Consciousness, at its simplest, is sentience or awareness of internal and external existence. Despite millennia of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and [also the] most mysterious aspect of our lives". Perhaps the only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Sometimes, it is synonymous with the mind, and at other times, an aspect of it. In the past, it was one's "inner life", the world of introspection, of private thought, imagination and volition. Today, it often includes some kind of experience, cognition, feeling or perception. It may be awareness, awareness of awareness, or self-awareness either continuously changing or not. There might be different levels or orders of consciousness, or different kinds of consciousness, or just one kind with different features. Other questions include whether only humans are conscious, all animals, or even the whole universe. The disparate range of research, notions and speculations raises doubts about whether the right questions are being asked.
Roger Wolcott Sperry was an American neuropsychologist, neurobiologist and Nobel laureate who, together with David Hunter Hubel and Torsten Nils Wiesel, won the 1981 Nobel Prize in Physiology and Medicine for his work with split-brain research. A Review of General Psychology survey, published in 2002, ranked Sperry as the 44th most cited psychologist of the 20th century.
Blindsight is the ability of people who are cortically blind due to lesions in their striate cortex, also known as the primary visual cortex or V1, to respond to visual stimuli that they do not consciously see. The term was coined by Lawrence Weiskrantz and his colleagues in a paper published in Brain in 1974. A similar paper in which the discriminatory capacity of a cortically blind patient had been studied was published in Nature in 1973.
Neurotrauma, brain damage or brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating trauma-induced damage, while neurotoxicity typically refers to selective, chemically induced neuron damage.
Phineas P. Gage (1823–1860) was an American railroad construction foreman remembered for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior over the remaining 12 years of his life—effects sufficiently profound that friends saw him as "no longer Gage".
Alexander Romanovich Luria was a Soviet neuropsychologist, often credited as a father of modern neuropsychological assessment. He developed an extensive and original battery of neuropsychological tests during his clinical work with brain-injured victims of World War II, which are still used in various forms. He made an in-depth analysis of the functioning of various brain regions and integrative processes of the brain in general. Luria's magnum opus, Higher Cortical Functions in Man (1962), is a much-used psychological textbook which has been translated into many languages and which he supplemented with The Working Brain in 1973.
Wilder Graves Penfield was an American-Canadian neurosurgeon. He expanded brain surgery's methods and techniques, including mapping the functions of various regions of the brain such as the cortical homunculus. His scientific contributions on neural stimulation expand across a variety of topics including hallucinations, illusions, and déjà vu. Penfield devoted much of his thinking to mental processes, including contemplation of whether there was any scientific basis for the existence of the human soul.
Split-brain or callosal syndrome is a type of disconnection syndrome when the corpus callosum connecting the two hemispheres of the brain is severed to some degree. It is an association of symptoms produced by disruption of, or interference with, the connection between the hemispheres of the brain. The surgical operation to produce this condition involves transection of the corpus callosum, and is usually a last resort to treat refractory epilepsy. Initially, partial callosotomies are performed; if this operation does not succeed, a complete callosotomy is performed to mitigate the risk of accidental physical injury by reducing the severity and violence of epileptic seizures. Before using callosotomies, epilepsy is instead treated through pharmaceutical means. After surgery, neuropsychological assessments are often performed.
Hemispherectomy is a very rare neurosurgical procedure in which a cerebral hemisphere is removed, disconnected, or disabled. This procedure is used to treat a variety of seizure disorders where the source of the epilepsy is localized to a broad area of a single hemisphere of the brain, notably Rasmussen's encephalitis. About one in three patients with epilepsy will continue to have persistent seizures despite epileptic drug therapy. Hemispherectomy is reserved for the most extreme cases of this one-third in which the individual’s seizures are irresponsive to medications or other less invasive surgeries and significantly impair functioning or put the patient at risk of further complications. The procedure successfully cures seizures in about 85–90% of patients. Additionally, it is also known to often markedly improve the cognitive functioning and development of the individual. Subtotal hemispherectomy sparing sensorimotor cortex can be performed with successful seizure control expected in 70–80% of patients. Even with the presence of widespread unilateral epileptogenicity or anatomic/functional imaging abnormalities, complete hemispherectomy can often be avoided, particularly when there is little hemiparesis.
Michael S. Gazzaniga is a professor of psychology at the University of California, Santa Barbara in the USA, where he heads the new SAGE Center for the Study of the Mind. He is one of the leading researchers in cognitive neuroscience, the study of the neural basis of mind. He is a member of the American Academy of Arts & Sciences, the Institute of Medicine, and the National Academy of Sciences.
Anthony David Bland was a supporter of Liverpool F.C. injured in the Hillsborough disaster. He suffered severe brain damage that left him in a persistent vegetative state as a consequence of which the hospital, with the support of his parents, applied for a court order allowing him to "die with dignity". As a result, he became the first patient in English legal history to be allowed to die by the courts through the withdrawal of life-prolonging treatment including food and water.
"Funes the Memorious" is a fantasy short story by Argentine writer Jorge Luis Borges (1899–1986). First published in La Nación of June 1942, it appeared in the 1944 anthology Ficciones, part two (Artifices). The first English translation appeared in 1954 in Avon Modern Writing No. 2.
Memory disorders are the result of damage to neuroanatomical structures that hinders the storage, retention and recollection of memories. Memory disorders can be progressive, including Alzheimer's disease, or they can be immediate including disorders resulting from head injury.
The lateralization of brain function is the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other. The medial longitudinal fissure separates the human brain into two distinct cerebral hemispheres, connected by the corpus callosum. Although the macrostructure of the two hemispheres appears to be almost identical, different composition of neuronal networks allows for specialized function that is different in each hemisphere.
Lawrence Weiskrantz was a British neuropsychologist. Weiskrantz is credited with discovering the phenomenon of blindsight, and with establishing the role of the amygdala in emotional learning and emotional behavior. Blindsight is when a person with a brain injury causing blindness can nevertheless detect, point accurately at, and discriminate visually presented objects.
Recovery from blindness is the phenomenon of a blind person gaining the ability to see, usually as a result of medical treatment. As a thought experiment, the phenomenon is usually referred to as Molyneux's problem. It is often stated that the first published human case was reported in 1728 by the surgeon William Cheselden. However, there is no evidence that Cheselden's patient, a boy named Daniel Dolins, actually recovered any vision. Patients who experience dramatic recovery from blindness experience significant to total agnosia, having serious confusion with their visual perception.
Elkhonon Goldberg is a neuropsychologist and cognitive neuroscientist known for his work in hemispheric specialization and the "novelty-routinization" theory.
Shell shock is a term coined in World War I by British psychologist Charles Samuel Myers to describe the type of post traumatic stress disorder many soldiers were afflicted with during the war. It is a reaction to the intensity of the bombardment and fighting that produced a helplessness appearing variously as panic and being scared, flight, or an inability to reason, sleep, walk or talk.
The Luria-Nebraska Neuropsychological Battery (LNNB) is a standardized test that identifies neuropsychological deficiencies by measuring functioning on fourteen scales. It evaluates learning, experience, and cognitive skills. The test was created by Charles Golden in 1981 and based on previous work by Alexander Luria that emphasizes a qualitative instead of quantitative approach. The original, adult version is for use with ages fifteen and over, while the Luria-Nebraska Neuropsychological Battery for Children (LNNB-C) can be used with ages eight to twelve; both tests take two to three hours to administer. The LNNB has 269 items divided among fourteen scales, which are motor, rhythm, tactile, visual, receptive speech, expressive speech, writing, reading, arithmetic, memory, intellectual processes, pathognomonic, left hemisphere, and right hemisphere. The test is graded on scales that are correlated to regions of the brain to help identify which region may be damaged. The Luria-Nebraska has been found to be reliable and valid; it is comparable in this sense to other neuropsychological tests in its ability to differentiate between brain damage and mental illness. The test is used to diagnose and determine the nature of cognitive impairment, including the location of the brain damage, to understand the patient's brain structure and abilities, to pinpoint causes of behavior, and to help plan treatment.
Barbara Arrowsmith Young is a Canadian author, entrepreneur and lecturer. She is the founder of the Arrowsmith School in Toronto and the controversial Arrowsmith Program which forms the basis of the school's teaching method. In 2012 she published The Woman Who Changed Her Brain which combines an autobiographical account of her own severe learning disabilities and the method she developed to overcome them with case studies of learning disabled children who she claims overcame similar problems by using her method.
