Lab: Cerebral Hemispheres & Cortex

What does the telencephalon become?

cerebral hemispheres

What does the diencephalon become?

thalamus, hypothalamus, epithalamus

What does the mesencephalon become?

mesencephalon

What does the metencephalon become?

pons and cerebellum

What does the myelencephalon become?

medulla

stellate cells

small star-shaped cortical interneurons with numerous dendrites

receive impulses from other areas

pyramidal cells

found in the cerebral cortex, have a triangular cell body and a single, long dendrite among many smaller dendrites

has one apical and 2 basal dendrites and a large axon responsible for sending impulses

Where does white matter lie in relation to gray matter in the brain?

white matter lies internal to grey matter

association fibers

Fibers that connect areas of the cerebral cortex within the SAME hemisphere

commissural fibers

connect one part of cortex to another part of cortex in the OTHER hemisphere

projection fibers

connect the cortex to the thalamus, brainstem, and spinal cord

Corticopedal projection fibers

fibers that come into the cortex from outside of the cortex

Corticofugal projection fibers

fibers that leave from the cortex and go outside of the cortex

molecular layer of cerebral cortex

most superficial (layer 1)

receives dendrites from all internal layers of the cortex and acts as a coordinating center where layers communicate action

external granular layer of cerebral cortex

layer 2

contains stellate cells

receives input from other cortical regions

external pyramidal layer of cerebral cortex

layer 3

contains pyramidal cells

sends output to other cortical regions

What type of fibers are involved in the external granular and pyramidal layers of the cerebral cortex?

association and commissural fibers

internal granular layer of cerebral cortex

layer 4

stellate cells that receive input from the thalamus and other brainstem areas

very thick in sensory areas of the cortex

striate cortex

another name for the primary visual cortex

the internal granular layer of this area is so thick that you can see a line through this layer even if brain is unstained

Internal pyramidal layer of cerebral cortex

layer 5

pyramidal cells that send axons to brainstem and spinal cord

very thick in motor areas of cortex

multiform layer

layer 6

sends axons back to thalamus

works to modulate what information thalamus sends to cortex

modulates what you pay attention to

works as brains equalizer

Brodmann's areas

Histologic regions of the cerebral cortex mapped by Brodmann. Often used to designate functional areas.

area 4

primary motor cortex (precentral gyrus)

area 6

premotor cortex

Layer 3 of area six synapses with what layer of area four?

Layer 2

area 8

frontal eye field

responsible for contralateral saccadic eye movements

area 44 and 45

Broca's area

responsible for expressive language

Areas 3, 1, 2

primary somatosensory cortex

Which layer of areas 3,2,1 is the thickest?

layer 4

Area 22 and occasionally 39 and 40

Wernicke's area

responsible for receptive language

expressive aphasia

inability to produce language despite being able to understand language

What causes expressive aphasia?

damage to Broca's area (area 44/45 on inferior frontal lobe)

What causes receptive aphasia?

damage to Wernicke's area (posterior 22, some 39 and 40)

receptive aphasia

The inability to understand language despite being able to hear it and produce it

area 41

primary auditory cortex

receives input from MGN and sends to area 42

Which layers are the thickest in area 41?

layer 4 because receiving from the thalamus

layer 2 because projecting to area 42

area 42

auditory association area

processes information here and send to area 22

Which layers are the thickest in area 42?

layer 2

layer 3

area 22

auditory association area

posterior part of Wernicke's

area 17

primary vision cortex

aka V1

processes as very general lines of various orientations and circles of color

Where does area 17 lies in relationship to the calcarine?

lies half above and half below calcarine processing input from the upper and lower retina respectively

Where does area 17 receive information from?

LGN

area 18

association visual cortex

aka V2

continues to process visual input

Where does area 18 receive information from?

receives input from area 17

Where does area 18 lie?

lies below and above area 17 on the occipital lobe

area 19

association vision cortex

aka V3

furthers visual processing

dorsal stream

visual information pathway from the occipital lobe to the parietal lobe

concerned with WHERE something is, orientation and guiding motor function

ventral stream

visual information pathway from the occipital lobe to the temporal lobe

concerned with WHAT something is

What can occur is the ventral stream is damaged?

agnosias

optic ataxia

can visually identify the orientation of an object, but motor action to the object is inaccurate

due to damage of the dorsal stream

visual neglect

failure to respond to visual stimulation on the side of the visual field that is opposite a brain lesion to the dorsal stream

visual-visual disconnection

caused by lesions of ventral stream

leads to agnosia

agnosias

disruptions in the ability to identify familiar objects

visual-verbal disconnections

due to lesions of the ventral stream

leads to anomias and alexias

anomia

Loss of the ability to name objects or retrieve names of people

alexia

inability to understand written words, difficulty reading

caused by a defect in the occipitotemporal corticofugal bundle (defect in LEFT inferior temporal gyrus)

visual-limbic disconnection

?

achromatopsia

inability to distinguish colors

prosopagnosia

inability to recognize faces

Simultagnosia

an inability to recognize and identify multiple objects in a visual scene; including distinct objects within a spatial layout and distinguishing between "local" objects and "global" objects

ex: seeing a forrest vs a tree

object agnosia

inability to recognize objects

pure alexia

an inability to read

object form topology hypothesis

Object form is represented in ventral temporal cortex continuously in a distributed and overlapping arrangement

locations, faces, written words, objects

T/F: the cortical networks for reading are parallel, simultaneous, and bidirectional

true

What does the rhombencephalon become?

pons, medulla, cerebellum

What does the prosencephalon become?

forebrain (telencephalon and diencephalon)

cerebral hemispheres and thalamus

What are the three subgyri that make up the inferior frontal gyrus?

opercular

trianglular

orbital gyrus

Which gyrus makes a C-shape cap around lateral fissure?

supra marginal gyrus

uncus

on medial surface of temporal lobe (olfactory area)

What lies above the calcarine sulcus?

cuneus

What lies below the calcarine sulcus?

lingual gyrus

What gyri of the temporal lobe are seen from the lateral view?

superior temporal gyrus

middle temporal gyrus

inferior temporal gyrus

What gyri of the temporal lobe are seem from an inferior view?

inferior temporal gyrus

lateral occipitotemporal gyrus

medial occipitotemporal gyrus

parahipocampal gyrus

uncus

What forms the floor of the inferior horn of the lateral ventricle?

hippocampus

What forms the roof of the anterior horn and body of the lateral ventricle?

corpus callosum

What forms the lateral wall of the anterior horn of the lateral ventricle?

head of caudate

What forms the medial wall of the anterior horns and body of the lateral ventricle?

septum pellucidum

Which part of the cerebral hemispheres is responsible for written words

LEFT inferior temporal gyrus

What forms the floor of the anterior horn of the lateral ventricle?

fornix