Brain Res. 2004 Jun;156(4):399-408
references.pmid: 15133651
references.citation: Exp Brain Res. 1999 Apr;125(4):410-6
references.pmid: 10323286
references.citation: J Neurosci. 1994 May;14(5 Pt 2):3208-24
references.pmid: 8182467
references.citation: J Neurosci. 2006 Apr 5;26(14):3642-5
references.pmid: 16597717
references.citation: Nat Rev Neurosci. 2006 Jul;7(7):511-22
references.pmid: 16791141
references.citation: J Neurophysiol. 2009 Feb;101(2):655-64
references.pmid: 19019979
references.citation: Trends Cogn Sci. 2001 Nov 1;5(11):487-494
references.pmid: 11684481
references.citation: Exp Brain Res. 1986;62(2):303-11
references.pmid: 3709715
references.citation: Eur J Neurosci. 2008 Oct;28(8):1696-704
references.pmid: 18973586
references.citation: Exp Brain Res. 2009 Mar;193(3):337-50
references.pmid: 19011846
references.citation: J Neurosci. 2005 Oct 26;25(43):9919-31
references.pmid: 16251440
references.citation: J Neurosci. 2009 Jan 7;29(1):169-78
references.pmid: 19129395
references.citation: Neurosci Biobehav Rev. 2005 May;29(3):431-44
references.pmid: 15820548
references.citation: Exp Brain Res. 1989;78(3):575-87
references.pmid: 2612600
references.citation: J Neurophysiol. 1999 Apr;81(4):1960-5
references.pmid: 10200230