Decerebration induced by surgical transection of cerebral ganglion of crayfish

Background: Since the neural structures of the crayfish brain closely resemble their equivalent in the mammals. This can be suggested by observing the similarity that exists in the brain divided by the surgical transection of the crayfish brain in which the protocerebrum remains attached to the first two cranial nerves, findings also described by Frederic Bremer in 1935 in cats with cerebral transection.Methods: Total 11 Adult male crayfish were trained to respond with defense reflex, the animals were placed in water at 0°C, remained without any movement, and subsequently through a small incision of 3 mm in diameter in the medial antero region and dorsal cephalothorax region, a surgical section of the cerebral ganglion was performed. Immediately after surgery, metal microelectrodes were implanted to collect the activity of the photoreceptors and visual fibers.Results: Once the defense reflex begins to recover in previously decerebrated crayfish, it means that it shows signs of reconnection. The isolated protocerebrum with the deutocerebrum olfactory lobe remain alive for several days and the neuronal connections were reestablished, as measured throughout the bilateral defense activity. The defense reflex was observed in all animals and then recovered after surgery.Conclusions: The crayfish is an excellent model to work the visual activity, all coding of visual information was suppressed in de-cerebrated crayfish. The recovery of the neural disconnection is observed from 40 days, where the defence reflex appears again before visual stimuli.

A Thin Left Atrial Antral Wall Around the Pulmonary Vein Reflects Structural Remodeling by Atrial Fibrillation and is Associated with Stroke

PURPOSE: Circumferential pulmonary (PV) vein isolation (CPVI) is the most important treatment strategy for atrial fibrillation (AF). While understanding left atrial wall thickness around PVs (PVWT) prior to catheter ablation is important, its clinical implications are not known. This study aimed to evaluate PVWT characteristics according to underlying disease and to identify associations between PVWT and reconnections of PV potentials (PVPs) in redo ablation. MATERIALS AND METHODS: In 28 patients who underwent redo-AF ablation, PVWT and reconnected PVPs were evaluated at 12 sites (1–12 o'clock) around each PV. Clinical characteristics including stroke and CHA₂DS₂-VASc scores were analyzed according to the PVWT. RESULTS: The PVWT was thicker in males than females (p0.6 mm predicted PV reconnections with a sensitivity of 76.7% and specificity of 52.2% with an area under the curve of 0.695. CONCLUSION: Thick PVWs were associated with diabetes and heart failure, and also showed significant inverse correlations with stroke and the CHA₂DS₂-VASc score. Thick PVWs were associated with reconnected PVPs after the CPVI, which were related to AF recurrence.