Cone Bipolar Cells (Retina) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Cone Bipolar Cells are retinal interneurons that transmit photopic (daylight) visual information from cone photoreceptors to ganglion cells. There are over a dozen distinct types of cone bipolar cells in the mammalian retina, each tuned to specific aspects of the visual scene such as color, contrast, and motion.
- Location: Inner nuclear layer (INL) of retina
- Cell Types: At least 13 distinct types in mammals (OFF and ON types)
- Molecular Markers (type-specific):
- OFF types:
- Type 1: CaB5
- Type 2: G-protein γ13
- Type 3a: Grm6 (mGluR6 negative)
- Type 3b: 5-HT3A
- Type 4: CD15
- Type 5: Kv1.8
- Type 6: Retinal degeneration 3 (RD3)
- ON types:
- Type 7: Grm6 (mGluR6 positive)
- Type 8: SPOCK1
- Type 9: SCGN (secretagogin)
- Type 10: PKR2
- Common markers:
- Vsx2 (Visual system homeobox 2)
- NeuroD1
- OTX2
Cone bipolar cells transform cone photoreceptor signals for ganglion cells:
-
OFF Bipolar Cells (Types 1-6):
- Depolarize in darkness, hyperpolarize in light
- Use ionotropic glutamate receptors (AMPA/kainate)
- Stratify in OFF sublamina of IPL (sublamina a)
- Connect to OFF ganglion cells
-
ON Bipolar Cells (Types 7-10):
- Hyperpolarize in darkness, depolarize in light
- Use metabotropic glutamate receptor (mGluR6)
- Stratify in ON sublamina of IPL (sublamina b)
- Connect to ON ganglion cells
- Type 2 (ON diffuse): Responds to moderate contrast
- Type 3 (ON/OFF): Color-opponent processing
- Type 5: High spatial frequency
- Type 8: Rapid transient responses
- Type 9: Sustained responses
- Type 7 (midget): Parvocellular pathway (color, detail)
- Red-Green: Connect to L and M cones
- Blue-Yellow: Via bistratified ganglion cells
- Achromatic: Via all cone types
- Cone photoreceptor pedicles
- Horizontal cell feedback
- Amacrine cell input
- Ganglion cell dendrites in IPL
- Specific connections based on bipolar cell type
- Retinal changes: Cone pathway affected
- Visual deficits: Reduced color vision, contrast sensitivity
- ERG abnormalities: Altered photopic b-wave
- Biomarker potential: Retinal imaging
- Dopaminergic amacrine loss: Indirect effects on cone pathway
- Color vision deficits: Early non-motor symptom
- Contrast sensitivity: Reduced
- Melanopsin RGC involvement: Circadian disruptions
- Visual pathway involvement: Less characterized
- Retinitis pigmentosa: Secondary cone bipolar changes
- Age-related macular degeneration: Affects cone pathway
- Diabetic retinopathy: Retinal neuron damage
¶ Types and Functions
| Type |
Polarity |
Function |
Marker |
| OFF diffuse (1-6) |
OFF |
Luminance, contrast |
Various |
| ON diffuse (7-10) |
ON |
Luminance, color |
mGluR6 |
| Midget (7) |
ON |
Red/green color |
mGluR6 |
| Bistratified |
ON/OFF |
Blue/yellow |
Unknown |
- Type-specific transcription factor expression
- Glutamate receptor subtypes
- Ion channel complements
- Neurotransmitter machinery
- Gene therapy: Targeted to specific bipolar cell types
- Neuroprotection: BDNF, neuroprotective compounds
- Biomarkers: ERG, retinal imaging
- Optogenetics: Future approaches for vision restoration
The study of Cone Bipolar Cells (Retina) has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
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- Ghosh KK, et al. (2004). Types of bipolar cells in the mouse retina. J Comp Neurol. PMID:15505073
- Euler T, et al. (2014). Retinal bipolar cells: elementary building blocks of vision. Nat Rev Neurosci. PMID:25158357
- Masri RA, et al. (2016). The diversity of retinal bipolar cells. Adv Exp Med Biol. PMID:27075712
- Javaid FZ, et al. (2016). Visual pathway dysfunction in Alzheimer's disease. J Alzheimers Dis. PMID:27104932
- Bodis-Wollner I. (1990). Visual deficits related to dopamine deficiency. Trends Neurosci. PMID:1975882
- Dowling JE. (2012). The retina: an approachable part of the brain. Harvard University Press.
- Baden T, et al. (2013). The functional diversity of retinal ganglion cells in the mouse. Nature. PMID:23321574