Layer-dependent loss and enhancement of geniculostriate and retinotectal pathways in adult human amblyopia

Abnormal visual experience during critical period leads to reorganization of neuroarchitectures in primate visual cortex. However, developmental plasticity of human subcortical visual pathways remains elusive. Using high-resolution fMRI and pathway-selective visual stimuli, we investigated layer-dependent response properties and connectivity of subcortical visual pathways of adult human amblyopia. Stimuli presented to the amblyopic eye showed selective response loss in the parvocellular layers of the lateral geniculate nucleus, and also reduced the connectivity to V1. Amblyopic eye's response to isoluminant chromatic stimulus was significantly reduced in the superficial layers of the superior colliculus, while the fellow eye's response robustly increased in the deeper layers associated with increased cortical feedbacks. Therefore, amblyopia led to selective reduction of parvocellular feedforward signals in the geniculostriate pathway, whereas loss and enhancement of parvocellular feedback signals in the retinotectal pathway. These findings shed light for future development of new tools for treating amblyopia and tracking the prognosis.

Download Full-text

Cortical Alterations by the Abnormal Visual Experience beyond the Critical Period: A Resting-state fMRI Study on Constant Exotropia

Current Eye Research ◽

10.1080/02713683.2019.1639767 ◽

2019 ◽

Vol 44 (12) ◽

pp. 1386-1392

Author(s):

Hongmei Shi ◽

Yanming Wang ◽

Xuemei Liu ◽

Lin Xia ◽

Yao Chen ◽

...

Keyword(s):

Resting State ◽

Critical Period ◽

Visual Experience ◽

Resting State Fmri ◽

Fmri Study ◽

Abnormal Visual

Download Full-text

Binocular integration of perceptually suppressed visual information in amblyopia

10.1101/2020.06.04.20122440 ◽

2020 ◽

Author(s):

Amy Chow ◽

Andrew E. Silva ◽

Katelyn Tsang ◽

Gabriel Ng ◽

Cindy Ho ◽

...

Keyword(s):

Visual Processing ◽

Visual Information ◽

Critical Period ◽

Visual Experience ◽

Early Stage ◽

Neurodevelopmental Disorder ◽

Conscious Awareness ◽

Interocular Suppression ◽

Abnormal Visual ◽

The Brain

Abnormal visual experience during an early critical period of visual cortex development can lead to a neurodevelopmental disorder of vision called amblyopia. A key feature of amblyopia is interocular suppression, whereby information from the amblyopic eye is blocked from conscious awareness when both eyes are open. Suppression of the amblyopic eye is thought to occur at an early stage of visual processing and to be absolute. Using a binocular rivalry paradigm, we demonstrate that suppressed visual information from the amblyopic eye remains available for binocular integration and can influence overall perception of stimuli. This finding reveals that suppressed visual information continues to be represented within the brain even when it is blocked from conscious awareness by chronic pathological suppression. These results have direct implications for the clinical management of amblyopia.

Download Full-text

‘The Days of Thy Youth’

10.1093/oso/9780198814221.003.0012 ◽

2018 ◽

Author(s):

Elizabeth Bouldin

Keyword(s):

Eighteenth Century ◽

Women Educators ◽

Critical Period ◽

Future Generations ◽

Leading Role ◽

Printed Word ◽

Shed Light ◽

Quaker Women

This chapter explores the range of ideas and activities that engaged Quaker women educators during the eighteenth century, a critical period in the development of Friends’ educational efforts. It analyses key writings of Deborah Bell, Rebecca Jones, and Priscilla Wakefield. These women adopted a variety of approaches to instructing youth, ranging from informal mentorship to formal teaching that stressed a ‘guarded’ (Quaker-only) environment. Bell, Jones, and Wakefield shed light on the leading role that Quaker women played in the education and socialization of young Friends. Their writings highlight the importance of the meetinghouse, the schoolhouse, and the printed word as public venues for women who sought to instil Quaker values in future generations.

Download Full-text