Erasing Memories

Memory erasing is a hot topic in Hollywood. From the 1997 sci-fi flick Men in Black to the 2004 romantic comedy Eternal Sunshine of a Spotless Mind, characters are constantly trying to erase painful or dangerous memories from their minds. While neuroscientists are currently aiming their memory-erasing efforts at clinical conditions such as post traumatic stress disorder, they are making progress that may one day allow you to erase any memory you desire.

Memory formation essentially works like this:

  • Sensory information (wind on your face, the smell of coffee, a Picasso painting) is encoded as electrical pulses called action potentials.
  • Action potentials cause glutamate, an important neurotransmitter, to exit one nerve cell (neuron), cross a small channel of space called a synapse, and bind to receptors on the next neuron, which chemically activates the next cell to transmit the impulse and glutamate-release along the chain of neurons. Read more here! ⇒
  • Ultimately, this signal reaches the areas of the brain responsible for encoding memory: the amygdala, and the hippocampus.
  • When the amygdala and the hippocampus are simultaneously activated by glutamate and an electrical pulse, that particular “community” of neurons is changed to become more sensitive to each other. In this way, a memory is formed.

Because memory is created by experience, we are sometimes stuck remembering experiences we’d rather forget. This is especially true for PTSD patients, whose traumatic experience causes significant neurological patterns to take root and, often times, disrupt their lives. To try and help these individuals, some scientists have begun to investigate ways to actually erase memories from our brains.

During his research on memory formation, Joe Tsien of the Medical College of Georgia found that the enzyme CaMKII plays a significant role in memory consolidation. However, in experiments with mice, Tsien found that if he increased CaMKII above a normal limit while the mouse was remembering an experience, the connections between the neurons suddenly weakened and the memory would vanish. This effect happens within a few minutes, and it is permanent and selective: the memory being recalled is erased, while all other memories are left intact. 1

Meanwhile, researchers at UCLA targeted the enzyme kinase M in their memory research. Using Aplysia—a type of marine slug, they first gave the slug a memory: a shock to its tail. For as long as a week after the initial shock, the slug would still retract its tail for a full 30 seconds when touched on the same spot, proving that it had formed a memory. Next, the researchers injected the slug with zeta inhibitory peptide, which blocked the activity of kinase M. When the slugs were prodded again twenty-four hours later, they flinched for only a moment before relaxing—the same reaction they showed when they were poked before the shock. 2 State University of New York professor Todd Sacktor has demonstrated similar results with rats. 3

The bottom line is that scientists are moving step-by-step toward being able to target memories in the brain and erase them. The closer we get to achieving this goal, however, the more closely we will have to examine the ethical implications, lest we end up with scenarios like those in Paycheck (2003) or Total Recall (1990)….

Resources from Wiley on This Topic
Rebuilding Shattered Lives: Treating Complex PTSD and Dissociative Disorders, 2nd Edition

by James A. Chu

Handbook of Neural Engineering

by Metin Akay

Enzyme Technologies: Metagenomics, Evolution, Biocatalysis and Biosynthesis

by Wu-Kuang Yeh, Hsiu-Chiung Yang, James R. McCarthy

1. Wang, H., Feng, R., Wang, L., Li, F., Cao, X., & Tsien, J. (2008). CaMKII Activation State Underlies Synaptic Labile Phase of LTP and Short-Term Memory Formation Current Biology, 18 (20), 1546-1554 DOI: 10.1016/j.cub.2008.08.064
2. Cai D, Pearce K, Chen S, & Glanzman DL (2011). Protein kinase m maintains long-term sensitization and long-term facilitation in aplysia. The Journal of neuroscience : the official journal of the Society for Neuroscience, 31 (17), 6421-31 PMID: 21525283
3. Shema, R., Sacktor, T., & Dudai, Y. (2007). Rapid Erasure of Long-Term Memory Associations in the Cortex by an Inhibitor of PKM Science, 317 (5840), 951-953 DOI: 10.1126/science.1144334

From Attention to Aggression: The Importance of Green Space

We’ve all taken a walk in the park to clear our minds and refresh our spirits. However, scientific studies show that time spent in green spaces can actually renew attention, reduce aggression, improve self-control, and even help to ease symptoms of ADHD. This is especially important as major cities such as San Diego, Washington D.C., Chicago, and Philadelphia lose their tree cover.

As early as the mid-1800s, city planners recognized the importance of green spaces. When his plan for New York City’s Central Park was put into place in 1865, Frederick Law Olmsted said, “It is a scientific fact that the occasional contemplation of natural scenes . . . is favorable to the health and vigor of men.” Over the next century, scientists developed theories and offered mounting evidence to prove that statement true.

In the 1980s, Stephen Kaplan, a psychology professor at the University of Michigan, developed the attention restoration theory (ART). In simple terms, this theory suggests that natural stimuli (trees, grass, stars, etc.) engage our involuntary attention, requiring little effort and energy to engage in the environment. Conversely, urban stimuli (cars, lights, billboards, etc.) demand voluntary attention. Voluntary attention requires considerable focus and energy and is therefore susceptible to attentional fatigue. Thus, exposure to the natural environment actually rejuvenates attentional capacities, because it gives voluntary attention a rest.

Kaplan published his theory in 1995.1 In the following years, a number of published studies supported and expanded upon ART. Scientists at the Landscape and Human Health Lab at University of Illinois, Urbana-Champaign were particularly prolific, producing findings such as:

  • Fatigued attention—caused by lack of exposure to natural greenery—can result in increased aggression.2
  • Decreased exposure to nature results in decreased self-control.3

These same scientists then hypothesized that attentional fatigue may exacerbate attention deficit symptoms and that natural landscapes could help to alleviate these symptoms. Several studies supported this hypothesis, including:

  • “Coping with ADD: The Surprising Connection to Green Play Settings” (Taylor, Kuo, & Sullivan, 2001)4
  • “A Potential Natural Treatment for Attention-Deficit/Hyperactivity Disorder: Evidence from a National Study” (Kuo & Taylor, 2004)5
  • “Children with Attention Deficits Concentrate Better after Walk in the Park” (Kuo & Taylor, 2008)6

Whether using parental observations and ratings or a digit span task, the studies all demonstrated that time spent in green spaces makes children with ADHD calmer, more responsive, and better able to concentrate. Even despite criticisms of some of the study designs7, the consensus remains that people who are exposed to the natural environment function better than people who are not. Therefore, we may be wise to more closely guard our diminishing urban parks and forests, or our mental health may suffer the consequences.

Resources from Wiley on This Topic
Handbook of Environmental Psychology

by Robert B. Bechtel and Arza Churchman

Conservation Psychology: Understanding and promoting human care for nature

by Susan Clayton and Gene Myers

1. KAPLAN, S. (1995). The restorative benefits of nature: Toward an integrative framework Journal of Environmental Psychology, 15 (3), 169-182 DOI: 10.1016/0272-4944(95)90001-2
2. Kuo, F., & Sullivan, W. (2001). Aggression and Violence in the Inner City: Effects of Environment via Mental Fatigue Environment and Behavior, 33 (4), 543-571 DOI: 10.1177/00139160121973124
3. TAYLOR, A. (2002). VIEWS OF NATURE AND SELF-DISCIPLINE: EVIDENCE FROM INNER CITY CHILDREN Journal of Environmental Psychology, 22 (1-2), 49-63 DOI: 10.1006/jevp.2001.0241
4. Taylor, A., Kuo, F., & Sullivan, W. (2001). Coping with add: The Surprising Connection to Green Play Settings Environment and Behavior, 33 (1), 54-77 DOI: 10.1177/00139160121972864
5. Kuo FE, & Taylor AF (2004). A potential natural treatment for attention-deficit/hyperactivity disorder: evidence from a national study. American journal of public health, 94 (9), 1580-6 PMID: 15333318
6. Faber Taylor, A., & Kuo, F. (2009). Children With Attention Deficits Concentrate Better After Walk in the Park Journal of Attention Disorders, 12 (5), 402-409 DOI: 10.1177/1087054708323000
7. Canu, W., & Gordon, M. (2005). MOTHER NATURE AS TREATMENT FOR ADHD: OVERSTATING THE BENEFITS OF GREEN American Journal of Public Health, 95 (3), 371-371 DOI: 10.2105/AJPH.2004.055962

Diagnosing Elderly Drivers and Psychiatric Patients

With the exception of new teenage drivers, elderly drivers have the highest rate of accidents per miles driven. Furthermore, older drivers are more likely than younger ones to be involved in multi-vehicle crashes, particularly at intersections. In some cases, these trends have been thought to be the result of visual impairments caused by bodily aging. However, some research has suggested that the brain, not the eyes, may be at fault.

The middle temporal visual area of the cerebral cortex (MT) is the part of the brain responsible for motion perception. In a young, healthy human, the MT suppresses irrelevant background motion and allows the person to focus on more immediate, important motions of smaller objects in the foreground. Elderly people, by contrast, are better at perceiving background motion.

Researchers at the University of Rochester recently demonstrated that the MT is responsible for this effect by inhibiting subjects’ MT using a process called Transcranial Magnetic Stimulation (TMS), and then testing how well the subjects could identify motions of smaller and larger objects on a computer screen. The scientists found that while the MT was inhibited, subjects could identify the motion of large, background-like objects more easily than smaller, foreground-like objects. These results suggest that an impaired MT may be what causes better perception of background motion in older adults.

Interestingly, patients with psychiatric disorders such as schizophrenia and depression also perceive background motion more easily than foreground motion. This suggests that in the future, rather than asking subjective questions such as Do you have trouble concentrating? Or Have you lost interest or pleasure in most daily activities?, psychiatrists may be able to use motion-detection tests to identify individuals suffering from these disorders.

Resources from Wiley on This Topic
Schizophrenia: Current science and clinical practice

by Wolfgang Gaebel

Normal Binocular Vision: Theory, Investigation and Practical Aspects

by David Stidwill and Robert Fletcher

1. “Older Drivers, Elderly Driving, Seniors At The Wheel.” May 2008. 11 April 2011.

2. Owsley, C. (1998). Visual Processing Impairment and Risk of Motor Vehicle Crash Among Older Adults JAMA: The Journal of the American Medical Association, 279 (14), 1083-1088 DOI: 10.1001/jama.279.14.1083

3. Tadin D, Silvanto J, Pascual-Leone A, & Battelli L (2011). Improved motion perception and impaired spatial suppression following disruption of cortical area MT/V5. The Journal of neuroscience : the official journal of the Society for Neuroscience, 31 (4), 1279-83 PMID: 21273412