Williams'+Syndrome+(Kaleb+Thomas)

Williams Syndrome =Introduction and Symptomology: =

Williams Syndrome is a genetic disorder that affects neurological and physical development. The condition is caused by the deletion of around 21 individual genes along the chromosome 7q11.23. It is characterized primarily by heightened empathy and social skills, hypersensitivity to auditory stimuli, and in some scenarios, intellectual disability. It is suggested that there are approximately 3 times more people with WS than are currently observed or studied in psychological and neurological literature.

Those with Williams Syndrome are said to have Elven facial features. These include"upturned nose, depressed facial bridge, broad mouth, and full lips" (Hopyan 42). A common complication with Williams Syndrome is congenital heart disease (occurred in 79% of one studied population). Those with Williams Syndrome have been historically regarded as mentally handicapped with a retard in learning being an issue. Today, however, they are commonly able to live functional and enriched lives and are more understood to be generally cognitively functional. WS people commonly present as extremely social due to the inhibition of social fear and anxiety mechanisms in the brain. Within the brain of a person with WS, the amygdala and linked prefrontal regions are most affected by the chromosomal fluke. The most relevant complication to the focus of this course occurs in visual processing pathways, specifically in the Dorsal Stream. The dorsal visual stream is associated with the perception of motion and 3D objects sees deficits that inhibit WS people from perceiving global visual stimuli in a neurotypical way.

Presentation of Social Affinity in WS:
People that present with Williams' Syndrome are most commonly recognized for their abnormally outgoing personalities. Known as having the charisma of a talk-show host, WS people are highly perceptive of nonverbal social cues. As developing children, WS people show neurotypical social navigation through turn-taking and social cueing. In social settings, WS infants and children respond to others with the expected matching or complementary verbal and physical responses. This is contrary to autistic individuals who lack social intuition due to a proposed absence of mirror neurons according to the [|Ramachandran Mirror Neuron Hypothesis]. Populations of WS children have been clinically tested for social tendencies, and the results show more of an inclination to mimicry and imitation in WS people as opposed to neurotypical children. Such sensitivity to the emotions of others plays a key role in the social profile of someone with WS, but their lack of development in other cognitive areas (such as "decision making based on affective displays" or "perspective taking" [Fidler 12-13]) takes the social keenness to an astronomical level. Thus, WS children are more likely to engage socially based on a tendency to imitate and the lack of a tendency to shy away from social interaction. Amygdala activity coming through from the ventral visual stream showed increased activity in WS people when faced with various non-social scenes. However, when presented with threatening faces, amygdala response showed a decrease. Thus, Williams people show high non-social anxiety while experiencing non-social scenes, but are more than fond of anything resembling human interaction.

Presentation of Musical Affinity in WS:
People with WS are commonly known to be rather skilled in musical improvisation and performance. They are sensitive to happy sounding tunes and are capable of "melodic consistency and musical expressiveness" (Talar Hopyan et al. 50). In contrast to the visual cognitive deficits, WS musicians are more likely to perform well with global musical interpretation as opposed to local pitch and rhythm discrimination. In fact, WS people perform below average to average on rhythm and pitch discrimination tasks compared to their cognitively matched peers. This may be due to the different sorts of activation that occur within prefrontal areas of the brain, as certain areas such as the polar MPFC are activated differently in neurotypicals during musical improvisation and are activated differently overall in WS.

=Functional Anatomical Review: =

Williams' syndrome is said to cause a disruption of visual processing in the dorsal, or "where" stream, of the visual pathway. The dorsal visual stream receives its input primarily from m-type ganglion cells in the ganglion cell layer of the retina. These cells form the optic nerve that flows out of the retina and decussates at the optic chiasm. Since the chiasm joins together retinal pathways from both eyes, it is known as the optic tract. Input from the nasal portions of the visual fields of both eyes will remain ipsilateral post-chiasm and input from the temporal portions of the visual field will decussate. This is demonstrated in the following diagram.



=Visual Input Pathways: = = = M-type ganglion cells are typically associated with rod cells in the periphery, large receptive fields, and a transient, firing rate. The input from these cells will travel to the ipsilateral and contralateral magnocellular layers of the LGN of the thalamus. Travelling along axons classified as optic radiations, the input is transported to the visual cortex in the occipital lobe. The layers of the primary visual cortex responsible for the delivery of raw visual input are 4C- Alpha and 4B. At 4C-Alpha, the receptive fields of cells are simple and complex. Both simple and complex cells receive input from multiple cells with round receptive fields, so the bar-shaped receptive field of the simple and complex cells begin to be orientation-selective. Complex cells, however, are orientation-selective but are not limited to specific portions of the visual field as are simple cells. Rather, they exercise orientation selectivity across the visual field. In layer 4B of the visual cortex, there are direction-selective cells; or cells that discharge in response to left-to-right or right-to-left movement across the visual field.

Continuing into the dorsal stream, one finds that layer 4B feeds into structures known as Thick Stripes (V2). Penultimately, the information is delivered to the MT where speed, direction, spatial and temporal frequency, and local/global motion are processed. The final stop of the dorsal visual stream is the MST which has both a ventral and dorsal division. The dorsal MST is responsible for interpreting self-propelled movement whereas the ventral stream perceives the movement of objects in the periphery. On the other hand, the ventral stream of visual processing is responsible for perceiving color, form, boundaries, contours, textures, etc. and flows through layer 4C beta of the striate cortex.



Presentation of the topic or issue in detail • Summary or concluding paragraph
A specific case of a WS person investigates the cortical operations of patient //KT.// KT showed physical deformations from birth but was raised typically in a household with two siblings. Various medical complications arose throughout KT's infancy and he showed the typical lack of social inhibition associated with WS. Motor development showed a slight retard in KT, as walking began after twenty months. Movement was not severely impacted, though some dystonic movement and posture were clear in KT's neck/shoulder regions. MRI displayed a phenomenon consistent with Autism: enlarged lateral ventricles. Additionally, KT's MRI showed agenesis of the Corpus Callosum, though communication between the left and right hemispheres was intact. KT was put through various motor and visuospatial tests and showed has was shown, trouble arose for the patient when asked to recreate them. KT could identify items but "without canonical views" (Nakamura 1816). In lay terms, KT could identify parts of a whole, but could not cognitively process them together as a whole; the local visual perception was intact, but the global visual perception was impaired. Motion perception and direction perception were left intact, however, as was indicated by normal performance on a task involving the eye-tracking of randomly moving dots on a screen.

To assess the visuospatial cognitive abilities of the subject, three tests were administered. In the first figure-copying task, KT was asked to recreate a series of geometric shapes comprised of small x's. Though KT was well aware that the 'x' was the building block of the geometric shapes, KT could not actually recreate the global shape. In a second task known as free-drawing, KT was asked to draw objects based on verbal descriptions. For example, KT was directed to draw a flower in a flower pot. Interestingly enough, KT had no problem drawing each item individually, but drew the flower next to the pot. Moreover, the pot was drawn from an inferior point of view; an odd perspective from which to draw such a mundane item. In another verbal drawing task, the subject was asked to draw a house with windows and a door. What resulted was a drawing of a house with windows and a separate illustration of a door below. A third task revealed that KT showed poor performance when asked to copy a drawing of a line through a graph of dots.

An example of how a WS subject would illustrate these requested tasks is found in the following visual aid:



Looking further into motion perception (or lack thereof), the test proposed to check the intactness of the magnocellular pathway is "to assess the direction discrimination of coherently moving dots in dynamic random noise" (Nakamura et al. 1813). When asked to indicate the direction of movement of the dots on the screen, KT's performance was within the mean range for children of a comparable age. He performed just as well for various other motion perception tasks. However, the accurate perception of motion was not a fail-safe indication of an intact MT (V5) in the dorsal pathway. Anatomically speaking, the V4 can be a compensatory brain area when V5/MT is non-functional. Thus, it is possible, though unlikely, that plasticity allowed KT's visual cortex to redesign itself as to retain motion perception without a typically functioning MT as MEG imaging returned neurotypical results. This ultimately brings us to the conclusion that some of KT's dorsal stream was left intact, allowing for proper motion detection, while other areas showed deficits resulting in poor spatial analysis of objects. The phrase 'selective dysfunction' is used to describe the lack of congruity in dorsal stream deficits.

Findings from other studies have proven that WS people, though impaired in their ability to form spatial representations, retain the executive functioning needed for this to occur. These executive processes are individual and separate and can be regarded as such in the visual processing pathways. Because WS people perform poorly in tasks that require visuospatial motor planning (i.e. copying illustrations), the dorsal visual stream deficit theory stands.

=Glossary:=
 * 1) ===MT: Also referred to as V5, this landmark in the visual pathway is generally responsible for the processing of local/global movement, speed, and frequency.===
 * 2) ===MST: The final stop in visual processing before the parietal cortex gets involved, the MST's ventral and dorsal portions are responsible for perception of movement of objects in the visual field and self-propelled motion, respectively.===
 * 3) ===Dorsal Visual Stream: Coming from m-type ganglion cells embedded in the retina, this stream of the visual pathway is responsible for perception of directional movement, spatial awareness, as well as coordination of movement towards objects.===
 * 4) ===Retina: The layer of the eye embedded in the sclera upon which light is refracted through the lens. The photoreceptors, bipolar cells, amacrine cells, and ganglion cells found in this area are responsible for light perception and coordinate ESP's, ISP's and ultimately Action Potentials in the ganglion cells which fire through the optic nerve/tract and are ultimately sent to the cortex for processing.===
 * 5) ===Simple Cells: Cells with rod-shaped receptive fields found in layer four of the visual cortex upon which many cells with round receptive fields synapse. The perceive various orientations of specifically dedicated areas of the visual field. ===
 * 6) ===Complex Cells: Cells with rod-shaped receptive cells found in layer four of the visual cortex that perceive a specific orientation at any area within the entire visual field. ===
 * 7) ===Visual Field: The entire area from which the retina perceives light that is ultimately perceived as sight; everything you see at any given time.===
 * 8) ===Corpus Callosum: Region of the brain facilitating communication between left and right hemispheres.===

=Questions:=

1. WS syndrome is hypothesized to affect which of the following: a. The magnocellular pathway b. The parvocellular pathway c. The koniocellular pathway d. A and C e. None of the aboce

2. The ventral portion of the MST is responsible for perception of self-propelled movement. T or F.

3. Williams Syndrome commonly causes cognitive deficits strong enough to inhibit one's ability to lead a functional life. T or F.

4. WS people have an affinity for social interaction due only to their mimicking and imitation tendencies. T or F.

5. Williams Syndrome delays sensorimotor development, musical development, and development of coordination of movement towards objects. T or F.

6. The dorsal visual stream is involved in: a. localization of visual stimuli b. 3D object perception c. Spatial and temporal frequency d. Coordination of action with objects e. All of the Above

7. If the V5 or MT of the dorsal visual pathway is damaged or inhibited, a patient may still be able to accurately perceive directional movement. T or F.

8. Which of the following tasks would someone with WS perform poorly on? a. Subject is asked to draw two triangles next to each other b. Subject is asked to trace a single straight black line across a blank white sheet of paper c. Subject is asked to illustrate a Christmas tree with a star and ornaments d. Subject is asked to indicate directional movement of a school of fish swimming in water e. C and D

9. The corpus callosum is: a. disconnected in WS brains b. enlarged in WS brains c. no diffferent in WS brains than in neurotypical brains d. underdeveloped in WS brains e. none of the above

10. Williams syndrome can cause specific anxieties. Which of the following is most likely to result in a fear response in WS? a. Increased activation to the dorsal MT in response to rapidly moving dots. b. Decreased activation of the hippocampus in response to food tasting. c. Increased activation of the amygdala in the presence of unfamiliar scenes. d. Decreased activation of the amygdala in the presence of intimidating faces. e. Decreased activation of the amygdala in the presence of unfamilar scenes.

Sources: https://www.thinglink.com/scene/487669296059645952 (photo) https://bioluliaes.wordpress.com/3-eso/3-coordination-function/3-2-sensory-receptors/3-2-1-vision/3-2-1-3-visual-pathways/ (photo) https://www.frontiersin.org/articles/10.3389/fncom.2014.00084/full http://www.forgottendiseases.org/assets/WilliamsSyn.html

Fidler, D. J., Hepburn, S. L., Most, D. E., Philofsky, A., & Rogers, S. J. (2007). Emotional Responsivity in Young Children With Williams Syndrome. //American Journal on Mental Retardation, // //112 //(3), 194. doi:10.1352/0895-8017(2007)112[194:eriycw]2.0.co;2

Fisher, M. H., Lense, M. D., & Dykens, E. M. (2016). Longitudinal trajectories of intellectual and adaptive functioning in adolescents and adults with Williams syndrome. //Journal of Intellectual Disability Research, // //60 //(10), 920-932. doi:10.1111/jir.12303

Hopyan, T., Dennis, M., Weksberg, R., & Cytrynbaum, C. (2001). Music Skills and the Expressive Interpretation of Music in Children with Williams-Beuren Syndrome: Pitch, Rhythm, Melodic Imagery, Phrasing, and Musical Affect. //Child Neuropsychology (Neuropsychology, Development and Cognition: Section C), // //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">7 //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">(1), 42-53. doi:10.1076/chin.7.1.42.3147

<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">Meyer-Lindenberg, A., Hariri, A. R., Munoz, K. E., Mervis, C. B., Mattay, V. S., Morris, C. A., & Berman, K. F. (2005). Neural correlates of genetically abnormal social cognition in Williams syndrome. //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">Nature Neuroscience, // //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">8 //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">(8), 991-993. doi:10.1038/nn1494

<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">Nakamura, M., Kaneoke, Y., Watanabe, K., & Kakigi, R. (2002). Visual information process in Williams syndrome: intact motion detection accompanied by typical visuospatial dysfunctions. //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">European Journal of Neuroscience, // //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">16 //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">(9), 1810-1818. doi:10.1046/j.1460-9568.2002.02227.x

<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">Rondan, C., Santos, A., Mancini, J., Livet, M. O., & Deruelle, C. (2008). Global and Local processing in Williams Syndrome: Drawing versus Perceiving. //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">Child Neuropsychology, // //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">14 //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">(3), 237-248. doi:10.1080/09297040701346321

<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">Strømme, P., Bjømstad, P. G., & Ramstad, K. (2002). Prevalence Estimation of Williams Syndrome. //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">Journal of Child Neurology, // //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">17 //<span style="background-color: #ffe7af; color: #333333; font-family: &#39;Times New Roman&#39;,Georgia,serif; font-size: 16px;">(4), 269-271. doi:10.1177/088307380201700406