Related Experiment Video
Updated: Jul 6, 2026
07:26
Assessing Pupil-linked Changes in Locus Coeruleus-mediated Arousal Elicited by Trigeminal Stimulation
Published on: November 26, 2019
Are locus coeruleus neurons involved in blinking?
Céline Dauvergne1, Albertine Ellen Smit, Jocelyne Valla
1Laboratoire de Physiologie de la Manducation, UP7, 4 place Jussieu, 75252 Paris Cedex 05, France.
Neuroscience Research
|April 11, 2008
Summary
The noradrenergic locus coeruleus (LC) participates in the reflex blink circuit. This study identified a sensory trigeminal complex-LC-superior colliculus loop involved in this reflex.
Area of Science:
- Neuroscience
- Ophthalmology
Background:
- The reflex blink circuit is crucial for ocular protection.
- The role of the noradrenergic locus coeruleus (LC) in this circuit is not fully understood.
Purpose of the Study:
- To investigate the involvement of the LC in the reflex blink circuit in rats.
- To elucidate the neural pathways connecting the LC to the reflex blink circuit.
Main Methods:
- Utilized c-Fos protein expression to identify active LC neurons following supraorbital nerve stimulation.
- Employed anterograde and retrograde neuronal tracers to map connections within the sensory trigeminal complex (STC), LC, and superior colliculus (SC).
Main Results:
- Localized LC neurons involved in reflex blinking via c-Fos expression after supraorbital nerve stimulation.
- Demonstrated trigemino-coerulear connections using anterograde tracing from the STC.
- Established coerulear-collicular connections using retrograde tracing from the SC.
- Identified a specific population of LC neurons projecting to the latero-caudal SC that are activated during reflex blinking.
Conclusions:
- Revealed the existence of a sensory trigeminal complex-locus coeruleus-superior colliculus (STC-LC-SC) loop.
- This loop is implicated in the neural circuitry of the reflex blink response.
Related Concept Videos
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
01:20Muscles of the Eye
The muscles of the eye are sophisticated structures that control eye movement and focus, allowing for the precise and rapid adjustments necessary for vision. The human eye is controlled by ten muscles — six extraocular muscles, three intraocular muscles, and one primary eyelid retractor muscle.
Extraocular Muscles
The six extraocular muscles surround the eyeball and control its movements. They are responsible for a wide range of eye motions, including looking up, down, left, right, and rotating...
Extraocular Muscles
The six extraocular muscles surround the eyeball and control its movements. They are responsible for a wide range of eye motions, including looking up, down, left, right, and rotating...
01:17Accessory Structures of the Eye
Optical perception, or vision, is an extraordinary sense dependent on converting light signals received via the ocular organs. These organs, known as eyes, are securely positioned within the bony cavities of the skull, called orbits. The orbits serve a dual purpose: a protective shield for the ocular globes and a stable attachment point for the soft ocular tissues. The eye's external protective mechanisms include the eyelids, which are edged with lashes that act as a barrier against foreign...
01:13Functional Brain Systems: Reticular Formation
The reticular formation is a complex network of gray and white matter located within the brainstem extending from the medulla to the midbrain.
Within the reticular formation, there are several distinct nuclei that can be classified into three broad categories. The Raphe nuclei are located along the midline of the brainstem. They are primarily known for their role in synthesizing and releasing serotonin, a neurotransmitter involved in regulating mood, appetite, sleep, and circadian rhythms. The...
Within the reticular formation, there are several distinct nuclei that can be classified into three broad categories. The Raphe nuclei are located along the midline of the brainstem. They are primarily known for their role in synthesizing and releasing serotonin, a neurotransmitter involved in regulating mood, appetite, sleep, and circadian rhythms. The...
01:21Brainstem: Control Centers of Medulla
The medulla oblongata is a crucial part of the brainstem responsible for controlling various autonomic and involuntary functions. It contains several nuclei, including the olivary, cuneate, gracile, and solitary nuclei.
Olivary Nucleus
The olivary nucleus, or inferior olivary nucleus, is located within the ventrolateral part of the medulla oblongata. It is primarily involved in motor coordination and motor learning. The olivary nucleus receives input from the spinal cord, cerebellum, and motor...
Olivary Nucleus
The olivary nucleus, or inferior olivary nucleus, is located within the ventrolateral part of the medulla oblongata. It is primarily involved in motor coordination and motor learning. The olivary nucleus receives input from the spinal cord, cerebellum, and motor...
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...