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Light from a single point of a distant object and light from a single point of a near object being brought to a focus. The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near object, then looking at a distant object (and vice versa), comprising coordinated changes in vergence, lens shape (accommodation) and pupil size.
Hyperfocus may in some cases also be symptomatic of a psychiatric condition. In some cases, it is referred to as perseveration [2] —an inability or impairment in switching tasks or activities ("set-shifting"), [8] or desisting from mental or physical response repetition (gestures, words, thoughts) despite absence or cessation of a stimulus.
Biologically, the behavior stems primarily from the brain's need for dopamine, which fuels feelings of reward, Dr. Khalid Afzal, associate professor of psychiatry and behavioral neuroscience at ...
There are many various reflexes that can occur simultaneously during a startle response. The fastest reflex recorded in humans happens within the masseter muscle or jaw muscle. The reflex was measured by electromyography which records the electrical activity during movement of the muscles. This also showed the response latency, or the delay ...
In teleosts, by contrast, a muscle projects from a vascular structure in the floor of the eye, called the falciform process, and serves to pull the lens backwards from the relaxed position to focus on distant objects. While amphibians move the lens forward, as do cartilaginous fish, the muscles involved are not similar in
Incyclotorsion is a term applied to the inward, torsional (rotational) movement of the eye, mediated by the superior oblique muscle of the eye. The superior oblique muscle is innervated by cranial nerve IV (trochlear nerve). Incyclotorsion may also be used to describe one part of the condition of the eye when a patient has an oculomotor nerve ...
Glutamate released from the upper motor neurons triggers depolarization in the lower motor neurons in the anterior grey column, which in turn causes an action potential to propagate the length of the axon to the neuromuscular junction where acetylcholine is released to carry the signal across the synaptic cleft to the postsynaptic receptors of the muscle cell membrane, signaling the muscle to ...
The examination of the corneal reflex is a part of some neurological exams, particularly when evaluating coma, such as FOUR score. Damage to the ophthalmic branch (V 1) of the trigeminal nerve results in absent corneal reflex when the affected eye is stimulated. Stimulation of one cornea normally has a consensual response, with both eyelids ...