Neuropsych Ch 13 -- Occipital Lobes

parieto-occipitaq sulcus

superior boundary of occipital lobe

on medial and lateral surfaces

divides temporal from occipital lines

pre-occipital notch

inferior boundary of occipital lobe

divides temporal from occipital lobes

calcarine sulcus

on medial surface of occipital lobe

divides visual cortex into upper and lower halves

what is the primary VC

BA 17

what are the secondary VC areas?

BA 18 and 19

primary visual cortex aka…

V1, striate, calcarine

primary visual cortex

highly layered

perception of color and of form and motion

what is the visual association area above calcarine

cuneus

what are the visual association areas below calcarine

fusiform and lingual gyri

extend into temporal lobe

what is the outside of V1 referred to as

extra-striate visual cortex (V2, V3, V4, V5)

thin stripes (V2)

color perception

thick stripes (V2)

form perception

pale stripes (V2)

motion perception

blobs (V1)

color perception

interblobs (V1)

form and motion perception

8 connections to the visual cortex

1. thalamus

2. hypothalamus

3. lateral geniculate nucleus

4. optic radiation

5. cerebral peduncle

6. tract

7. chiasm

8. optic nerve

dorsal stream

motion info flows from V1 to parietal lobe

ventral stream(s)

object info flows from V1 to temporal lobe

where do the dorsal and ventral streams mix and flow into?

superior temporal sulcus pathway from V1

what is the ventral stream particularly tuned to?

identifying body parts, faces, and bodies in motion

what is the dorsal stream particularly tuned to?

movement (of eyes, grasping objects, etc)

7 ventral stream regions

1. LO — lateral occipital

2. FFA — fusiform face area

3. EBA — extrastriate body area

4. FBA — fusiform body area

5. STS — superior temporal sulcus

6. STSp — superior temporal sulcus (posterior)

   1. PPA — parahippocampal place area

LO — lateral occipital (ventral)

object analysis

FFA — fusiform face area (ventral)

face analysis

EBA — extrastriate body area (ventral)

body analysis

FBA — fusiform body area (ventral)

body analysis

STS — superior temporal sulcus (ventral)

analysis of biological motion

STSp — superior temporal sulcus, posterior (ventral)

moving body analysis

PPA — parahippocampal place area (ventral)

analysis of landmarks

5 dorsal stream regions

1. LIP — lateral intraparietal sulcus

2. AIP — anterior intraparietal sulcus

3. VIP — ventral intraparietal sulcus

4. PRR — parietal reach region

5. cIPS — intraparietal sulcus

LIP — lateral intraparietal sulcus (dorsal)

voluntary eye movement

AIP — anterior intraparietal sulcus (dorsal)

object-direction grasping

VIP — ventral intraparietal sulcus (dorsal)

visuomotor guidance

PRR — parietal reach region (dorsal)

visually guided reach

cIPS — intraparietal sulcus (dorsal)

object-directed action

five categories of vision

1. vision for action

2. action for vision

3. visual recognition

4. visual space

5. visual attention

vision for action

visual processing required to direct specific movements (dorsal stream)

action for vision

eye movements for searching

visual recognition

for things we have seen before or generalize to type of object

visual space

object location

1. relative to the person = egocentric space

   1. relative to other objects = allocentric space

visual attention

selecting what to attend to

Milner & Goodale Model — patients with specific lesions help show what?

dissociation of ventral and dorsal streams

Milner & Goodale Model — where did DF have damage?

bilateral lateral occipital

Milner & Goodale Model — though blind, what could DF do?

shape her hand in response to reaching for something she couldn’t see (dorsal stream was in tact)

what can patients with dorsal stream damage do?

see the object but can’t reach out and properly grasp for it

dorsal stream must be for what?

visual control of action

what activates ventral stream

faces

what activates dorsal stream

spatial stimuli

what activates different visual areas (not dorsal or ventral)

color, motion, and shape of objects

where did patient BK have damage

ischemic damage to V1

BK could…

couldn’t see objects location but could preceive its content (blindsight)

where did DB have damage

surgical removal of angioma (including part of V1)

DB could…

no knowledge of seeing an object but can report accurately on its properties

DF damage

carbon monoxide poisoning resulted in bilateral occipital damage

DF had

visual agnosia

cannot make a whole form its parts

object ataxia

can recognize an object but can’t grab it

prosopagnosia

face blindness

can identify people if they have a detail that isn’t face specific (birth mark, facial hair, hair style, etc.)

can tell human from primate and other animals

what is the problem causing prosopagnosia

problem with gestalt identification of the whole face

bilateral occipital damage needed to produce prosopagnosia