cumul psych bio saq

imaging technique intro

"Various research techniques are used to investigate the relationship between the brain and behavior. In the past, researchers used victims of an accident or invasive techniques such as postmortem autopsy to study the human brain. Modern imaging techniques are non-invasive; we can see the structure and the processing of the brain without posting harm to participants. There are two types of techniques in studying the brain – structural and functioning imaging. Structural imaging techniques are useful for showing the physical and anatomical parts of the brain. On the other hand, functional imaging techniques enable the researcher to see the functioning of the brain by providing temporal resolution.

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MRI specific

One structural techniques is MRI (magnetic resonance imaging) —brain imaging technique allowing us to see the 2d or 3d structure of the human brain including abnormalities (tumors, skull defects) and structural differences (differences in gray matter density in a certain region). It is composed of a very powerful magnet, radio waves, gradients, and the computer. The use of such magnetic technology allows MRI to have greater resolution, more detail, and be safer without the use of radiation. To explain how the MRI functions, the magnet revolves around the machine. Protons/hydrogen atoms in the body are magnetic and align with the magnetic field. When RF pulse is applied, atoms spin the other way. When the RF pulse is turned off, the protons realign to its original equilibrium position. The atoms produce tiny magnetic fields. These signals are then processed to create detailed images of the internal structures of the body.

link back to imaging

localization intro

localization def. strict and relative. principle mass action lashley, equipotentiality. thesis

localization def

Localization is the idea that specific areas of the brain have specific functions. For example, the hippocampus is associated with memory and the amygdala with emotions. There are two different ideas within localization: strict and relative localization. Strict localization is the idea that there is a clear association between psychological functions and specific brain areas such as the language area speech production in the Broca’s area. Relative localization is the idea that the brain functions through distributive functioning. This may be related to Lashley’s principle of mass action which states that learning is distributed across all parts of the brain rather than being stored in a single region. Equipotentiality is the complementary principle of mass action, stating that in the event of damage to one area of the brain, other parts of the brain can sometimes assume the role of the damaged region.

scoville and milner study

1966 milner longitudinal case study to understand the effects that the surgery had on patient HM who had suffered from anterograde amnesia after a surgery by Scoville to cure epileptic seizures. This surgery removed parts of medial temporal lobe and hippocampus. Milner employed method triangulation, performing psychometric testing, directly observing HM behavior, interviewing him and his family members, and performing cognitive tests such as memory recall tests and learning tasks (reverse mirror drawing).

scoville and milner results

test results showed that HM could not acquire new episodic knowledge (memory of events) and semantic knowledge (general knowledge). Also, HM was able to form a cognitive map of the spatial layout of his house which showed how spatial memory was encoded differently. HM was able to remember motor skills (showing how procedural memories also encoded differently).

link back to localization

In essence, Milner suggests how the critical function in converting memories of experiences from STM to LTM may be associated with the medial temporal lobe and hippocampus. Researchers found that STM is not stored in the hippocampus as HM was able to retain information for a while if he rehearsed it. Since HM was able to retain some memories for events that happened long before his surgery indicated that the medial temporal region is not the site of permanent storage but rather plays a role in transferring information from STM to LTM. To link back, thus, supporting the idea of localization of function,

neuroplasticity intro

"The brain is a dynamic system that interacts with the environment. Not only can the brain determine and change behavior, but behavior and environment can change the brain. neuroplasticity --> functional and structural. High levels of stimulation and numerous learning opportunities may lead to an increase in the density of neural connections (synapses) – called long term potentiation (LTP). LTP argues that the repetition of a task results in neuroplasticity and it leads to dendritic branching (neurons connecting to create a new trace in the brain when learning something new). A lack of potentiation as a result of discontinued behavior may lead to neural pruning (the process by which extra neurons and synaptic connections are eliminated).

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draganski study

2004 field exp investigate whether learning a new skill - in this case, juggling - would affect the brains of participants. The participants were 24 volunteers between the ages of 20 and 24 (21 females and 3 males). All participants were non-jugglers at the start of the study. Each participant had an MRI scan at the start of the study to serve as a base rate for grey matter and brain structure. Participants were allocated to one of two conditions - the jugglers and the non-jugglers. Those that were in the juggling condition were taught a three-ball cascade juggling routine. They were asked to practice this routine and to notify the researchers when they had mastered it. At that point, the jugglers had a second MRI scan. After the scan, they were told not to juggle anymore and then a third and final scan was carried out three months later. The non-juggling group served as a control group for the duration of the study. The researchers used voxel-based morphometry [VBM] to determine if there were significant differences in neural density (grey matter) in the brains of jugglers vs. non-jugglers.

draganski result

originally they found no significant regional differences in the grey matter between the two conditions. However, at the end of the first part of the study, the jugglers showed a significantly larger amount of grey matter in the mid-temporal area in both hemispheres - an area associated with visual memory. Three months after the participants stopped juggling - when many were no longer able to carry out the routine - the amount of grey matter in these parts of the brain had decreased but not to full extent of the control group. There was no change throughout the study in the non-juggling sample.

link back to neuroplast

"To link back, the study supports neuroplasticity by showing how engaging in a new skill / experience (juggling) may induce structural changes in the brain. Draganski’s study supports the idea of neuroplasticity, both dendritic branching and neural pruning. As the gray matter in the medial temporal lobe, which is an area associated with coordination and visual memory, changed its density based on learning juggling. An increase in gray matter in the medial temporal lobe illustrated dendritic branching. The decrease in gray matter density when the participants did not practice juggling illustrated neural pruning.

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neurotransmitter intro

nt define. neurotransmission. excitatory and inhibitory. agonist and antagonist. acetycholine

nt? and transmission

Neurotransmitters are brain chemicals that help facilitate communication among neurons and can have a different effect on the post-synaptic neuron. Neurotransmitters are released in the synapse, the gap between neurons. They are part of the nervous system and are responsible for regulating rapid processes such as neurotransmission. The electrochemical process of communication between neurons is called neurotransmission. During neurotransmission, neurotransmitters transmit electrical signals (action potential) from one neuron to another across the synaptic cleft when electrical impulse builds up. Then, each neurotransmitter fits into specific receptor sites like lock and key, in which they can be reuptaken by transporter proteins or broken down by enzymes in the synapse.

excitatory and inhibitory / agonist antagonist

Excitatory effect involves making a target neuron more likely to fire an action potential such as acetylcholine. Inhibitory effect involves making a target neuron less likely to fire an action potential such as serotonin. Agonist any chemical that enhances effect of neurotransmitter while antagonist decreases the effect of a neurotransmitter by blocking receptor site.

ach example

acetylcholine (Ach) that may play an important role in learning & spatial memory and attention and is found in both the central (brain and spinal cord) and peripheral nervous system (nerve to muscle, nerve to organs). Ach is typically an excitatory neurotransmitter, which has an excitatory effect on encoding new knowledge. The antagonist of ach is scopolamine which blocks ach receptor site and decreases availability of ach assisting in encoding of memories and learning.

antonova study

In 2011, lab experiment to determine how blocking the acetylcholine receptors with scopolamine affects spatial memory on a sample of 20 healthy male adults, with mean age of 28. repeated measures and a double blind procedure, the participants were randomly allocated to ½ conditions (injected with scop or placebo 90 minutes before Arena task). The participants were then put into an fMRI where they were scanned while playing the "Arena task." (a complex VR game in which the researchers observe how well the participants can create spatial memories). (DESC) Practice trials were conducted to minimize the confounding variables. The participants' brain activity was measured for six trials. The participants returned between 3 - 4 weeks later and redid the test with the opposite treatment.

arena task

The goal is for the participants to navigate around an "arena" to reach a pole. After they have learned where the pole is located, the screen would go blank for 30 seconds. During this time, the participants were told to actively rehearse how to get to the pole in the arena. When the arena reappeared, the participant was now at a new starting point in the arena. The participants would have to use their spatial memory to determine how to get to the location of the pole.

antonova results

"The participants in scopolamine group demonstrated more errors and took longer but the difference was not that significant. However, when participants were injected with scopolamine, they demonstrated a significant reduction in the activation of the hippocampus according to fMRI.

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link back to nt

"To link back, the results show that acetylcholine could play a key role in the encoding of spatial memories in humans, given that the hippocampus activation was significantly lower in the scopolamine group, an antagonist of acetylcholine. The hippocampus is associated with memory consolidation. Hence, the use of fMRI demonstrated support for the effects of the neurotransmission of acetylcholine, on human memory.

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hormones

hormone intro

hormone def. how they bind. one oxytocin. thesis

hormone def

A hormone is a chemical messenger released in the bloodstream that helps to regulate bodily functions such as growth, metabolism, and reproduction. Hormones regulate relatively slower processes, unlike neurotransmitters which regulate fast almost automatic processes. Hormones are part of the endocrine system and there are around 50 hormones for humans. They can only produce reactions in certain cells (target cells) which have appropriate receptor sites for the hormone. When the hormone binds to the target cell, it either increases or decreases its function.

oxytocin example

One hormone is oxytocin, which is produced in the hypothalamus where it is either released through the pituitary gland or to other parts of the brain and spinal cord. Here, it binds to oxytocin receptors to influence behaviour and physiology. Oxytocin is known as the “love hormone” and plays a role in social bonding, childbirth, attachment, and maternal trust. For men, oxytocin may have a role in modulating sexual and social behaviour.

scheele study

lab experiment. he role of oxytocin in modulating social distance between men and women. The participants were 86 heterosexual men (varying relationship status). A double blind independent measures design, a researcher administered either oxytocin or a placebo intranasally. There were two independent tasks. In the first task (the stop-distance paradigm), subjects were positioned at one end of the room with their toes on the mark on the floor, while an attractive female experimenter was positioned on the other side of the room. The subject was then required to move slowly towards the female and stop when they felt slightly uncomfortable.

scheele second task

In the second task (“approach/avoidance task”), subjects viewed a series of pictures on a screen with their head positioned on a chin rest at a constant distance. 4 types of pictures were flashed for two seconds each: positive social (attractive), non-social (beautiful landscape), negative social (mutilations), non social (dirt). They were instructed to pull the joystick if they liked the photo to increase its size and to push the joystick to reduce the size (this simulated approach and avoidance).

scheele results

The results for the first task showed that oxytocin only stimulated men in monogamous relationships to maintain greater distance with the woman. For the second task, only the positive social group (attractive women) was affected by oxytocin and relationship status. Participants who received oxytocin had slower reaction time (pulled joystick more reluctantly) if they were in a relationship.

link back to hormones

To link back, the first task showed that oxytocin caused men in relationships to stay away from attractive women who were not their partner and the second task showed oxytocin selectively inhibits approach to certain stimuli (attractive women) for men in relationships only. Scheele suggests that oxytocin hormone triggers monogamous heterosexual males to be protective and conservative which promotes fidelity.

pheromone intro

pheromone def. 2 types - primer and signaling. increasingly suggested humans have them. androstadienone. thesis

pheromones

A pheromone is a chemical messenger that communicates information (such as territory, fertility, and sexual attractiveness) from one member of a species to another via scent. They are produced by scent glands found in various parts of the body such as mouth, paws, anus, etc. They are received by receptors in the nostril called vomeronasal organ found in some animals such as reptiles and some mammals. There are 2 types of pheromones - primer (long term physiological changes such as hormonal effects) and signaling(rapid behavioral effects such as mating). Humans may have this organ as well, but researchers still aren't sure if it is actually used. It is increasingly suggested that humans may also communicate dominance through chemical compounds.

androstadienone

One potential human pheromone is androstadienone (AND), a human steroid that is present in male semen and sweat. It heightens sympathetic arousal, alters levels of cortisol, and promotes a positive mood state in females. AND is also found to activate the hypothalamus in heterosexual females and homosexual males only. Estratetraenol [EST] is the female equivalent

lundstrom and olsson study

In 2005, Lundstrom and Olsson conducted a lab experiment to study the effect of AND on a woman's mood. The participants were 37 heterosexual women with a mean age of 25. The study had a 2x2 lab experiment with IVs being the presence of AND and sex of experimenter, the DV was the women’s moods measured through self report questionnaires. The women were exposed to either AND or control solution and in the presence of either male or a female experimenter. Results showed that AND increased women’s mood in the presence of a male experimenter and had no effect when the experimenter was female.

link back to pheromone

To link back, the study showed how AND (potential human pheromone) pheromones may impact emotions and behavior. Since AND is considered as a sex pheromone, it increased female mood in the presence of a male experiemnter, suggesting it may increase male’s attractiveness to female. Hence, the study shows the effect of pheromones.

genetics and behavior

role of genes intro

gene def, genetic research, diathesis stress theory. 5-htt. thesis

gene definition

unit of heredity, a region of DNA that encodes a specific trait or function. The second principle of the biological level of analysis states that patterns of behavior can be inherited. Likewise, genetic research argues that the inherited genetic predisposition may partly explain depression.

diathesis stress theories

Diathesis-stress theories of depression argue that an individual's reaction to stressful events depends on their genetic makeup. If an individual has a specific genetic predisposition toward a disorder (genotype), then interaction with stressors in the environment may cause these genes to be expressed.

5htt gene

Particulalry, the 5-HTT is a serotonin transporter gene. Serotonin transporters are responsible for reuptake of serotonin in brain synapses. Serotonin is a neurotransmitter that is responsible for mood regulation. If serotonin is being reuptaken, this means serotonin is not being fired to the post-synaptic neuron, preventing mood regulation. Alleles are different forms of a gene and can be dominant or recessive. A variant of 5-HTT gene more associated w depression has two short alleles.

caspi study

quasi experiment to determine whether there is evidence for a gene-environment interaction (G x E) for a mutation of the serotonin transporter gene - 5-HTT. The serotonin transporter is involved in the reuptake of serotonin in brain synapses. The sample included 847 New Zealand 26 year olds. All were members of a cohort that had been assessed for mental health on an every-other-year basis until they were 21. They were divided into three groups based on their 5-HTT alleles: group 1 had two short alleles, group 2 one short and one long, group 3 two long. The variant of the 5-HTT gene has shorter alleles. The participants were asked to fill in a "Stressful life events" questionnaire which asked them about the frequency of 14 different events - including financial, employment, health, and relationship stressors - between the ages of 21 and 26. They were also assessed for depression.

caspi result

The results showed that people who had inherited one or more short versions of the allele demonstrated more symptoms of depression and suicidal ideation in response to stressful life events. The effect was strongest for those with three or more stressful life events.

link back to role of genes

To link back, the results illustrate how simply inheriting the gene was not enough to lead to depression, but the genes' interaction with stressful life events increased one's likelihood of developing depression. This was especially when there were 3 or more stressful life events. Hence, the 5-HTT gene can be seen as a predisposition for depression given that environmental stressors exist.

genetic similarity intro

Genetic research in humans is mostly based on correlational studies because there are too many confounding variables that are difficult to control. One of the ways to study the possible correlation between genetic inheritance and behavior is twin research. There are two types of twins. Monozygotic twins share 100% genetic makeup because they develop from the same zygote. As a result, monozygotic twins share the same sex and traits. Dizygotic twins share 50% genotypes because they develop from two different zygotes. They have the same genetic similarity as siblings. Concordance rate is the percent of cases in which both twins have a particular attribute. Twin research is based on a systematic analysis of the similarity between MZ and DZ twins based on the assumption that any heritable trait will be more concordant in identical twins than in non-identical twins. This essay will explain one twin study with reference to Kendler.

kendler study

2006 correlational study, Kendler wanted to investigate the level of heritability of depression among twins. The sample was made up of approx 15,500 complete twin pairs in the national Swedish twin registry. Only twins whose zygosity could be verified were included. Researchers used a team of trained interviewers to carry out telephone interviews. They assessed lifetime major depression by using modified DSM-IV criteria. They also asked questions about twin’s shared environment -- such as when they were living in the same household -- and “individual-specific environment” -- adult personal life events.

kendler results

The results indicate that the concordance rate for major depression was significantly higher for female-female MZ followed by male MZ then DZ male then DZ female. Regardless of gender, the concordance rate for MZ twins were significantly higher. They also found no correlation between the number of years living together. There were also no significant differences seen in role of genetics and environmental factors in major depression when the cohort was split into pre and post WWII.

link back to genetic similarity / twin study

To link back, the study suggests that MZ twins have a higher depression concordance rate than DZ twins because MZ twins share greater genetic makeup than DZ twins. This suggests that the depression rate can be attributed to inherited genetics. Hence through the use of twin studies, Kendler demonstrates how depression may be inherited genetically.

intro kinship study

Genetic research on human behavior is often based on correlational studies, as there are too many confounding variables that are difficult to control. One of the ways to investigate the potential relationship between genetics and inherited behavior is through kinship studies. Kinship studies are used to investigate whether a behavior runs in the family. Kinship studies have several basic characteristics: they measure the frequency of a behavior across generations or the frequency of a behavior within a generation and are often longitudinal. Kinship studies use case-control studies. Case control studies are retrospective. The researchers clearly define two groups at the start of the study: one with the behavior and the other without the depression. The researchers then look back to identify any statistically significant differences in the rate of exposure to a defined risk factor, specifically the potential for genetic inheritance. If the risk of developing a behavior increases within a family, it indicates that the behavior is likely influenced by a heritable factor. This essay will explain kinship studies with reference to Weissman.

weissman study

In 2005, Weissman conducted a longitudinal family study of a sample of 161 grandchildren and their parents and grandparents to study the potential genetic nature of Major Depressive Disorder. The study took place over twenty years, looking at families at high and low risk for depression. The original sample of depressed patients (now, the grandparents) was selected from an outpatient clinic. The original sample of parents and children was interviewed four times during this period, along with their current grandchildren (3 generations). The non-depressed participants were selected from the same local community. Data was collected from clinicians, blind to past diagnoses of depression or data from past interviews. Children were evaluated by two experienced clinicians (child psychiatrist and psychologist). The inter-rater reliability of their diagnoses was rather high for MDD.

weissman results

"The researchers found high rates of psychiatric disorders in the grandchildren with two generations of major depression. By 12 years old, more than half of the grandchildren were already showing signs of a psychiatric disorder - most commonly anxiety. Children had an increased risk of any disorder if depression was observed in both the grandparents and the parents, compared to children whose parents were not depressed. In addition, the severity of a parent's depression was correlated with an increased rate of mood disorders in the children. On the other hand, if a parent was depressed but there was no history of depression in the grandparents, there was no significant effect of parental depression on the grandchildren.

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link back to kinship study

To link back, Weissman used a kinship study to illustrate the inheritability of depression across generations. This is a kinship study because it observed the behavior of MDD across generations and was longitudinal and case-control study with two clearly defined groups, one with MDD and one without. Weissman et al’s use of kinship study enabled researchers to identify statistically significant differences between the rate of psychiatric disorders of children to 2 generations of depression from non-depressed parents, showing how depression can be partly explained by inherited genetics.

evolution intro

evolution def. differential fitness. survival of fittest. natural selection darwin. evolutionary psych. thesis

evolution def

process that results in changes in the genetic material of a population over time due to the transmission of heritable characteristics. It reflects the adaptations of organisms to their changing environments and can result in altered genes, novel traits, and new species. Evolutionary processes depend on both changes in genetic variability and changes in allele frequencies over time.

differential fitness

idea that there is variation in the traits of individual organisms from the same population, meaning they are adapted to their environment to varying degrees.

survival of fittest

Organisms that are well adapted to the environment have higher changes of surviving and producing offspring. Those that are less adapted die out or are unable to produce offspring –

natural selection and evolutionary psych

"explains how species acquire adaptive characteristics to survive in an ever-changing environment. According to the theory of natural selection, those members of a species who have characteristics that are better suited to the environment will be more likely to breed and thus pass on these traits./ / theoretical approach to psychology that attempts to explain useful psychological traits—such as mate/partner selection, emotions, language—as the functional products of natural selection. In mating behavior, attraction evolved to motivate individuals to select and focus courtship attention on a favored partner.

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buss study

self report questionnaire 1989, gender and cultural diff in mate preferences. over 10,000 participants from 30+ countries and cultures. high diversity in ethnic polticial and religious, but most from urban educated literarte background. data collected on ratings and rankings of 18 different mate characteristics (dependable character, intelligence, chastity, good financial prospects, etc.). Participants were asked to rate the characteristics on a scale from 0 (irrelevant or unimportant) to 3 (indispensable) and from 1 to 13 in order of which characteristics were most desirable in a mate.

buss results

showed that both sexes ranked “kind,understanding” and “intelligent” higher than earning potential and physical attractiveness. Females preferred cues about mate being related to resource acquisition (earning potential, ambition) more than males. Males preferred cues related to “reproductive capacity” such as physical attractiveness (evolutionary traits related to producing healthy offspring) and youth (approximately age 25) more than females.

link back to evol

"study shows how mating preferences in behavior can be explained via evolution.broadly supports the evolutionary hypothesis for mate preferences and sex differences. Buss found that there were universal differences and similarities between the sexes based on evolutionary mechanisms - reproductive traits. Females -- good provider, enabling a male to provide better protection and resources for a female and her offspring. Males -- reproductive capacity. Male’s age preferences align with the female's period of peak fertility. may not want to exert effort and resources into trying with a female lacking fertility. Hence, Buss’s study illustrates a valid evolutionary explanation of behavior.

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