Dinishak.com MindBlog

All things between psychology and technology

February 2nd, 2012

The human eye has 125 million rods, each one containing 1000 folds in its photoreceptor
membrane, with each fold containing 1 million molecules of photoceptor. This extraordinary
light-sensing array can detect one single photon, which is 10 to the (-11 power) watts
(which is 0.00000000001 watts Wow!).

December 7th, 2011

Today in brain cutting didactic we saw a patient who had a massive infarct. It got me thinking about why a stroke is called a stroke.

According to the Oxford English Dictionary, a sudden, inexplicable cerebrovascular accident was first likened to a “stroke of God’s hand” in 1599. The relationship of a cerebral infarction to an act of God exists in other cultures as well: the Greek verb plesso means to “stroke, hit, or beat,” and the derivative plegia gives us our term hemiplegia.
Dirckx JH: Stroke. Stroke 17:559, 1986.

November 16th, 2011

The first description of a neurologic disease appears in the Smith papyrus, which is the oldest known medical text. This ancient papyrus, translated by Edward Smith, consists of a number of “case reports” of different diseases, presented and discussed by an unknown Egyptian author, written about 3300 BC. One of the cases is a person with a traumatic head injury, which is the earliest known description of a neurologic problem.

November 16th, 2011

Doing some reading and I came across a list of people who probably had AD:

1. Ronald Reagan—U.S. president
2. Charlton Heston—actor
3. Rita Hayworth—actress
4. Immanuel Kant—philosopher
5. Ralph Waldo Emerson—writer
6. Maurice Ravel—composer
7. John James Audubon—painter

March 12th, 2011

It is usually considered that the sense of smell is poorly developed in humans, in comparison, for example, to lower vertebrates, such as rats and mice. However, in view of its evolutionary significance, it seems very unlikely that the sense of smell is trivial in guiding human behavior.

The fragility of the fibers in the olfactory mucosa of the nose, their delicate passage through the cribriform plate, and the course of the olfactory tract along the orbital surface of the brain underly the vulnerability of this sensory modality to external trauma—for example, from head injury. This is compounded by the locations of structures receiving the central representations of smell, such as, for example, the primary olfactory cortex and olfactory tubercle, which lie vulnerable on the undersurface of the brain overlying the anterior perforated space.

Smell sensations may occur as part of an aura in temporal lobe epilepsy. Traditionally referred to as uncinate seizures (simple partial seizures in today’s terminology), the seizure focus was thought to be in the uncus, overlying the amygdala. However, olfactory inputs also end in the anterior insula, which thus may be associated with the experience. These aurae therefore have some localizing value, but they are not of lateralizing significance.

The olfactory system is involved in several neuropsychiatric disorders. In depression, for example, the sense of smell can be diminished, as may be other sensory modalities, such as taste or touch. Diminished smell sensation also has been reported in Alzheimer’s disease and Parkinson’s disease, especially the Lewy body variant but not sufficiently reliably to be used in any diagnostic way (Hawkes, 2003). Diminished smell also may be observed early in the course of schizophrenia and may be associated with smaller perirhinal cortices as measured with MRI (Turetsky et al., 2003). Thus, disturbances of smell in such disorders may be associated with underlying neuroanatomical deficits, rather than being simply a manifestation of a psychosis or deteriorating intellect.

March 12th, 2011

Stories of interest for March 11th

March 9th, 2011

Stories of interest for March 8th

March 8th, 2011

Stories of interest for March 7th

March 5th, 2011

Stories of interest for March 4th

February 21st, 2011

Stories of interest for February 20th

February 19th, 2011

Stories of interest for February 18th

February 15th, 2011

Stories of interest for February 14th

February 14th, 2011

Stories of interest for February 13th

February 7th, 2011

Stories of interest for February 5th through February 6th:

February 6th, 2011

Stories of interest for February 5th

February 5th, 2011

Stories of interest for February 4th

February 4th, 2011

Stories of interest for February 3rd

January 28th, 2011

Stories of interest for January 27th

December 8th, 2010

Stories of interest for December 7th

December 4th, 2010

Stories of interest for December 2nd through December 3rd:

December 3rd, 2010

Stories of interest for December 2nd

November 27th, 2010

Stories of interest for November 26th

November 21st, 2010

Stories of interest for November 20th

November 20th, 2010

Stories of interest for November 19th

November 19th, 2010

Stories of interest for November 18th