Nervous System Quiz

Anatomy and Research Methods Part 1

• The nervous system is divided into two major parts: central nervous system (CNS) and peripheral nervous system (PNS).
• The CNS includes the brain and spinal cord.
• The PNS connects the brain and spinal cord to the rest of the body.
• The PNS is further divided into somatic and autonomic nervous systems.
• The somatic nervous system is voluntary.
• The autonomic nervous system is involuntary.
• The autonomic nervous system is divided into sympathetic and parasympathetic nervous systems.
• The sympathetic nervous system is involved in "fight or flight" responses.
• The parasympathetic nervous system is active during relaxation.

Anatomical Directions in the Nervous System

• Dorsal: Toward the back, away from the ventral (stomach) side.
• Ventral: Toward the stomach, away from the dorsal (back) side.
• Anterior: Toward the front.
• Posterior: Toward the rear end.
• Superior: Above another part.
• Inferior: Below another part.
• Lateral: Toward the side, away from the midline.
• Medial: Toward the midline, away from the side.
• Proximal: Located close (approximate) to the point of attachment.
• Distal: Located more distant from the point of origin or attachment.
• Ipsilateral: On the same side of the body.
• Contralateral: On the opposite side of the body.
• Coronal plane: A plane showing brain structures as seen from the front.
• Sagittal plane: A plane showing brain structures as seen from the side.
• Horizontal plane: A plane showing brain structures as seen from above.

Anatomical Terms Referring to Parts of the Nervous System

• Lamina: A row or layer of cell bodies separated by a layer of axons and dendrites.
• Column: A set of cells perpendicular to the surface of the cortex, with similar properties.
• Tract: A set of axons (projection) within the CNS.
• Nerve: A set of axons in the periphery, from CNS to muscle/gland, or sensory organ to CNS.
• Nucleus: A cluster of neuron cell bodies within the CNS.
• Ganglion: A cluster of neuron cell bodies, usually outside the CNS (e.g, sympathetic nervous system).
• Gyrus: A protuberance on the surface of the brain.
• Sulcus: A fold or groove that separates one gyrus from another.
• Fissure: A long, deep sulcus.

The Spinal Cord

• Part of the CNS, found within the spinal column.
• Communicates with sense organs and muscles (except those of the head).
• Cell bodies of sensory neurons are located in clusters outside the spinal cord.
• Consists of gray matter and white matter.
• Gray matter: located in center of the spinal cord; densely packed cell bodies and dendrites.
• White matter: mostly myelinated axons carrying information from gray matter to brain or other spinal cord areas.

The Brain

• The brain has three main parts: forebrain, midbrain, and hindbrain.

The Brainstem: Hindbrain and midbrain

• Brainstem is located at the bottom of the brain and is made up of hindbrain and midbrain.
• Hindbrain structures (excluding cerebellum), midbrain, and other central structures make up the brain stem.
• Hindbrain: Medulla, Pons, Cerebellum
• Located at the posterior portion of the brain
• Midbrain: middle part of the brain.

The Hindbrain

• Medulla: located just above the spinal cord.
• Responsible for vital reflexes (breathing, heart rate, vomiting, salivation, coughing, sneezing).
• Pons: located on each side of the medulla.
• Axons from each brain half cross to the opposite spinal cord side (e.g., left hemisphere controls right body).
• Cerebellum: structure with deep folds in hindbrain.
• Regulates motor movement, balance, and coordination.
• Important for shifting attention between auditory and visual stimuli.

The Medulla and the Cranial Nerves

• Cranial nerves allow medulla to control sensations from the head, muscle movements in the head, and parasympathetic outputs.

The Cranial Nerves

• Olfactory (I): Smell
• Optic (II): Vision
• Oculomotor (III): Eye movements, pupil constriction
• Trochlear (IV): Eye movements
• Trigeminal (V): Skin sensations from much of the face; jaw muscles for chewing/swallowing
• Abducens (VI): Eye movements
• Facial (VII): Taste from anterior tongue; facial expressions, crying, salivation
• Vestibulocochlear (VIII): Hearing; equilibrium
• Glossopharyngeal (IX): Taste & sensations from posterior tongue; swallowing, salivation
• Vagus (X): Sensations from neck & thorax; controls throat, esophagus, & larynx. Parasympathetic nerves control stomach, intestines, etc.
• Accessory (XI): Neck & shoulder movement
• Hypoglossal (XII): Tongue movements

The Forebrain

• The most anterior and prominent part of the mammalian brain, with two cerebral hemispheres.
• Consists of the outer cortex and subcortical regions.
• Outer portion is known as the "cerebral cortex".
• Each side receives sensory information and controls motor from the opposite side of the body.

The Limbic System

• Consists of interlinked structures that form a border around the brainstem.
• Includes olfactory bulb, hypothalamus, hippocampus, amygdala, cingulate gyrus.
• Associated with motivation, emotions (eating, drinking, sexual activity, anxiety, aggression).

The Forebrain-Subcortical Regions

• Pituitary gland: hormone-producing gland at the base of the hypothalamus.
• Basal ganglia: comprises the caudate nucleus, putamen, and the globus pallidus.
• Associated with planning of motor movement and emotional expression; critical for gradual learning of skills and habits.

The Forebrain-The Hippocampus

• A large structure located between the thalamus and cerebral cortex.
• Toward the posterior portion of the forebrain.
• Critical for certain types of memory, especially memories for individual events.

The Ventricles

• Four fluid-filled cavities (ventricles) within the brain's central canal containing cerebrospinal fluid. Cerebrospinal fluid (CSF).
• Provides cushioning for the brain.
• Reservoir for hormones and nutrition for the brain and spinal cord.

The Meninges

• Membranes that surround the brain and spinal cord.
• Contain pain receptors.
• Meningitis is inflammation of the meninges.
• Swollen blood vessels in the meninges are the cause of migraine headaches.

The Cerebral Cortex

• Most prominent part of the mammalian brain.
• Consists of cellular layers on the outer surface of the cerebral hemispheres
• Divided into two halves.
• Joined by bundles of axons (corpus callosum and anterior commissure).
• More highly developed in humans than other species.
• Contains up to six distinct laminae (layers; parallel to surface), and columnar structures (perpendicular to laminae).

The Four Lobes of the Cerebral Cortex

• The cerebral cortex consists of four lobes: occipital, parietal, temporal, and frontal.

Areas of the Human Cerebral Cortex

• Different parts of the cerebral cortex are responsible for different functions.

Functional Areas of the Cerebral Cortex

• Motor areas: Primary motor cortex, premotor cortex, frontal eye field, Broca's area, and the prefrontal cortex.
• Sensory areas and related association areas: Primary somatosensory cortex, somatosensory association cortex, gustatory cortex (in insula), Wernicke's area, primary visual cortex, visual association area, primary auditory cortex, auditory association area.

The Occipital Lobe

• Located at the posterior end of the brain.
• Known as the striate or primary visual cortex.
• Highly responsible for visual input
• Primary visual cortex (V1) focuses on basic feature extraction (like edges, motion, contrast).
• Visual association area is for higher-order processing (interpreting, integrating, giving meaning to these features).

The Parietal Lobe

• Contains the postcentral gyrus (primary somatosensory cortex).
• Primary target for touch sensations and information from muscle stretch receptors.
• Processes and integrates information about eye, head, and body positions, from muscles and joints.
• Essential for spatial and numerical information (e.g., counting).

Approximate Representation of Sensory and Motor Information in the Cortex

• Different areas of the cortex represent different parts of the body (e.g., lips, face, hands, and feet have larger representation areas).

The Temporal Lobe

• Located on the lateral portion of each hemisphere near the temples.
• Primary auditory cortex processes initial sound features (pitch, loudness).
• Auditory association areas are for higher-order processing.
• Involved in understanding, interpreting, and recognizing auditory stimuli. (e.g., language, music, and other environmental sounds).

The Frontal Lobe

• Contains prefrontal cortex and precentral gyrus.
• Precentral gyrus is the primary motor cortex, controlling fine motor movements.
• Prefrontal cortex integrates sensory and other cortical information.
• Critical for planning, complex behavior(s), and some aspects of emotions.
• Includes several areas in the prefrontal cortex and the temporoparietal junction, known as the default network.

The Binding Problem

• Refers to how visual, auditory, and other brain areas combine experiences to create a perception of a single object.
• Perhaps the brain binds activity in different areas when they produce synchronous waves of activity.
• Binding occurs when a person perceives two sensations as occurring at the same time and in the same place., such as a ventriloquist's use of visual stimulus to alter auditory response.

Species Differences in Prefrontal Cortex

• Humans have a substantially larger prefrontal cortex compared to other mammals.

The Prefrontal Cortex

• Responsible for higher functions, such as abstract thinking, planning.
• Critical for our ability to remember recent events.
• With damage to the prefrontal cortex, people exhibit delayed response tasks (responding to something after a delay).

Prefrontal Lobotomy

• Surgical disconnection of the prefrontal cortex from the rest of the brain.
• Historically performed on people with mental disorders; often with severe effects.

Beyond Gray Matter: The Connections

• The Human Connectome Project maps long-distance brain connections.
• Brain connections are correlated with behavioral tendencies.
• Parts of the cortex are interdependent and communicate with each other in complex ways.

Research Questions

• Key aspects to research include: specific brain functions affected by damage, neurological/psychological disorders connected to damage, recent research findings from 2016 onward about brain functions and disorders, or case studies describing brain damage/recovery..