Ans. a. Mid pontine lesions (Ref: style="font-size: 1.04761904761905em; font-family: Times New Roman, Times, serif">.edu/s3/chapter07.html)The Blink Reflex Test (BRT) is a neurophysiological examination used for evaluation of brainstem reflex circuits.:In vertebrate anatomy the brainstem (or brain stem ) is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. It is usually described as including the medulla oblongata (myelencephalon), pons (part of metencephalon), and midbrain (mesencephalon).Pons:The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and postureA number of cranial nerve nuclei are present in the ponsMid-pons: the 'chief' or 'pontine' nucleus of the trigeminal nerve sensory nucleus (V)Mid-pons: the motor nucleus for the trigeminal nerve (V)Lower down in the pons: abducens nucleus (VI)Lower down in the pons: facial nerve nucleus (VII)Lower down in the pons: vestibulocochlear nuclei (vestibular nuclei and cochlear nuclei) (VIII)The corneal eye blink reflex neural circuit consists ofTrigeminal 1deg afferent (free nerve endings in the cornea, trigeminal nerve, ganglion, root, and spinal trigeminal tract), which end on - Trigeminal 2deg afferent in the spinal trigeminal nucleus, some of which send their axons to - Reticular formation intemeurons, which send their axons bilaterally to - Facial motor neurons in the facial nucleus, which send their axons in the facial nerve to - Orbicularis oculi, which functions to lower the eyelid