The NITRC 1000 Functional Connectomes Project and the Human Connectome Project have recently made large amounts of human connectome data available for public research in the form of connectivity matrices. These data have been extensively analyzed with respect to their network topology, which has revealed a number of complex network properties, including small-world and scale-free characteristics and high modularity and clustering. However, these studies have been conducted almost exclusively on binarized networks generated by thresholding to remove negative edge weights associated with negative temporal correlations in fMRI data. The present study proposes a comparison of the characteristics of networks generated exclusively from either …show more content…
In particular, this data lends itself well to the tools and techniques for network analysis, as the human connectome is itself a complex network II. RELATED WORK In 2009, the US National Institute of Health launched the Human Connectome Project (HCP). The goal of the project is to build a network map of the neural connections of the human brain in order to investigate the normal functionality of the brain, as well as to examine the anatomical anomalies that occur in diseases such as schizophrenia and autism. Data from the early stages of the project were recently made publicly available. The dataset includes group-averaged data which have been extensively analyzed, as well as largely unprocessed data from individual subjects. The HCP experimental group consists of twins with non-twin siblings who are 22-35 years in age [1]. The inclusion of twins and non-twin siblings is intended to provide discrete levels of similarity between individuals within the study group. Monozygotic twins should exhibit the greatest degree of similarity with respect to genetic and environmental factors, whereas dizygotic twins and non-twin siblings are exposed to similar environmental factors but have diminished
Have you ever been lost in a location foreign to you? Typically, a person who is lost will use a map to gather their bearings before heading off in the correct direction. A similar approach can be used to discuss recent brain mapping technology, the primary research of Dr. Allen Jones. Dr. Allen Jones is a brain research whose ultimate goal is to unveil a complete map of the human brain, using recent brain imaging and histological techniques. In his TED talk entitled, A Map of the Brain, Dr. Allen Jones discusses a brief overview of the anatomical structures of the brain, as well as, the methods and conclusions of his brain research.
Sibling studies theoretically control for social and environmental confounders, and monozygotic twin studies would be the ideal model for genetic and environmental control of potential risk factors for neurodevelopmental disorders. This type of studies supported the importance of genetic and social/environmental variables as risk factors for learning disabilities. Genetic vulnerability can be related to an increased risk for surgical disease (62, 71).
Table 3-1 examines the correlations between selected characteristics for the identical twins separated at birth and the twins raised together. When compared to each other, they both have very similar brain wave activity, blood pressure and heart rate in the physiological characteristics. The Raven intelligence test was very similar, but the WAIS IQ displayed a bit of difference when compared to the other comparisons made. Personality wise, they typically had similar personalities at the same rate as twins raised together. Psychological interests were off a little bit, but still very similar. The twins that were separated at birth had less similar psychological interests compared to the twins
Parallel to this, the focus on genetics is Particularly convicted in twin studies, which establish a comparison between monozygotic twins that are identical and dizygotic twins, which are opposingly non-identical. This distinction can be identified in Torgersens study, which compared MZ and same sex DZ twins where one proband had an anxiety disorder, and it was discovered that such disorders were 5x more frequent in MZ twin pairs, who mutually shared identical genetics.
The biological explanation of schizophrenia also claims that the disorder can be inherited. The more common the disorder is among the biological relatives and the closer the degree of genetic relatedness increases the risk of the child developing schizophrenia. Gottesman’s research (1991) found a genetic link with schizophrenia when looking at children and their relatives. The research discovered that children with two schizophrenic parents have a concordance rate of 46% compared to children who just have one schizophrenic parent to children who have a concordance rate of 13% and siblings just 9%. The genetic theory of schizophrenia also suggests that monozygotic twins (twins who a genetically identical) should have a higher concordance rate of schizophrenia than dizygotic twins (twins who are not genetically identical) because they have a closer degree of genetic relatedness.
Identical twins can be compared to see whether when one twin has a disorder, the other one has it too. This provides us with a concordance rate the extent to which two individuals are similar to each other in terms of a particular trait. There are low concordance rates for some mental disorders e.g. phobias but relatively high concordance rates for others e.g. schizophrenia.
Genetic factors of schizophrenia can be explained using studies on twins and studies on family history. With twin studies researchers want to establish the degree of concordance. This is
the brain, such as neurons, glial cells, and how its billions of neural connections make up the
Resting-State functional MRI (rsfMRI) has been drawing increased attention (Biswal et al., 2010) and can be divided into two categories (Lee et al., 2013; Song et al., 2011). The first category is Resting-state functional connectivity (RsFC), which is a task-independent metric of brain activity that is primarily based on based on correlations between low-frequency fluctuations of the blood oxygen level dependent (BOLD) signal between disparate brain regions
Twin studies have been a large part of the growing debate on whether genetics or environment (nature v. nature) is responsible for the cognitive, socio-cultural and biological development. In order to properly assess twin studies it is important to know why and how they are relevant in psychology. Identical twins are especially effective in research particularly in the field of developmental psychology and behavioral genetics due to the monozygotic genes which means they originate from a single zygote (fertilized egg) which essentially means they share 100% of the same genes. Due to this exact copy of genes between twins means this can be efficiently be used in order to observe the impact of
In a study of 44 sets of twins, there was a high concordance rate of autism and other disorders on the ASD spectrum for monozygotic twins (92%)5. This suggests that the genetic similarity between MZ twins influences their risk of expressing Autism. Dizygotic twins however, had a much lower concordance5, supporting the hypothesis that there is a correlation between genetic similarity and Autism risk. According to the study, complications during pregnancy are not likely to be the cause of autism, but simply happen more often in twin pregnancies5. The association of severe brain damage in pregnancy and Autism has not been found in singletons5. In 29 cases of twins discordant for Autism, biological hazards associated with brain damage usually affected the autistic twin. This
This can also be accounted for distant relatives who are unlikely to share the same environment. We can therefore assume that to confirm a genetic base for schizophrenia, research must separate genetic influences from environmental influences. In order to do this, researchers must look at the evidence presented through twin studies. A set of MZ twins share the same genes, therefore if only one of the develops schizophrenia, it is more likely to be through environmental factors.
1978 shields discussed 11 studies of the identical and non-identical co-twins of over 1300 schizophrenics from seven countries and then of these comparisons showed a higher concordance rate among identical twins. (A, C, Smith 1982 p.g 93) Research is still going on today to find out more about how genes and life events influence who gets schizophrenia.
Across studies of 10,000 twins, the intelligence test scores of identical twins reared together are virtually as similar as those of the same person taking the same test twice…Likewise, the test scores of identical twins reared separately are similar enough to lead twin researcher Thomas Bouchard (1996) to estimate that ‘about 70 percent’ of intelligence score variation ‘can be attributed to genetic variation. (p. 455)
Aim: The aim of this experiment was to explore the synergistic effects of heritability and environment in the cases of two brothers with schizophrenia.