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Dear Keith, making smooth pursuit eye movements without a target indeed is not impossible, as instead often claimed, although not too common. I don't know how freqeutnly this occurs in children, but in adults there are studies clearly showing this phenomenon under certain circumstannces.For example, we can pursue the reconstructed representation of a stimulus (the "percept") rather than the retinal stimulus (e.g., Steinbach 1976). Also, after stimulus offset pursuit continues for a short while (e.g., Whittaker & Eaholtz 1982), and anticipatory smooth eye movements can be volitionally controlled (e.g., Barnes et al 1997). We documented sustained (up to about 20 seconds) smooth pursuit eye movements during mental extrapolation of motion (de'Sperati and Santandrea 2005). Arousal/attention level seems to be a relevant factor, and perhaps children have a different relationship between arousal/attention, saccades and smooth pursuit. All the best _______________________________________________ Claudio de'Sperati, PhD Associate Professor, Università Vita-Salute San Raffaele Via Olgettina 58, 20132 Milano, Italy Phone no. +39 02 2643 4859, Fax no. +39 02 2643 4892 Home page: http://www.unisr.it/docenti/ricerca/desperati/ _______________________________________________ ----- Original Message ----- From: "Ramesh Mishra" <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, March 14, 2008 5:21 AM Subject: Re: [EM_LIST] smooth pursuit without a target > A very good observation indeed. I too have seen so sometimes. > Ramesh Mishra > > > On 3/14/08, Keith_Karn <[log in to unmask]> wrote: > > Dear Eye-movement list members - > > The other day I was watching my 5 year old daughter learn to roll her > > eyes. I was surprised by what I saw - not that a 5 year old rolling her > > eyes isn't surprise enough. ;-) It appeared that she was marking > > smooth (pursuit-like) eye movements without a target. I've just > > observed a few others trying a similar movement (moving the eyes back > > and forth while close to their maximum deviation in the orbit). It > > appears that others can make similar movements. Has this type of eye > > movement been previously documented? > > > > Keith Karn > > [log in to unmask] > > > > -- > > EYE-MOVEMENT mailing list ([log in to unmask]) > > N.B. Replies are sent to the list, not the sender > > To unsubscribe, etc. see http://www.jiscmail.ac.uk/files/eye-movement/introduction.html > > Other queries to list owner at [log in to unmask] > > > > > -- > Ramesh Kumar Mishra PhD > Centre for Behavioural and Cognitive Science > University of Allahabad > Allahabad 211002 > India > Email:[log in to unmask] > Ph-91-0532-2460738 ( work) > Mob-91-9451872007 > Fax-91-0532-2460738( work) > Personal page: http://www.cbcs.ac.in/~rkmishra.htm > Home page: www.cbcs.ac.in > > -- > EYE-MOVEMENT mailing list ([log in to unmask]) > N.B. Replies are sent to the list, not the sender > To unsubscribe, etc. see http://www.jiscmail.ac.uk/files/eye-movement/introduction.html > Other queries to list owner at [log in to unmask] -- EYE-MOVEMENT mailing list ([log in to unmask]) N.B. Replies are sent to the list, not the sender To unsubscribe, etc. see http://www.jiscmail.ac.uk/files/eye-movement/introduction.html Other queries to list owner at [log in to unmask]