Class Notes (834,756)
Canada (508,705)
Psychology (7,776)
PSYB65H3 (519)
Lecture 5

Psyb65 - lecture 5.docx

5 Pages
131 Views
Unlock Document

Department
Psychology
Course
PSYB65H3
Professor
Zachariah Campbell
Semester
Winter

Description
Psyb65 – lecture 5 Sensory Motor Functions and Dysfunctions Visual System - Look at this from bird’s eye view – tip: draw the diagram on the back of exam paper for midterm - Involved with seeing and recognizing things in your universe - General organization o Function is dependent on its anatomy and organization o Retinas (each of your eyes) anatomically, are divided right down the centre in each eye o Your world (what you see when you look out) is your visual field divided right down the centre where your nose is  Also divided into right visual half field and left visual half field (the word half is rarely used) (must look straight ahead for this to make sense) o Portion of retina toward the outside portion of your head is referred to the temporal portion of your retina (temporal – side) o Portion which is closest to your nose is referred to the nasal portion of your retina o Anatomy of them is completely different because the way they are connected is very different o Information from each retina leaves through an optic nerve (nerve as it leaves the retina)  The 2 nerves cross (known as an optic chiasm) – point where the nerves from the back of your eyes come together  Portions cross and meet and then separate again (optic tract) o The part of your retina from the temporal portion (outside portion), as it continues back, it comes to the optic chiasm and stays on the same side of the brain – meaning it does not cross *  Nerves coming from the temporal portion, hit the optic chiasm and keep going on the same side of the brain o Nasal portion of each retina (part closest to your nose), that half, whenever they go toward the optic chiasm, they cross over to the opposite side of the brain * o This creates a system o Retina is part of your nervous system o If something is in your right visual field, it will hit the nasal portion of the right eye and temporal portion of the left eye and vice versa  Everything in your right visual field ends up in your left cortex; left visual field goes into right cortex o Everything from the temporal portion continues to the same side of the brain while everything from the nasal portion crosses over - Damage o Tell the person to close one eye and look the other person right in the nose – ask them if they see any fingers moving – ask them what they can see  By figuring out what they can see, you can tell where the tumor is o Refer to slide* - right side of picture is person’s actual visual field – what the person can see/ what is damaged in person’s visual field, not in the retina  Have to look at one eye at a time – close one eye  o 2. Left eye is not infected (can see everything perfectly normal)  If you cover your left eye, you will be completely blind in your right eye o 3. If you slice through the optic chiasm (tumor blocking that area) you are cutting off the fibres that cross over not the ones on the outside – nasal portion of each eye will be blind  Right eye, outside portion will be blind, left outside portion will be blind therefore lesion is in the centre o 4. Tumor on the right temporal side – left visual field of outside of the right eye will be blind – if temporal portion of right eye is dead, you can’t see off to the left o 5. Losing right hand side of right eye – therefore right eye is blind in the left (severed temporal portion)  Severed fibres that cross (nasal) therefore also blind to the left nasal portion o 7. If you go all the way to the cortex and there is damage, you will be blind in the opposite visual field of each eye however there is a small part in the middle called macular sparing - What kind of function do things have as we move down this system o The more central the neuron, o Neurons and retina are able to detect a single spot of light on a single receptive field  Is light shining on this particular field  Each neuron builds upon information from neuron beneath it  Area 17 of cortex (bottom of image – primary receptive area) neurons respond to bars of light that is oriented in a particular direction  Will not respond to bars of light in different orientations o When you get to the associational cortex (in temporal area) a neuron responds to complex images (ie. hand or face) and recognizes it  Taken information from simpler neurons and puts them together o When you get up to damage of visual cortex  Complete damage leads to blindness of opposite visual field  Won’t be quite blind – little part in centre that you see but shouldn’t be able to – macular sparing o If you have small areas of damage in the level of occipital cortex – you will lose portions of your opposite visual field – certain areas where you will be blind  *always opposite visual field o If damage is very small, it can result in a schotoma – small area of blindness caused by damage to occipital cortex  If it’s very small you may not even notice it o Person has difficulty in visualization of complex objects if damage is in areas 20/21 - Perceptual disorders/ visual agnosias o Visual agnosia – although you can see the object and pick it up, you don’t know what it
More Less

Related notes for PSYB65H3

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit