Conclusive Evidence for Human Transneuronal Retrograde Degeneration in the Visual System

Abstract

For several decades there was controversy concerning the existence of transneuronal retrograde degeneration in the human visual system in spite of a substantial body of data indicating this degeneration in certain species of nonhuman primate. Over the past few years, however, compelling evidence both from human magnetic resonance imaging and optical coherence tomography has shown conclusively transneuronal retrograde degeneration in both the white matter of the optic tract and in the ganglion cells of the retina. In this review the evidence for primate degeneration and degeneration in non-visual human neural systems are discussed before the presentation of the recent human data.

Macular Ganglion Cell Layer and Peripapillary Retinal Nerve Fibre Layer Thickness in Patients with Unilateral Posterior Cerebral Artery Ischaemic Lesion: An Optical Coherence Tomography Study

“…As neuro-rehabilitation techniques are being developed, a deeper knowledge of mechanisms behind the human visual system TRD could prevent the death of ganglion cells connecting to spared cortical areas. 1 Our study presents several limitations. The sample is small and heterogeneous in terms of time gap between the vascular event and study inclusion.…”

“…Transneural retrograde degeneration (TRD) occurs in presynaptic neurons after loss of postsynaptic target. 1,2 In the visual system, degeneration of retinal ganglion cells (RGCs) (second-order neurons) would follow a posterior cortical damage (third-order neurons). 1 According to classical teaching, patients with acquired damage to the postgeniculate region show no fundoscopic abnormality.…”

“…1,2 In the visual system, degeneration of retinal ganglion cells (RGCs) (second-order neurons) would follow a posterior cortical damage (third-order neurons). 1 According to classical teaching, patients with acquired damage to the postgeniculate region show no fundoscopic abnormality. However, in congenital lesions, it is described as a typical pattern of optic nerve atrophy similar to the one found in optic tract pathology.…”

“…4 In the past years, evidence of TRD in the human visual system has been emerging. 1 Newer imaging methods such as spectral-domain optical coherence tomography (SD-OCT) provide an easy in vivo visualization of the retinal ganglion cell layer (GCL) and retinal nerve fibre layer (RNFL). Peripapillary RNFL measurements have been used to characterise ganglion cell changes in posterior lesions.…”

Quantifying the pattern of optic tract degeneration in human hemianopia

“…In contrast to the literature from the macaque, the existence of TRD in the human visual system had been controversial until the application of non-invasive human imaging approaches to show conclusive evidence across multiple patients with hemianopia 14. The retinal nerve fibre layer is reduced in patients with congenital and acquired hemianopia, as shown with optical coherence tomography 15.…”