Monthly Archives: April 2011

Diagnosing Elderly Drivers and Psychiatric Patients

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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.” SmartMotorist.com. May 2008. 11 April 2011. http://www.smartmotorist.com/traffic-and-safety-guideline/older-drivers-elderly-driving-seniors-at-the-wheel.html.

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

Lactococcus lactis

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In Wisconsin, the United States’ top cheese-producing state, it follows that the microbe responsible should finally earn accolades. Here is a profile of the illustrious microbe:

Name: Lactococcus lactis

Honors and Awards: A bill to recognize L. lactis as Wisconsin’s state microbe was passed by the Assembly on April 15, 2010 and awaits approval from the Senate.

Work Experience:

  • Cheese-making—Uses enzymes to convert lactose (milk sugar) into lactic acid. The acid lowers the milk’s pH, causing it to curdle; the curds are then removed to make cheese and whey. Used especially in the production of Cheddar, Colby, cottage cheese, cream cheese, Camembert, Roquefort, and Brie; also in curdled dairy products such as buttermilk and sour cream.
  • Vaccine delivery—Generates proteins from pathogens on the microbe’s cell surface and, when administered, induces an immune response to the protein and provides immunity to the pathogen. Primarily administered via mucosal pathways, especially to provide immunity to Streptococcus pyogenes, which causes strep throat.1 Oral administration2 is also being developed, which may help with HIV immunization3, gluten sensitivity4, and prevention of other respiratory diseases.

Other Popular Microbes:

  • Saccharomyces cerevisiae (yeast), crucial for making bread, beer, and wine; might California consider nominating this microbe?
  • Corynebacterium glutamicum, assists in the production of the sweetener aspartame; a potential Florida state microbe?
  • Clostridium thermocellum, useful for the creation of ethanol and natural wood glue; perhaps a state microbe for Iowa?

1 Mannam, P., Jones, K., & Geller, B. (2004). Mucosal Vaccine Made from Live, Recombinant Lactococcus lactis Protects Mice against Pharyngeal Infection with Streptococcus pyogenes Infection and Immunity, 72 (6), 3444-3450 DOI: 10.1128/IAI.72.6.3444-3450.2004

2 Villena, J., Medina, M., Raya, R., & Alvarez, S. (2008). Oral immunization with recombinant Lactococcus lactis confers protection against respiratory pneumococcal infection Canadian Journal of Microbiology, 54 (10), 845-853 DOI: 10.1139/W08-077

3 Xin, K. (2003). Immunogenicity and protective efficacy of orally administered recombinant Lactococcus lactis expressing surface-bound HIV Env Blood, 102 (1), 223-228 DOI: 10.1182/blood-2003-01-0110

4 Huibregtse, I., Marietta, E., Rashtak, S., Koning, F., Rottiers, P., David, C., van Deventer, S., & Murray, J. (2009). Induction of Antigen-Specific Tolerance by Oral Administration of Lactococcus lactis Delivered Immunodominant DQ8-Restricted Gliadin Peptide in Sensitized Nonobese Diabetic Ab Dq8 Transgenic Mice The Journal of Immunology, 183 (4), 2390-2396 DOI: 10.4049/jimmunol.0802891