The visual system begins with light entering the eyes and being registered by the retina. Optical information is sent via the thalamus to the primary visual cortex (V1) where initial processing begins. Signals then travel along two pathways - the ventral "what" pathway to the temporal lobe and dorsal "where" pathway to the parietal lobe. Damage to different parts of the visual system can cause blindness, visual agnosia, or visual neglect depending on the location of the lesion. Understanding the neurobiology of perception, memory, emotion and other functions is important for research in artificial intelligence.

1. The Visual System

2. Part I: Identify the parts of the nervous
system that are active in the Visual System

3. The Visual System: Overview
Eyes register optical information
Eyes send this information via the Thalamus to Primary Cortex V1 (Occipital Cortex)
The brain begins to process the signals into vision
The signals are then sent on to other brain regions via
 Two pathways from V1
 “What” pathway to Temporal Visual Cortex called Ventral Pathway
 “Where” pathway to Parietal Cortex called Dorsal Pathway
Convergence on Frontal Cortex

4. Human Visual Brain: positions of V1 – V5
areas
1. V1 and V2 are involved in basic
visual features
2. V3 and MT/V5 are involved in
1. Motion detection
2. Spatial localization
3. Hand and eye movements
3. V3/Vp is involved in shape
perception
4. V4 is involved in color vision

5. Anatomy of Pathway to Visual Cortex

6. Human Brain: From Eyes to Visual Cortex
The last layer of cells in the retina is
known as the Retinal Ganglion cells
or just Ganglion cells.
They come in two varieties:
1. Parvocellular (P) cells carry
information about colour
2. Magnocellular (M) cells carry
information about movements
and flicker

7. From Eye to Striate Cortex
The outputs of different ganglion
cells in each eye project
1. to specific layers of the LGNs
(C = contralateral, I = ipsilateral)
2. Then to striate cortex (V1)
3. Then to discrete stripes of V2
4. Then to areas V3 – V5

8. The Parietal Cortex: Pathway Inputs
The Parietal Cortex receives input
from two pathways:
1. The Superior Colliculus (SC)
route
1. Not all the Ganglion cell axons lead
to the LGN, some head off to the SC
and Pulvinar route
2. LGN/V1 route and the Dorsal
Pathway

9. Mapping of the Retinal image in the
Striate Cortex

10. Mapping of the Retinal image in the
Striate Cortex
NORMAL IMAGE
INVERTED IMAGE
(JUST FOR VISUALIZATION)

11. Part II: Describe the functions of the nervous
system that are apparent and/or impaired in
the Visual System

12. Blindness
Both eye and brain are required for
functional vision
Two kinds of blindness:
Normal blindness (eye dysfunction)
Cortical blindness (brain dysfunction)

13. “What”/”Where” Pathway

14. What/Where Pathways
Evidence from Neuropsychology
Visual agnosia:
Inability to identify objects
and/or people
Caused by damage to inferior
(lower) temporal lobe
Disruption of the “what”
pathway
Visual neglect:
Inability to see objects in the
left visual field
Caused by damage to right
parietal lobe
Disruption of the “where”
pathway

15. Damage to the Parietal lobe
(the Dorsal Pathway)
Damage to the Parietal lobe leaves
only the ventral route intact and
would be responsible for the optic
ataxia (Balint-Holmes syndrome)

16. Damage to the Inferotemporal lobe
(The Ventral Pathway)
Damage to the Inferotemporal lobe
leaves only the Dorsal route intact
and maybe responsible for Visual
form of Agnosia

17. Primary Visual Cortex V1 Damage
Damage to the Primary Visual
Cortex V1, so information cannot
reach the Ventral Pathway at all,
but the Dorsal Pathway can be
stimulated via information through
the Superior Colliculus and Pulvinar

18. Part III: Ways in which Neurobiology has
allowed me to analyze the events and
phenomena around me

19. Topics that I was taken from this class that I
will be using in my research on Artificial
Intelligence
Understanding the components of all perceptual
pathways: Transduction, Transmission and
Modulation are the keys for the comprehension of
our Perception of the world
Optical illusions show that What we see, it is not
the reality of the world. What we see , it is only an
interpretation of the reality, based on our past
experiences which are saved in our memories,
The different type of brain’s memories are the
elements that provide us with our identity of who
we are
The Neurobiology of Consciousness is the most
important question in our lives. We learned the
basic concepts of Neurobiology in this class which
it is the first step in getting into the world of
consciousness
It has been important that I understood the
following concepts of anatomy:
 Anatomy of the Senses
 Anatomy of Emotion
 Anatomy of Attention
 Anatomy of Memory
 Anatomy of Language
 Anatomy of Object Recognition
 Anatomy of Consciousness

20. Anatomy
ANATOMY OF THE ATTENTION ANATOMY OF THE SENSES

21. Anatomy
ANATOMY OF MEMORY ANATOMY OF EMOTION

22. Anatomy
ANATOMY OF LANGUAGE ANATOMY OF CONSCIOUSNESS

23. Anatomy of object Recognition

24. References
1. Principles of Neural Science, 5th ed, E. Kandel, 2013
2. Neuroscience, 5th ed, D. Purves, 2013
3. Neuroanatomy, 2nd ed, H. Blumenfeld, 2010
4. Vision and Brain, J. Stone, 2012
5. The Brain Book, R. Carter, 2009
6. Understanding Vision, L. Zhaoping, 2014
7. Vision, D. Marr, 1982
8. Neurophysiology, R. Carpenter and B. Reddi, 5th ed, 2012
9. Medical Neurobiology, P. Mason, 2011
10. Fundamental Neuroscience, 4th ed, D.Haines, 2013
11. Mapping the Mind, 2nd ed, R. Carter, 2010
12. Visual Perception, 3rd, ed, N. Wade, M. Swanston, 2013