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Short answer
The superior colliculus (Latin name: colliculus superior) is a layered structure at the roof, or tectum, of the midbrain. Its best-established function is orienting: it helps generate saccadic eye movements and gaze shifts toward objects of interest. Research also links it to covert attention, defensive behaviour and perceptual decisions.
Definition and scope
Basso and May describe the superior colliculus (SC) as a layered structure at the roof (tectum) of the midbrain and as a critical node in the network that reorients an organism toward objects of interest (Basso and May, 2017). “Colliculus superior” is the Latin anatomical form of the same name; searchers use both, and this page treats them as one structure.
In birds and other non-mammals the homologous structure is the optic tectum. The same review notes that mammalian colliculi and non-mammalian optic tecta both serve orienting, so the literature on the two is often read together.
How the superior colliculus is organised
The layers fall into two divisions (Basso and May, 2017). The dorsal, visuosensory division contains the stratum zonale, the stratum griseum superficiale and the stratum opticum. The ventral, motor division contains the stratum griseum intermediale and the deeper layers. Each division carries its own map: a map of visual space in the superficial layers, and a map of saccadic eye movements in the ventral layers, with auditory and somatosensory maps aligned to them.
| Feature | Superficial (visuosensory) layers | Deeper (motor) layers |
|---|---|---|
| Map | Visual space. Neurons respond almost exclusively to visual stimuli at specific locations in the contralateral hemifield (Gandhi and Katnani, 2011). | Saccadic eye movements, aligned with auditory and somatosensory maps (Basso and May, 2017). Organised for changes in gaze; no spatial organisation for other effectors has been detected (Gandhi and Katnani, 2011). |
| Main inputs | Retina (M- and K-type ganglion cells), striate and extrastriate cortex, ventral lateral geniculate nucleus, parabigeminal nucleus, pretectum and locus coeruleus. | Described as receiving inputs from virtually the entire brain and parts of the spinal cord. |
| Main outputs | To the lateral geniculate nucleus and the pulvinar. | Descending to the pons and spinal cord, and ascending to thalamic nuclei; the ascending outputs appear denser than the descending ones. |
Source for the input and output rows: Basso and May (2017).
What the superior colliculus does: functions studied
Function of the superior colliculus: saccades and gaze
The SC is essential for generating and controlling saccadic eye movements (Liu et al., 2022). Inactivating it has profound effects on gaze through the saccadic component, while skeletomotor effectors, particularly in mammals, are minimally impaired (Gandhi and Katnani, 2011). In other words, the deficit is specific to where the eyes and gaze go, not a general loss of movement.
Covert spatial attention and decisions
Inactivation studies, notably by Krauzlis and colleagues, suggest a role in the location of covert spatial attention. Basso and May add a nuance: the SC may set decision criteria rather than perceptual sensitivity, and motor-layer activity has been proposed to act as a probabilistic population code for saccade choice, not only for the saccade vector. A separate review reports that the SC plays a causal role in a visual perceptual decision-making task (Liu et al., 2022).
Defensive behaviour and prey capture
Work reviewed by Liu and colleagues links defined SC cell types to behaviour. The SC mediates visually evoked flight, through a route involving the amygdala; parvalbumin-positive (PV+) SC neurons have been shown to induce flight and freezing; and a robust pathway from the SC to GABAergic neurons of the zona incerta provokes prey-capture behaviour (Liu et al., 2022).
Superior colliculus versus optic tectum
Use “superior colliculus” for the mammalian structure and “optic tectum” for the homologous structure in birds and other non-mammals. Both are orienting centres (Basso and May, 2017). Where a paper uses a term you do not recognise, check which species it used before comparing results.
Where it matters for labs: how the SC is studied
For lab managers and researchers planning or reading SC studies, the technique used determines what a result can show. The table maps techniques named in the sources to what they have been used to show.
| Technique | What it has been used to show | Source |
|---|---|---|
| Inactivation or lesions (for example muscimol, lidocaine) | Large effects on gaze through the saccadic component, with minimal skeletomotor impairment; a role in the location of covert spatial attention. | Gandhi and Katnani, 2011; Basso and May, 2017; Liu et al., 2022 |
| Optogenetics and chemogenetics (DREADDs), with cell-type markers | Links between defined cell types (GABAergic or glutamatergic subtypes) and behaviours such as flight, freezing and prey capture. | Liu et al., 2022 |
| Viral tracing (AAV, rabies, HSV) | Connectivity: which regions send input to, and receive output from, the SC. | Liu et al., 2022 |
The same review also names electrophysiology, calcium imaging, fiber photometry, two-photon imaging, functional ultrasound imaging and single-cell transcriptomics among the methods used on the SC, and lists species including mice, rats, cats, tree shrews, hamsters, macaques, owl monkeys, marmosets, humans, zebrafish, lampreys, pigeons and amphibians. Because many of these studies use laboratory animals, institutional oversight applies: see research animal, IACUC, OLAW and the PHS Policy. For documenting a lab procedure, see standard operating procedure (SOP).
Common misunderstandings
- “It is only an eye-movement centre.” Saccades are its best-documented output, but the sources above also tie it to attention, decisions and defensive behaviour.
- “Its attention role is settled.” The attention link is inferred largely from inactivation studies, and Basso and May argue the SC may set decision criteria rather than perceptual sensitivity.
- “It is one uniform population.” Cell-type work distinguishes GABAergic subtypes (including PV+, VIP+, somatostatin+ and cholecystokinin+ cells) and glutamatergic subtypes (including Pitx2+ and Cbln2+ cells), and different types are linked to different behaviours (Liu et al., 2022).
- “Inactivating it paralyses movement.” Effects are concentrated on gaze; skeletomotor effectors are minimally impaired in mammals.
FAQ
What is the function of the superior colliculus?
It reorients an organism toward objects of interest, chiefly by generating saccadic eye movements and gaze shifts. Studies also link it to covert spatial attention, perceptual decision-making and defensive behaviours such as flight and freezing.
What does “colliculus superior” mean?
It is the Latin anatomical name for the superior colliculus, the layered structure at the roof (tectum) of the midbrain. The non-mammalian homologue is the optic tectum.
Sources
Checked 2026-10-29.
- Basso MA, May PJ. Circuits for Action and Cognition: A View from the Superior Colliculus. Annual Review of Vision Science 2017;3:197-226. DOI 10.1146/annurev-vision-102016-061234. https://pmc.ncbi.nlm.nih.gov/articles/PMC5752317
- Gandhi NJ, Katnani HA. Motor Functions of the Superior Colliculus. Annual Review of Neuroscience 2011;34:205-231. DOI 10.1146/annurev-neuro-061010-113728. https://pmc.ncbi.nlm.nih.gov/articles/PMC3641825
- Liu X, Huang H, Snutch TP, Cao P, Wang L, Wang F. The Superior Colliculus: Cell Types, Connectivity, and Behavior. Neuroscience Bulletin 2022;38(12):1519-1540. DOI 10.1007/s12264-022-00858-1. https://pmc.ncbi.nlm.nih.gov/articles/PMC9723059/
