The deep layers of the superior colliculus (SC) constitute a critical integration center for multimodal sensory information and the generation of orienting responses including eye movements, head movements, and attention shifts. Neurons in the stratum griseum profundum (SGP) and stratum album profundum (SAP) receive convergent visual, auditory, and somatosensory inputs to coordinate behavioral responses to salient stimuli. Dysfunction of deep SC neurons contributes to attention deficits, visuospatial impairments, and gait disturbances in neurodegenerative diseases.[1]
| Property | Value |
|---|---|
| Location | Dorsal midbrain tectum |
| Layers | Stratum griseum profundum, stratum album profundum |
| Cell Types | Saccade-related, fixation, multimodal integration |
| Key Inputs | Visual cortex, basal ganglia, parietal cortex |
| Key Outputs | Brainstem premotor areas, thalamus, spinal cord |
| Clinical Relevance | PSP, Parkinson's disease, Alzheimer's disease |
The superior colliculus has seven layers, with the deep layers including:[2]
Deep SC neurons include several functional classes:[3]
| Cell Type | Properties | Function |
|---|---|---|
| Saccade-related burst neurons | Pre-motor burst before saccade | Eye movement command |
| Fixation neurons | Tonic firing during fixation | Maintain gaze position |
| Buildup neurons | Gradually increasing activity | Saccade target selection |
| Multisensory neurons | Convergent visual-auditory-somatosensory | Spatial orientation |
| Omni-stop neurons | Fire at saccade termination | Movement termination |
Major inputs to deep SC:[4]
Major outputs from deep SC:[5]
Deep SC neurons encode saccade vectors using a place code:[6]
Deep SC neurons demonstrate multisensory integration principles:[7]
The SC contributes to attention allocation:[8]
Deep SC is prominently affected in PSP:[9]
| Pathological Change | Clinical Manifestation |
|---|---|
| SC neuronal loss | Slow, hypometric saccades |
| Tau pathology in SC | Vertical gaze limitation |
| Brainstem gliosis | Square wave jerks |
| Reduced SC volume | Impaired antisaccades |
Saccadic deficits in PSP include:[10]
SC dysfunction contributes to non-motor features in PD:[11]
The basal ganglia-SC pathway is affected in PD:[12]
Visual attention deficits in AD involve SC dysfunction:[13]
SC-related deficits in HD include:[14]
Assessment of deep SC function includes:[15]
SC can be evaluated with:[16]
Eye movement training may help neurodegenerative patients:[17]
SC as a potential DBS target:[18]
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Hikosaka O, Takikawa Y, Kawagoe R. Role of the basal ganglia in the control of purposive saccadic eye movements. Physiological Reviews. 2000;80(3):953-978. https://doi.org/10.1152/physrev.2000.80.3.953. 2000. ↩︎
Gandhi NJ, Katnani HA. Motor functions of the superior colliculus. Annual Review of Neuroscience. 2011;34:205-231. https://doi.org/10.1146/annurev-neuro-061010-113728. 2011. ↩︎
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Stein BE, Stanford TR. Multisensory integration: current issues from the perspective of the single neuron. Nature Reviews Neuroscience. 2008;9(4):255-266. https://doi.org/10.1038/nrn2331. 2008. ↩︎
Krauzlis RJ, Lovejoy LP, Zénon A. Superior colliculus and visual spatial attention. Annual Review of Neuroscience. 2013;36:165-182. https://doi.org/10.1146/annurev-neuro-062012-170249. 2013. ↩︎
Steele JC, Richardson JC, Olszewski J. Progressive supranuclear palsy. A heterogeneous degeneration involving the brain stem, basal ganglia and cerebellum with vertical gaze and pseudobulbar palsy, nuchal dystonia and dementia. Archives of Neurology. 1964;10(4):333-359. https://doi.org/10.1001/archneur.1964.00460160003001. 1964. ↩︎
Bhidayasiri R, Riley DE, Somers JT, et al. Pathophysiology of slow vertical eye movements in progressive supranuclear palsy. Annals of Neurology. 2001;50(5):638-644. https://doi.org/10.1002/ana.1252. 2001. ↩︎
Terao Y, Fukuda H, Ugawa Y, Hikosaka O. New perspectives on the pathophysiology of Parkinson's disease as assessed by saccade performance: a clinical review. Clinical Neurophysiology. 2013;124(8):1491-1506. https://doi.org/10.1016/j.clinph.2013.01.021. 2013. ↩︎
Hikosaka O, Wurtz RH. Visual and oculomotor functions of monkey substantia nigra pars reticulata. I. Relation of visual and auditory responses to saccades. Journal of Neurophysiology. 1983;49(5):1230-1253. https://doi.org/10.1152/jn.1983.49.5.1230. 1983. ↩︎
Scinto LF, Daffner KR, Dressler D, et al. A potential noninvasive neurobiological test for Alzheimer's disease. Science. 1994;266(5187):1051-1054. https://doi.org/10.1126/science.7973660. 1994. ↩︎
Lasker AG, Zee DS, Hain TC, Folstein SE, Singer HS. Saccades in Huntington's disease: initiation defects and distractibility. Neurology. 1987;37(3):364-370. https://doi.org/10.1212/wnl.37.3.364. 1987. ↩︎
Leigh RJ, Zee DS. The Neurology of Eye Movements. 5th ed. New York: Oxford University Press; 2015. https://doi.org/10.1093/med/9780199969679.001.0001. 2015. ↩︎
Gallea C, Popa T, Hubsch C, et al. Intrinsic connectivity of the superior colliculus in humans. Human Brain Mapping. 2014;35(4):1454-1466. https://doi.org/10.1002/hbm.22262. 2014. ↩︎
Anderson TJ, MacAskill MR. Eye movements in patients with neurodegenerative disorders. Nature Reviews Neurology. 2013;9(2):74-85. https://doi.org/10.1038/nrneurol.2013.274. 2013. ↩︎
Coizet V, Overton PG, Redgrave P. Collateralization of the tectonigral projection with other major output pathways of superior colliculus in the rat. Journal of Comparative Neurology. 2007;500(6):1034-1049. https://doi.org/10.1002/cne.21234. 2007. ↩︎