Biological Perspective Studies

How well does biological psychology explain others and you?

Galvani (1791)• It was through the accidental overlap of these two seemingly dissimilar

areas of scientific effort that Galvani made his greatest discoveries. He noticed that the dissected legs of frogs in his laboratory seemed to jump to life under various conditions. For instance, when one of his assistants placed a scalpel against the exposed nerve of one specimen, which was sitting on a table previously used in electrostatic experiments, the legs of the frog suddenly kicked. In a similar event, when Galvani used a scalpel made of steel to cut the leg of a frog anchored on a brass hook, the leg visibly twitched. Based on such unusual observations Galvani concluded that there was a type of electrical fluid inherent in the body, which he dubbed animal electricity. According to his view, the nervous system delivered animal electricity to muscle tissue.

http://www.magnet.fsu.edu/education/tutorials/pioneers/galvani.html

Von Helmholtz (1850)• Helmholtz' technique was quite simple. He first cut out a muscle and an attached

nerve fiber from a frog's leg. The experiment then consisted of stimulating the nerve at various distances from the muscle and measuring the length of time between nerve stimulation and muscle contraction. First, he electrically stimulated the nerve close to the point at which it attaches to the muscle, then he stimulated the nerve farther from this point of attachment. He found that the second reaction time (that is, the time between stimulation and contraction) was longer than the first. To obtain an estimate of the nerve impulse speed, he used a simple bit of reasoning: The difference in time between the two measurements must correspond to the time it takes the nerve impulse to travel the distance between the two points of stimulation (see Fig. 1). Hence, the distance between the point of stimulation divided by the time difference between the conditions of stimulating close to the muscle versus stimulating farther away should yield an estimate of nerve impulse speed. This is how he obtained his estimate of fifty to one hundred meters per second.

http://www3.wheatonma.edu/kmorgan/BrainMindBehavior/NerveImpulse.html

Golgi (1875)• Camillo Golgi was responsible for inventing a specific staining technique for neurons,

which he called "the reazione nera" (the black reaction). It consisted in fixing silver chromate particles to the neurilemma (the neuron membrane) by reacting silver nitrate with potassium bichromate. This resulted in a stark black deposit on the soma as well as on the axon and all dendrites, providing a exceedingly clear and well contrasted picture of neuron against an yellow background (see picture below). For the first time, neuroanatomists could follow where the ramifications went in and out a particular spot in the nervous system, and describe with exquisite detail all the richness of these ramifications. A marvelous picture of complexity emerged, and Golgi was able to explore it in full, describing for the first time, for example, that axons also gave collaterals, which provided a divergence of connexion which was heretofore suspected of, but not proven.

• Golgi defended the reticularist position, though, because he could not see with certainty that axons did not fuse to other cells. He wrote: “There is certainly to be found a very widespread network of filaments anastomosing one with the other throughout the gray matter of the brain.”

http://www.cerebromente.org.br/n17/history/neurons3_i.htm

Ramon y Cajal (1906)• Particularly relevant were Cajal s conclusions about the way action currents

propagate in neuronal networks, always in the direction of dendrites to axons, and there to the dendrites or soma of other neurons. He called this the Law of Dynamic Polarization , which was another fundamental contribution to neurophysiology.

• The neuronal doctrine had four tenets: • The neuron is the structural and functional unit of the nervous system;• Neurons are individual cells, which are not continuous to other neurons,

neither anatomically nor genetically;• The neuron has three parts: dendrites, soma (cell body) and axon. The axon

has several terminal arborizations, which make close contact to dendrites or the soma of other neurons;

• Conduction takes place in the direction from dendrites to soma, to the end arborizations of the axon

http://www.cerebromente.org.br/n17/history/neurons3_i.htm

Loewi (1921)• Loewi's experiment

– Loewi arranged two frog's hearts so that the baths they were in could be circulated through both preparations by way of a pump that could be turned on and off.

– One heart still had the vagus nerve attached. Stimulation of the vagus nerve slows the heart rate.

– If the pump was turned off, and one heart was stimulated, there was no effect on the second heart.

– If the pump was turned on, and one heart was stimulated, after a delay the second heart was also affected.

– This showed that something released by the nerve and that could circulate in the bath must be influencing heart rate. This had to be a chemical substance.

• Loewi was convinced the chemical substance was acetylcholine, since direct application of acetylcholine to the heart muscle also caused it to slow.

• But he couldn't prove it, so he called the chemical substance vagusstoff.• Later it was demonstrated that vagusstoff was, in fact, acetylcholine.http://ww2.coastal.edu/kingw/psyc460/neurotransmitters/discovery/discovery.html

J.Z. Young (1936)• He then made a careful study of the anatomy of the mantles, and in his classical

paper on `The functioning of the giant nerve fibres of the squid' (Young, 1938), he showed that the third order giant axons served to bring about the precisely coordinated contraction of the mantle causing expulsion of a powerful jet of water propelling the animals rapidly backwards or forwards according to the position of the funnel, sometimes accompanied by a slug of `ink' to assist the animal's escape.

• Having confirmed that the squid giant axons did conduct action potentials, and having with R. J. Pumphrey in 1938 (Young and Pumphrey, 1938) looked at the effect of their diameter on the rate of conduction, the only respect in which J.Z. subsequently involved himself in research on the ionic basis of conduction was to measure their electrolyte content (Young and Webb, 1945).

http://jeb.biologists.org/content/208/2/179.shorthttp://www.science.smith.edu/departments/NeuroSci/courses/bio330/squid.html

Hodgin and Huxley (1939, 52)

• Hodgkin and Huxley's work with the giant squid axon was the first to use mathematical models to represent biological systems. Due to Hodgkin and Huxley's findings, we are able to understand how an action potential propagates along a nerve and the functions of their associated ion channels.

• The Resting Potential• The Model Cell• The Constant Field Equation• The Resting Membrane Potential• The Action Potentialhttp://www.swarthmore.edu/NatSci/echeeve1/Ref/HH/

Harlow• In 1848, Gage, 25, was the foreman of a crew cutting a railroad bed in Cavendish, Vermont. On

September 13, as he was using a tamping iron to pack explosive powder into a hole, the powder detonated. The tamping iron—43 inches long, 1.25 inches in diameter and weighing 13.25 pounds—shot skyward, penetrated Gage’s left cheek, ripped into his brain and exited through his skull, landing several dozen feet away. Though blinded in his left eye, he might not even have lost consciousness, and he remained savvy enough to tell a doctor that day, “Here is business enough for you.”

• Gage’s initial survival would have ensured him a measure of celebrity, but his name was etched into history by observations made by John Martyn Harlow, the doctor who treated him for a few months afterward. Gage’s friends found him“no longer Gage,” Harlow wrote. The balance between his “intellectual faculties and animal propensities” seemed gone. He could not stick to plans, uttered “the grossest profanity” and showed “little deference for his fellows.” The railroad-construction company that employed him, which had thought him a model foreman, refused to take him back. So Gage went to work at a stable in New Hampshire, drove coaches in Chile and eventually joined relatives in San Francisco, where he died in May 1860, at age 36, after a series of seizures.

Read more: http://www.smithsonianmag.com/history-archaeology/Phineas-Gage-Neurosciences-Most-Famous-Patient.html#ixzz2kySYrhR3

Broca (1860s)• Broca is most famous for his discovery of the speech production center of the brain

located in the ventroposterior region of the frontal lobes (now known as Broca's area). He arrived at this discovery by studying the brains of aphasic patients. His first patient in the Bicêtre Hospital was Leborgne, nicknamed "Tan" due to his inability to clearly speak any words other than "tan".

• In 1861, through post-mortem autopsy, Broca determined that Tan had a lesion caused bysyphilis in the left cerebral hemisphere. This lesion was determined to cover the area of the brain important for speech production, affecting syntactic skills of patients. (Although history credits this discovery to Broca, another French neurologist, Marc Dax, made similar observations a generation earlier.) Today the brains of many of Broca's aphasic patients are still preserved in the Musée Dupuytren, and his collection of casts in the Musée d'Anatomie Delmas-Orfila-Rouvière. Broca presented his findings on the localisation of language at the 1868 British Association meeting in Norwich, chaired by Joseph Dalton Hooker, and the subsequent discussions included Hughlings Jackson.

http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Paul_Broca.html

Wernike (1870s)• In 1873, Wernicke studied a patient who had suffered a stroke. Although the man

was able to speak and his hearing was unimpaired, he could barely understand what was said to him. Nor could he understand written words. After he died, Wernicke found a lesion in the rear parietal/temporal region of the patient's left brain hemisphere. Wernicke concluded that this region, which is close to the auditory region of the brain, was involved in speech comprehension. Wernicke named the syndrome sensory aphasia, although now it is usually called Wernicke's aphasia. The affected region of the brain is known as Wernicke's area. The syndrome is sometimes called fluent aphasia since the victim is capable of speech; however words may be misused and the speech may be disordered or even without content. For this reason, scientists now believe that Wernicke's area may be involved in semantic processing, and it is sometimes called the receptive language area.

Read more: Carl Wernicke - Describes Wernicke's aphasia, Describes Wernicke's encephalopathy - Right Hemisphere Of The Brain, Right Brain, and Brain - JRank Articles http://psychology.jrank.org/pages/652/Carl-Wernicke.html#ixzz2kyTsiT62

Heath (1950s)

• Abstract (1963)• Studies are described of two human patients under treatment

with ICSS. Their subjective reports in association with stimulation to reward areas of the brain are presented. The data indicate that patients will [See Figure 6. in Source PDF] [See Figure 7. in Source PDF] stimulate regions of the brain at a high frequency for reasons other than to obtain a pleasurable response. These data extend information obtained from ICSS in animals.

http://ajp.psychiatryonline.org/article.aspx?articleID=149327

http://www.tulanelink.com/tulanelink/twoviews_04a.htm

Olds and Milner (1954)• POSITIVE REINFORCEMENT PRODUCED BY ELECTRICAL STIMULATION

OF SEPTAL AREA AND OTHER REGIONS OF RAT BRAIN.• Journal of Comparative and Physiological Psychology, Vol 47(6), Dec

1954, 419-427. doi: 10.1037/h0058775• After implantation of electrodes at various points in the brains of rats,

the animals were placed in a Skinner box, arranged in such a manner that they could stimulate themselves by pressing the lever. The results indicate that various places exist in the brain "where electrical stimulation is rewarding in the sense that the experimental animal will stimulate itself in these places frequently and regularly for long periods of time if permitted to do so." The reward phenomenon appears most reliably when the electrodes are placed in the septal region, where an extreme degree of control was observed.

http://psycnet.apa.org/index.cfm?fa=search.displayRecord&uid=1955-06866-001

Hetherington and Ranson

• A.W Hetherington and S.W Ranson conducted one of the first experiments studying regulation of feeding behavior in the 1940s in which they used a Horsely-Clark instrument to make hypothalamic lesions. They found that lesions in the lateral hypothalamus caused the rats to stop eating, while lesions in the ventromedial hypothalamus caused the animals to overeat, leading to obesity.

https://wiki.brown.edu/confluence/display/BN0193S04/Historical+Background

Milner (1957) and Corkin (1997)

• HM

Gazzaniga and Sperry

• http://www.nature.com/news/the-split-brain-a-tale-of-two-halves-1.10213

Rosenzweig and Bennett (1972) ratsDavidson et al. (2004) monks

Vestergaard-Poulsen et al. (2009) meditationGallese (1996) rhesus monkeysIacoboni (2004) fMRI humans

Bouchard (1990) twinsNewcomer et el. (1999) cortisol

Fisher (2004) dopamineMartinez and Kesner (1991) Ach ratsBaumgartner et al (2008) oxytocin

Bremner et al. (2003) PTSDAshtari (2009) MRI substance abuse

Harris and Fiske (2006) fMRI studentsCaspi et al. (2003) 5-HTT gene

Fessler et al. (2005) pregnancy sensititvity