Stimulating Neural Circuits with Magnetism

Brain stimulation might sound like some Frankensteinian demonstration from a Victorian science fair. But in reality, it is a contemporary technique making a huge impact in neuroscience by addressing a longstanding limitation of traditional methods for investigating human brain function. Such techniques, like EEG and fMRI, can only be used to infer the effects of a stimulus or task on brain activity, and not vice versa. For example, a scientist might use EEG to study the effect of a task like arm movement on brain activity, but how can one study the effect of brain activity on arm movement?Continue reading

A Tale of Two Aphasias

Paul Broca
Paul Broca

It’s 1861, and the French neurologist Paul Broca is examining a new patient. Dr. Broca is puzzled because all the patient can say is “tan.” When Dr. Broca asks him questions, Tan cannot seem to form the words. However, it is clear that Tan can understand language because, when he asked to whistle or sing a melody, he can do so without a problem. Something is wrong with his ability to speak! When he is asked to speak grammatically or create complete sentences, he cannot do it – not even in writing! Dr. Broca doesn’t know what to do for Tan, since he knows that Tan must have brain damage… but where?Continue reading