The Impact of Multivesicular Release on the Transmission of Sensory Information by Ribbon Synapses.

The statistics of vesicle release determine how synapses transfer information, but the classical Poisson model of independent release does not always hold at the first stages of vision and hearing. There, ribbon synapses also encode sensory signals as events comprising two or more vesicles released simultaneously. The implications of such coordinated multivesicular release (MVR) for spike generation are not known. Here we investigate how MVR alters the transmission of sensory information compared with Poisson synapses using a pure rate-code. We used leaky integrate-and-fire models incorporating the statistics of release measured experimentally from glutamatergic synapses of retinal bipolar cells in zebrafish (both sexes) and compared these with models assuming Poisson inputs constrained to operate at the same average rates. We find that MVR can increase the number of spikes generated per vesicle while reducing interspike intervals and latency to first spike. The combined effect was to increase the efficiency of information transfer (bits per vesicle) over a range of conditions mimicking target neurons of different size. MVR was most advantageous in neurons with short time constants and reliable synaptic inputs, when less convergence was required to trigger spikes. In the special case of a single input driving a neuron, as occurs in the auditory system of mammals, MVR increased information transfer whenever spike generation required more than one vesicle. This study demonstrates how presynaptic integration of vesicles by MVR can increase the efficiency with which sensory information is transmitted compared with a rate-code described by Poisson statistics.SIGNIFICANCE STATEMENT Neurons communicate by the stochastic release of vesicles at the synapse and the statistics of this process will determine how information is represented by spikes. The classical model is that vesicles are released independently by a Poisson process, but this does not hold at ribbon-type synapses specialized to transmit the first electrical signals in vision and hearing, where two or more vesicles can fuse in a single event by a process termed coordinated multivesicular release. This study shows that multivesicular release can increase the number of spikes generated per vesicle and the efficiency of information transfer (bits per vesicle) over a range of conditions found in the retina and peripheral auditory system.

Analysis of psychiatric consultations in the department of neurology and stroke unit: diagnosis and therapy. / Analiza konsultacji psychiatrycznych w oddziale neurologii i oddziale udarowym: rozpoznania i terapia.

OBJECTIVES: The aim of this study was to analyze psychiatric consultations of patients hospitalized in the Department of Neurology and Stroke Unit (DN/SU) of University Clinical Center in Katowice from 2017 to 2018. METHODS: A retrospective analysis of psychiatric consultations, psychiatric diagnoses (according to the ICD-10) and treatment recommendations was done. RESULTS: 719 psychiatric consultations were performed in all hospital departments in the analyzed period. 488 (67.87%) consultations were conducted in the Department of Neurology and Stroke Unit. Most patients who required psychiatric consultations were diagnosed with Huntington's disease (n = 25; 37.31%), Parkinson's disease (n = 60; 23.9%) and epilepsy (n=40; 22.73%). The most commonpsychiatric diagnoses included organic mental disorders (n=229; 55.85%), particularly organic mood disorders (n =73; 14.96%) and organic anxiety disorders (n =32;6.56%) whereas in thecase of vascular diseases themost common diagnoses included disturbances of consciousness associated with delirium (n =30; 40.54%). The majority of consultations (n = 388; 79.51%) resulted in the onset or modification of pharmacological treatment. The most frequently prescribed drugs were: neuroleptics (n =174; 35.66%), mostly atypical (n = 152; 87,36%), and antidepressants (n = 230; 47.13%), mostly SSRIs (n = 216; 93.91%). In patients > 60 years of age organic disorders were more prevalent (n =179; 66.30% vs. n = 49; 35.0%) and neuroleptics were more frequently prescribed (n = 131; 42.12% vs. n= 44; 24.86%) compared to patients < 60 years. CONCLUSIONS: Patients in the department of neurology and stroke unit underwent a psychiatric consultation most frequently. Optimizing the care of aneurological patient is related to close cooperation of a neurologist and a psychiatrist, as well as developing and updating common positions for the management of selected disease entities.

Pancreatic heterotopia in the gallbladder: an incidental finding after cholecystectomy.

Ectopic pancreas in the gallbladder is found very rarely in histological examination after cholecystectomy. The etiology of this entity is not yet clear, but there exist several hypotheses about its origin. Our histological study revealed both exocrine and endocrine components of pancreatic tissue as shown by H&E and immunohistochemical staining of a gallbladder sections of a 55-year old man. Ectopic pancreatic tissue may be an underestimated cause of acute idiopathic pancreatitis thus detailed postoperative histological examination may decrease the number of acute pancreatitis cases without the known cause.