Robert Galbraith Heath (May 9, 1915 – September 21, 1999) was an American psychiatrist.   He followed the theory of biological psychiatry that organic defects were the sole source of mental illness,  and that consequently mental problems were treatable by physical means. He published 425 papers and three books.    One of his first papers is dated 1946.  He was profiled as a "famous American psychiatrist" in 1983 by Psychiatric Annals . 
Heath founded the Department of Psychiatry and Neurology at Tulane University, New Orleans, in 1949 and remained its chairman until 1980.    He performed many experiments there involving electrical stimulation of the brain via surgically implanted electrodes. He placed deep brain stimulation (DBS) electrodes into the brains of more than 54 patients.     Indeed, he has been cited as the first, or one of the first, researcher(s) to have placed electrodes deep into the brains of living human patients.   It has been suggested that this work was financed in part by the government, particularly the CIA or U.S. military.   
In 1972, he claimed to have converted a homosexual man to heterosexuality using DBS.   Heath also experimented with the drug bulbocapnine to induce stupor, and LSD,   using prisoners in the Louisiana State Penitentiary as experimental subjects.  He worked on schizophrenia patients, which he regarded as an illness with a physical basis.  Today Heath's work is considered highly controversial and is only rarely used as reference material.   
Heath was born on May 9, 1915 in Pittsburgh, Pennsylvania.   He was encouraged by his father, who was a general medical practitioner, to enter the medical field as well.  He received medical and undergraduate education from the University of Pittsburgh, where he graduated in 1938.    He became determined to find his career in neurology after his father died. He then trained in neurology at the Neurological Institute of New York, and became a fellow at Pennsylvania Hospital.   During World War II, he was drafted into the U.S. Navy to work as a psychiatrist.   After returning from the war, he studied at the College of Physicians and Surgeons, at Columbia University.  Heath married and had five children.   He died on September 21, 1999 in St. Petersburg, Florida at the age of 84. 
Heath began electrical brain stimulation experiments on schizophrenia patients in 1950.  In 1954, Heath published a monograph called "Studies in Schizophrenia" detailing his deep brain stimulation experiments on 25 schizophrenic patients.  The study's methodology was met with much criticism at the time.  Some of the patients experienced seizures or fatal brain abscess.  In 1956, he published findings claiming the ability to induce symptoms of schizophrenia by injecting the blood of schizophrenia patients into the bodies of healthy patients. In particular, he claimed to have isolated a protein ( taraxein ) that could induce this effect.  His findings produced widespread attention, both within the scientific community and the general public. The scientific community tended towards skepticism of his claims, and attempts to replicate his findings ensued. However, these attempts to confirm his findings mostly failed.  Psychiatry textbooks in the 1960s lent some credence to his claims, though this ceased to be the case by the 1970s and 1980s.  Heath continued to defend his findings and theory of schizophrenia until at least 1996. 
Heath was experimenting in 1953 on inducing paroxysms through brain stimulation.  During the course of his experiments in deep brain stimulation, Heath experimented with gay conversion therapy, and claimed to have successfully converted a homosexual patient, labeled in his 1972 paper as Patient B-19. At the time, homosexuality was considered a psychiatric disorder under the DSM-II.   The patient, who had been arrested for marijuana possession, was implanted with electrodes into the septal region (associated with feelings of pleasure), and many other parts of his brain. The septal electrodes were then stimulated while he was shown heterosexual pornographic material. The patient was later encouraged to have intercourse with a sex worker recruited for the study. As a result, Heath claimed the patient was successfully converted to heterosexuality. This research would be deemed unethical today for a variety of reasons. The patient was recruited for the study while under legal duress, and further implications for the patient's well-being, including indications that electrode stimulation was addictive, were not considered.    In 1973, his ethical conduct during these studies was questioned by a subcommittee of the U.S. Senate.  Heath's experiment was also criticized by Fred Mettler, who was previously his mentor. 
Heath conducted a study on two rhesus macaques trained to smoke "the equivalent of one marijuana cigarette a day, five days a week for six months"  and concluded that cannabis causes permanent changes in the brain. Nonetheless, he supported cannabis decriminalization.  He later conducted a National Institutes of Health-funded study on 13 rhesus monkeys, with one rotating group representing "heavy smokers" whose cannabis dosage was believed to be comparable to three marijuana cigarettes smoked daily, a "moderate" group that was given the equivalent of one joint a day, and a third group that puffed inactive cannabis. He concluded, "Alcohol is a simple drug with a temporary effect. Marijuana is complex with a persisting effect."  According to the BBC, "His findings of permanent brain damage have been dismissed by similar, independently conducted studies. But other scientists have argued these methods of animal research are inconclusive."  According to NORML, Heath's "work was never replicated and has since been discredited by a pair of better controlled, much larger monkey studies, one by Dr. William Slikker of the National Center for Toxicological Research and the other by Charles Rebert and Gordon Pryor of SRI International." 
A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the hands. In some people, a tremor is a symptom of another neurological disorder.
Electroconvulsive therapy (ECT) is a psychiatric treatment where a generalized seizure is electrically induced to manage refractory mental disorders. Typically, 70 to 120 volts are applied externally to the patient's head, resulting in approximately 800 milliamperes of direct current passing between the electrodes, for a duration of 100 milliseconds to 6 seconds, either from temple to temple or from front to back of one side of the head. However, only about 1% of the electrical current crosses the bony skull into the brain because skull impedance is about 100 times higher than skin impedance.
Transcranial magnetic stimulation (TMS) is a noninvasive form of brain stimulation in which a changing magnetic field is used to induce an electric current at a specific area of the brain through electromagnetic induction. An electric pulse generator, or stimulator, is connected to a magnetic coil connected to the scalp. The stimulator generates a changing electric current within the coil which creates a varying magnetic field, inducing a current within a region in the brain itself.
Deep brain stimulation (DBS) is a neurosurgical procedure involving the placement of a medical device called a neurostimulator, which sends electrical impulses, through implanted electrodes, to specific targets in the brain for the treatment of movement disorders, including Parkinson's disease, essential tremor, dystonia, and other conditions such as obsessive-compulsive disorder (OCD) and epilepsy. While its underlying principles and mechanisms are not fully understood, DBS directly changes brain activity in a controlled manner.
Anosognosia is a condition in which a person with a disability is cognitively unaware of having it due to an underlying physical or psychological condition. Anosognosia can result from physiological damage to brain structures, typically to the parietal lobe or a diffuse lesion on the fronto-temporal-parietal area in the right hemisphere, and is thus a neuropsychiatric disorder. A deficit of self-awareness, it was first named by the neurologist Joseph Babinski in 1914. Phenomenologically, anosognosia has similarities to denial, which is a psychological defense mechanism; attempts have been made at a unified explanation. Anosognosia is sometimes accompanied by asomatognosia, a form of neglect in which patients deny ownership of body parts such as their limbs. The term is from Ancient Greek ἀ- a-, 'without', νόσος nosos, 'disease' and γνῶσις gnōsis, 'knowledge'. It is also considered a disorder that makes the treatment of the patient more difficult, since it may affect negatively the therapeutic relationship.
Neurotechnology encompasses any method or electronic device which interfaces with the nervous system to monitor or modulate neural activity.
In the anatomy of the brain, the centromedian nucleus, also known as the centrum medianum, is a part of the intralaminar thalamic nuclei (ITN) in the thalamus. There are two centromedian nuclei arranged bilaterally.
Brain implants, often referred to as neural implants, are technological devices that connect directly to a biological subject's brain – usually placed on the surface of the brain, or attached to the brain's cortex. A common purpose of modern brain implants and the focus of much current research is establishing a biomedical prosthesis circumventing areas in the brain that have become dysfunctional after a stroke or other head injuries. This includes sensory substitution, e.g., in vision. Other brain implants are used in animal experiments simply to record brain activity for scientific reasons. Some brain implants involve creating interfaces between neural systems and computer chips. This work is part of a wider research field called brain–computer interfaces.
Corpus callosotomy is a palliative surgical procedure for the treatment of medically refractory epilepsy. In this procedure the corpus callosum is cut through in an effort to limit the spread of epileptic activity between the two halves of the brain.
Vagus nerve stimulation (VNS) is a medical treatment that involves delivering electrical impulses to the vagus nerve. It is used as an add-on treatment for certain types of intractable epilepsy and treatment-resistant depression.
Theta waves generate the theta rhythm, a neural oscillation in the brain that underlies various aspects of cognition and behavior, including learning, memory, and spatial navigation in many animals. It can be recorded using various electrophysiological methods, such as electroencephalogram (EEG), recorded either from inside the brain or from electrodes attached to the scalp.
The septal area, consisting of the lateral septum and medial septum, is an area in the lower, posterior part of the medial surface of the frontal lobe, and refers to the nearby septum pellucidum.
Electrocorticography (ECoG), or intracranial electroencephalography (iEEG), is a type of electrophysiological monitoring that uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex. In contrast, conventional electroencephalography (EEG) electrodes monitor this activity from outside the skull. ECoG may be performed either in the operating room during surgery or outside of surgery. Because a craniotomy is required to implant the electrode grid, ECoG is an invasive procedure.
Transcranial direct current stimulation (tDCS) is a form of neuromodulation that uses constant, low direct current delivered via electrodes on the head. It was originally developed to help patients with brain injuries or neuropsychiatric conditions such as major depressive disorder. It can be contrasted with cranial electrotherapy stimulation, which generally uses alternating current the same way, as well as transcranial magnetic stimulation.
Ablative brain surgery is the surgical ablation by various methods of brain tissue to treat neurological or psychological disorders. The word "Ablation" stems from the Latin word Ablatus meaning "carried away". In most cases, however, ablative brain surgery does not involve removing brain tissue, but rather destroying tissue and leaving it in place. The lesions it causes are irreversible. There are some target nuclei for ablative surgery and deep brain stimulation. Those nuclei are the motor thalamus, the globus pallidus, and the subthalamic nucleus.
Xanomeline is a small molecule muscarinic acetylcholine receptor agonist that was first synthesized in a collaboration between Eli Lilly and Novo Nordisk as an investigational therapeutic being studied for the treatment of central nervous system disorders.
The long-term effects of cannabis have been the subject of ongoing debate. Because cannabis is illegal in most countries, clinical research presents a challenge and there is limited evidence from which to draw conclusions. In 2017, the U.S. National Academies of Sciences, Engineering, and Medicine issued a report summarizing much of the published literature on health effects of cannabis, into categories regarded as conclusive, substantial, moderate, limited and of no or insufficient evidence to support an association with a particular outcome.
Neuromodulation is "the alteration of nerve activity through targeted delivery of a stimulus, such as electrical stimulation or chemical agents, to specific neurological sites in the body". It is carried out to normalize – or modulate – nervous tissue function. Neuromodulation is an evolving therapy that can involve a range of electromagnetic stimuli such as a magnetic field (rTMS), an electric current, or a drug instilled directly in the subdural space. Emerging applications involve targeted introduction of genes or gene regulators and light (optogenetics), and by 2014, these had been at minimum demonstrated in mammalian models, or first-in-human data had been acquired. The most clinical experience has been with electrical stimulation.
A peripheral nerve interface is the bridge between the peripheral nervous system and a computer interface which serves as a bi‐directional information transducer recording and sending signals between the human body and a machine processor. Interfaces to the nervous system usually take the form of electrodes for stimulation and recording, though chemical stimulation and sensing are possible. Research in this area is focused on developing peripheral nerve interfaces for the restoration of function following disease or injury to minimize associated losses. Peripheral nerve interfaces also enable electrical stimulation and recording of the peripheral nervous system to study the form and function of the peripheral nervous system. For example, recent animal studies have demonstrated high accuracy in tracking physiological meaningful measures, like joint angle. Many researchers also focus in the area of neuroprosthesis, linking the human nervous system to bionics in order to mimic natural sensorimotor control and function. Successful implantation of peripheral nerve interfaces depend on a number of factors which include appropriate indication, perioperative testing, differentiated planning, and functional training. Typically microelectrode devices are implanted adjacent to, around or within the nerve trunk to establish contact with the peripheral nervous system. Different approaches may be used depending on the type of signal desired and attainable.
Amygdalotomy is a form of psychosurgery which involves the surgical removal or destruction of the amygdala, or parts of the amygdala. It is usually a last-resort treatment for severe aggressive behavioral disorders and similar behaviors including hyperexcitability, violent outbursts, and self-mutilation. The practice of medical amygdalotomy typically involves the administration of general anesthesia and is achieved through the application of cranial stereotactic surgery to target regions of the amygdala for surgical destruction. While some studies have found stereotactic amygdalotomy in humans to be an effective treatment for severe cases of intractable aggressive behavior that has not responded to standard treatment methods, other studies remain inconclusive. In most cases of amygdalotomy in humans, there is no substantial evidence of impairment in overall cognitive function, including intelligence and working memory, however, deficits in specific areas of memory have been noted pertaining to the recognition and emotional interpretation of facial stimuli. This is because there are specialized cells in the amygdala which attend to facial stimuli.