November 30, 2006

Evolution Again

D. Buss again (see prior post): "Ancestral conditions that favored the dissolution of a mateship constituted a recurrent adaptive problem over human evolutionary history and thus imposed selection pressures for the evolution of strategic solutions."(p. 171) The only selection pressure was on having an intact brain. The strategies are only an outgrowth of that. Each strategy isn't a trait undergoing selective pressure.

Humans today face a completely different landscape than those at the beginning of recorded history. Any evolutionary biologist would agree that it is too short a time for significant evolution via natural selection. And yet, we operate in this changed world without much difficulty. Without any appreciation for history, one might posit that humans are evolved to operate computers: our manual dexterity to enter keystrokes, our ability to multi-task many windows at once, even our language to write HTML code. This is of course preposterous, just as most of Dr. Buss's arguments are.

I think the important question is how we are able to adapt to such varied environments? How did we become repositories of information, manipulators of tools, possessors of language? These were the skills that when applied to old problems, such as having babies, yielded the many strategies discussed in Buss's book. For another example, writing is not evolved. It is an exaption born of our ability for language, but it is writing that has made today's civilizations possible.

November 29, 2006

Dr Pangloss

The Evolution of Desire by David Buss talks about sex a lot. It comes from the group of writers and academics espousing Evolutionary Psychology. It's a sexy discipline.

This from Wikipedia and the man often mentioned in the same breath as evolutionary psychology: "Evolutionary Psychology is, to quote Steven Pinker, 'not a single theory but a large set of hypotheses' and a term which 'has also come to refer to a particular way of applying evolutionary theory to the mind, with an emphasis on adaptation, gene-level selection, and modularity.'" O boy. If it is a set of hypotheses that can't be tested, is it science? Is it truly informative? The short answer is no? I'll leave the argument against adaptationist thinking to Gould and Lewontin.

I heard about the Spandrels of San Marco in undergrad. It was not until tonight that I read the full article. The Proceedings of the Royal Society of London Biology are kind enough to offer the article here. You may only be able to access it by starting through google. Search The Proceedings of the Royal Society of London Biology. The full citation is at the bottom.

Like a choice philosophic passage or engrossing novel, this paper engages and excites. It underlines the idea that adaptionist thinking cannot be applied to the varied expressions of human behavior. Humans are the undetermined animal, as well as the exploitative animal, the opportunist, the conniver, the schemer.

In his book, Buss catalogues a variety of behaviors that in large, he considers selected adaptations. In my mind they are no more than expressions of underlying drives, their manifestation different in males and females. Human behavior is contextual. The variety is a response to different contexts. The fact that humans can display such different behaviors is testament to our freedom from biologic behavioral constraints.

1. Gould, S. J. And Lewontin, R. C., "The Spandrels of San Marco and the Panglossian Paradigm: A Critique Of The Adaptationist Programme," Proceedings Of The Royal Society of London, Series B, Vol. 205, No. 1161 (1979), Pp. 581-598.
2. Buss, David. "The Evolution of Desire: Strategies of Human Mating," 2nd Edition. NY: Basic Books, 2003.

November 27, 2006


"He then found that if he spent time engaged in imitating the components that make up a smile, his mood lifted. 'That was like an epiphany,' he recalls." This is from the article by Siri Schubert in the current SA Mind. It discusses the work of Paul Ekman.

Laughter Clubs seem to have understood this a few years ago. Dr. Madan Kataria (laughing man on right) started the first laughing club on March 13, 1995. He now is the godfather of laughter yoga.

Jackass as therapy may take a while to gain currency.

Gelastic seizures are left out of Bradley and Daroff but they are no less real. Maybe I wasn't looking in the right place in the index. I had the opportunity to see gelastic seizure earlier this year and they are striking to say the least. The young woman appeared possessed. The laughter was quiet but maniacal. The cause of her seizures was HSV encephalitis years earlier.

"It has been suggested that normal laughter is the result of an interaction of several different brain structures: the frontal and temporal neocortex; the temporo-basal cortex; the visual, olfactorial, and auditorial associative areas; the limbic system with the cingulate gyrus; and the brainstem. The motor manifestations of laughter and the feeling of amusement or mirth have been claimed to be separable functions and, consequently, neurologically dissociated (Lopes da Silva et al 1990; Arroyo et al 1993). Gelastic seizures have been observed to be associated with many different conditions: mainly hypothalamic hamartomas, but also as a seizure manifestation in connection with temporal and frontal lobe lesions as well as other focalities." link
Laughter and mirth may be "neurologically dissociated", but one can not emulate laughter without feeling happy.

November 25, 2006

Miller-Fisher Syndrome

Miller-Fisher Syndrome Miller-Fisher Syndrome is considered a variant of Guillain-Barre Syndrome. It is characterized by ophthalmoplegia, ataxia, and areflexia.

As a resident I was called to see a 2-year-old with the rapid onset of ptosis. At least this is how it was described by the outside doctor. He also noted that the child had difficulty walking. With this information, he considered myasthenia.

The child had a upper respiratory infection 4-5 days prior to presenting. Otherwise he was in good health. The night before he presented, the mother noted that he had very wide eyes. In the morning the child had drooping eyes and difficulty walking. With these symptoms the mother brought him to the outside hospital.

On exam, the child's eyes were very wide with slowly drooping eyelids. Once the eyes were closed they snapped back open. His eyes were always in a midline position. Pupils were reactive. With testing, the child was unable to move his eyes horizontally and upward gaze also seemed impaired. His gait was markedly unsteady. He appeared as if he were aboard a ship. His strength, as much as can be tested in a 2-year-old, seemed normal. Reflexes were absent.

Clinically, this is a case of MFS. An LP and GQ1b antibodies will be obtained to make the definitive diagnosis. The LP should show albuminocytologic dissociation If the patient's condition worsens, plasma exchange or IVIG can be given, but the condition is considered benign, and usually completely resolves.

November 13, 2006

Frontotemporal Dementia

Alois Alzheimer famously described a case of a 51-year-old female with delusions and memory impairment in a 1907 paper. His observations were coupled with his neuropathological findings of neuritic plaques and neurofibrillary tangles, the pathologic hallmarks of the disease. Originally used to describe a rare form of pre-senile dementia, those who suffer from Alzheimer's Disease are mainly elderly patients with functional decline in memory, language, visuospatial function, and executive function.

Frontotemporal Dementias affect less patients but the results are equally if not more devastating. Age of onset is usually around 50 to 60. The causes are heterogeneous. As the name suggests, frontotemporal dementias are marked by a preponderance of atrophy in the frontal and temporal lobes. Bifrontal atrophy leads to disinhibition and socially inappropriate behavior. Depending on the location of atrophy, varying degrees of aphasia, semantic dementia, prosopagnosia, and limb apraxia can be seen. FTD can present as a progressive behavioral disturbance or a progressive language disturbance. Among those exhibiting the latter, disinhibition, overactivity, and restlessness are associated with prominent orbitofrontal involvement. Loss of motivation is associated with dorsolateral frontal involvement.

A female with a psychiatric history was admitted from an outside hospital. Her illness began when she was 53: she was hospitalized in a psychiatric hospital for frank delusions. She is now 61 with marked dementia. She cannot form new memories; she exhibits diffuse hyperreflexia with upgoing toes bilaterally; she has a tendency to retropulse; she perseverates and cannot be redirected easily. Her age and severe cognitive impairment together with long-tract signs suggest FTD, although the length of her course argues against it. She is no longer in contact with her family and her caretaker is no longer able to manage her at home.