Telencephalon

What did theory did neuroscientist Paul Maclean develop that divides the brain into three parts based on their functions?

Triune brain theory

What are the three parts of the brain avvording to their functions

Reptillian, Limbic, Neocortex

Reptilian brain

• Instinctual or dinosaur brain

• Seen in brainstem to the cerebellum

• Most basic functions needed for survival

Limbic Brain

• Emotional or feeling brain

• Hippocampal area 

Neocortex

• Rational or thinking brain

• More superficial, largest part of brain that differentiates humans from animals 

Cerebral Cortex develops from what

Telencephalon

• secondary brain vesicle 

Cerebral cortex is a layer of _____ capping the ____ core of the cerebral hemispheres

gray matter, white matter

What are the Supratentorial structures

Diencephalon, Telencephalon

Diencephalon is the ____”_____ tube”

older, inner tube

Components of diencephalon

Limbic lobe, amygdala, basal forebrain, olfactory structures, hypothalamus, and thalamic nuclei 

Functions of diencephalon

• Internal regulation

• Consciousness

• Emotion

• Motivation

Telencephalon is the ____ “___ tube”

newer, outer

Telencephalon is composed of

neocortex, basal ganglia, thalamic nuclei connections

Function of telencephalon

• Higher cognition

• Language

• Motor programming

• Sensory processing (visual, somatosensory, auditory)

Formation of the cortex begins with the appearance of ____ at around how many days of gestation

neural plate, 18 days of gestation

Differentiation of cerebral vesicles occur at what day

33 days or 5 weeks

Ventricular zone

proliferation of precursor cells that will eventually populate the cerebral cortex

When do 6 layers become distinguished

6th to 8th month

When is myelination fully completed?

2 years old or 24 months

4 stages of development

1. Determination

2. Proliferation

3. Migration 

4. Maturation

What are the three types of cortex

• Isocortex

• Allocortex 

• Mesocortex

How many layers of cells does isocortex have?

Classic 6 layers of cells (homogenetic)

What is isocortex also called?

Neocortex (homogenetic)

What does the isocortex deal with

motor and sensory controls

Isocortex comprises how much % of cerebral cortex? and what does it overshadow

90%, overshadows allocortex

How many layers of cells does allocortex have

3 layers of cells (heterogenetic)

Allocortex is more dominant in what animals

lower animals (rats)

Allocortex is ___ and receives what influences?

Primitive, olfactory influences

What are the components of allocortex

archicortex, palleocortex

Archicortex

Hippocampal formation (basic emotional processing)

Palleocortex

Entorhinal ; primary olfactory, rostral insular cortex, piriform cortex, and primary olfactory cortex

Two components of mesocortex

periarchicortex, periallocortex

Where is mesocortex located

between isocortex and palleocortex

How many layers of cells does mesocortex have

4-5 layers of cells

Mesocortex is found in much of _______ (above _______), in _____, ______,_____ cortices 

cingulate gyrus, above corpus callosum

entorhinal, parahippocampal, and orbital cortices 

Principal or Projection neurons provide information to what areas

more distant areas

Principal or Projection neurons provide what outputs

corticocortical and corticosubcortical

outputs

What are the two types of principal neurons

• Pyramidal neurons

• Fusiform, spindle neurons 

What layers are pyramidal neurons found in?

All layers except layer 1

Largest pyramidal cell and what layer is it found in?

BETZ cell (Layer 5)

What are fusiform, spindle neurons

small neurons with elongated perikarya

where are fusiform, spindle neurons found?

Deepest cortical laminae, Layer 5 or 6

Interneurons are concerned with what

local information processing, within the same neuronal population

Three types of interneurons

Stellate or Granule, Horizontal cells of Cajal, Cells of Martinotti

Only type of excitatory interneurons in cortex

Stellate or granule

Where are stellate neurons most numerous

Lamina 4

Stellate or Granule neurons are

small star shaped neurons with short, extensively branches, spiny dendrites and short axons

Horizontal cells of Cajal

small fusiform neurons with long axes directed parallel to cortical surface

Where are horizontal cells of cajal found

lamina 1

Cells of Martinotti

Multipolar with short branching dendrites and axons

Where are cells of martinotti found

deeper cortical laminae

what are the 6 layers of the cerebral cortex

Layer 1 (Molecular)

Layer 2 (External Granular)

Layer 3 (External Pyramidal)

Layer 4 (Internal Granular)

Layer 5 (Internal Pyramidal)

Layer 6 (Multiform Layer)

Layer 1 (Molecular) is primarily a what

synaptic area, where information is relayed

Layer 1 consists primarily of

scattered sparse interneurons

Layer 1

Few, small cells and numerous dendrites and axons; interwoven; parallel to surface 

Layer 2 (External granule)

dense packing of small and medium sized neuron and interneurons

Layer 3 (External pyramidal)

consists of pyramidal neurons that increase in size

Layer 4 (Internal Granular)

Consists primarily of densely packed small stellate cells with processes that terminate within the same layer and pyramidal cells

Layer 4 is ____ center and especially well-developed in what areas

chief receptive area (incoming impulses)

well developed in primary sensory cortical areas 

Layer 5 (Internal pyramidal)

• Contains large and medium-sized pyramidal cells, stellate cells, and cells of Martinotti

• Includes cells of Betz

Layer 5 is biggest in ____ gyrus and is ____center

precentral gyrus

chief discharge center for efferent impulses 

Layer 6 (Multiform layer)

• Consists of cells of varying shapes and sizes, including fusiform cells and the cells of Martinotti, which are prominent in this area

• Long axis perpendicular to surface; contribute to efferents 

Central sulcus of Rolando

Seperates frontal from parietal lobe

Primary motor from primary somatosensory

Lateral fissue (sylvian)

seperates frontal and parietal from temporal

landmark for supramarginal gyrus for wernickes area

parieto-occipital sulcus

separates parietal from occipital

preoccipital notch

separates temporal from occipital

What are the Sulci and fissures of the frontal lobe

1. Central sulcus of rolando

2. Precentral sulcus

3. Superior and Inferior Frontal sulcus

4. Lateral fissure (ant. ramus)

5. Lateral fissure (ascending ramus)

6. Frontolateral sulcus 

• Within Broca’s area

7. Olfactory sulcus

8. Orbital sulcus 

Gyri of Frontal Lobe

1. Precentral gyrus 

2. Superior frontal gyrus

3. Middle frontal gyrus 

4. Inferior frontal gyrus

• Into 3 parts

  • Pars Triangularis (Brocas)

    • triangular-shaped gyrus

      below the inferior frontal

      sulcus

  • Pars Opercularis (Brocas)

    • closely related to temporal lobe

  • Pars Orbitalis (semantic processing

5. Gyrus rectus

6. Orbital gyri (intellectual and emotional expression)

Precentral/paracentral is the primary ____ and BA __

somatomotor, BA 4

Frontal eye field extends between BA’s _ & _ ; primarily BA 

BA 6 & 8, primarily 6

CN’s 3,4,6

Frontal eye field is for 

voluntary eye movement 

Lesions in frontal eye field and manifestations

Irritative

• away from lesion

Destructive 

• towards the lesion 

Language in frontal 

• Inferior frontal gyrus left is what area and is composed of what

Broca’s area (pars opercularis, triangularis)

Pars opercularis (BA 44)

Broca’s aphasia

Can understand, cant speak

Expressive aphasia 

Sulci of parietal lobe

1. Postcentral sulcus

2. Intraparietal sulcus 

3. Marginal sulcus of ramus 

Gyri of parietal lobe

1. Postcentral gyrus

2. Inferior parietal gyrus

3. Paracentral lobule

4. Precuneus

Postcentral gyrus

• Extends to medial surface (BA 3,1,2)

• Continuous with posterior paracentral gyrus

  • Rostral border: imaginary line 

  • Caudal border: marginal sulcus

Post central and post paracentral gyrus

primary somatosensory cortex

[Inferior parietal gyrus]

Angular Gyrus

BA 39, Caudal end, semantic processing

[Inferior parietal gyrus]

Supramarginal gyrus 

BA40, phonological processing (spoken and written language) and emotional response 

Wernickes area

BA 39 & 40'

• Can speak, cant understand 

Precuneus

Superior parietal gyrus (Medial surface; precuneus)

Visuomotor, cognitive, sensory, higher order, working memory, and attention 

Temporal lobe sulcus and gyrus

1. Superior temporal sulcus

2. Superior temporal gyrus

• Transverse gyrus (Heschl)

  • BA 41, Primary auditory 

3. Middle temporal sulcus

4. Collateral sulcus 

Occipital lobe Lesions

One side → homonymous hemianopsia

Occipital lobe sulcus

1. Parieto-occipital sulcus 

• Separates cuneus from precuneus 

2. Occipital sulcus

3. Calcarine 

4. Primary visual cortex

• BA 17 

Insular lobe

Gyri longi (1 set) ; Gyri Brevis (1 set)

Continuous with frontal, parietal, and temporal

Insular lobe function

unclear; receives nociceptive and visceromotor inputs

Function of Limbic lobe

linked to circuits that influence complex functions such as memory, learning, and behavior

Parts of Limbic lobe

• Subcallosal

• Cingulate

• Isthmus

• Parahippocampus

• Uncus

Hippocampal formation function

Memory: new learning ability

Amygdaloid complex function

major processing center for emotions

Primary motor area: ___, what gyrus and BA

frontal, precentral gyrus BA 4

Primary somatosensory: ____, what gyrus and BA

parietal, postcentral gyrus BA 3,1,2

Primary visual: __ is bounded by what and BA

Occipital, calcarine sulcus BA 17

Primary auditory:___ is what gyrus and BA

temporal, transverse gyrus of herschl BA 41,42

Thalamic nuclei

Helps move information upwards toward primary sensory cortices 

Thalamus

Major relay station of any sensory information towards cortex (except olfaction)

Somatosensory cortex receives somatotopic input from ____ and ____ of thalamus

ventroposterolateral and ventroposteromedial of the thalamus

Somatosensory cortex consists of ___ cortex (layer ___)

granular crotex (layer 4)

Sensory homunculus

visual representation of the body based on the degree of sensory innervations