![]() ![]() Sloper would prefer a daughter who was "clever" and for all of Aunt Penniman's instruction, Catherine has remained not-so-clever in her father's eyes. It is not at all difficult for Catherine to be "good," but Dr. As a young girl and even as a young woman, Catherine finds herself unable to live up to her father's paradigm of what a good daughter would be. Catherine SloperĬatherine is the heroine of the novel and for most of the novel, Catherine is surrounded by dominating individuals who seek to make decisions for her. When it counts most - in his family - the doctor's skills are judged and are found wanting. And Sloper's celebrity is of little use in swaying Catherine to obey his wishes. A famous doctor, Sloper cannot save his wife or son from death once they take ill. Sloper knows both of these facts so well - the contrast between his highs and lows is significant. Sloper is so intelligent - and especially because Dr. Sloper is a great man of society, a local celebrity in Washington Square. Sloper often neglects to credit these two (adult) individuals with their due respect. Even in his interactions with his two sisters, Lavinia Penniman and Elizabeth Almond, Dr. Sloper becomes a largely symbolic father figure. Sloper's clever mind and admittedly accurate criticism of Catherine's suitor, Morris Townsend, make it difficult to write the doctor off as a simple villain. Certainly, he treats his daughter, Catherine, harshly. The I-LABS MEG Brain Imaging Center system allows co-registration of EEG and MEG.Doctor Austin Sloper is among Henry James' most complex characters. MEG provides also more accurate spatial localization of neural activities than EEG, a complementary method of recording brain activity. While fMRI measurement requires the complete absence of subject movement during recording, MEG measurement does not, so children can move their heads within the MEG helmet.įinally and most importantly, MEG provides us with temporal characteristics about brain activation with sub-millisecond precision, whereas fMRI measurement provides poor temporal information. MEG does not make any operational noise, unlike fMRI. This means that MEG can be recorded in sleeping subjects. MEG signals are able to show absolute neuronal activity whereas the fMRI signals show relative neuronal activity, meaning that the fMRI signal analysis always be compared to reference neuronal activity. MEG signals are obtained directly from neuronal electrical activity. fMRI signals reflect brain activity indirectly, by measuring the oxygenation of blood flowing near active neurons. The technologies complement each other, but only MEG provides timing as well as spatial information about brain activity. MEG has advantages over both fMRI and EEG. A magnetically shielded room houses the equipment, and mitigates interference. Due to low impedance at this temperature, the SQUID device can detect and amplify magnetic fields generated by neurons a few centimeters away from the sensors. The SQUID sensors are bathed in a large liquid helium cooling unit at approximately -269 degrees C. Therefore, MEG scanners require superconducting sensors (SQUID, superconducting quantum interference device). ![]() These neuromagnetic signals generated by the brain are extremely small-a billionth of the strength of the earth’s magnetic field. While the magnitude of fields associated with an individual neuron is negligible, the effect of multiple neurons (for example, 50,000 – 100,000) excited together in a specific area generates a measureable magnetic field outside the head. ![]() Electromagnetic fields are generated by the net effect of this slow ionic current flow. How does MEG work?Īt the cellular level, individual neurons in the brain have electrochemical properties that result in the flow of electrically charged ions through a cell. It allows the measurement of ongoing brain activity on a millisecond-by-millisecond basis, and it shows where in the brain activity is produced. Magnetoencephalography (MEG) is a non-invasive technique for investigating human brain activity. ![]()
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