The Original GPS
Media Source:
http://www.newscientist.com/article/dn23986-cells-that-help-you-find-your-way-identified-in-humans.html#.Ugb7YpLI2Sp

Introduction:
Navigation is a task we manage without a second thought, however complex processes
occur in the brain to allow this automatic operation. New Scientist’s website recently published an article on a study conducted by Jacobs et al (2013), on cells which allow navigational processes in the brain, known as grid cells.

Previously, grid cells have been identified in animals as being important in sending sensory information regarding spatial awareness to place cells that also send information to the hippocampus for the formation of memories of an environment. Preceding evidence pointing to the existence of grid cells was due to functional magnetic resonance imaging (see figure 3) showing firing patterns of grid cells in rats (Jacobs et al, 2013). Now, substantial evidence has been presented for the discovery of grid cells in humans in what is known as the entorhinal cortex, through invasive brain recordings. occur in the brain to allow this automatic operation.

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Image 1

We chose to investigate navigation in the brain due to this groundbreaking discovery of grid cells. It has implications for people with navigation problems, in particular those with Alzheimer’s disease. By examining this neural circuit, treatments can be developed to stimulate these grid cells. Navigation is something of second nature and especially in the modern technology driven decade, it is something we take for granted with the aid of GPS satellite navigation etc. Therefore we decided as a group that it would be an interesting avenue of research- understanding how humans naturally navigate.



Neuroscientific context:

Navigation Cells:

There are three known types of brain cells that control navigation in animals. They are head-direction cells, place cells and grid cells.
Grid Cells.jpg
Figure 1: Grid cell firing pattern

Head-Direction cells have been found to fire depending on the direction the animal moves in the horizontal plane, similar to the workings of a compass. (Gibson et al, 2013) These cells are scattered throughout the brain, but are mostly concentrated in the limbic system, more specifically in the Papez circuit. (Taube, J.S., 2011) The firing is often regulated by visual landmarks, and can be influenced by motor and proprioceptive information.

Place cells are found in the hippocampus, also known as the memory centre and they behave in a similar fashion to head-direction cells to provide information about the location of the animal. Together with thalamic head direction cells, they make up a system for spatial orientation. (Knierim et al, 1995)

Grid cells are neurons that have been found to exist in various animals including rats, and mice; however, it is only very recently that the real possibility of grid cells existing in humans has had any evidence to support it. Grid cells are found in the medial entorhinal cortex in the medial temporal lobe of the brain, an area responsible for navigation and memory as it is adjacent to the hippocampus. They form the third part of this environment-dependent spatial coordinate system (Sargolini F., 2006). Grid cells use a matrix made up of triangles to signify specific locations in an environment, whether familiar or unfamiliar to an animal. They function by firing signals when the animal reaches the vertices of these triangles via temporal oscillations of neurons in the brain. (Koenig, J., 2011)

Brain Regions involved in navigation:


The ability to orientate within familiar environments is dependant on the formation and use of a mental representation of the environment, much like a cognitive map. A study conducted on the formation and use of these cognitive maps (Iaria, G 2007) proposes the retrosplenial and hippocampal brain regions (part of the cerebral cortex and located in the medial temporal lobe, shown in Figure 1) directly impact topographical orientation. The study suggests that the anterior hippocampus is active during the formation of the cognitive map, whereas the posterior
Medial Cerebral Cortex of the Brain.png
Figure 2. Image adapted from Gray's Anatomy
hippocampus is more active during the use of the map. The study also shows


Furthermore, the reterosplenial cortex (part of the cingulate cortex) was found to be involved in both the formation and the use of navigational maps. This highly regulated process works by updating the individual’s l location as the frame of reference changes, thereby assisting the hippocampus in navigation.

Further evidence to suggest the hippocampus’s involvement in spatial navigation arises from Elanor, A et al. 1997 study on London taxi drivers. The results compare the size of the anterior and posterior hippocampi in both controls and taxi drivers. The size of the posterior hippocampus of taxi drivers was significantly larger compared to controls. Where as the size of the anterior hippocampus was larger in controls as opposed to taxi drivers. These findings are in accordance with the notion that the posterior hippocampus stores a spatial representation of the environment. There is also a slight expantion to accommodate the amplification of this representation in people with a greater dependence on navigational skills.

This amplification also leads to the redistribution of grey matter as well as an increase in tissue volume in the hippocampus.
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Figure 3: fMRI scans
The reason for this dramatic increase in both size and volume may be due to the fact that the hippocampus may grow new neurons or the already hippocampal neurons may form new connects with each other. A particular type of non- neuronal cell called a glial cell, who’s function is to support and protect neurons may also aid to the increase in the hippocampal volume, however their growth rate is not as extensive as neurons.

Relationship to Alzheimer's Disease:


Alzheimer’s disease is a progressive neurodegenerative disease, caused by the deterioration of neurons in the cerebral cortex. This is a part of the brain that is vital for cognitive function, therefore it results in a decline of cognitive function; memory loss being a common symptom. Through conducting this study,important observations of the entorhinal cortex were made. This is significant as the entorhinal cortex is one of the first areas to be affected by Alzheimer’s disease. Learning more about this part of the brain can not only help people be better navigators of their world, but may also help those with Alzheimer’s’ or similar conditions return to normal cognitive functioning in that area.

A study conducted last year by The University of California, Los Angeles showed the importance of the entorhinal cortex in cognitive function, using a virtual taxi game where participants (who already had electrodes implanted in their brains for medical reasons) were required to use their navigation skills. Results showed that stimulating the entorhinal cortex with electrodes whilst participants were navigating in this virtual simulation, improved their navigational abilities as they recognised landmarks more quickly (Suthana, N et al. 2012). This positive correlation strongly implies the importance of the entorhinal cortex in navigation. Thus this study shows how memory enhancing stimulation could be applied during the learning phase of people, in particular Alzheimer's patients, to assist in the formation of spatial memories.

This is why research on the neurological processes behind human navigation can be beneficial in shedding more light on Alzheimer’s disease, one day resulting in the development of new and improved treatments for people suffering with the condition. As it is a very debilitating condition that affects more than 12 million individuals worldwide, improving our knowledge on the topic is vital.



Critical Analysis of Media and Article


The article titled Cells that help you find your way identified in humans has been published in The New Scientist website’s health section in August of this year. This news article covers the findings of a journal article, "Direct recordings of grid-like neuronal activity in human spatial navigation", that was published online in Nature Neuroscience. The news article was published very soon following the release of the journal article, in fact on the same date. New scientist is a highly reputed publication that
maintains its high standards by publishing articles about new findings 'ASAP' and retaining a high level of accuracy and quality of work.

Upon reading the article, it is evident in the informal tone of voice that it is targeted at a wider audience niche in comparison to the journal article it describes. Jargon is explained in layman’s terms and complex concepts relating to the neuron types and regions of the brain are described clearly for anyone with or without a scientific background to understand. By alluding to everyday analogies the author makes it easier to grasp concepts such as how grid cells work, for example “imagine a carpet in front of you has a grid pattern…”.

The media article succinctly summarizes the findings of the study conducted by Jacobs et al published in nature of neuroscience journal. The journal article is a lot more detailed, and caters to a scientifically literate audience. It has been published in a prestigious journal, Nature, indicating the importance of these findings. There are however, a few inadequacies in the media article as it fails to explain methods. Exactly how the firing of cells were visualized via electrodes and recorded was not described in the article. On the other hand, as the target audience isn’t specifically scientists and researchers, this information is adequate for the average reader’s understanding of the research. Unlike the media article, the journal article shows statistical significance of the research in figures and graphs that back up the findings.

The media article quotes an academic from the Radboud University Nijmegen in the Netherlands, giving credibility to the report and adding a more opinionated tone to the article. The report does still maintain an unbiased tone, as the description of the study is purely objective. The article employs modality in hopeful and promising language with implications for future research in the field, in particular related to Alzheimer’s disease.

Overall the article is a legitimate source as it not only comes from The New Scientist, but also reports accurately on published findings from a journal article and provides a link to the article itself. The style of writing was appropriate for the context and target readers, as is evident in the catchy titles and subheadings.





Appendix


This project provided us an avenue to go out and look into recent neuro-scientific research advances that have been made. We created a Facebook group to maintain contact throughout this project as it was the easiest means of meeting up; however we allocated face-to-face meet up times as well. Additionally having an online platform to upload documents on each of our allocated parts of this project was very useful. Thus we linked various articles we all found interesting. We individually came up with very different areas of neuroscientific research, such as the effects of chocolate on brain function at older ages to how autism affects males and females differently. However once we came across this article, we unanimously agreed it was the most interesting and pursued the topic, since navigation is a skill that we use subconsciously every day, and this article highlights the discovery of grid cells in humans – one more piece to completing the puzzle that is the brain!

We used Google search engine primarily as our means of searching. This brought us a wide variety of media from blog entries, to journal articles, to online newspaper articles. Having found this article we also used Google Scholar to read the journal article in question, as well as conduct our own research to further our understanding on the scientific content. In addition, we used PubMed as it is an excellent central search engine for biomedical literature, and it narrowed down the results specific to our search on grid cells in humans. The use of certain journal articles allowed us to compare our chosen article with similar research conducted on grid cells, and this gave us an indication of the authenticity of our article as it provided us with solid evidence and insight into the function and mechanisms of grid cells.

The comments from reviewers served as a useful checklist for our final editing. The feedback was mostly positive, with strong points being the choice of article, well-written segments, a good use of references and suitability to the target audience. The suggestions and mentions of ‘weak points’ were helpful and we took many of them on board, for example: we incorporated images and figures into the text to both make it more aesthetically appealing and also to better explain some concepts. We proofread the entire article to make the writing style more uniform and improve readability. We added a table of contents for ease of navigation. We received a couple of comments regarding the colour scheme – we chose better colours for readability, but retained the original idea where major headings were coloured, and subheadings were not, thus creating a distinction between the two. Overall the reviews were a good source of constructive criticism and we benefited from them.




References

Figure 1: Grid Cells in Rats and Bats [Image] (2011) Retrieved from
http://www.nature.com/nature/journal/v479/n7371/fig_tab/479046a_F1.html

Figure 3: fMRI adaptation to running direction and to runs at 60° from it. [Image] (2010) Retrieved from
http://www.nature.com/nature/journal/v463/n7281/fig_tab/nature08704_F4.html#figure-title

Gibson, B., Butler, W.N., Taube J.S., (2013). The head-direction signal is critical for navigation requiring a cognitive map but not for learning a spatial habit. Current biology 23 (16), 1536-1540. doi: 10.1016/j.cub.2013.06.030.

Kneirim, J.J., Kudrimoti, H.S., McNaughton, B.L. (1995). Place cells head direction cells, and the learning of landmark stability. Journal of Neuroscience 15 (3 pt 1), 1648-1659. Retrieved from http://www.ncbi.nlm.nih.gov/m/pubmed/7891125

Koenig, J., Linder, A.N., Leutgeb, J.K., Leutgeb, S., (2011). The spatial periodicity of grid cells is not sustained during theta oscillations. Science 332 (6029), 596-595. Doi: 10.1126/science1201685

Iaria, G., (2007). Retrosplenial and hippocampal brain regions in human navigation: complementary functional contributions to the formation and use of cognitive maps.. Eur J Neuroscience, 3, 890-9. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/17298595.

Maguire, E. A., Gadian, N. G., Johnsrude, I. S., Good, C. D., Ashburner, J., Frackowiak, R. S., & Fith, C. D., (2000). Navigation-related structural changes in the hippocampi of taxi drivers. Retrieved from: http://www.holah.co.uk/study/maguire/.

Sargolini, F., Fyhn, M., Haftin T., McNaughton, B.L., Witter, M.P., Moser, M., Moser, E.I. (2006). Conjunctive representation of position, direction, and velocity in entorhinal cortex. Science 312(5774), 758-762. Doi: 10.1126/science.1125572.

Scientific American. (2011). Cache Cab: Taxi Drivers' Brains Grow to Navigate London's Streets. Retrieved from: http://www.scientificamerican.com/article.cfm?id=london-taxi-memory.

Suthana, N., PhD., Haneef, Z., M.D., Stern, J., M.D., Mukamel, R., PhD., Behnke, E., B.S., Knowlton, B., PhD., & Fried, Itzhak,M.D., PhD. (2012). Memory enhancement and deep-brain stimulation of the entorhinal area. The New England Journal of Medicine, 366(6), 502-10. doi: 10.1056/NEJMoa1107212

Taube, J.S. (2011). Head direction cell firing properties and behavioural perfomance in 3-D space. Journal of Physiology 589(Pt 4), 835-841. doi: 10.1113/physiol.2010.194266.

Thomas H., (2013) Cells that help you find your way identified in humans. Retrieved from: :http://www.newscientist.com/article/dn23986-cells-that-help-you-find-your-way-identified-in-humans.html#.Ugb7YpLI2Sp.





Topic: The Original GPS

Lakshini Ranganathan: z3372597
Namrata Pulapaka: z3372596
Mansi Shah: z3332981
Ivana Manzoni: z3418538

Media Article Link:

http://www.newscientist.com/article/dn23986-cells-that-help-you-find-your-way-identified-in-humans.html#.Ugb7YpLI2Sp

Looks good. You may have to work hard on the media analysis - it is always easier if the publisher has done a terrible job, but I think considering what made it deemed newsworthy, and comparing it to the original article should give you enough to work with.
Approved.

Allocation of Jobs:

  • Introduction - Lakshini
  • Analysis + research
    • Grid Cells - Namrata
    • Brain regions involved in Navigation - Mansi
    • Relationship to Alzheimer's - Ivana
  • Critically analysing media and article - Everyone
  • Appendix - Everyone

Deadlines:

  • Scaffold with dot points on each topic - Week 5, Monday 26th August
  • Analysis, Search Strategy and Appendix - Week 6, Monday 2nd September
  • Finalise Draft - Week 6, Friday 6th September
  • Draft due Week 7 - Monday 9th September 10AM
  • Edit - Week 8, Wendesday 18th September
  • Final due Week 9 - Monday 23rd September 10AM

Meetings:
  • Online meeting, each member discussed roles, and possible topics- Saturday 10th August
  • Face-to-face meeting to discuss draft - Friday 16th August
  • Face-to-face meeting to finalise draft- Friday 6th September
  • Face-to-face meeting before final submission- Friday 20th September


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