The deep cerebellar nuclei (DCN) integrate various inputs to the cerebellum and form the final cerebellar outputs critical for associative sensorimotor learning. However, the functional relevance of distinct neuronal subpopulations within the DCN remains poorly understood. Here, we examined a subpopulation of mouse DCN neurons whose axons specifically project to the ventromedial (Vm) thalamus (DCN^Vm neurons), and found that these neurons represent a specific subset of DCN units whose activity varies with trace eyeblink conditioning (tEBC), a classical associative sensorimotor learning task. Upon conditioning, the activity of DCN^Vm neurons signaled the performance of conditioned eyeblink responses (CRs). Optogenetic activation and inhibition of the DCN^Vm neurons in well-trained mice amplified and diminished the CRs, respectively. Chemogenetic manipulation of the DCN^Vm neurons had no effects on non-associative motor coordination. Furthermore, optogenetic activation of the DCN^Vm neurons caused rapid elevated firing activity in the cingulate cortex, a brain area critical for bridging the time gap between sensory stimuli and motor execution during tEBC. Together, our data highlights DCN^Vm neurons' function and delineates their kinematic parameters that modulate the strength of associative sensorimotor responses.
Animals ; Blinking ; Cerebellar Nuclei/physiology* ; Cerebellum ; Mice ; Neurons/physiology* ; Thalamus

PURPOSE: We investigated the incidence of exposure keratopathy, cornea protective changes in tear film such as corneal sensitivity, tear film stability, and tear secretion after frontalis suspension, and the correlation of these with lagophthalmos. METHODS: The corneal sensitivity test, tear film break-up time (tBUT) measurement, and basic secretion test were performed prospectively in patients who had undergone frontalis suspension. RESULTS: The mean lagophthalmos was highest at postoperative 1 week and then gradually decreased. There were no significant changes in corneal sensitivity, tBUT or tear secretion after surgery. No significant differences were found in those parameters between eyes with lagophthalmos of 3 mm or more and those less than 3 mm, nor did these parameters differ between eyes with clear cornea and exposure keratopathy. Only tBUT at postoperative 1 week was significantly shorter in eyes with lagophthalmos 3 mm or more than those less than 3 mm. The average level of lagophthalmos in eyes with exposure keratopathy (15/33 eyes, 45.4%) was more than 3mm at every follow-up period, which was significantly higher than for eyes with a clear cornea. CONCLUSIONS: Tear physiology tends to maintain normal function despite poor blinking induced by lagophthalmos. The cornea is thought to be protected by these functions of tear film. The factor most influential on cornea status was the level of lagophthalmos, and exposure keratopathy should be carefully examined during postoperative period in eyes with higher lagophthalmos, especially more than 3 mm.
Blinking ; Cornea ; Follow-Up Studies ; Humans ; Incidence ; Physiology ; Postoperative Period ; Prospective Studies ; Tears*

PURPOSE: To evaluate the results of levator resection in patients with myopathic ptosis. METHODS: The medical records of consecutive patients who underwent levator resection surgery performed for myopathic ptosis between October 2009 and March 2013 were reviewed. Indications for surgery were ptosis obscuring the visual axis and margin-reflex distance < or =2 mm. Surgical success was defined as clear pupillary axis when the patient voluntarily opened his eye and margin-reflex distance > or =3 mm. We analyzed the effect of levator function and Bell's phenomenon on the rates of success and corneal complication. RESULTS: This series included six male and six female patients. Levator function was between 4 and 12 mm. We performed bilateral levator resection surgery in all patients. The mean follow-up time was 14.8 months (range, 6 to 36 months). No patient was overcorrected. Adequate lid elevation was achieved after the operation in 20 eyes. Ptosis recurred in three out of 20 eyes after adequate lid elevation was achieved. Our overall success rate was 70.8%. In three eyes with poor Bell's phenomenon, corneal irritation and punctate epitheliopathy that required artificial eye drops and ointments developed in the early postoperative period, although symptoms resolved completely within 2 months of the resection surgery. No patients required levator recession or any other revision surgery for lagophthalmos or corneal exposure after levator resection. CONCLUSIONS: Levator resection seems to be a safe and effective procedure in myopathic patients with moderate or good Bell's phenomenon and levator function greater than 5 mm.
Adult ; Aged ; Blepharoptosis/*surgery ; Blinking/physiology ; Female ; Humans ; Male ; Middle Aged ; Muscular Diseases/*surgery ; Oculomotor Muscles/*surgery ; *Ophthalmologic Surgical Procedures ; Postoperative Complications