From four million Indians suffering from Alzheimer’s currently, the number is set to reach 7.3 million by 2030. India is also second in the world of dementia sufferers with an estimated 4.1 million patients. As research races to find a cure to these mystifying diseases, the answer may lie in the enigma of human memory.
Left the house for work but could not remember whether you had locked the door? Greeted by someone warmly at a party but cannot recall their name though you can remember their face? The right word hovers on the tip of your tongue during an interview but just can’t remember it? If it happens too often, it’s time to consult a neurophysician.
According to the US National Institute on Aging, Alzheimer’s is a prevalent disease leading to forgetfulness, especially but not necessarily only among the aged. Memory loss is a growing problem across the world, and is, according to scientists and therapists, caused by chronic medical and psychological conditions, trauma, medications, drug and alcohol abuse and infections. Scientists at the Bengaluru Institute of Science researching the effects of Alzheimer’s disease on the brain made a startling discovery recently.
The results published in the Journal of Neuroscience concluded that the early breakdown of F-actin—a binding protein necessary to maintain memory links—leads to memory loss.They chose two sets of one month-old mice, and the DNA of one was modified with the Alzheimer’s gene. Both groups were then trained to fear a specific location where they were given mild electric shocks.
The first set froze with fear when taken to the location while the Alzheimer’s-infected mice did not, indicating they had forgotten their painful past experience. Then the scientists injected the affected mice with a chemical that prevents the breakdown of F-actin and found they exhibited a fear response. In animal models, American scientists have discovered that fear memories can be selectively erased through the ablation of specific groups of brain cells.
This involves locating and manipulating engrams, which are a collection of cells that when activated express a memory. It changes when we learn something and fires again when we recall something.
In 1949, Canadian neuroscientist Donald Hebb theorised that “neurons that fire together, wire together”, implying that repeated firing of connections between neurons encouraged the encoding of memories. Hebb’s Rule remains the reigning theory of memory today.
Research on postmortem brain tissue of an Alzheimer’s patient indicated a gradual breakdown of F-actin over time—a warning of the early onset of the feared disease. Over four million Indians suffer from some form of dementia, with Alzheimer’s affecting around 1.6 million—a number set to reach 7.3 million by 2030, according to international healthcare agencies. The study of human memory has now become part of cognitive psychology and neuroscience, which linked together, is known as cognitive neuroscience.
MYSTERIOUS FRONTIER
The study of Alzheimer’s and dementia is leading scientists and medical researchers to delve deeply into the twilight zone called memory. Cognition is what holds mankind together; without memory the world will come to a stop. There will be no society, nationhood, history, scientific advancements, growth and the other aspects of civilisation.
What is memory? It’s the process of acquiring, storing, retaining and subsequently retrieving information for use. Through encoding, information is stored in the brain for later use. Interestingly, we are unaware of most of this stored memory until an occasion to use parts of it arises and retrieval begins.
Jee Hyun Kim, DECRA Fellow, Behavioural Neuroscience, Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, says: “Memory is difficult to define without being circular. People often define memory as ‘something you can remember’. But we cannot deny the existence of a memory when there is no recollection.”
The study of engrams is perhaps the most significant process in memory science today. Though it was the German evolutionary biologist Richard Semon who coined the ‘engram’ in 1904, Quanta Magazine records that it was the famed psychologist Karl Lashley who postulated that the brain stores a memory by strengthening the connections between a specific set of neurons, which fire in the same pattern when it is recalled.
THOUGHT TRAINING
Memory training is an expanding field of study that is helping memory loss patients exponentially. The current World Memory Champion, Alex Mullen, can memorise the order of a deck of cards in 17 seconds—the world record. Memory athletes can recall thousands of words,numbers and images.
However, a study by Martin Dresler, a neuroscientist at Radboud University in the Netherlands, reports anyone can train their brains to repeat such feats. After just six weeks of practicing such techniques, the brain scans of study subjects started to resemble memory athletes. Neuroscientists and psychologists are curious about how memories store information. Why do people forget recent happenings while some distant events are recalled perfectly?
The ‘cognitive revolution’ during the 1950s and 1960s led to several new theories on memory such as ‘the magical number seven, plus or minus two’, memory multi-store false memories and memory models that can be run as computer simulations. Researchers have discovered that ironically, the human brain has a distinct ‘negativity bias’, focusing more on unpleasant experiences. Scientists speculate that this is an evolutionary function developed during hunter-gatherer times.
LOSING TIME
The most common culprit of memory loss seems to be lifestyle. Rohit, a 31-year-old entrepreneur from Delhi, started a finance company with just two employees two years ago. He was in charge of HR, making financial deals, marketing, promotion, and general administration. This left him little time to sleep and relax. Recently his memory collapsed. “Initial clinical diagnoses indicated stress and anxiety. Work-related tension reduces the brain’s capacity to retain memories,” says Dr Jitendra Nagpal, Head of the Psychiatry Department in Moolchand Hospital, Delhi. Experts reveal that memory loss affects people aged between 30 and 45 the most. “It’s shocking to see schoolchildren becoming victims of short-term memory loss,” says Dr Sameer Parikh, director, National Mental Health Programme of Fortis Group of Hospitals.
Every 10th patient in India has memory-related problems. Lack of sleep is another lifestyle-related consequence, leading to memory loss among the young. “Seven to eight hours of sleep is a must for the brain to function properly and rejuvenate. It’s while you’re asleep that your brain consolidates and stores memories,” explainS Dr Anshu Rohatgi, senior neurologist at Sir Gangaram Hospital, Delhi. Memory loss can also arise from metabolic imbalance due to thyroid dysfunction and vitamin deficiencies as well as by severe depression, which is often misdiagnosed as dementia.
Dr Mathew Abraham, senior consulting neurologist at Aster Medcity in Kochi, opines that memory loss doesn’t have a specific age group. “However, the chances increase as the age goes up. The factors include irreversible ones like obvious age and then genetics. The causes also include reversible ones like a clot in the head, a severe hit on the head and even hypothyroid. Also, once a person reaches 60 years of age, he/she will have a five percent risk. Every five years, this increases by another five percent. But ageing doesn’t necessarily mean memory loss. There are people who are sharp as a needle at 90 and there are those who have memory loss at 70,” he says.
Alcoholism is another widespread cause of the illness. Forty-two-year-old Ankit (name changed), an executive with a multinational company in Delhi, had been a heavy drinker for almost 15 years. He realised that his memory was slipping. Over time, he began to forget where he had kept his car keys or wallet. “When he reached the hospital, Ankit was puzzled and confused,” says Dr Nagpal. Clinical investigations revealed mild atrophy of the brain—a major cause of memory loss among young patients. Ankit was put on the ‘Quit Alcohol Programme’ and advanced medication was given to control his craving for alcohol. Supplementary therapy, specific brain exercises and a radical lifestyle change improved his condition. “Within eight months, he was back to normal,” says Dr Nagpal.
The Wernicke-Korsakoff syndrome is a consequence of chronic alcohol abuse, leading to brain damage that directly affects memory. While Wernicke’s disorder damages the nerves of both the central and peripheral nervous system due to poor nutrition, Korsakoff’s syndrome cripples memory and impairs problem-solving skills and learning abilities.
Dr G S Chandraleka, professor and head of Psychiatry Department, Saveetha Medical College, Chennai, says that there are three types of memory loss: caused due to aging, head injury, or trauma and psychological memory loss or amnesia. “After the age of 60, minimal memory loss would occur, subsequently it advances with age. The elderly remember incidents that had happened 20 years ago but forget where they had kept the house keys. Simple brain exercises and being active will slow down the process.” Memory loss due to head injury or trauma will slowly come back depending on the site and depth of the injury. And psychological memory loss occurs when you want to forget something unpleasant, he adds.
To deal with the crisis, scientists have evolved many memory enhancement programmes which are now being used by corporates. These are held as workshops, online classes and visual demonstrations. Games and books to sharpen memory are available in the market. Workshops are conducted in schools to enhance the memory of children. The computer-based CogMed memory training is considered effective. There are also memory boosting apps.
TOTAL RECALL
Is there a cure for memory-affected ailments? The purpose of research costing billions in government and private funding is to find solutions to two main branches of neuroscience: cure for memory loss and a cure for trauma. One of the least discussed issues is post traumatic stress disorder (PTSD) among the Indian security forces; suicidal tendencies arising from organic brain damage resulting from engagement with the enemy or insurgents, exposure to war trauma, death and a diminished personal life are worrying doctors.
Violence, sexual abuse and other emotionally traumatic events can result in dissociative amnesia, which temporarily erases details of the event from the mind until they are ready to cope. Sometimes this may never happen.
“Manipulating memories means erasing bad memories to treat the patient. They keep recalling the incidents, have nightmares and cannot function normally. In such cases, experts try to manipulate memories through medication and with the help of different therapies,” explains Dr Nimesh Desai, director, Institute of Human Behaviour and Allied Sciences, Delhi.
“In certain cases, patients take almost six months to recover. But in a few cases where the trauma is deep-rooted they take as long as three years to mend.” Research scientists at the National Brain Research Centre, Gurugram, are now using Artificial Intelligence to develop a smart diagnostics system to predict the onset of Alzheimer’s disease by imaging different activities of brain, studying chemical reactions, cell degeneration, neuron functions, longitudinal clinical studies and various test patterns.
ETHICAL CROSSROADS
Doctors and scientists are troubled over the morality of manipulating and erasing memory. Research in Memory Science is pushing medical and ethical boundaries. Neuroscientist Sheena Josselyn finally proved the engram’s existence with an experiment that familiarised mice with a particular cocaine-related place.
Here the memory was erased by killing the cells that were part of the relevant engram. The mice behaved as if they never had cocaine in that environment and no longer preferred the place. “By just manipulating cells that we think are important, we got the animal to act is if it never had cocaine before,” said Josselyn.
She argues that while sometimes people with drug problems recover in rehab where cues associated with drugs are removed, they could relapse once they are back in a narcotic environment, where their memory of drugs and locations are revived. Josselyn believes it could be the first step in treating cocaine addiction. She is working to next decode the engram’s molecular structure, which could lead to new treatments for addiction, Alzheimer’s disease and other diseases.
THE DEMENTIA CRISIS
Alzheimer’s disease is the most common form of dementia but has numerous subtypes. Usually it first appears as irritability, confused behaviour, confused visual interpretations and difficulty in performing daily activities. Memory disturbance is the last stage. The ‘Dementia India’ report published by the Alzheimer’s and Related Disorders Society of India notes that India is second in the number of dementia-affected.
Maharashtra and Uttar Pradesh are predicted to have over 5,00,000 patients by 2026. There is no cure for Alzheimer’s yet. With the aged population in India increasing—the largest being in Kerala—this poses a massive healthcare risk. India has not yet moved on the World Health Organisation’s global plan on dementia adopted at the 70th World Health Assembly in May 2017. “People here are still not aware about this disease. If diagnosed early, we could at least make life better for the patient with the help of medication and other therapies,” says Dr Anjali Chhabria, a leading psychiatrist in Mumbai.
The Alzheimer’s and Related Disorders Society of India (ARDSI) has asked for a dementia plan or policy to be funded, monitored and implemented in all states by the health ministry. The Kerala State Initiative on Dementia, the first public-private partnership for dementia care and awareness, is a positive start. Curiously, an exhaustive Indian neurological study proves that onset of dementia is delayed in bilingual people, regardless of their education and immigration status.
Often Alzheimer’s is confused with dementia and nothing can be further from the truth. There are three known types of dementia. The National Institute on Aging defines dementia as a brain disorder that affects communication and daily activities while Alzheimer’s disease is a form of dementia that impacts specific sections of the brain that control thoughts, memory and language. Dementia can also be caused by vascular disease of the brain associated with Parkinson’s disease and third, where the brain’s fluid cavities are larger than normal.
BN Gangadhar, director, National Institute of Mental Health and Neurosciences, Bengaluru, says,
“When we are working under stress, the mind fails to register the things that we don’t pay attention to. The solution is to optimise brain usage by training yourself to be mindful. Generally, a healthy person starts noticing memory loss after the age of 45 years. But one should be aware of whether it is happening at an early age or later and whether it is getting worse. If not treated, it may turn into serious diseases like dementia.”
The famous case of ME—a 101-year-old female piano player discovered by Stanford musicologist Eleanor Selfridge-Field at a Christmas party in Florida—may hold understanding of dementia. She suffered from vascular dementia, and was unsure of her surroundings and could recognise only those she had met before her 70s. However, miraculously she could play nearly 400 songs just by accessing a memory of previously stored musical engrams and could also learn new songs simply by listening to them.
With such unexplained miracles and untold tragedies that are related to ageing, trauma and lifestyle, human memory remains an unexplained continent that lies beyond the door of a multitude of memories, both individual and universal.
THE MIND THEORIES
False Retentions
Memories can be implanted in our minds through verbal suggestions.
Multi Store
Of the huge amount processed of an event or surroundings, most sensory information ‘decays’ leaving a small portion intact. But rehearsal of remembering shifts this to the long-term memory store, where it could stay for even a lifetime.
Levels of Processing
Shallow processing is when we read a news story, but deep processing is thinking about the repercussions of the story.
Working Memory
Subconscious sensory information is governed by a central HQ that behaves like a computer processor accessing data on a hard disk.
Interference
Memories can be edged out of the brain by new information whilst existing information can inhibit memorising new information.
Flashbulb
Vivid snapshots at the time of a traumatic event to which we may not be personally connected such as watching a terrorist attack on TV.
Trigrams
Meaningless lists of three letters given to subjects to remember lost recall value after 18 seconds.
Miller’s Magic Number
People can only hold an average of seven chunks of information in their short-term memory. For example, most people can remember a seven-digit phone number but would find it difficult to remember a 10-digit number. Miller hit upon 7 +/- 2 as a “magical” number in understanding memory.
WHAT ARE FLASHBACKS?
Flashbacks are involuntary recreations of intense past memories that the individual often feels is real, often caused by trauma or highly-charged emotional events and occur during high stress. Their exact cause is unclear. Canadian neurosurgeon Wilder Penfield recreated flashbacks in some patients by probing parts of the temporal lobe of the brain.
With bureau inputs