Author Archives: CCADMIN

Extra-Striate Visual Areas

Due to the heavy burden of the packing problem, the brain alleviates some responsibility of off-loading information to the extra-striate visual areas. These areas are specialised for particular visual data. Colour information is relayed to V4, motor information is relayed to V5, and lastly, object

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Secondary visual cortex: V2

The secondary visual cortex envelops V1 and is organised into parallel stripes running perpendicular to the V1/V2 border. Stripes that respond to the same region of the retina run adjacent to each other, preserving the retinotopic map. These stripes come in three types: thick, think and pale. Pale stripes are known as interstripes as they run between thick and thin stripes. Input is fed to the pale stripes from the hypercomplex cells of V1, and it is then forwarded to the LGN via the parvocellular layer. The main job of the pale stripes is to respond to oriented lines. Secondly, thick stripes receive input from layer 4B of V1 and respond to specific orientations as well as cells of binocular disparity. Output from the thick stripes is passed onto V5 via the magnocellular pathway. Lastly, thin stripes receive inputs from colour blobs of V1, hence they are sensitive to colour or brightness. Output from the thin strips project to V4 via the parvocellular stream.

V4

V4 is the colour area, and cells here respond to colour, simple shapes and objects. As colour does not have its own parameter, it does not have an accurate retinotoic map. As such, V4 serves as the first indication of decline in retinal location and the rise of feature based primary indices.

V5

As mentioned above, the thick stripes of V2 project to V5. V5 is known as the motor areas it responds to motion and stereo disparity. Non-spatial parameters are beginning to take precedence over maintaining the retinotopic map as it is no longer maintained here. Zeki (1990) confirmed the hypothesis found when he found that paths across the retina become more chaotic the further they are from the striate cortex.

The Inferotemporal Cortex

Each point of the inferotemporal cortex represents a different view of a face. Despite the highly abstract parameter, nearby cells represent similar views of the face. Over the past years, there has been discussion over whether inferotemporal cortex cells are grandmother cells. The inferotemporal cortex was monitored while a patient was shown various faces; one cell seemed to respond only to pictures of Jennifer Aniston of Friends (Connor, 2005). Nearby cells did not seem to respond to different views of Jennifer Anniston, but they did respond to characters from the same shows. These findings suggest that nearby cells represent many parameters that occur nearby in time. The temporal proximity of views experienced in everyday life may be reflected in the physical proximity of cells in the cortex.

Methods Used for Studying Infants’ Perception

Part of getting onto a good masters or Ph.D programme means having real-life experience. As only a second year undergraduate that can sometimes seem like an age away, but time really does fly by. In order to get some experience in research I transcribed videos for a developmental researcher at my department. Even though my job was pretty menial in the whole scale of things, writing down all the speech and movements of infants really made me appreciate something substantial; infants are very hard to understand and observe. Their intentions, their desires and even just their knowledge can be difficult to interpret. As such, psychologists use a set of methods to study infant perception, intentions, desires and capabilities.

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This post will deal with studying infant perception.

Preference Technique

Basic set-up

1. A researcher presents two stimuli to an infant simultaneously

2. The researcher monitors the infant’s eye movement. Researchers use various techniques for this, one being the ASL Model 504.

3. If the infant looks more at one stimulus than the other, it is inferred that the infant prefers that stimulus over the other.

If accurate, measures of the eye movements can be made, this technique is quite simple and effective. The infants preference can be inferred because of habituation, a fancy word for boredom.

Habituation

Habituation and dishabituation are another method used to study infant perception and preference. After looking at a stimulus for a certain amount of time, we become bored of it. Just like after awhile we stop feeling the clothes on our body. Our brain gets bored with the touch sensation, and so eventually it stops informing us of it. On this basis, psychologists infer that babies will stop looking at a stimulus if they gets bored of it. If a stimulus is then presented with a new stimulus, it is likely he or she will prefer looking at the new stimulus that the infant has not seen before. If the infant does prefer the new stimulus, we can infer that the infant is capable of discriminating between the two stimuli. Discrimination between two stimuli allows researchers to detect the stage of perceptual development of infant has reached.

Conditioning

Classical and operational conditioning are terms you should be familiar with have you ever taken an introductory psychology course. Conditioning with infants consists of the same learning system. Fortunately, infant studies usually just involve rewarding the infant with pleasant sounds or images, usually of or from their mother.

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Basic set-up

1. Infant is given a dummy or pacifier

2. Researcher waits for the infant to begin sucking on it at their usual rate

3. If the infant begins sucking at a faster rate than usual they are rewarded with the sound of their mothers voice

4. The infant will soon learn that as long as her or she continues sucking at the increased rate, they will hear their mother’s voice

5. After awhile, habituation sets in as the baby loses interest in the sound and their sucking rate decreases

6. The researcher then proceeds to introduce a new sound

7. If the infant is capable of discriminating the new sounds, they will begin to suck more again to her this new sound

All of these various tests of perception, as mentioned above are used to measure the development of infants.

The Striatum

The striatum is the largest collection of neurons in the basal ganglia. Composed of the caudate nucleus and putamen, the basal ganglia, as the name suggests, sits at the base of the cerebrum. It receives input from regions of the cerebral cortex, the limbic system, and the sensorimotor and motivational systems via the thalamus. In addition to the cerebrum, the striatum receives input from the brainstem including the substantia nigra and the raphe nuclei of the reticular formation. The dopamine and serotonin of these two structures serve a modulatory function. Anatomists organise the striatum on the “basis of differential connectivity and distribution of neurochemical markers” (Redgrave, 2007). Processing strong excitatory input, the striatal neural circuits generate a strong inhibitory output, which controls the output of basal ganglia further along in the motor loop.

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The major cytology of the striatum is GABAergic medium spiny neurons (MSN), making up about 95% of the total cellular structure. MSNs are organised into two groups based on the peptide they contain, substance P and enkephalin and the proportion of dopamine receptors (D1 or D2) they contain. MSNs create dense networks of axon collaterals. As projection neurons, the MSNs create this dense network by forming axon collaterals with one another. Tunstall et al, 2002 found that almost 30% form an axon collateral with a neighbouring MSN. Research has shown that the function of these collaterals is in cellular recognition and “classification of cortical patterns” (Blomeley, et al. , 2009).

The striatum is a vital part of the basal ganglia, and all pathways run through it. From the striatum onwards, the pathway either becomes direct or indirect. As shown in the figure below.

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Citations:

Blomeley, C. P., Kehoe, L. A., & Bracci, E. (2009). Substance P mediates excitatory interactions between striatal projection neurons. The Journal of Neuroscience29(15), 4953-4963.

Redgrave, P. (2007). Basal ganglia. Scholarpedia, 2(6): 1825.

Basal Ganglia: Substance P

As mentioned in my last post on basal ganglia, the majority of the striatum consists of medium spiny neurons. These medium spiny neurons are GABAergic and organised based on the peptide they contain as well the dopamine receptors they contain. One these peptides is called substance P (SP). As a neuropeptide, SP functions as a neurotransmitter as well as a neuromodulator. Other than GABA, SP functions as a neurotransmitter in MSNs. Specifically, SP-releasing neurons mediate “synaptic communication between MSNs” (Blomeley, et al. , 2009).

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Previously it was thought that striatal projection neurons like MSNs only inhibit each other; however, a study by Blomeley, et al. , 2009 has proven that they can also interact in an excitatory manner. Studies have shown the synaptic NK1 receptors, whose major receptor molecule is SP are present in a glutamteric terminals in the stiratum (Jakab et al., 1996). In the study by Blomeley, the importance of these NK1 receptors was investigated. The results suggest that SP plays a crucial role in facilitating the release of glutamate between medium spiny neurons. In other words, communication between the neurons is increased by SP attaching NK1 receptors found on the terminals of glutamate releasing MSNs.

Citations:

Blomeley, C. P., Kehoe, L. A., & Bracci, E. (2009). Substance P mediates excitatory interactions between striatal projection neurons. The Journal of Neuroscience29(15), 4953-4963.

Neuroscience: The Nervous System

he nervous system is the body’s speedy, electrochemical communication system. It consists of all the nerve cells of the peripheral and central nervous systems.

The central nervous system consists of the brain and spinal cord. The peripheral nervous system is the sensory and motor neurons that connect the central nervous system to the rest of the body. Nerves are the neural cables of the nervous system containing many axons. They are part of the peripheral nervous system. They are connected to the central nervous system by muscles, glands, and sense organs.

Sensory neurons carry incoming information from the sense receptors to the central nervous system. Interneurons are part of the central nervous system. They internally communicate and intervene between the sensory inputs and motor inputs. They are the most common type of neuron. Motor neurons carry outgoing information from the central nervous system to the muscles and glands.

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– The Peripheral Nervous System –

The peripheral nervous system is made up of the somatic nervous system and the autonomic nervous system. The somatic nervous system controls the body’s skeletal muscles. The autonomic nervous controls the glands and muscles of the internal organs. It is broken down into the sympathetic and the parasympathetic nervous system. The sympathetic nervous system arouse the body, mobilising its energy in stressful situations (fight or flight response). The parasympathetic nervous system calms the body, conserving its energy.

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– The Central Nervous System –

The spinal cord is the information highway connecting the peripheral nervous system to the brain. Ascending neural tracts send up sensory information. Descending neural tracts send down motor control information. Reflexes are the body’s autonomic response to stimuli controlled by the spinal cord. They are composed of 1 sensory neuron and 1 motor neuron that communicate through one interneuron. Because they only run through your spinal cord, they react automatically without your brain being involved in the process. The spine sends information back to the brain. Bodily pain or pleasure is controlled by the brain.

The brain receives information, interprets it and then decides on a response. It functions like a computer, receiving slightly differing images of an object from the eyes, it computes the differences and infers how far the object must be to project such a difference.

Neural networks are interconnected neural cells which, with experience, can learn, as feedback strengthens or inhibits connections that produce certain results. Stephen Kosslyn and Oliver Koening proposed to think of neural networks as networks of people. Neuron network with nearby neurons with which the can have short, fast connections. Each layer of a neural connects with various cells in the next layer. Learning occurs as feedback strengthens connections that produce certain results. New computer models simulate this process plus the excitatory and inhibitory conniptions to mimic the brain’s capacity for learning.

 

Profile of a psychologist: Philip Zimbardo

Philip Zimbardo, Psychology

Philip Zimbardo, Psychology

Philip G. Zimbardo is world renowned for his controversial study, the Stanford Prison experiment. In more recent years he has become known for his theory known as the “Lucifer Effect,” in which he investigates the question “What makes good people do bad things?” A Professor Emeritus of Psychology at Stanford University and currently still teaching, Zimbardo also holds the title of two-time past president of the Western Psychological Association and past president of the American Psychological Association. As a social psychologist, Zimbardo constantly questions how we interact and influence others in our society; however, most notably, he seeks to discover how our environment is and will remain our strongest influence.

Philip Zimbardo was born in 1933 to a Sicilian-American family in New York City, New York. His academic career landed him classmates with another future social psychologist, Stanley Milgram, in James Monroe High School. Next he merited a BA from Brooklyn College and a PhD from Yale University. After several years of teaching a universities all across the United States, he finally started his professorship at Stanford in 1968. Since 2000, Zimbardo has been on a mission to bring psychology to the forefront of research and also the public eye by presenting a TV series on “discovering psychology” and lecturing at TED, to name a few.

zimbardo2Inspired by Stanley Milgram’s obedience studies in 1963 that demonstrated the moral aberration people are willing to commit to obey authority, Zimbardo aimed to discover what makes people concede their moral compass when put in a place of power. Zimbardo wanted to uncover under what circumstances people would “willing use (or abuse) power granted to them.” In light of this curiosity, he carried out the Stanford Prison experiment in 1971. His subjects were twenty-four, mentally healthy, American, university students. The similarity of subjects attempted to control for all dependent variables. Randomly, the students were assigned the role of “guard or prisoner.” Then one morning the “prisoners” were arrested by real police officers whom booked to them be transferred to the mock prison built in the basement of the Stanford Psychology Department.

zimbardo3Once transferred into the “prison,” the “prisoners” were “stripped, searched, deloused, and given uniforms and bedding.” The prisoners were then stripped of their identify and dehumanised by the “guards” who were told to  refer to them by assigned numbers. To heighten their lack of freedom, the “prisoners” also had a chain bolted around one ankle. The “guards” wore military inspired uniforms, sunglasses (to prevent eye-contact) in addition to carrying keys, whistles, handcuffs and clubs. The “guards” patrolled 24 hours a day and where given full control of the “prisoners” to maintain order. It did not take long for the environment to quickly turn “threatening” forcing the experiment to end prematurely after only six days.

Every single “guard” became “abusive and authoritarian; prisoners were denied food or bedding, hooded, chained, and made to clean toilet bowls with their hands.” The “prisoners” were used as playthings to take part in the “guards” degrading games. One prisoner had to be released after only thirty-six hours after suffering a nervous break.

Zimbardo’s findings, the basis for the Lucifer Effect showed the world that good people can be induced to evil by “immersion” in “total situations.” Total situations have an “apparently legitimizing ideology and approved rules and roles.”  Zimbardo served as an expert witness in the defense of a guard during the Abu Ghraib trails, which as Zimbardo discusses in his TED video, showed many parallels with the Stanford Prison Experiment. The Abu Ghraib prison abuse against Iraqi prisoners by American soliders gathered wide controversy. Please view the TED video for further information. The scary thing Zimbardo explains is that “any deed that any human being has even done, however horrible, is possible for any of us to do – under the right or wrong situational pressures.” However, as Zimbardo discusses in his final chapter of The Lucifier Effect, his book, these situational pressures not only shows human capacity for evil but also for heroism.

Citations:

Collin, Catherine. The Psychology Book. New York: DK Pub., 2012. Print.

“Philip G. Zimbardo.” Philip G. Zimbardo. N.p., n.d. Web. 09 Aug. 2012. <http://www.zimbardo.com/&gt;.

Zimbardo, Philip G. The Lucifer Effect: Understanding How Good People Turn Evil. New York: Random House, 2007. Print.

Profile of a Psychologis: Hermann Ebbinghaus

herrmannBorn in Bramen, Germany in 1850, Ebbinghaus was the first psychologist to study learning and memory by conducting experiments on himself. At age seventeen, he commenced his study of philosophy at Bonn University on the eve of the Franco-Prussian War. After completing his studies, he travelled to France and England, conducting research on the “power of memory.” In 1885, he published Memory “detailing the nonsense syllable” research. The nonsense syllable, logatome or pseudoword is a string of syllables that resembles a real word is in fact “nonsense.” In the psychology of learning nonsense syllables are used as a way to examine speech recognition. After becoming professor at Berlin University, he established two psychological laboratories there. Finally, he moved to Berslau University, founded another laboratory, teaching there until his death in 1909.

Inspired by philosophers by the likes of John Locke and David Hume, Ebbinghaus argued that “remembering involves association,” linking things or ideas by similarities such as “time, place, cause or effect.” The goal of his research was to test how association can improve memory. To verify the accuracy of his findings, he recorded the results mathematically to see if “memory follows verifiable patterns.” This would become known as the Forgetting Curve.

To start his memory experiments, Ebbinghaus began by memorising lists of words to test his recall abilities. He then created 2,3000 nonsense syllables, three letters each with the same pattern consonant-vowel-consonant, to prevent association. He then grouped these nonsense syllables into lists, looked over the list for a few seconds, waited fifteen seconds to then try a second time. He then repeated his process until he could correctly recite the series. Alternating the list lengths and learning intervals, Ebbinghaus also tested how these variables effected the speed of learning and forgetting.

herrmann1Ebbinghaus discovered that material  he found meaningful, such as a poem, was up to ten times more easily remembered than the nonsense syllables. He also found that more time he spent memorising the list, the easier it was and the less time it took to reproduce the list from memory. In addition, he found that the information remembered after the first repetitions, were the most effectively remembered after time had passed. Finally, Ebbinghaus also found that typically, a very rapid loss of recall occurs in the first hour, followed by lowered rate of recall loss. To clarify, after nine hours sixty percent is forgotten and after twenty four hours, two-thirds of recall is lost. Plotted on a mathematical graph, Ebbinghaus’s findings shows a clear “forgetting curve” starting with a “sharp drop, followed by a shallow slope.”

Ebbinghaus’ findings still remain the basis of the psychology of learning and memory.

Citation:

Collin, Catherine. The Psychology Book. New York: DK Pub., 2012. Print.

The Brain: Introduction, Brain Scans and Imagery

Scanning of a human brain by X-rays

Scanning of a human brain by X-rays

The brain enables the mind: seeing, hearing, remembering, thinking, feeling, speaking and dreaming.

Science now enables us to know about the living brain through lesions. Lesions are destroyed tissue. A brain lesion is naturally or experimentally caused destruction of brain tissue, which selectively removes tiny clusters of normal or defective brain cells without harming the surroundings. We can also probe the brain with tiny electrical pulses. Scientists can look upon on the messages of individual neurons and on mass action of billions of neurons. We can see colour representations of the brain’s energy – their consuming activity. These tools facilitated the neuroscience revolution.

The oldest method of studying the brain-mind connection is to observe the effects of brain disease and injuries. This has been going on for more than five thousand years. In the past two centuries, physicians have been recording the results of damage to specific brain areas. Some noticed that damage to one side of the brain often caused numbness or paralysis on the opposite side of body. This suggested that that somehow the right side of the body is wires to the left side and vice versa.

Other scientists noticed that damage of the back of brain disrupted vision and that damage to the left front part of the brain caused speech difficulties. These discoveries have helped scientists map the brain. Today scientists are able to electrically, chemically or magnetically stimulate various parts of the brain to record the effects. Modern electrodes are so small that they can detect the electro pulse in a single neuron.

scan2An electroencephalogram or EEG is an amplified recording of the waves of electrical activity that travels across the brain’s surface. These waves are measured by electrodes placed on the scalp when presented with a stimulus.

A positron emission tomography or PET scan is a visual display of brain activity. It detects where a radioactive form of glucose travels to whists the brain performs a given task.

A magnetic resonance imaging system or an MRI is a technique that uses magnetic fields and radio waves to produce computer generated images that distinguish among different types of soft tissue. It also allows us to see structures within in the brain. MRIs align the spinning atoms in our brain through the use of a magnetic field as well as causing a pulse of radio waves that disorients them momentarily. When the atoms return to normal spin the release detectable signals. MRIs can also detect oxygen-laden blood flow.

Citation

Myers, David G. Psychology . 6. Worth Publishers, 2001. Print.Myers, David G. Psychology . 6. Worth Publishers,2001. Print.

Profile of a Psychologist: Paul Ekman

ekmanSome of you may have seen the crime-procedural drama “Lie to Me.” It ran on FOX between 2009-2011 until it got cancelled. The show stared  Tim Roth as Cal Lightman, who along with his colleagues of the Lightman Group were consultants for the police and FBI. The Lightman Group specialised in applied psychology, specifically interpreting mirco-expressions and body language. What many people may not know; however, is that the techniques utilised by the Lightman Group in “Lie to Me” are based on the work of psychologist Paul Ekman.

Ekman was born in Newark, New Jersey in 1934 but after the outbreak of World War II, moved across the country. At a mere fifteen, Ekman joined the University of Chicago where he became interested in “Freud and psychotherapy.” This inspired him to apply to Adelphi University where he earned his doctorate in clinical psychology. After a stunt working for the US Army, he went on to join the University of San Francisco where he began research into “nonverbal behaviour and facial expressions.” This work lead to further studies on the “concealment of emotions in facial expressions.” Being appointed to professor of psychology at UCSF in 1972, Ekman stayed there until his retirement in 2004.

Emotions play a huge role in emotional disorders and psychotherapy; however, when Ekman began his studies in the 70s, the subfield was practically unexplored. In the early days of psychotherapy emotions were seen as symptoms rather than “something to examined in their own right.” Ekman was one the first psychologists to realise that emotions are as much a vital part in psychotherapy as processes, drives and behaviour. He came to realise the importance of emotions through his work with nonverbal behaviour and facial expressions.

ekman2Before Ekman’s experiments it was believed that physical expression of emotions were learnt according to a set of social conventions, implying that how we express ourselves differes from culture to culture. However, through his travels across the globe, photographing people – ranging from developed countries to untouched tribes in the Amazon – he found that even the tribespeople, untouched by media and the outside world, could interpret emotions through facial expressions as well as people in developed countries. This suggests that physical expression of emotions are universal and a product of evolution not social conventions. A post in the Immersion Blog makes a great point regarding Ekman’s credibility, which has been disputed by critics claiming that facial expressions are for communications purposes only and not subconsciously reflecting our internal life. Robbie Cooper, the blogger, refutes this claim arguing that

                “We only think about expression when we want to use our body for communication on a conscious level. And a lot of the time we aren’t very good at faking internal states. If someone is playing a role in a social situation, it’s often expected of them, but much of the time we aren’t fooled by the performance. Which I think is one of the reasons why great actors are fascinating.” 

Ekman put forth six basic emotions – surprise, anger, happiness, fear, sadness and disgust – and decided because of their ubiquitous nature, these six basic emotions must be quintessential to our psychological make-up. He noted that specific facial expressions relate to each one of these six basic emotions and must in turn be involuntary emotional responses. Furthermore, these responses occur before the mind has time to register the cause and can thus be read to reveal our internal state. Ekman’s research became the basis of his F.A.C.E. training programme aimed to familiarise people, specifically officers of the law and security professionals dealing with deception on a daily basis, with “microexpressions.” Microexpression is term coined by Ekman as the involuntary emotional response, reflected in our facial expression before our brain has time to process the cause.

In Ekman’s 2003 book, Emotions Revealed, he states that emotions can be far more powerful than any of the drives listed by Freud such as sex, hunger and the will for life. These revelations are revolutionary as they completely altered the way in which emotions were seen to play a role in psychological disorders. For example, unhappiness can override the will to live and fear and shame, a biproduct of trauma, can override sexual drive.

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itations:

Cooper, Robbie. “Ekman Emotion Recognition Test.” Web log post. Immersion Blog. N.p., 29 June 2009. Web. 21 Aug. 2012. <http://blog.robbiecooper.org/2009/06/29/ekman-emotion-recognition-test/&gt;.

Myers, David G. Psychology . 6. Worth Publishers, 2001. Print.Myers, David G. Psychology . 6. Worth Publishers,2001. Print.