Interest in the hippocampal formation and its role in navigation and memory arose in the second part of the 20th century, at least in part due to the curious case of Henry G. Molaison, who underwent brain surgery for intractable epilepsy. The temporal association observed between the removal of his entorhinal cortex along with a significant part of hippocampus and the developing severe memory deficit inspired scientists to focus on these regions. The subsequent discovery of the so-called place cells in the hippocampus launched the description of many other functional cell types and neuronal networks throughout the Papez-circuit that has a key role in memory processes and spatial information coding (speed, head direction, border, grid, object-vector etc). Each of these cell types has its own unique characteristics, and together they form the so-called “Brain GPS”. The aim of this short survey is to highlight for practicing neurologists the types of cells and neuronal networks that represent the anatomical substrates and physiological correlates of pathological entities affecting the limbic system, especially in the temporal lobe. For that purpose, we survey early discoveries along with the most relevant neuroscience observations from the recent literature. By this brief survey, we highlight main cell types in the hippocampal formation, and describe their roles in spatial navigation and memory processes. In recent decades, an array of new and functionally unique neuron types has been recognized in the hippocampal formation, but likely more remain to be discovered. For a better understanding of the heterogeneous presentations of neurological disorders affecting this anatomical region, insights into the constantly evolving neuroscience behind may be helpful. The public health consequences of diseases that affect memory and spatial navigation are high, and grow as the population ages, prompting scientist to focus on further exploring this brain region.

Drop foot is defined as difficulty of dorsiflexion of the foot and ankle due to weak anterior tibial, extensor hallucis longus and extensor digitorum longus muscles. Cauda equina syndrome, local peroneal nerve damage due to trauma, nerve entrapment, compartment syndrome and tumors are common etiologies. A 32-year-old male patient was applied with difficulty in dorsiflexion of both of his toes, feet and ankles after he had squatted in toilette for 6-7 hours (because of his haemorrhoid) after intense alcohol intake 2 weeks before. Acute, partial, demyelinating lesion in head of fibula segment of peroneal nerves was diagnosed by electromyography. This case was reported since prolonged squatting is an extremely rare cause of acute bilateral peroneal neuropathy. This type of neuropathy is mostly demyelination and has good prognosis with physical therapy and mechanical devices, but surgical intervention may be required due to axonal damage. People such as workers and farmers working in the squatting position for long hours should be advised to change their position as soon as the compression symptoms (numbness, tingling) appear.

Purpose - Methylation is a key epigenetic modification of DNA and regarding its impact on epilepsy, it is argued that “DNA methylation may play an important role in seizure susceptibility and maintenance of the disorder”. DNA methylation status of KCC2 (SCL12A5) and NKCC1 (SCL12A2) associated with refractory temporal lobe epilepsy was investigated in our study. Materials and methods - Thirty-eight patients with temporal lobe epilepsy (TLE) who were diagnosed by video EEG monitoring and 32 healthy control subjects were included in the study. Twenty-three patients in TLE group were men and the remaining 15 were women. Among them, 27 had unilateral temporal focus (9 with right; 18 with left) and 11 patients had bilateral TLE. We analyzed promoter region methylation status of the KCC2 (SCL12A5) and NKCC1 (SCL12A2) genes in the case and control groups. Gene regions of interest were amplified through PCR and sequencing was accomplished with pyro-sequencing. Results - We found a significant relationship between TLE and methylation on the NKCC1. However, there was no association between TLE and methylation on the KCC2 gene. Also, we found no association between right or left and unilateral or bilateral foci of TLE. There was no relationship between TLE and methylation on the NKCC1and KCC2 genes in terms of mesial temporal sclerosis in cranial MRI, head trauma or febrile convulsions. Conclusion - The methylation of NKCC1 can be a mecha­nism of refractory temporal lobe epilepsy. There are limited findings about DNA methylation in TLE. Therefore, further studies with large sample sizes are necessary.

[A case of extensive bilateral frontotemporal schizencephaly is alleged - more extensively in the left hemisphere - which associated with polymicrogyria. The cortical anomaly was discovered only incidentally by MR examination in a 22 year-old man who suffered from headache due to a mild head trauma. Neurological examination proved to be negative. He had no complaints or symptoms a few weeks later. The developmental anomalies in corticalisation are shortly overviewed in this group together with the possible causing factors. It has been emphasized the importance of the precise intrauterine and/or postpartum differential diagnosis between schizencephaly, porencephaly and other failure in corticalisation.]

[In Hungary, the treatment approach for medial femoral neck fractures depends on the type of fracture and the overall condition of the patient. An obvious goal is to minimise the most common complications of the applied method, namely avascular necrosis of the head and redisplacement, while maintaining a low-risk and minimally invasive technique. Following the surgical method most commonly used in our country, we combined the double cannullated screws technique with the compressing HeadLess Screw System. This way we succeeded to achieve intraoperative compression, which provides intensified stability while retaining the principles of minimally invasive techniques.]