Tag Archives: vision

Mon-ayyy I can see!

Posted on June 28, 2019 by | 2 comments

I’ve worn glasses ever since I was in second grade. Yes, I was unfortunately THAT Asian girl who wore her hair in a middle part, high ponytail every day and had blue plastic glasses. Ever since I got glasses, naturally, my vision has gotten worse and I currently stand at a -9.00 prescription for my contacts. As someone who has had bad vision for two-thirds of her life, I was particularly intrigued by our vision module during our “Arts on the Brain” class. We began to explore the world of sight and learned that many famous artists had some sort of visual impairment. Claude Monet, a French impressionist painter, had cataracts which are speculated to have aided him in trailblazing the Impressionist art style. Our class wrapped lab goggles in plastic wrap to mimic the effects of cataracts, and we were able to see the beautiful gardens in Giverny through Monet’s eyes. This led me to research more about the cognitive effects of having visual impairments, specifically cataracts, and what Monet’s cognitive state might have been like.

Left to Right: original photo, drawing, drawing with cataract glasses

First, what exactly are cataracts? A cataract is a clouding of the lens in the eye, which lies behind the iris and the pupil. Our lens is analogous to a camera lens, hence the name, and it refracts light rays to help focus on image on the retina. A clear lens lets us see a clear picture. The lens is made of water and protein that is arranged in a precise way to keep the lens clear and let light pass through it. However, as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it even harder to see (NEI, 2015). Usually, aging is the most commons cause for cataracts, but traumatic injuries, UV exposure, and certain medical problems can also lead to the development of cataracts (Boyd, 2018).

Normal eye vs. Eye with cataract

Monet was diagnosed with cataracts in both eyes in 1912 at the age of 72, which aligns with what we would expect for age-induced cataracts. Monet was very reluctant to go through cataract surgery, and in the end, he only had restorative surgery in one eye. His left eye, clouded by a dense yellow cataract, could not see violets and blues, but his right eye could see these colors clearly. This distortion in color perception and acuity had an impact on his work where tones became muddier and darker and forms became less distinct. Monet apparently complained that “colors no longer had the same intensity for me” and that “reds had begun to look muddy”, and that “my painting was getting more and more darkened” (Gruener, 2015). Monet was audibly upset about his impairment, but I wonder if his mood or cognitive state would have been improved if he had gotten the surgery in both of his eyes.

Monet’s paintings of water lilies are impacted (Left 1889 vs. Right 1915)

Some studies have been conducted that look at the impact of cataract surgery on cognitive function in an aging population. A study by Jefferis et al. looked at the effect of cataract surgery on cognition, mood, and visual hallucinations in older adults who had bilateral cataracts. Participants, who were all 75 years of age or older, were assessed pre and post-operatively. The investigators measured visual acuity through logMAR, Addenbrooke’s Cognitive Examination (ACE-R), the 15-item Geriatric Depression Scale (GDS-15), and the North East Visual Hallucinations Inventory (NEVHI) (Jefferis et al., 2015). ACE-R evaluated six cognitive domains: orientation, attention, memory, verbal fluency, language, and visuospatial ability (Mioshi et al., 2006). Small but significant benefits in cognitive scores were seen 1 year after surgery, but there was no statistically significant difference in mood or hallucinations.

A different study by Fukuoka et al. in 2016 found that cataract surgery could improve cognition, although there was insufficient evidence for a definite conclusion (Fukuoka et al., 2016). A follow-up study in 2018 found that cataract surgery may play a role in reducing the risk of developing mild cognitive impairments independently of visual acuity, but not for dementia (Miyata et al., 2018). A loss of vision can be associated with loss of cognition. It is interesting to see how when the sensory input of sight is disturbed, there are cognitive effects that occur. The relationship between vision and cognition have not been explored extensively, but there are specific visual disorders that have been shown to share common pathogenic pathways with Alzheimer’s disease (Rogers & Langa, 2010). Some speculate that individuals with visual impairment allocate more attention resources to processing sensory information, leaving fewer resources for cognitive tasks (Lindenberger & Baltes, 1994). Additionally, there is a common factor to vision and cognition and that is the degeneration of central nervous function (Christensen et al., 2001. These studies provide great insight into how Monet or even people like our grandparents might be affected by declining vision.

Cute elderly couple with glasses

Cataracts and cognitive impairment are both age-related diseases. Especially with how the proportion of older adults are increasing in the world, it is important to see how we can improve their quality of life as they get older. These studies allowed us to gain more insight into how vision or sight for older populations may have an additional benefit of cognitive improvement.

References

Boyd K (2018) What Are Cataracts? American Academy of Ophthalmology https://www.aao.org/eye-health/diseases/what-are-cataracts

Fukuoka H, Sutu C, & Afshari NA (2016) The impact of cataract surgery on cognitive function in an aging population. Current Opinion in Ophthalmology 27:3-8

Gruener A (2015) The effect of cataracts and cataract surgery on Claude Monet. British Journal of General Practice 65:254-255

Jefferis JM, Clarke MP, & Taylor JP (2015) Effect of cataract surgery on cognition, mood, and visual hallucinations in older adults. J Cataract Refract Surg 41:1241-1247

Lindenberger U, Baltes PB. Sensory functioning and intelligence in old age: a strong connection. Psychol Aging 1994; 9:339–355

Miyata K, Yoshikawa T, Morikawa M, Mine M, Okamoto N, Kurumatani N, Ogata N (2018) Effect of cataract surgery on cognitive function in elderly: Results of Fujiwara-kyo Eye Study. PLoS One 13

National Eye Institute (2015) About Cataracts. National Eye Institute https://nei.nih.gov/health/cataract/cataract_facts

Rogers MA & Langa KM (2010) Untreated poor vision: a contributing factor to late-life dementia. Am J Epidemiol 171:728-235

Tay T, Wang JJ, Kifley A, et al. Sensory and cognitive association in older persons: findings from an older Australian population. Gerontology 2006; 52:386–394

Pictures:

At Giverny: My own

Cataracts: https://nei.nih.gov/health/cataract/cataract_facts

Monet, Bridge over a Pond of Water Lilies (1889): https://www.metmuseum.org/art/collection/search/437127

Monet, Water Lilies (1915):

https://www.royalacademy.org.uk/exhibition/painting-modern-garden-monet-matisse

Old people with glasses: https://www.aoa.org/patients-and-public/good-vision-throughout-life/adult-vision-19-to-40-years-of-age/adult-vision-over-60-years-of-age

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the sky is more than blue

Posted on June 10, 2019 by | 2 comments

“Why is the sky blue?” The question that children love to ask. Frankly, I want to know the answer too. Before tackling this question, we need to answer the question, “What color is the sky?” To me, the sky’s the limit (pun intended). Today on this beautiful and sunny day, the sky is blue, but when it is cloudy and gloomy, the sky is grey. At night the sky is black with the presence of stars that are spread throughout the galaxy. The sky can present itself as a spectrum of colors. During sunrise it is a refreshing mixture of yellow, orange, and blue. During sunset, the sky is a gorgeous blend of the rainbow from royal purples to warm, sultry reds. The colors of the sky can vary depending on your location on Earth. For example, during the northern lights, it is an array or colors that light up the sky. There are numerous answers to what the color of the sky actually is, but these are just examples of how I see the sky.


However, the perception of color is really at the core of this question. When we think about how we perceive the color of the sky, the answer to this simple question becomes quite complicated. There are many different ways that people see different ranges of color. This is quite special because these experiences and qualities allow for us to experience the world quite differently. People with “normal vision” will perceive the sky differently than others with something such as synesthesia.

Based on my thought process to answer this question, I really dove into different ways people with synesthesia are different in terms of how they perceive the world. Synesthesia is a phenomenon in which people experience unusual percepts elicited by the activation of a sensory modality that is unrelated or a cognitive process (Safran and Sanda, 2014). It is truly fascinating that people experience the world in such a distinct and unique way.

The literature provides great resources to better understand how people with synesthesia process many different stimuli in the world. In a study by Itoh et al. (2019), the experimenters performed a Stroop-like test in individual with synesthesia. The Stroop test is a neuropsychological test to test the ability to inhibit cognitive interference that happens when the processing of a specific feature of a stimulus disrupts the simultaneous processing of a different stimulus (Scarpina and Tagini, 2017).  For example, one must say the color of a word and not the actual word itself. When the color of the word and the word itself differ, this task seems to become increasingly difficult. The authors did this with people with synesthesia, except with an auditory stimulus because some people with synesthesia relate a color and sound together. This was done to test the automaticity of pitch class with relation to color. They did this by presenting pitch class names (e.g., do, re, and mi) in font colors that lined up with their color sensations. These results showed that people with synesthesia had decreased time in identifying font color when the color was incongruent with their associated pitch class names, concluding that pitch-class synesthesia is a genuine type of synesthesia (Itoh et al., 2019).

Stroop Test

 

Synesthetes have been implicated to have a cross activation of visual areas that processes shape and color, supporting how visual stimuli lead to their unique perceptions of the world (Amsel et al., 2017). A review by Safran and Sanda (2014) took a look into how people with color synesthesia have varying associations in regards to perceptions, emotions, and consciousness. For example, synesthetes showed improved digit identification because each number is represented by a color, making a specific digit stand out. Some synesthetes experience their emotions and understanding through color, as shown in the review. An example that was shown was how a painting called “Vision” showed how the synesthetic painter drew out the visual experience of a needle puncture during an acupuncture session (Safran and Sanda, 2014).

“Vision” (Safran and Sanda, 2014)

 

To me, I would interpret it as a red splotch that could be blood. Clearly, my interpretation is far less poetic and meaningful when compared to the synesthete’s perception. Even within this review, the authors explored and reviewed many different ways that people with synesthesia navigate the world around them.

It is genuinely mind-blowing how the person on my right can interpret the world completely differently than the person on my left. I never would have imagined how a simple question like, “What color is the sky,” could be such an intriguing conversation starter.

 

References

Amsel, B. D., Kutas, M., & Coulson, S. (2017). Projectors, associators, visual imagery, and the time course of visual processing in grapheme-color synesthesia. Cognitive Neuroscience, 8(4), 206–223. https://doi.org/10.1080/17588928.2017.1353492

Itoh, K., Sakata, H., Igarashi, H., & Nakada, T. (2019). Automaticity of pitch class-color synesthesia as revealed by a Stroop-like effect. Consciousness and Cognition, 71, 86–91. https://doi.org/10.1016/j.concog.2019.04.001

Safran, A. B., & Sanda, N. (2015). Color synesthesia. Insight into perception, emotion, and consciousness: Current Opinion in Neurology, 28(1), 36–44. https://doi.org/10.1097/WCO.0000000000000169

Scarpina, F., & Tagini, S. (2017). The Stroop Color and Word Test. Frontiers in Psychology, 8.   https://doi.org/10.3389/fpsyg.2017.00557

Images

Media Library

https://study.com/academy/lesson/the-stroop-effect-in-psychology-definition-test-experiment.html

 

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Hallucinations or Chromesthesia?

Posted on June 10, 2019 by | 2 comments

When we visited the Musée D’Orsay a couple of weeks ago, I was disappointed to hear that The Starry Night painting by van Gogh was at another exhibition; I had looked forward to the opportunity of seeing it in person. Although this was not possible, this past weekend we travelled to Arles, the town where van Gogh lived most of his life. It was a wonderful experience to walk around the areas where he painted his most famous works! Vincent van Gogh, one of the most famous painters from the mid-1800s, was also a man who lived a struggling life. Being somewhat of an outcast, he was ostracized by his community leading him to live a life of loneliness. Over the years, he spiraled into a routine of drinking absinthe that eventually led to the deterioration of his health. He was diagnosed with epileptic seizures and lived in and out of an asylum in Arles, France. Few know that he did his most famous works while he was suffering from these manic and depressive episodes. Seeing as how we have learned so much about him and even visited his hometown, I decided to look more into his medical diagnosis.

Starry Night: One of Vincent van Gogh’s most famous paintings

When you look at The Starry Night, you probably wonder how is it that van Gogh was able to see those colors in the sky when you can only see dark shades of blue at night. There are various theories as to why he decided to paint it that way, but one of those theories was that van Gogh had synesthesia. Synesthesia is a condition when stimulation in one sense automatically leads to sensations in another sense (Bradford 2017). For example, a person might see a letter and automatically associate it with a color. In the case of van Gogh, there is some evidence that points to him having chromesthesia. Chromesthesia is a subset of synesthesia in which certain sounds are associated with colors. “Vincent Van Gogh explained in his letters that for him, sounds had colors and that certain colors, like yellow and blue, were like fireworks for his senses” (Katie 2018). Could it be that he had synesthesia.

A famous cafe in Arles, France painted by van Gogh

Synesthesia is still a widely unknown occurrence. There are 6 regions in the brain, primarily in the motor and sensory cortex, where higher activation levels are observed, V4 (involved in color perception) being one of them (Rouw et al. 2011). For this reason, there are two differing hypotheses as to how it arises, one of them being that there is somehow a disinhibition when relaying back sensory information to the different brain areas, meaning that essentially anyone has the potential to develop synesthesia. The other theory is that there is a cross-activation mediated through white matter pathways that occurs between the different sensory cortex areas; this is something you are born with, so only those people are able to develop it.

To test this out, researchers performed a visual imagery task to induce synesthesia in a group of individuals (Nair and Brang 2019). They were put in a dark environment to simulate visual deprivation and were then asked about the shapes of multiple letters through audio. The results show that there was significantly more visual imagery when a sound was presented right after the audio recording. The fact that it took approximately 5 minutes to induce these sensations points to the theory that everyone is born with the capacity to be synesthetic, but it only appears when one of the other senses is deprived.

Could this be what van Gogh was experiencing? In a 2016 case study, they describe how a 20-year-old woman who was diagnosed with social phobia and schizophrenia due to her avoidance of social groups and claims that she could see colors when she heard sounds. The doctors thought that she was suffering from hallucinations. In reality, she had savant abilities and synesthesia. To have someone be misdiagnosed only a couple of years ago, makes you wonder if maybe the doctors missed something when diagnosing van Gogh. At a young age, when he took piano lessons, he described the experience as overwhelming because each note was associated with a different color He was disregarded and His teacher believed him to be insane and wouldn’t allow him to continue the lessons (Taggart 2019). Could it be that he was never understood because he did in fact think distinctly due to his ability to perceive the world in a different way? A question that may never be answered, but could give us a little more insight into one of the greatest artistic minds of that time. Maybe for van Gogh, the sky was in fact joyous and explosive, not just a simple color.

 

The cafe that inspired van Gogh’s painting

References

Bradford, Alina. “What Is Synesthesia?” LiveScience, Purch, 18 Oct. 2017, www.livescience.com/60707-what-is-synesthesia.html.

Bouvet L, Barbier J, Cason N, Bakchine S, Ehrlé N (2017) When synesthesia and savant abilities are mistaken for hallucinations and delusions: contribution of a cognitive approach for their differential diagnosis, The Clinical Neuropsychologist, 31:8, 1459-1473

Katie. “Vincent Van Gogh and the Power of Synesthesia in Art.” Exploring Your Mind, Exploring Your Mind, 20 June 2018,

Nair A, Brang D (2019) Inducing synesthesia in non-synesthetes: Short-term visual deprivation facilitates auditory-evoked visual percepts, Consciousness and Cognition, 70: 70-79.

Rouw, Romke, et al. “Brain Areas Involved in Synaesthesia: A Review.” Journal of Neuropsychology, John Wiley & Sons, Ltd (10.1111), 16 Sept. 2011

Shovava, and Shovova. “5 Synesthesia Artists Who Paint Their Multi-Sensory Experiences.” My Modern Met, 28 Feb. 2019

Picture 1: https://www.overstockart.com/painting/van-gogh-starry-night

Picture 2: https://en.wikipedia.org/wiki/Café_Terrace_at_Night

Picture 3: https://fineartamerica.com/featured/cafe-van-gogh-forum-square-arles-aivar-mikko.html

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Paul Cézanne, Museum Fatigue Advocate

Posted on June 10, 2019 by | 5 comments

Have you ever experienced museum fatigue? I thought that I made up this term to describe my own experiences, but upon performing a quick Google search, I discovered that this is actually a phenomenon first described in 1916 (Gilman, 1916).

Interior of the Musée d’Orsay (Image from TripSavy.com)

Going to a museum may seem like a passive process, but to me, it is actually quite a bit of work!

Navigating large crowds and carrying a heavy backpack for several hours is enough to wear me out. But even more so, interpreting piece after piece of artwork—each of which leaves a lot of room for interpretation—is a laborious effort leading to mental exhaustion. Though it is uncomfortable, I think that this is the way it should be. If you don’t experience some fatigue, are you fully engaged with and appreciating the art?

Exterior of Musée d’Orsay (Image from SortiraParis.com)

One particular French artist I have learned about in class is Paul Cézanne, and he seems to have been an especially avid proponent of museum fatigue; although his works were rejected from museums during his lifetime, it seems as if he were intentionally inducing this exhaustion. In the Post-Impressionistic style (abandoning the detailed, picture-perfect landscapes characteristic of Realism), Cézanne produced blurry, unfinished images in order to accentuate the mind’s interpretation process. Leaving blank spots peeking through the blobs of color is a technique called nonfinito, and it’s a bit like trailing off in the middle of a sentence—a visual ellipsis. In this way, the viewer’s interpretation is unique to the way the mind fills in the gaps at that particular moment, influenced by all of the emotions and experiences one brings to the table.

It turns out that this reflects how the brain works when interpreting all visual stimuli: even looking at the same things twice may trigger different responses from neurons dedicated to processing visual information (Jeon et al., 2018).

First, let’s start with some background information about vision and how our

The occipital lobe, shown in yellow (Image from The Science of Pscychotherapy.com)

brains process signals coming from our eyes.

Light enters the eye and reaches the retina at the very back. There, it stimulates light-responsive cells called photoreceptors (rods and cones). Signals from all these cells go through the optic nerve, the optic tract, a structure called the thalamus, and eventually reach the part of the brain that deals with visual information. This area is called the occipital lobe, and the section that is first to receive these signals is called the primary visual cortex, or V1. Here, there are cells that have been shown to respond to basic details of a scene like the width and orientation of lines (Gawne, 2015). Each cell is “tuned” to respond best to a certain width and a certain orientation, and logically, this is called neuronal tuning (Butts and Goldman, 2006). The conditions determining the responsivity of the neurons get more and more complex as the signals are processed (Tsunoda et al., 2001).

The perception of visual information (Image from Slideplayer.com)

As one views the same image, it would make sense that the same neurons respond each time. But, this is not exactly the case: In one experiment by Jeon et al. 2018 in the journal Nature, researchers found that the same neurons aren’t reliably activated by the same stimuli.

In the study, the researchers showed mice lines of different orientations and widths. Using a technique called two-photon calcium imaging, they looked at the activity of neurons in the V1 (Jeon et al., 2018). This technique involves installing an apparatus on the head of a mouse. Based on the movement of fluorescing ions, it lets us see what neurons are active as the mouse is awake and interacting with the world (Mitani and Komiyama, 2018).

Some of the images shown to mice in the Jeon et al. (2018) experiment (Image from the journal Nature)

Tracking around 300 neurons, the researchers determined the qualities of the image (such as the angle and the width of the lines) for which a neuron was most likely to respond. Then, performing the test one week later and again two weeks later, they compared the preferences of the neurons. While the majority of individual qualities were relatively stable over time, the researchers found that fewer than half of the neurons had exactly all of the same preferences as before.

What does this all mean? In the past it has been shown that the visual cortex is highly plastic, or able to rearrange and reorganize its connections based on new information (Hofer et al., 2009).  However, these results provide even more insight into how our visual systems adapt and change: some parts can remain stable while others change their responsivity in order to incorporate new information, altering our perception of the world around us.

So, our perception of static scenes is actually not static at all; it is being altered constantly! That boulangerie we pass on the way to class is not perceived by our brains in exactly the same manner every day.

Portrait of a Woman by Paul Cezanne (Image from the Metropolitan Museum of Art)

That leads me to wonder: especially when looking at one of Cézanne’s paintings—since he left so much for the viewer’s mind to fill in—do we ever experience the same thing twice?  This may very well be the most intriguing thing about his work, making it both timeless and malleable. A perfect excuse to visit the Musée d’Orsay just one more time.  The unfortunate result is only that this “museum fatigue” may become an increasingly common affliction. However, it’s likely already a common experience for all the museum-goers of the world, and I’m not afraid. It certainly won’t deter me from absorbing all of the Post-Impressionism art I can while I’m here!

 

References:

Butts, D.A., Goldman, M.S. (2006). Tuning curves, neuronal variability, and sensory coding. PLOS Biology. 4:92. doi: 10.1371/journal.pbio.0040092.

Gawne, T. (2015). The responses of V1 cortical neurons to flashed presentations of orthogonal single lines and edges. Journal of Neurophysiology. 113:2676-2681. doi: 10.1152/jn.00940.2014

Gilman, B. I. (1916). Museum Fatigue. The Scientific Monthly. 2:62–74.

Hofer, S. B., Mrsic-Flogel, T. D., Bonhoefer, T. & Hubener, M. (2009). Experience leaves a lasting structural trace in cortical circuits. Nature. 457:313–317.

Jeon, B. B., Swain, A.D., Good, J. T., Chase, S. M., Kuhlman, S.J. (2018). Feature selectivity is stable in primary visual cortex across a range of spatial frequencies. Nature. 8:15288. doi:10.1038/s41598-018-33633-2.

Mitani, A., Komiyama, T. (2018). Real-time processing of two-photon calcium imaging data including lateral motion artifact correction. Frontiers in Neuroinformatics. 12:98. doi: 10.3389/fninf.2018.00098

Tsunoda, K., Yamane, Y., Nishizaki, M., Tanifuji, M. (2001). Complex objects are represented in macaque inferotemporal cortex by the combination of feature columns. Nature Neuroscience. 4:832-838. doi: 10.1038/90547.

 

Image links:

https://www.tripsavvy.com/thmb/l0SeupBCtJWyVCf7U_I4BGsPql8=/960×0/filters:no_upscale():max_bytes(150000):strip_icc()/8414359797_20e28f27f2_o-56a403d25f9b58b7d0d4f0e6.jpg

https://www.sortiraparis.com/images/55/1467/108625-jeu-de-piste-gratuit-au-musee-d-orsay.jpg

https://www.thescienceofpsychotherapy.com/wp-content/uploads/2018/10/bigstock-Female-Occipital-Lobe-Brain.png

https://slideplayer.com/slide/6900016/23/images/4/Figure+4.1+%28a%29+Side+view+of+the+visual+system%2C+showing+the+three+major+sites+along+the+primary+visual+pathway+where+processing+takes+place%3A+the+eye%2C+the+lateral+geniculate+nucleus%2C+and+the+visual+receiving+area+of+the+cortex..jpg

https://collectionapi.metmuseum.org/api/collection/v1/iiif/656892/1571903/restricted

Hyperlinked videos and sites:

https://www.youtube.com/watch?v=fZDAwXh54is

https://goo.gl/maps/GM2ZURPTLpia3V7b9

https://www.paulcezanne.org/

 

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Watch your step!

Posted on June 8, 2015 by | 4 comments

Dear Friend,

The phrase “Attention à la marche en descendant du train” echoed through the platform as I grabbed my bag and stepped from the train. Ready to explore the beautiful, world-renowned city of Paris, I proudly raised my head and firmly stepped forward with intent. However, I couldn’t help but ask two very important questions. Where am I, and where can I find the delicious food?

Thoughts of savory crepes, warm baguettes, and chocolate-filled croissants distracted me during my voyage, somehow causing me to step off at the wrong station. I stopped and unfolded my pocket metro map, promptly realizing my disorientation landed me somewhere in the center of the complex Parisian underground maze. I wondered how I lost track of time so fast by simply staring through the window of the train. I was practically blinded by my quest for French desserts, but just about ready to go back home to Cité Universitaire.

map

In the two subsequent weeks that zoomed by, I paid much closer attention to my surroundings. Though I indulged in wonderful Parisian delicacies, and adapted to the city life, I also started perceiving my environment with more respect for sensory information. Doing so kept me from getting lost and allowed me to focus more. This habit greatly coincided with our neurosciences classes that started focusing on the brains interaction with bodily functions like motion, vision, and hearing.

With my senses primed, I took note of Paris’ every little detail, and learned how to travel as an expert tourist and passenger, exploring what Paris has to offer both above and below ground.

Above ground, I saw beautiful gardens and remarkable architecture. I experienced the jostling waves of the Seine while on a boat tour, and got dizzy staring up at the Eifel tower. I also heard countless sirens, and noticed pedestrians don’t care about traffic lights.

Below ground, I listed to musicians perform inside metro hallways and I watched entertainers dance in moving trains, all accompanied by the hum of bustling crowds and the sound of screeching metal pressing together to slow down trains. In this wild sub-terrain, I also noticed that closing automatic doors don’t care about rushing passengers, and warnings of “attention à la marche” exist for a reason.

train1Some things however literally caught my eye. As I stared outside of a train window one day, I caught a short glimpse of a nearby pole while we zoomed by. This was strange considering how slow and peaceful the buildings and scenery in the background passed by. I looked more closely, noticing the tracks below the train and the platform steps to the side of the train, moved incredibly fast while the landscape a few hundred meters out barely seemed to move at all. At this speed, the steps were actually dangerous!

 

I realized my mind must be playing tricks on me since the train was moving at the same speed compared to the ground, shared by both the tracks and the landscape. A few days later, I noticed this effect again at the roundabout circling the Colonne de Juillet at the Place de la Bastille (a great monument, see link 1)where cars near me seemed to move faster than those furthest away. I wanted to know more so, like any student investigator, I decided to search and see if neuroscience could provide and answer to this puzzling question.

Bastille

Screenshot at Bastille from GoogleMaps

The above process, called motion parallax. is a visual cue that signals depth where objects that are closer appear as if they move further across the visual field, while those that are farther away move less (Kim et al., 2015)

 

A recent study by Kim et al. (2015) looks at the neuroscience behind this cue and explores a specific area of the brain called the middle temporal (MT) area that could be responsible for the perception of depth from motion parallax. Although another study by Nadler et al. (2008) found that this part of the brain carries information about depth, it was not necessarily clear what kind of information was transmitted. The data from Kim et al. (2015) fill this gap by hypothesizing that the MT specifically carries information about the perception of depth.

The experimenters take two male monkeys, trained to respond to dots they see on a screen, and set them up with recording devices for their eyes. Researchers then fix the monkeys with electrodes in their MT areas, located by the use of MRI imaging. Finally, testing involves placing monkeys on a motion platform where the monkeys’ eye movements and brain signals provide computer-collected data.

The results from Kim et al. (2015) show that the MT will actually predict a monkey’s decision regarding its perception about depth. This paper gives a lot of support to the field of neuroscience because it reveals more information about the MT with sound methods.

The study finds that the MT further contributes to the perception of depth but it does not show that the area is entirely responsible perception. Although very recent, this article comprises one train-cart in a long train of studies on the MT. It lacks particular novelty and demonstrates that there is still much to learn about vision and the brain. Research in animals should definitely continue, but it would find it very interesting blend more than one study to find bigger applications. For example, Nawrot and Stroyan (2012) show that humans require about 30ms to detect depth from motion parallax. What if scientists could use deep brain stimulation (DBS) in the MT to provide brain enhancement for car accident prevention? I am incredibly excited for this research to continue.

Through my city travels, I hope to walk down the beautiful streets of Paris and remember that neuroscience allows me to navigate safely and effectively. My time in Paris is showing me that even though life has twists and turns, senses are needed to make “sense” of them (pun intended). I hope one day, a breakthrough in research and technology will allow us to better watch our steps!

References:

Kim HR, Angelaki DE, DeAngelis GC (2015) A functional link between MT neurons and depth perception based on motion parallax. J Neurosci 35:2766–2777 Available at: http://www.ncbi.nlm.nih.gov/pubmed/25673864 [Accessed June 8, 2015].

Nadler JW, Angelaki DE, DeAngelis GC (2008) A neural representation of depth from motion parallax in macaque visual cortex. Nature 452:642–645 Available at: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2422877&tool=pmcentrez&rendertype=abstract [Accessed June 8, 2015].

Nawrot M, Stroyan K (2012) Integration time for the perception of depth from motion parallax. Vision Res 59:64–71 Available at: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3349336&tool=pmcentrez&rendertype=abstract [Accessed June 8, 2015].

 

link 1 http://www.discoverfrance.net/France/Paris/Monuments-Paris/Bastille6.shtml

link2 http://psych.hanover.edu/Krantz/MotionParallax/MotionParallax.html

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Musée du Louvre

Posted on June 11, 2013 by | 14 comments

The overwhelming feeling landing in Paris just a few short weeks ago can only be described as a combined wave of nervousness, anxiety and excitement.  I didn’t expect to feel that sensation again so soon, but walking into the Louvre brought the same, overwhelming rush. I was amazed by the architecture of the building and its’ perimeter and tried not to look like a typical tourist stopping to take pictures along every step of the way. After attempting to blend in with the crowd by buying some “French” coffee, we grabbed a map of the museum and (blindly) picked a starting point.

Musée du Louvre

We started with the Ancient Egyptian exhibit, which was confusing given the French descriptions mounted by all of the pieces. The intricacies of the hieroglyphics, artwork and tools, however, transcended the language barrier. After walking through, we were tired (we had climbed the Eiffel Tower earlier that day) and decided to head to one more piece before completing our day—the famous Mona Lisa.

Ancient Egyptian Art

Following the crowd, we made our way to the other side of the museum and quickly saw the international amalgamation surrounding this infamous painting. How is it that this one painting can draw so much attention from so many different people? Part of the interest in this picture lies in the mystery behind its creation—why did Leonardo da Vinci paint this picture? Who is the woman depicted here? Is she real? These questions are unanswered and add to the mystery associated with this artwork. One of the elements of this painting that interests people from across disciplines and countries is the ambiguity in Mona Lisa’s smile.  When we look at this infamous smile in the context of neuroscience, we should consider the role of visual perception. Visual perception in itself is a bridge between art and science, as this is the type of information processing that takes different visual stimuli from our environment and processes them into a “single”, interpretable unit. Visual perception is broken down into different elements such as visual closure, memory, form constancy, spatial skills and more (Chakravarty 2011). All of these factors contribute to how we perceive the outside world via our vision.

Scientists have taken this described cognitive approach to vision and have applied it to different areas of the brain. They have found that vision and interpretation of what we see relies on multiple brain areas. The primary visual area is referred to as V1, and next to this area are different, specialized regions such as V3 (recognizes the shape and size of an object), V4 (color perception) and V5 (essential in identifying object motion) (Chakravarty 2011).

The Mona Lisa

Taking a step back, it is clear that there are multiple parts of the brain with their own specific, intricate mechanisms that can affect the way faces and objects, for example the Mona Lisa, can be perceived and processed across any given population. The human visual system has allowed us to, over time, develop specific visual skills that correspond to face perception (Haxby et al., 2000). For example, individuals with brain damage in the ventral occipitotemporal cortex (an area in the brain associated with visual perception) have difficulty in recognizing faces—but can recognize objects with ease (Haxby et al., 2000). This condition, prosopagnosia, is one that supports the claim that there are very specific areas in the brain associated with face perception—perhaps providing a neurological reasoning behind the fascination with the Mona Lisa. The fact that this is a portrait of a mysterious face might be driving the worldwide fascination.

When actually getting a better look at the Mona Lisa after pushing through the crowds of people, the neuroscience student in me couldn’t help but wonder how many different neurobiological systems were working in order for me to appreciate this piece of art. I had to focus on the picture, discern the face from the background, take in account of the colors, recognize that this was a portrait, and attempt to make associations and recall what I had learned about this piece in my high school art class. Aesthetic preference is yet another factor that has significant neurological underpinnings. Cela-Conde (2011) found, through various neuroimaging studies, that certain areas in the brain (the hippocampus, parahippocampal gyrus and the amygdala) are all actively engaged when individuals are aesthetically pleased with a piece of artwork. When patients with neurological conditions (in which these areas degenerate) are presented with previously “pleasing” pieces of artwork, the patients show a completely altered taste and preference. This supports that these areas of the brain have some influence over the cognitive perception and appreciation of artwork. Similarly, studies have reported that damaging the amygdala (an area of the brain primarily associated with emotion) can alter artistic, visual preference. Individuals with amygdala damage generally expressed a liking for “…geometrical shapes, landscapes and color arrangements” when compared to the healthy, control groups (Cela-Conde et al., 2011).

Mona Lisa Selfies...

Perhaps the fascination with the Mona Lisa is brought about by the evolutionarily driven sensitivity to faces. Or, maybe there is a genetic predisposition in some of our brain’s visual areas to appreciate certain types of artwork. Some scientists even suggest that the ambiguity in her smile activates area V5, an area of the brain involved in perceiving movement, which enhances aesthetic appeal (Chakravarty 2010). Regardless of the reasoning, there are complex neurological mechanisms by which we process not only the Mona Lisa, but also every other sculpture, painting or realistically anything in our visual field. Visual perception in itself relies on cognitive theories and activation of various brain areas to yield some form of appreciation of art—now try not to think about that next time you go to a museum.

Written by: Noareen Ahmed

References:

Cela-Conde C, Agnati L, Huston J, Mora F, Nadal M (2011) The neural foundations of aesthetic appreciation. Progress in Neurobiology 94: 39-48.

Chakravarty A (2010) Mona Lisa’s smile: A hypothesis based on a new principle of art neuroscience. Medical Hypotheses 75: 69-72.

Haxby J, Hoffman E, Gobinni M (2000) The distributed human neural system for face perception. Trends in Cognitive Sciences 4: 223-233.

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