Introduction to Neuroanatomy Structure-function relationships Localization of function in the CNS Non-invasive brain imaging CAT: structure, low resolution MRI: structure, high resolution PET: function, low resolution fMRI: function, high resolution

Dual approach to learning neuroanatomy: Functional anatomy Neural structures that serve particular functions; e.g., pain path from skin to cortex for perception Regional anatomy Localization of structures in particular brain regions

Lecture objectives: First half of lecture: Overview of brain structures to “demystify” anatomical content in Neural Science lectures Survey brain structure-function relations to provide background for first labs First half of lecture: Quick review of basic CNS organization Use development to understand principles of structural organization of CNS Second half: Functional localization

Introduction to Neuroanatomy I: Regional Anatomy

CNS Organizational Principles 1) Tubular organization of central nervous system 2) Columnar/longitudinal organization of spinal and cranial nerve nuclei 3) Complex C-shaped organization of cerebral cortex and deep structures

Brief Overview of Mature CNS Neuroanatomy Tubular organization of central nervous system Columnar/longitudinal organization of spinal and cranial nerve nuclei Nuclei: locations of neuron cell bodies w/in the central nervous system Ganglia: locations of neuron cell bodies in the periphery Nerves: locations of axons in the periphery Tracts: locations of axons w/in the central nervous system

SC Dorsal surface Dorsal root Ventral root Gray matter White matter Spinal nerve Ventral surface NTA 1-4 SC

Brief Overview of Mature CNS Neuroanatomy 1) Tubular organization of central nervous system 2) Columnar/longitudinal organization of spinal and cranial nerve nuclei 3) Complex C-shaped organization of cerebral cortex and nuclei and structures located beneath cortex Lateral ventricle Basal ganglia Hippocampal formation & Fornix

Neural Induction •Portion of the dorsal ectoderm becomes committed to become the nervous system: Neural plate

Ectoderm Neural plate Neural groove Neural tube wall: neurons & glia of CNS Neural tube Neural tube cavity: ventricular system Neural crest: PNS neurons, etc White matter Gray matter NTA 3-1

Neural Tube Development Brain vesicles: Rostral Forebrain Midbrain Neural Tube Development Hindbrain Rostral neural tube forms the brain Caudal neural tube forms the spinal cord Spinal cord Caudal Cephalic flexure NTA 3-2 NT development

…by the 5 vesicle stage, all 7 major brain divisions are present Cerebral hemisphere Lateral ventricle Forebrain Midbrain Diencephalon Midbrain Hindbrain 3rd ventricle Pons & Cerebellum Cerebral aqueduct Medulla 4th ventricle Spinal cord Central canal Cephalic flexure …by the 5 vesicle stage, all 7 major brain divisions are present NTA 3-2 3 & 5 ves stages

MidsagBrain The cephalic flexure persists into maturity

NTA 1-13 axes

Spinal cord & brain stem have a similar developmental plan Segmentation Nuclear organization: columnar

SC dev NTA 3-7 Dorsal horn Alar plate Sulcus limitans Central canal Basal plate Ventral horn Dorsal horn Central canal Ventral horn NTA 3-7 SC dev

Dorsal horn Dorsal root Ventral root Ventral horn

Similarities between SC and brain stem development •Sulcus limitans separates sensory and motor nuclei •Nuclei have columnar shape Key differences 1) central canal enlargement  motor medial and sensory lateral 2) migration away from ventricle 3) >> sensory and motor

Alar plate and migrating neuroblasts Basal plate NTA 3-8 BS dev

Medulla development NTA 3-9 4th Vent Alar plate Sulcus limitans Striated/somite Autonomic. Striated/branchio. 4th Vent Alar plate Vestibular/auditory. Somatic sensory. Taste/viscerosensory Sulcus limitans Basal plate Inferior olivary nucleus Alar plate Basal plate NTA 3-9

Pons development NTA 3-10 4th Vent Alar plate Basal plate Striated/branchio. Alar plate Striated/somite Vestibular/auditory. Somatic sensory. Taste/viscerosensory Autonomic. Basal plate Sulcus limitans Pontine nuclei Alar plate Basal plate NTA 3-10

Midbrain development NTA 3-11 More like spinal Cerebral aq. Alar plate Somatic sensory. Autonomic. Striated/somite Basal plate Red nucleus Sub. nigra Sulcus limitans More like spinal Cord b/c fewer nuclear classes and cerebral aqueduct Basal plate NTA 3-11

Similarities between forebrain and hindbrain/spinal development •Tubular Key differences 1) CH more complex than BS/SC 2) Cortical gyri more complex anatomy than nuclei 3) Subcortical nuclei are C-shaped Confusing: structure in two places on image

Diencephalon Thalamus Hypothalamus Gateway to cortex Control of endocrine and bodily functions Circadian rhythms Etc.

NTA 3-14 CH dev

Cerebral Cortex Development Parietal Frontal Occipital Temporal

Forebrain Development & C-shaped Structures Cerebral cortex (NTA 3-15) Lateral ventricles (NTA 3-16) Striatum (NTA 3-16) Hippocampal formation and fornix (NTA 3-17)

Summary 7 Major components of the central nervous system & Ventricles All present from ~ 1st prenatal month Longitudinal organization of SC and BS nuclei Columns Anatomical and functional divisions C-shape organization of cerebral hemisphere structures and diencephalic Cerebral cortex Lateral ventricle Striatum Hippocampal formation and fornix