Neuroscience Quiz on Brain and Nervous System

Introduction to Neuroscience

• The course aims to examine the structure and function of the nervous system from a preclinical perspective.
• The nervous system is comprised of many subsystems organized hierarchically, performing functions from simple to complex.
• Key textbooks include 4th edition "Essential Neuroscience" and 3rd edition "Neuroanatomy Through Clinical Cases".

Required Textbooks

• "Essential Neuroscience" (4th edition) is a required textbook.
• "Neuroanatomy Through Clinical Cases" (3rd edition) is another required textbook.
• "Nolte's The Human Brain in Photographs and Diagrams" (5th edition) is recommended as an atlas.
• Other recommended alternative atlases include "Basic Clinical Neuroscience", and "Netter's Atlas of Neuroscience".
• OMS2 will continue using the Blumenfeld textbook.

Objectives

• Apply systems biology principles to the study of the nervous system.
• Define the emergent properties of the central nervous system.
• Sketch the basic organization of the CNS and PNS.
• Interpret block diagrams of the nervous system.
• Identify important facts and organizational features about the brain.
• Discuss the nervous system at cellular and systems levels.
• Use neuroscientific and neuroanatomical terminology to discuss function.

Neurological Organization

• The nervous system is a beautiful, elegant, and complex system in the body.
• It is interconnected and performs processing that is simultaneously local and distributed, serial and parallel, hierarchical and global.
• Structures can be described on multiple levels, including macroscopic brain divisions, connecting pathways, individual brain cells, and signaling molecules.
• Neural structures are anatomically described using terms like dorsal, ventral, anterior, posterior, superior, inferior, rostral and caudal.

Nervous System Components

• The central nervous system (CNS) consists of the brain and spinal cord located inside the dura sac.
• The peripheral nervous system (PNS) comprises nerves (cranial and spinal), ganglia (sensory and autonomic), and the enteric nervous system.

Nervous System Origin

• Subset of cells in the ectoderm form the nervous system.
• The neural tube forms the brain and a caudal continuation in the spinal cord.
• The ventricular system is formed by the fluid-filled cavities in the developing neural tube.
• Neural crest cells form the peripheral nervous system.

Neuroanatomical Localization

• Anatomical directions are determined by the central axis of the body.
• The relationship of rostral and caudal is modified in different areas of the brain such as rostral to caudal referring to the nose and tail, respectively, in reptiles.

Neuroanatomical Planes

• Horizontal planes are regularly used in gross anatomical study and medical imaging.
• Sagittal and coronal planes are frequently used in gross anatomical and histological, and medical imaging studies.
• These planes are essential for visualizing and understanding different structures.

Clinical Imaging

• Clinical imaging of the head and brain provide vital structural information of human brain.
• Specific structures and anatomical landmarks can be identified through clinical imaging techniques.

The Human Brain

• The human brain represents 2% of the body mass.
• The brain consumes 20% of the body oxygen, 14% of total blood flow, and 25% of total body glucose.
• Blood flow through the brain is primarily regulated by the autonomic nervous system.

Cellular Composition

• The nervous system is composed of neurons and neuroglia (glia).
• Neurons are the computational units of the nervous system (80/100 billion in the human nervous system).
• Glial cells support neurons in different ways.

Neuron & Synapse Movement

• Materials moving away from the soma (cell body) towards the axon terminal are called anterograde.
• Materials moving towards the soma (cell body) from the axon terminal are called retrograde.
• Neurons communicate via synapses.

The CNS Organization

• Gray matter features high concentrations of nerve cell bodies.
• White matter contains bundles of axons (tracts) in the CNS, often organized as myelinated axons.
• The neural tube's differentiation determines adult derivative size, shape, and location.

Peripheral Nervous System

• Ganglia are aggregates of nerve cell bodies.
• Nerves are collections of axons.
• Ganglia and nerves are located outside the dura sac.
• Ganglia are either sensory (dorsal root ganglia), cranial nerves, or autonomic (visceral).

Pathways

• Pathways are series of neurons responsible for specific types of information.
• Attributes like the type of carried information, length of pathway, and chemical coding may vary.

Functional Systems

• These are distinct pathways based on functions.
• Examples include the anterolateral system, dorsal column-medial lemniscus system, and corticospinal system.
• Damage to these long tracts can cause repeatable lesion signs and patterns.

Reflexes

• Reflexes are involuntary responses triggered by stimuli
• Key examples include the myotatic reflex (also called deep tendon reflex)
• Clinical terms for reflexes range from areflexia to hyperreflexia.

Drawing of Neurons and Synapses

• Draw and interpret schematic representations of pathways within the central nervous system.

Topographical Division of Nervous System

• The nervous system can be topographically divided into central and peripheral components.
• Functionally, it is divided into sensory, motor, and integrative components.
• The somatic and visceral nervous systems are based on the targets for motor innervation.

Sections of the Spinal Cord

• The spinal cord at a typical thoracic level serves as the simplest model for nervous system organization.
• Parts of the spinal cord include the dorsal (posterior) and ventral (anterior) horns.

Spinal Cord and PNS

• Spinal cord links the peripheral nervous system (PNS) to the brain.
• Spinal nerve roots are connected to its spinal segments.
• The spinal cord also organizes spinal reflexes and communicates with various levels of the spinal cord itself through ascending and descending tracts.

Brain Stem and its Sections

• The brainstem includes the medulla oblongata, pons, and midbrain.
• It plays roles in cranial nerve nuclei, cardiorespiratory center functions, and links the cortex to the cerebellum.
• These areas are critically important for integrated functions.

Cerebellum

• The cerebellum is located below the tentorium cerebelli and topographically positioned in the brainstem
• but considered as a separate unit.
• It receives highly processed sensory input, modulates motor output, and anatomically has a foliate cerebral cortex.

Forebrain

• The forebrain includes structures like the diencephalon (thalamus and hypothalamus) and cerebral hemispheres (composed of cerebral cortex and subcortical gray matter).
• White matter tracts connect regions in the forebrain and other nervous system structures.

Cranial Nerves

• Cranial nerves are numbered I-XII, with olfactory (I) and optic (II) functioning as part of the central nervous system.
• Cranial nerves from III to XII are attached to the brainstem and act as peripheral nerves.
• Some cranial nerves incorporate autonomic components.

Regional and Systemic Studies

• The nervous system can be studied using a hierarchical approach.
• Systems and pathways within the nervous system can traverse several regions.

Somatosensory System

• The somatosensory systems (carrying touch/sensory information) use distinct pathways for various modalities, such as vibration. - Lesions above the decussation cause contralateral (opposite side of the body) sensory deficits.

Somatosensory Information Processing

• The thalamus acts as a processing center, relaying somatosensory information from the body to the primary somatosensory cortex of the brain (postcentral gyrus). - The thalamus contains the ventral posterolateral (VPL) nucleus that receives and relays somatosensory information.

Motor Systems

• The corticospinal tract is a key pathway for voluntary limb movements (also known as the pyramidal tract).
• Lesions of the corticospinal tract cause contralateral weakness.
• Other motor pathways include those originating in the brainstem, connecting with spinal cord.

Motor Output Regulation

• Basal ganglia and the cerebellum regulate motor output.
• Using loops of neurocircuitry, these structures primarily influence upper motor neurons.
• Basal ganglia are crucial for initiation and program selection of movements.
• The cerebellum is involved in sensorimotor integration and coordination.

Key Anatomical/Neuroscientific Terms

• A list of terms important in the study of the nervous system's anatomy and neurological function, including ipsilateral/contralateral, commissure/decussation/projection and their functions, along with nerve fiber composition in white and gray matter.

Functional Systems Approach

• Functional systems are studied by identifying motor and sensory pathways and understanding how they typically organize through regions.