Study Guide for Clinical Neuroscience for Speech Language Pathology SLP 5125

Central Nervous System (CNS)

Includes the brain and spinal cord.

Peripheral Nervous System (PNS)

Consists of nerves and ganglia outside the brain and spinal cord.

Medulla Oblongata

Controls basic life functions like breathing, heartbeat, and blood pressure.

Pons

Involved in sleep regulation, facial movements, and other motor functions.

Cerebellum

Coordinates voluntary movements, balance, and posture.

Midbrain

Responsible for auditory and visual reflexes and involved in movement and arousal.

Diencephalon

Includes the thalamus and hypothalamus.

Thalamus

Acts as a relay station for sensory information.

Hypothalamus

Regulates body temperature, hunger, thirst, and other homeostatic processes.

Telencephalon

Cerebral Cortex

Frontal Lobe

Responsible for motor function, problem-solving, spontaneity, memory, language, initiation, judgment, impulse control, and social and sexual behavior.

Parietal Lobe

Processes sensory information, spatial awareness, and the perception of stimuli.

Temporal Lobe

Involved in auditory processing and is also important for processing semantics in speech and vision.

Occipital Lobe

Primarily responsible for visual processing.

Hippocampus

Critical for the formation of new memories and is also associated with learning and emotions.

Amygdala

Involved in processing emotions such as fear, anger, and pleasure.

Basal Ganglia

Responsible for voluntary motor control, procedural learning, and habit formation.

Limbic System

Includes the hippocampus, amygdala, and parts of the thalamus and hypothalamus. Involved in emotion, motivation, learning, and memory.

Cingulate Cortex

Part of the limbic system, it plays a role in emotions and behavior regulation.

Cell Body (Soma)

Contains the nucleus and most organelles. Integrates signals from dendrites.

Dendrites

Branch-like extensions that receive signals (chemical or electrical) from other neurons.

Axon

- A long, tubular extension that transmits signals away from the cell body.

- Covered by a myelin sheath (in some neurons) for faster signal transmission.

Axon Hillock

- Junction between the axon and cell body.

- Initiates the generation of action potentials.

Myelin Sheath

Fatty covering that insulates and speeds up the conduction of nerve impulses.

Nodes of Ranvier

Gaps in the myelin sheath where the axon is exposed.

Axon Terminals

- Branching ends of the axon.

- Release neurotransmitters to communicate with other neurons or target cells.

Nucleus

Contains genetic material (DNA) and regulates cell activities.

Endoplasmic Reticulum (ER)

Rough ER synthesizes proteins essential for cellular function.

Mitochondria

Produces energy (ATP) through cellular respiration.

Golgi Apparatus

Packages and processes proteins for secretion.

Microtubules and Microfilaments

Maintain cell shape and provide structural support.

Synaptic Vesicles

Small sacs in axon terminals containing neurotransmitters.

Neurotransmitters

Chemical messengers that transmit signals across synapses.

Receptors

Proteins on the cell membrane bind neurotransmitters, initiating a response.

Voltage-Gated Ion Channels

Regulate the flow of ions (e.g., sodium, potassium) across the cell membrane during action potentials.

Resting Membrane Potential

The electric charge is across the cell membrane when the neuron is not transmitting signals.

Action Potential

Brief electrical impulse that travels down the axon.

Synapse

The junction between neurons where information is transmitted.

Postsynaptic Density

A specialized region on the postsynaptic membrane where neurotransmitter receptors are concentrated.

Neuroglia (Glial Cells)

Support cells that provide nutrients and insulation and help repair damaged neurons.

Types of glial cells include

Astrocytes, oligodendrocytes, microglia, and ependymal cells.

Sensory Neurons

Transmit sensory information from receptors to the central nervous system.

Motor Neurons

Transmit motor signals from the central nervous system to muscles and glands.

Interneurons

Facilitate communication between sensory and motor neurons within the central nervous system.

Astrocytes

Function: Provide structural support, regulate ion concentration, and nourish neurons.

Location: Throughout the CNS.

Oligodendrocytes

Function: Produce myelin, which insulates axons and speeds up signal transmission.

Location: In the CNS, where they form myelin sheaths around axons.

Microglia

Function: Act as immune cells, removing debris and pathogens in the CNS.

Location: Scattered throughout the CNS.

Ependymal Cells

Function: Produce cerebrospinal fluid (CSF) and line the brain's ventricles.

Location: In the brain ventricles' walls and the spinal cord's central canal.

Overview of Blood Supply to the Brain

The brain receives its blood supply primarily from two major arteries: internal carotid and vertebral arteries.

Internal Carotid Arteries

Location: Enter the skull through the carotid canal.

Supply: Brain and eyes.

Vertebral Arteries

Location: Arise from the subclavian arteries.

Supply: Brain and spinal cord.

Basilar Artery

Location: Formed by the fusion of vertebral arteries.

Supply: Supplies the pons, cerebellum, and the inner ear.

Posterior Cerebral Arteries (PCA)

Branching: Originate from the basilar artery.

Supply: Occipital lobes, parts of the temporal lobes, and the midbrain.

Circle of Willis

Formation: An anastomotic ring of arteries at the base of the brain.

Purpose: Provides collateral circulation and equalizes blood pressure.

Components: Internal carotid arteries, anterior cerebral arteries, anterior communicating arteries, posterior communicating arteries, and posterior cerebral arteries.

Middle Cerebral Artery (MCA)

Location: Arises from the internal carotid artery. Runs laterally within the cerebral hemispheres.

Supply:

Superior Division: Supplies the frontal and parietal lobes.

Inferior Division: Supplies the temporal lobe.

Associated Symptoms of MCA Stroke

Contralateral Hemiplegia/Hemiparesis: Weakness or paralysis on the opposite side of the body.

Contralateral Sensory Loss: Loss of sensation on the opposite side.

Anterior Cerebral Artery (ACA)

Location: Arises from the internal carotid artery. Travels along the midline of the brain.

Supply: Supplies the superior and medial aspects of the frontal and parietal lobes.

Associated Symptoms of ACA Stroke

Contralateral Hemiplegia/Hemiparesis: Mainly affecting the lower limbs.

Urinary Incontinence: Loss of bladder control.

Abulia: Reduced spontaneity and initiative.

Posterior Cerebral Artery (PCA)

Location: Arises from the basilar artery.

Supply: Supplies the occipital lobes, inferior and medial temporal lobes, and parts of the thalamus and midbrain.

Associated Symptoms of PCA Stroke

Homonymous Hemianopsia: Loss of vision in the same visual field of both eyes.

Memory Impairment: Especially if the hippocampus is affected.

Visual Agnosia: Difficulty recognizing familiar objects. Thalamic

Pain Syndrome: Pain and sensory abnormalities in the contralateral side of the body.

Dorsal induction (3-7 weeks)

A process where signals from the dorsal organizer induce neural tube formation.

Ventral induction (2-3 months)

A process when the face and brain develop out of the superior end of the brain (e.g., telencephalon)

Neural proliferation (3-4 months)

Rapid cell division of neural progenitor cells in the ventricular zone of the neural tube (neurogenesis).

Neuronal migration (3-5 months)

Movement of neurons from their place of origin to their final destination.

Cortical organization (5 months to years postnatal)

Arrangement of neurons into functional layers and columns in the cerebral cortex.

Myelination (Birth to years postnatal)

Process where axons are coated with a myelin sheath for faster signal transmission.

Ischemic Stroke

Caused by a blockage (clot or thrombus) in a blood vessel supplying the brain.

Thrombotic Stroke

Caused by a blood clot forming within a blood vessel in the brain.

Embolic Stroke

Caused by a clot that forms elsewhere and travels to the brain.

Hemorrhagic Stroke

Caused by bleeding within or around the brain.

Intracerebral Hemorrhage (ICH)

Bleeding within the brain tissue.

Subarachnoid Hemorrhage (SAH)

Bleeding into the space between the brain and the skull.

Transient Ischemic Attack (TIA)

Often referred to as a "mini-stroke," it is a temporary disruption of blood flow to the brain. Symptoms resolve within 24 hours.

Olfactory Nerve (CN I)

Anatomical Location: Olfactory epithelium in the nasal cavity.

Function: Sensory, responsible for the sense of smell.

Optic Nerve (CN II)

Anatomical Location: Retina of the eye.

Function: Sensory, carries visual information from the retina to the brain.

Oculomotor Nerve (CN III)

Anatomical Location: Midbrain.

Function: The motor controls most eye movements, including raising the eyelid and directing the pupil.

Trochlear Nerve (CN IV)

Anatomical Location: Midbrain.

Function: Motor control of downward and inward eye movement.

Trigeminal Nerve (CN V)

Anatomical Location: Pons.

Function: Sensory (ophthalmic, maxillary, and mandibular branches), provides sensation to the face, and controls corneal reflex. Motor control chewing muscles.

Abducens Nerve (CN VI)

Anatomical Location: Pons.

Function: Motor control lateral eye movement.

Facial Nerve (CN VII)

Anatomical Location: Pons.

Function: Motor control facial expressions, salivary glands, and tear glands. Sensory taste on the anterior two-thirds of the tongue.

Vestibulocochlear Nerve (CN VIII)

Anatomical Location: Pons and medulla.

Function: Sensory, responsible for hearing and balance.

Glossopharyngeal Nerve (CN IX)

Anatomical Location: Medulla.

Function: Motor control pharynx muscles involved in swallowing. Sensory, taste on the posterior one-third of the tongue, monitors blood pressure and blood gases.

Vagus Nerve (CN X)

Anatomical Location: Medulla.

Function: Motor control muscles of the pharynx and larynx (speech and swallowing). Sensory regulates heart rate, digestion, and other involuntary functions. Sensory monitors visceral sensations.

Accessory Nerve (CN XI)

Anatomical Location: Spinal cord and medulla.

Function: Motor control of neck and shoulder muscles.

Hypoglossal Nerve (CN XII)

Anatomical Location: Medulla.

Function: Motor control muscles of the tongue.

Sagittal Plane

Divides the brain into left and right halves.

Median (Mid-Sagittal)

Divides the brain into equal left and right halves.

Parasagittal

Divides the brain into unequal left and right portions.

Coronal (Frontal) Plane

Divides the brain into front (anterior) and back (posterior) portions.

Horizontal (Transverse) Plane

Divides the brain into upper (superior) and lower (inferior) portions.

Electroencephalogram (EEG)

Records electrical activity of the brain through electrodes on the scalp.

Magnetoencephalogram (MEG)

Measures magnetic fields generated by neural activity.

Computed Tomography (CT)

Utilizes X-rays to create cross-sectional images of the brain.

Positron Emission Tomography (PET)

Measures radioactive tracer uptake to assess metabolic activity.

Single-Photon Emission Computed Tomography (SPECT)

It is similar to PET but uses different radioactive tracers.

Magnetic Resonance Imaging (MRI)

Utilizes magnetic fields and radio waves to create detailed images.

Functional Magnetic Resonance Imaging (fMRI)

Measures blood oxygen level-dependent (BOLD) signal changes.

Projection Fibers

Also known as long fibers, these extend between different nervous system regions.

Association Fibers

Connect different parts of the same hemisphere.

Commissural Fibers

Connect corresponding regions of the two hemispheres.