9.14 Homework Assignment 3 Worksheets

9.14 Worksheets

Courtesy of MIT Press. Used with permission. Schneider, G. E. Brain structure and its origins: In the Development and in Evolution of Behavior and the Mind. MIT Press, 2014. ISBN: 9780262026734.

1 1Preview:

a The

thickening

b embryonic

neural tube d

a. Endbrain (telencephalon) Forebrain

b. ‘Tweenbrain (diencephalon) (prosencephalon)

c. Midbrain (mesencephalon)

Courtesy of MIT Press. Used with permission. Schneider, G. E. Brain structure and its origins: In d. Hindbrain (rhombencephalon) the Development and in Evolution of Behavior and the Mind. MIT Press, 2014. ISBN: 9780262026734. e. Spinal cord

Fig 1.3 2 1Preview:

The a thickening

embryonic

b neural tube

a. Endbrain (telencephalon) Forebrain

b. ‘Tweenbrain (diencephalon)(prosencephalon)

e c. Midbrain (mesencephalon)

d. Hindbrain (rhombencephalon)

e. Spinal cord

Courtesy of MIT Press. Used with permission. Schneider, G. E. Brain structure and its origins: In the Development and in Evolution of Behavior and the Mind. MIT Press, 2014. ISBN: 9780262026734. 3 2 Synapses: varied structural arrangements: Consider the functional possibilities

1. Axo-somatic 2. Axo-dendritic (to dendritic shaft or dendritic spine)

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in Fig 1-13a evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

4 3 Synapses: varied structural arrangements: Consider the functional possibilities 6. Serial synapses Gating mechanisms… 7. Synapses without a postsynaptic site (not illustrated)

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

Fig 1-13c 5 4 Synapses: varied structural arrangements: Consider the functional possibilities Cell 3 3. Axo-axonal Presynaptic inhibition and facilitation 4. (Also: dendro-dendritic, Cell 2 dendro-axonal…) Cell 1 5. Reciprocal synapses

Courtesy of MIT Press.Used with permission. Fig 1-13b Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

6 5 Hamster Brain (similar to rat)

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

Adult Newborn 8 6 Pallium (medial, dorsal, lateral)

Study the names of these subdivisions. Learn which is which.

Schematic of pre- mammalian brain

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

10 7 Locate a local reflex channel. What function might such a pathway serve?

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

11 8 Mammalian brain diagrams

Schematic side view

Top view, embryonic brain (with spinothalamic tract)

Schematic side view

Top view, embryonic brain (with dorsal root axon)

Neural groove

Roof plate Neural tube Dorsal root Alar plate and ganglion neural crest Basal plate Floor plate Ganglia of sympathetic NS

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

15 9 Closure of neural tube with formation of peripheral ganglia: A______B______Neural X stage

Neural Y stage

C______D______Neural __Z______I and neural __ZZ__ E______F______Ganglia of __J__ G______nervous system H______Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in

evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 16 REVIEW Some neurodevelopment terms to be familiar with

ectoderm (vs. mesoderm and endoderm), ventricular layer, intermediate layer, marginal layer (= matrix layer, mantle layer, zonal layer) modes of migration, radial glia (radial astrocytes), ependyma, sulcus limitans, separating alar and basal plates, neural crest, dorsal and ventral roots and rootlets.

See Nauta & Feirtag, ch.10, and other texts

17 10

Internal Structure

Spinal Cord Segment C1

Segment C5

Internal structure of Segment C8

spinal cord: Segment T2 Note the lateral horn Segment T10

Segment L1

Segment L4

Segment S4

Image by MIT OpenCourseWare.

18 11

Termination of dorsal root fibers

Figures removed due to copyright restrictions. Please see course textbook or: Rexed, Bror. "A Cytoarchitectonic Atlas of the Spinal Coed in the Cat." Journal of Comparative Neurology 100, no. 2 (1954): 297-379. 19 12 Adult spinal cord, schematic frontal section: reflex and lemniscal channels

Dorsal columns Dorsal root fibers of various sizes

Spinoreticular Spinothalamic axons tract

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

20 12 Adult spinal cord, schematic frontal section: reflex and lemniscal channels

A Dorsal root fibers of various sizes

C B

D Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 21 13 The body surface represented at the hindbrain-spinal cord boundary

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

22 13 The rostral-most end of the spinal cord

D A B

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

23 14

Dorsal Median Sulcus Dorsal Funiculus

Lissauer's Zone

Substantia Gelatinosa Dorsal Lateral Funiculus Spinocerebellar Tract Clarke's Column 4 (nucleus dorsalis) 5 Lateral Horn 6

Central Canal 7 8 9

Ventral Funiculus Anterior White Commissure Ventral Median Fissure 1 millimeter

Image by MIT OpenCourseWare.

Fig 9-9 Clarke’s Column and dorsal spino-cerebellar tract 24 Adult spinal cord: 15 some descending and intrinsic axons

Proprio- spinal Corticospinal axons axons (after their decussation)

Rubrospinal axons

Reticulospinal, Vestibulospinal, Fastigiospinal (from Cb), Tectospinal

Corticospinal axons, uncrossed (variable in quantity) Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 25 Adult spinal cord: some descending and intrinsic axons 15 (fill in the blanks)

__B______A____ axons axons (after their decussation)

___C______axons

___D_____spinal, ___E_____spinal, Fastigiospinal

(from Cb), ___F_____spinal

______G______axons, uncrossed (variable in quantity)

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

26 16

Dorsal root ganglion

Sympathetic Descending nervous system reticulospinal Spinal nerve fibers axons, schematic xxxx Paravertebral To ganglion striated section of spinal xxxxxx muscles Prevertebral cord, thoracic level xx ganglion, e.g., celiac Smooth muscle: Glands; intestinal tract; blood vessels, erector pili (hairs); sweat glands. Cardiac muscle

Courtesy of MIT Press.Used with permission.. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

27 17

Vagus nerve

(10th cranial nerve)

Thoraco -lumbar

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

28 17 A. Which ganglion is this?

____X_____ nerve

(10th cranial nerve)

Thoraco -lumbar

C. Which ganglia

are these? Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

29 18

Interventricular Foramen

Choroid Plexus of Choroid Plexus of Third Ventricle Lateral Ventricle

Lateral Aperture Choroid Plexus of Fourth Ventricle

Median Aperture Central Canal

Ventricular system Image by MIT OpenCourseWare. Fig 9a-1 30 19 Meninges & Glia

Dura Astrocyte Arachnoid

Pia Pial-glial membrane

Ependymal cells lining the ventricle

Satellite oligodendrocytes (oligodendroglia) Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 31 19 Meninges & Glia (Identify structures indicated)

A B C

D E

F cells lining the ventricle

Satellite oligodendrocytes Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 32

20 Basic subdivisions, embryonic neural tube: a Where is the rhombus?

What is it?

c a. Spinal cord a. Sp inal corda. Endbrain b. Hindbrain d (telencephalon) b. Hi(rhombencephalon) ndbrain Forebrain

(rhombencephalonb. ‘Tweenbrain c. Midbrain (prosencephalon) (diencephalon) c. Midbrain(mesencephalon)

e (mesencephalon) c. Midbrain d. ‘Tweenbrain d. ‘T weenbrain (mesencephalon) (di encephalon) (di encephalon) d. Hindbrain (rhombencephalon Reminder: Students Courtesy of MIT Press.Used with permission. should understand and Schneider, G. E. Brain structure and its origins: in the development and in know this figure! evolution of b ehavior and the mind. MIT Press, 2014. ISBN:9780262026734. e. Spinal cord 33 21 Embyonic spinal cord & hindbrain compared: identify the indicated structures Embryonic spinal cord (in cross section) A_ plate C zone D zone E zone B plate

Sulcus F Embryonic hindbrain Secondary sensory cell groups in D zone of A plate A plate

Motor neuron cell groups

in D zone of B plate B plate

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 34 22 Notes on hindbrain origins: definitions • Segmentation above the segments of the spinal cord: The somitomeres & branchial arches in the mesoderm, and the rhombomeres of the CNS • See Nauta & Feirtag, ch.11, p. 170, on the “branchial motor column” -- in addition to the somatic and visceral motor columns. Sulcus limitans

Visceral motor column Alar plate Somatic motor column

Branchial motor column Basal plate Reticular formation Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

35 23 Columns in spinal cord

Columns in Hindbrain

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in Fig 10-9 evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 36 24 Adult caudal hindbrain of mammal principle cell columns and fiber tracts (schematic) Vestibular, auditory (VIII); th caudally—nuc. gracilis & 4 cuneatus (dorsal column ventricle nuclei)

Trigeminal (V, sensory from face)

Visceral sensory & motor (III in midbrain; VII, IX & X – parasympathetic Descending pathways: Branchial motor column: Rubrospinal nuc. ambiguus (IX, X – Vestibulospinal swallowing & vocalization) Tectospinal Corticospinal facial (VII), masticatory (V) = pyramidal Somatic motor column: tract Medial Spinothalamic III, IV (midbrain) & VI – eye Reticulospinal: lemniscus movements not shown tract XII – tongue movements Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. Fig 10-10 37 25 Evolution of Brain 4 Endbrain Expansion of midbrain with evolution of distance-receptor ‘tweenbrain senses: visual and auditory, Midbrain receptors with advantages over Anti-predator olfaction for speed and sensory behavior: acuity, for early warning and for turning away, anticipation of events. fleeing …………………………….. Motor side: 1) escape loco- Orienting: motion; 2) turning of head turning of head and eyes with modulation by & eyes toward motivational states, including those triggered by olfactory sense.

1. Dorsal columns 2. Nuclei of the dorsal columns 3. Medial lemniscus

4. Ventrobasal nucleus of thalamus (n. ventralis posterior) 5. Thalamocortical axon in the “internal capsule”nucleusnucleus 6. Corticofugal axons, including corticospinal components. Called “pyramidal tract” in hindbrain below pons. 7. Pons Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 39 27 Frontal section, middle of mammalian midbrain:

Superior Colliculus

Central Gray Area (periaqueductal gray)

Red Nucleus

Ventral Tegmental Area

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

40 27 Frontal section, middle of mammalian midbrain: Identify the indicated structures

F B C

E Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

41 Midbrain Locomotor Region (MLR): 28 Localization in cat by electrical stimulation studies Parasagittal section Frontal section Inferior Colliculus IC IC SC Midbrain Th Locomotor Midbrain Area Locomotor BC LL NR Area M P P Hypothalamic Locomotor Area Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

Th = thalamus BC = brachium conjunctivum M = mammillary body (axons from cb) NR = nuc. ruber (red nuc.) LL = lateral lemniscus III = oculomotor nerve (auditory) P = pons Fig 14-1 SC = superior colliculus 42 29 Midbrain neurons projecting to spinal cord and hindbrain for motor control Superior Colliculus (optic tectum)

Red nucleus (n. ruber) Tectospinal tract Rubrospinal tract

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

43 30 Midbrain areas that influence moods and motivational states:

Superior Colliculus Central gray area

(CGA) Brachium of Inferior Colliculus (auditory pathway, midbrain to thalamus)

Oculomotor nucleus Spinothalamic tract (some fibers terminate in SC)

Medial lemniscus Cerebral peduncle: contains Red corticospinal + corticopontine fibers, + cortex to hindbrain fibers nucleus (n. ruber) Tectospinal tract Rubrospinal tract

Ventral Tegmental Area (VTA) Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

Connections to the CGA, also called the Periaquaductal Gray (PAG), and to the VTA enabled control of or influence on moods/motivations crucial for survival: defensive, aggressive, sexual. Activation of these

areas is accompanied by feelings of pain (CGA) or pleasure (VTA). 44 31 Midbrain: Species comparisons Rodent

Note the great differences in the size of the cerebral peduncles at the base Human of the brain

(Sections are not Tree drawn to the same scale) Shrew (Squirrel is similar)

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in Fig 11-3 evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 45 32 Rostral end of the thickening neural tube in mammals: descriptive terms

LVA LG Forebrain MG Midbrain Thickened Ventricular Hindbrain Layer

LVA = Lateral ventricular angle region LG = Lateral Ganglionic Eminence

MG = Medial Ganglionic Eminence Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 46 32 Rostral end of the thickening neural tube in mammals: identify the abbreviations shown

LVA Forebrain

LG MG Midbrain

Thickened Hindbrain Ventricular Layer

LVA = X LG = Y

MG = Z Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. 47 33 a The lateral forebrain bundle: major origins and course

a Note the different names at different levels. All these names b occur frequently in discussions of brain structure and connections c

d a. Endbrain Cortical white matter to (telencephalon) Internal capsule

b. ‘Tweenbrain Cerebral peduncles e (diencephalon) (includes fibers to ‘tweenbrain, midbrain, pons, remainder of c. Midbrain hindbrain, spinal cord)

(mesencephalon) d. Hindbrain Pyramidal tract Courtesy of MIT Press.Used with permission. (rhombencephalon) Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734. e. Spinal cord Corticospinal tract

Fig 12-6 48

33 a Descending axons from somatosensory and motor cortical areas: a Note the different names at different levels. Fill in the blanks. b

c a. Endbrain Cortical white matter to (telencephalon) ____A______capsule d b. ‘Tweenbrain Cerebral ____B______(diencephalon) (includes fibers to ‘tweenbrain, midbrain, pons, remainder of c. Midbrain hindbrain, spinal cord)

e (mesencephalon) d. Hindbrain ______C______tract (rhombencephalon)

e. Spinal cord ______D______tract

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

Fig 12-6 49

‘Tween- Lateral forebrain brain bundle and Medial forebrain bundle Endbrain

limbic & Lateral forebrain bundle MFB

Medial forebrain bundle

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

50 34

‘Tween- A brain What bundle of axons are all these? and What group of axons are these? B Endbrain

C --Identify the What bundle of axons are these? axon groups indicated D What group (bundle) of axons?

Courtesy of MIT Press.Used with permission. Schneider, G. E. Brain structure and its origins: in the development and in evolution of behavior and the mind. MIT Press, 2014. ISBN:9780262026734.

51 Check your knowledge of brain structures: Neuroanatomy review • Subdivisions of CNS; definitions of cell types – Shapes of the neural tube at various levels • Sensory channels of conduction; dermatomes • Diaschisis: lesion-produced deafferentation causes a functional depression of neurons • Evolution of neocortex with major ascending and descending pathways to it and from it • Spinal cord structure; differences between levels • Propriospinal system • Autonomic N.S. and its components • Hindbrain organization; distortions of the basic plan • Cranial nerves: the 5th (trigeminal nerve) 52

Neuroanatomy review continued • Midbrain: tectum and tegmentum; species differences; outputs for three major types of movement • Diencephalon: two major and two additional subdivisions (functional/structural) • Telencephalon: the endbrain (cerebral hemispheres and basal forebrain); origins of two major pathways for descending axons (Both contain some ascending axons also.) • Some major axonal pathways in mammals: – Spinoreticular, trigeminoreticular tracts (mostly ipsilateral) – Spinothalamic tract; longest axons reach the ventrobasal nuc. of thalamus (VB = VPM and VPL) – Dorsal columns, connecting to the medial lemniscus pathway, which projects to the ventrobasal nuc. of thalamus – Corticospinal & corticopontine pathways (the former connect to all levels of CNS, the latter connecting to the pons, hence to cerebellum) 53 35

P1 Mesencephalon P2 Mes. MP DP P3 Diencephalon Telencephalon 1st P4 R1 Str. P5 R2 Rhombencephalon R3 P6 R4 OB DD OB R5 D D R6 Eye Stalk V R7 C R 2) Puelles & Rubenstein,’93 1) Embryonic brain with curved longitudinal axis

MP DP Neuromeric models of P3 P4 embryonic mammalian LP VP P5 Str. brain Pa P6 3) Revision of the model

Image by MIT OpenCourseWare. Fig 12-8 54 MIT OpenCourseWare http://ocw.mit.edu

9.14 Brain Structure and Its Origins Spring 2014

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