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Updated: Aug 16, 2026

Preterm EEG: A Multimodal Neurophysiological Protocol
Published on: February 18, 2012
Motion- and orientation-specific cortical responses in infancy
Oliver Braddick1, Deirdre Birtles, John Wattam-Bell
1Department of Experimental Psychology, University of Oxford, UK. oliver.braddick@psy.ox.ac.uk
Insights
Infant visual cortex develops orientation selectivity early. Direction selectivity emerges later, appearing around 11-13 weeks, suggesting separate developmental timelines for visual processing in infants.
Area of Science:
- Neuroscience
- Developmental Psychology
- Visual Neuroscience
Background:
- Infants develop visual evoked potential (VEP) responses in early infancy.
- These VEPs indicate the emergence of cortical orientation-selectivity and directional motion selectivity.
- The precise timing and intrinsic nature of direction selectivity development remain unclear.
Purpose of the Study:
- To investigate if the later development of directional motion selectivity in infants is intrinsic.
- To determine if stimulus characteristics influence the emergence of direction selectivity.
- To directly compare the development of orientation and direction selectivity in the same infants.
Main Methods:
- Recorded steady-state orientation-reversal (OR-) VEPs and direction-reversal (DR-) VEPs in infants aged 4-18 weeks.
- Utilized random pixel patterns and gratings for DR-VEPs at various velocities and reversal rates.
- Compared DR-VEP emergence across different stimulus types, speeds, and reversal rates.
Main Results:
- All infants showed significant orientation-reversal responses.
- Direction-reversal responses were present in <25% of infants under 7 weeks, rising to >80% by 11-13 weeks.
- A reversal rate of 2 Hz elicited DR-VEPs approximately 2 weeks earlier than 4 Hz stimulation.
Conclusions:
- Human cortical direction selectivity develops independently from orientation selectivity.
- Direction selectivity emerges at a later developmental stage than orientation selectivity.
- The developmental timeline for direction selectivity is robust across tested stimulus parameters.
Abstract:
During the first 3 months, infants develop visual evoked potential (VEP) responses that are signatures of cortical orientation-selectivity and directional motion selectivity. Orientation-specific cortical responses develop in early infancy. This study compared these responses directly in the same infants, to investigate whether the later appearance of direction selectivity was intrinsic, or a function of the spatio-temporal characteristics of the stimuli used. Steady-state orientation-reversal (OR-) VEPs and direction-reversal (DR-) VEPs were recorded in infants aged 4-18 weeks. DR-VEPs were elicited with random pixel patterns and with gratings spatially similar to those used for OR-VEPs, at velocities of 5.5 and 11 deg/s, and reversal rates of 2 and 4 reversals/s. Infants throughout the age range showed significant responses to orientation-reversal. Direction-reversal responses appeared in less than 25% of infants under 7 weeks of age, rising to 80% or more at 11-13 weeks, whether tested with dots or gratings and for both speeds and reversal rates. However, 2 reversals/s elicits the DR-VEP on average about 2 weeks earlier than 4 reversal/s stimulation. We conclude that human cortical direction selectivity develops separately from orientation-selectivity and emerges at a later age, even with tests that are designed to optimise the former.
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