Our lens:
- Makes sure that light converges to a single point in our retina
- Does this using accommodation
- Near target: thick lens
- Far target: broad lens
Accommodation is not enough: you also need convergence.
Retina
- We use degrees to measure sizes of things we see visual angle
- Retinal layers:
- In our fovea: there are only cones.
When light hits the rod (or cone) the rhodopsin is broken down and cell hyperpolarizes. So less activity when there is light.
- We have 3 types of cones and 1 rod.
- Rods are more sensitive to cones.
- We don’t see color with rods.
Purkinje shift: the sensitivity to higher wavelengths is less in the dark because rods are insensitive to red (long wavelengths).
Cones are not sensitive to low amounts of light.
Temporal summation: photons reaching a rod add up over time, so fewer are necessary for a response.
What if one of the cone types is missing? Then you are color deficient.
- The L-cone and M-cone missing picture looks quite the same, cause they have overlap in their wavelengths.
There is always photon noise.
So:
- Light of the retina is noisy
- The density of receptors determines spatial acuity
- Type of receptor determines temporal acuity/sensitivity
- Stimulus-point on the retina has a spread with gradual slope towards un-stimulated area
We do not perceive light, we perceive changes in light (intensity) across space and/or time.
Horizontal cells:
- Create a sharper picture
Amacrine cells (not very important for exam)
Bipolar cells (important):
- On center (inverting)
- Off center (non-inverting)
Center-surround organisation
Three types of ganglion cells
- M cells (large receptive field)
- Have on and off cells and different cells for different colors
- Slow temporal response
- P cells (small receptive field)
- Fast
- L cells
- No center surround because we only have a few cones
Center-surround is important!
Questions? Let me know in the contribution section!
Follow me for more summaries / lecture notes!
Join with a free account for more service, or become a member for full access to exclusives and extra support of WorldSupporter >>
Contributions: posts
Spotlight: topics
Online access to all summaries, study notes en practice exams
- Check out: Register with JoHo WorldSupporter: starting page (EN)
- Check out: Aanmelden bij JoHo WorldSupporter - startpagina (NL)
How and why use WorldSupporter.org for your summaries and study assistance?
- For free use of many of the summaries and study aids provided or collected by your fellow students.
- For free use of many of the lecture and study group notes, exam questions and practice questions.
- For use of all exclusive summaries and study assistance for those who are member with JoHo WorldSupporter with online access
- For compiling your own materials and contributions with relevant study help
- For sharing and finding relevant and interesting summaries, documents, notes, blogs, tips, videos, discussions, activities, recipes, side jobs and more.
Using and finding summaries, notes and practice exams on JoHo WorldSupporter
There are several ways to navigate the large amount of summaries, study notes en practice exams on JoHo WorldSupporter.
- Use the summaries home pages for your study or field of study
- Use the check and search pages for summaries and study aids by field of study, subject or faculty
- Use and follow your (study) organization
- by using your own student organization as a starting point, and continuing to follow it, easily discover which study materials are relevant to you
- this option is only available through partner organizations
- Check or follow authors or other WorldSupporters
- Use the menu above each page to go to the main theme pages for summaries
- Theme pages can be found for international studies as well as Dutch studies
Do you want to share your summaries with JoHo WorldSupporter and its visitors?
- Check out: Why and how to add a WorldSupporter contributions
- JoHo members: JoHo WorldSupporter members can share content directly and have access to all content: Join JoHo and become a JoHo member
- Non-members: When you are not a member you do not have full access, but if you want to share your own content with others you can fill out the contact form
Quicklinks to fields of study for summaries and study assistance
Main summaries home pages:
- Business organization and economics - Communication and marketing -International relations and international organizations - IT, logistics and technology - Law and administration - Leisure, sports and tourism - Medicine and healthcare - Pedagogy and educational science - Psychology and behavioral sciences - Society, culture and arts - Statistics and research
- Summaries: the best textbooks summarized per field of study
- Summaries: the best scientific articles summarized per field of study
- Summaries: the best definitions, descriptions and lists of terms per field of study
- Exams: home page for exams, exam tips and study tips
Main study fields:
Business organization and economics, Communication & Marketing, Education & Pedagogic Sciences, International Relations and Politics, IT and Technology, Law & Administration, Medicine & Health Care, Nature & Environmental Sciences, Psychology and behavioral sciences, Science and academic Research, Society & Culture, Tourisme & Sports
Main study fields NL:
- Studies: Bedrijfskunde en economie, communicatie en marketing, geneeskunde en gezondheidszorg, internationale studies en betrekkingen, IT, Logistiek en technologie, maatschappij, cultuur en sociale studies, pedagogiek en onderwijskunde, rechten en bestuurskunde, statistiek, onderzoeksmethoden en SPSS
- Studie instellingen: Maatschappij: ISW in Utrecht - Pedagogiek: Groningen, Leiden , Utrecht - Psychologie: Amsterdam, Leiden, Nijmegen, Twente, Utrecht - Recht: Arresten en jurisprudentie, Groningen, Leiden
JoHo can really use your help! Check out the various student jobs here that match your studies, improve your competencies, strengthen your CV and contribute to a more tolerant world
2381 |
Add new contribution