scholarly journals Connections between intrinsically photosensitive retinal ganglion cells and TBI symptoms

Neurology ◽  
2020 ◽  
Vol 95 (18) ◽  
pp. 826-833
Author(s):  
Jason Elenberger ◽  
Bohan Kim ◽  
Alexander de Castro-Abeger ◽  
Tonia S. Rex
Keyword(s):  
Retinal Ganglion Cells ◽  
Sleep Disturbances ◽  
Sleep Problems ◽  
Ganglion Cells ◽  
Light Sensitivity ◽  
Retinal Ganglion ◽  
Root Cause ◽  
Light Sensing ◽  
Pupillary Constriction ◽  
Anxiety Depression

The majority of patients with traumatic brain injury (TBI) are classified as having a mild TBI. Despite being categorized as mild, these individuals report ongoing and complex symptoms, which negatively affect their ability to complete activities of daily living and overall quality of life. Some of the major symptoms include anxiety, depression, sleep problems, headaches, light sensitivity, and difficulty reading. The root cause for these symptoms is under investigation by many in the field. Of interest, several of these symptoms such as headaches, ocular pain, light sensitivity, and sleep disturbances may overlap and share underlying circuitry influenced by the intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells are light sensing, but non–image forming, and they influence corneal function, pupillary constriction, and circadian rhythm. In this review, we discuss these symptoms and propose a role of the ipRGCs as at least one underlying and unifying cause for such symptoms.

Electrophysiology of retinal ganglion cells in the mouse: a study of a normally pigmented mouse and a congenic hypopigmentation mutant, pearl

1982 ◽  
Vol 48 (4) ◽  
pp. 968-980 ◽  
Author(s):  
G. W. Balkema ◽  
L. H. Pinto
Keyword(s):  
Receptive Field ◽  
Retinal Ganglion Cells ◽  
White Light ◽  
Light Adaptation ◽  
Ganglion Cells ◽  
Action Spectrum ◽  
Receptive Fields ◽  
Light Sensitivity ◽  
Retinal Ganglion ◽  
Criterion Response

1. The organization of the receptive fields of retinal ganglion cells in te normal mouse was studied qualitatively in recordings from 43 single axons in the optic nerve and optic tract, and the light sensitivity was studied quantitatively in 26 of these cells by measuring incremental sensitivity. 2. The receptive fields of normal animals were elliptical, had concentric center and peripheral subdivisions, and had an antagonistic center/surround organization; the receptive-field centers ranged from 1.95 to 83 degrees in diameter, with a median of 7 degrees. 3. The incremental sensitivity to white light was measured using a criterion response of 10 extra spikes; the most sensitive dark-adapted cell required a stimulus luminance of 3.5 x 10(-3) cd/m2 to generate a criterion response. 4. The action spectrum measured at seven different wavelengths (433-619 nm) from ganglion cells in the normally pigmented mouse resembled the CIE (International Commission on Illumination, CIE 1957 (11)) relative scotopic luminous efficiency function (41) and is consistent with a curve having a peak around 500 nm. 5. On light adaptation with blue light (less than 460 nm), the sensitivity to longer wavelength stimuli increased by 0.2-0.5 log units relative to the sensitivity to the shorter wavelengths; these results are compatible with the presence of a photoreceptor sensitive to long wavelengths in the normally pigmented mouse (C57BL/6J+/+). 6. The organization of the receptive fields of 48 retinal ganglion cells from the hypopigmentation mutant pearl (C57BL/6J-pe) was also studied qualitatively; the receptive field organization was similar to that of the normally pigmented mouse. 7. In 25 cells from dark-adapted pearl mice, the incremental sensitivity to white light was, on the average, 1.6 log units less than that for normal mice. 8. The dark-adapted action spectrum of pearl mice was similar to that of normally pigmented mice. However, a shift in sensitivity to longer wavelengths did not occur on selective light adaptation with the most luminous blue light (less than 460 nm) background that we could produce. 9. We conclude that pearl is one of the mammalian genes that codes for functions that affect dark-adapted retinal sensitivity. The results of this study and past studies suggest that the pearl gene's action on light sensitivity is predominantly within the retina and before (distal to) the ganglion cells.

Calcium Signals Induced By Tonic Firing In Rat Retinal Ganglion Cells

2012 ◽  
Vol 3 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Kyril I. Kuznetsov ◽  
Vitaliy Yu. Maslov ◽  
Svetlana A. Fedulova ◽  
Nikolai S. Veselovsky
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Calcium Signals ◽  
Tonic Firing

Objective Measurement of Sustained Pupillary Constriction: A Pilot Study Using an App-Based Pupilometer

2020 ◽  
pp. 57-63
Keyword(s):  
Ganglion Cells ◽  
Modern Technology ◽  
Objective Measurement ◽  
Retinal Ganglion ◽  
Case Examples ◽  
Pupillary Reaction ◽  
Sympathetic Nervous Systems ◽  
Pupillary Constriction ◽  
The Individual ◽  
The Right

Background: The pupillary reaction is controlled by the two main branches of the autonomic nervous system, namely the parasympathetic and sympathetic nervous systems. New discoveries in pupil research has identified that intrinsically photosensitive retinal ganglion cells have an impact on pupillary constriction, particularly sustained pupillary constriction. In the current paper, an objective measurement of sustained pupillary constriction versus the inability to maintain sustained pupillary constriction are observed. The variability in the sustained pupillary constriction, i.e. Alpha Omega pupil, can be objectively identified with the use of modern technology. Case Examples: Two female subjects were adapted to dim illumination, and then two objective pupil measurements of the right eye using Reflex – PLR Analyzer by BrightLamp© (Indianapolis, IN, USA) with sustained illumination were obtained. Subject 1, a 25 year-old-female, demonstrated normal ability of the pupil to constrict and sustain constriction for 10 seconds. She was used as a control for subject 2. Subject 2, a 27 year-old-female, demonstrated the inability to sustain pupillary constriction. She reported being under great psychological stress. Her pupil began to re-dilate between 2 and 3 seconds after the initial constriction. Conclusion: Objective pupillometry can be used to assist in many diagnoses and provides the clinician invaluable information on the state of the individual, and qualifications of sustained pupillary constriction can now be assessed in an objective manner.

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