The neurology in the Hellenistic era: An harmonization of the philosophy with the science

In the Hellenistic era the foundation of the city of Alexandria implied from the very beginning an intensive and very productive interaction between the Egyptian cultural heritage and the Greek civilization and culture. The city under the Ptolemean dynasty became a cosmopolitan, multicultural, social, religious, political, economical and educational metropolitan center with extensive impact upon the civilization of the Hellenistic World. Alexandria soon acquired one of the biggest libraries of world, as well as many Academies and Schools of Philosophy, Medicine, Mathematics, The Alexandrian School of Medicine flourished for more than four centuries cultivating medicine, associated with natural sciences, moral sciences, philosophy, history, and mathematics. In Alexandria the Neurosciences flourished, under the enlightened government and liberal opinions of Ptolemy Soter and his immediate successors Philadelphus and Euergetes, who patronized science and philosophy and encouraged scientific research. Ptolemeos Philadelphos was the first ruler of the hellenistic era, who enabled physicians to dissect the human body. Among the famous physicians of the Alexandrian era were Herophilos and Erasistratos, who were the first anatomists who dissected and described in details the parts of the human body, including the brain. Herophilos is well known since he developed the theory of the great diagnostic value of the pulse in heart diseases and stroke, maintaining that the pulse is not an innate faculty of the arteries, but one they derive from the heart itself. He distinguished the pulse from the palpitations, tremors and muscular spasms and he introduced the portable water clock in order to measure the pulse of the patients. Herophilos was involved mainly in Microanatomy and Clinical Neurology. Dissecting the brain he use to make three dimensional sections in order to obtain a stereotactic perception of the brain structures, revealing at the same time the ventricular system and the subcortical gray matter. Herophilos described (a) the durra matter and the venous sinuses of the skull, particularly the straight venous sinus and the confluence of the sinuses on the occipital bone, which is called torcular Herophilii (b) the lower angle of the floor of the fourth ventricle, which was called 'calamus scriptorius;' (c) the vascular plexuses, which are found in the cerebral ventricles and he first applied to them the name of choroid plexuses or vascular membranes. Herophilos also distingushed the cranial and spinal nerves into those of sensation and those of voluntary motion Herophilos believed that the ventricles are the seat of the human intelligence. Erasistratos of Chios or Ceos (304-250 BC) studied medicine and philosophy in Athens under Metrodoros. In 280 BC he went to island of Cos, the birthplace of Hippocrates, in order to study medicine and anatomy under Praxagoras. Erasistratos was recognized as one of the most famous neurologists in the Hellenistic period. He attempted to combine Microanatomy with Neurophysiology. Erasistratos studied and described the cortex of the brain, describing the morphology of the gyri and the sulci of the surface of the brain and claiming that the centers of the higher mental faculties are located in the cortex of the brain hemispheres He noticed also that the difference between the human brain and the brain of the animals is mostly based on the number of the gyri, which are more numerous in man than in animals, which is presumably related to the superior cognition of humans. He made a sharp distinction between the cerebrum and the cerebellum and he emphasized the role that the cerebellum plays in the harmony of the movements. He claimed that the peripheral nerves are not plenty of spirit, as it was thought in hippocratian theory, but they are solid structures, composed of microtubules that communicate with the brain. According to Erasistratos the vital spirit reaches the brain by the blood circulation and it is transformed in the brain substance in to animal spirit, which is carried to all of the organs and the parts of the body via the cranial and the spinal nerves, vitalizing them. Erasistratus distinguished the physical from the mental or psychological disorders and he introduced methods of psychotherapy in order to treat patients suffered from mental or psychosomatic syndromes, as he did in the case of the serious illness of Antiochus, son of the Seleucus the 1st, the Nicator, King of Syria. Galen of Pergamus (130 AC) was one of the highest authorities in Medicine in Hellenistic and Roman era with extensive impact on the Medieval and Modern Medicine. He wrote more than 400 dissertations on every field of Medicine. His works are deeply influenced by Hippocrates, Aristotle, Herophilos and Erasistratos. Galen gave an exact definition in the term symptom, syndrome and disease and made a clear distinction between them. He also consistently stressed that a functional disorder could never arise without an involvement of a particular organ. Galen described numerous neurological and psychiatric disorders and classified then as syndromes. Galen strongly believed in the psychosomatic unity of man and he did not recognize any disease of the psyche as being independent of the human body. On the brain and the spinal cord Galen thought that both of them perceive and analyze sensory stimuli and at the same time they send motor impulses to every part of the body. He found that traverse hemisection at higher levels of the spinal cord induces paralysis in the ipsilateral limbs of the body and sensory disturbances concerning the perception of pain and temperature in the contralateral ones. He claimed also that in cases, in which the face is simultaneously affected with the limbs, the causative factor must be located in the brain. More precisely he emphasized that if the face is affected at the same side with the body and some of the cranial nerves are also involved, the cause of the paralysis is definitely located in the brain. He thought that the spinal cord is the prolongation of the brain substance in the spinal canal and he did not make any mention of the medulla oblongata. Galen has had the feeling that the afferent as well as the efferent pathways of the central nervous system may be crossed either in the brain or in the spinal cord. Galen believed that the serious neurological diseases provoke loss of consciousness frequently and loss of motion which may be attributed to the escape of the cerebral spirit from the brain, particularly from the ventricles of the brain. Galen accepted entirely the Hippocratic concept that in apoplexy the paralysis of one half of the body is caused by a contralateral morphological or functional defect of the brain. The cerebellum according to Galen is involved in the motion and motor performances. The cerebellum is also involved with the end of the life, since the psyche is located in the forth ventricle and its escape is protected by the lower vermis of the cerebellum. Galen regarded the cerebellum and the pons as a single functional unit. Galen described the cranial nerves as being seven pairs and thought that the hypoglossal nerve is the last one situated in the borders between the brain and the spinal cord. Galen recognized also that the phrenic nerve, arising from the 3rd mylotome of the spinal cord innervates the diaphragm and it is therefore involved in breathing. One of the main contributions of Galen in anatomy and physiology of the cranial nerves was the definition of the important role that the recurrent branch of the vagus nerve plays for the formation of the voice. He found that the recurrent branch of the vagus nerve innervates the muscles of the vocal cords and therefore unilateral lesion of that nerve causes dysphonia, though bilateral lesion causes aphonia. Galen also mentioned that the spinal nerves are originated from the spinal cord by two separate roots, the anterior root and the posterior one. One of them is involved in sensation and the other in motion. On epileptic seizures Galen stated that the tonic-clonic convulsions or spasms are phenomena of intensive irritation of the brain or of obstruction of the ventricles and the pores and channels of the brain... The aura as a premonitory sensation of an epileptic attack is mostly projected into the viscera as an unusual gastric complaint. Galen stated also that the administration of some medications may be beneficial in controlling the seizures, though others may aggravate them. Galen made also a sharp distinction between the convulsions of organic origin and the hysterical ones. The loss of consciousness, described as syncope or lipothymia, was attributed by Galen to a failure of integrative action of the brain, the heart and the lungs. Galen highlighted also that the most serious loss of consciousness occurs whenever the heart is affected or the brain is severely involved. Galen described lethargus as an unusual condition, which is characterized by clouding of the mind and acute deterioration of the mental functions such as memory, learning and cognition. He also distinguished lethargos from karos, which is characterized by loss of the intellectual functions of the man and fall in a sleep like condition with the eyes closed. Galen mentioned that in contrast to apoplexy the recovery from karos is usually complete, a fact which has validity in the differential diagnosis of those conditions. Galen defined coma as the most serious condition of loss of consciousness and as a deeper state than karos. He distinguished also coma in two types (a) deep unconsciousness with the eyes closed and (b) deep unconsciousness with the eyes open, called it sleepless coma. Galen described an other also condition concerning the level of the consciousness, defining it as katalepsis, katochi, kataphora or katochos. He described katalepsis as a semi comatous condition, associated with titanic or hysterical rigidity, muscular stiffness and very often with a febrile delirium. In one of his descriptions of catalepsy Galen mentioned most of the clinical findings in Parkinson's disease or Paralysis Agitans, such as the tremor, the rigidity, the bradykinesia, the bradyphrenia and the occasional mental deterioration of the patient, the inexpressive face with overconfident expression of the eyes, which are open and unbliking. On headache Galen gave a description of lasting value. He described the unilateral headache as hemicrania or heterocrania, which is originated either by superficial stimuli of the skull or by functional disturbances of the deep structures of the head, such as the brain and the meninges. He also stated that the tension headache is either associated with the anxiety, having therefore a psychogenic origin or it is associated with irritation of the stomach. He also described headache associated with severe vertigo and gait instability, a condition which reminds Meniere's disease. Galen distinguished delirium, the mental derangement, in two types (a) in delirium without fever, called by Galen paraphrosyne and (b) in delirium with fever called by Galen phrenitis. The main diagnostic criteria of paraphrosyne are the hallucinations and the erroneous reasoning of paranoid type as well as the behavioral disturbances. Phrenitis is always associated with febrile conditions and it is attributed the irritation of the brain by the fever or by toxic humors. In serious cases phrenitis appears, in the advanced stages, as a fatal complication of the primary disease. Galen described the deterioration of mental activities as morosis or moria. Morosis is a mild form of dementia. Dementia or anoia according to Galen is characterized by serious impairment of the memory and loss of judgment. It is a paralysis of the thinking faculties. Galen gave also a precise description of the phenomenology of mania and melancholy. He stressed also that melancholy may cause a dementia like state, which is reversible He also stated that excessive alcohol consumption may lead to dementia with visual hallucinations and in more severe cases into coma and death. In mental retardation or Micronesia Galen noticed that rarely the patients had facial dimorphism, such as large and outstanding ears or hypertelorism. Galen treated the mental disease and the psychopathologic conditions by the administration of sedative drugs; He also applied physical therapy, based on hydrotherapy, local application of heat and sunbathings. He applied also psychotherapy in order to strength the reasoning power of the patient and to enforce his self-control. In not severe cases of psychological disturbances or psychosomatic disorders he re-commended occupational therapy, participation in lectures and proper education, travels and creative activities. He advised the relatives to express kindness and to avoid criticism to patients who suffered from depression.

Key words: Natural Philosophy, Hellenistic Era.