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Questions and Answers
What comprises the forebrain?
Which lobe of the brain is primarily responsible for vision?
What is the function of the gray matter in the spinal cord?
What separates the frontal lobe from the parietal lobe?
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Which lobe is referred to as the emotional center of the brain?
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In the brain, where is the white matter primarily located?
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What are gyri and sulci of the cerebral cortex?
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Which of the following correctly describes the structure of the brain's cortex?
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What role does the temporal lobe serve in the brain?
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What anatomical feature is known as the lateral fissure?
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What structural feature is particularly associated with the limbic lobe?
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Which component of the central nervous system is correctly paired with its description?
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Which of the following lobes is primarily associated with cognitive functions like motor activity?
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In the structure of the brain, where is gray matter typically located?
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Which anatomical feature is used to split the occipital lobe from the parietal and temporal lobes?
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What is the primary function of the soma in a neuron?
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Which type of synapse is associated with someone who has been performing a task for many years?
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What occurs during the depolarization phase of an action potential?
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Which type of channel opens in response to a specific molecule binding to it?
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What is the nature of EPSP and IPSP in terms of their potential generation?
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What defines the process of spatial summation in graded potentials?
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What is the significance of reaching -55 mV for an action potential?
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Which factor does NOT influence the speed of action potentials in axons?
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During which phase of action potential do sodium gates close and potassium gates open?
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What initiates the exocytosis of neurotransmitter vesicles in the axon terminal?
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What describes the function of the myelin sheath in neuron communication?
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Which type of synapse is typically identified with a long-term learned behavior?
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What is the primary role of ligands in neuron channels?
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What characterizes the graded potentials generated in dendrites?
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Which neuronal component is most directly involved in receiving stimuli?
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The human adult spinal cord terminates at which vertebral level?
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The meningeal layer most intimately attached to the CNS is?
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Dentate or denticulate ligaments are tiny, thin anchors of the spinal cord and are composed of pia mater.
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The filum terminale anchors the spinal cord to the sacrum.
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Oligodendrocytes are cells that produce myelin in the peripheral nervous system.
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Which fiber listed below is unmyelinated and is responsible for 'slow pain'?
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An equilibrium potential is defined as:
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What type of channel opens due to a change in intracellular charge and is typically located on axons or axon terminals?
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What is the typical resting membrane potential in most neurons?
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GABA is the most prevalent neurotransmitter in the human brain and is inhibitory.
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What function is associated with the frontal eye fields?
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Which area is responsible for the interpretation of sensory information related to touch and pressure?
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Where is the primary auditory area located?
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What is the primary function of the primary visual cortex?
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Which area is primarily responsible for taste sensation?
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Which area is primarily responsible for higher order thought processes?
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What is the role of the primary motor area located in the precentral gyrus?
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What is the main function of the posterior part of the parietal lobe?
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Where in the brain would you find areas dedicated to hearing and memory?
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What is the primary function of the supplementary motor area within the brain's motor areas?
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Which type of cortex is defined as being involved in higher order information processing of a single sensory or motor modality?
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Which area of the parietal lobe is responsible for sensory perception, particularly how we feel sensations? Pick 2
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Which area is NOT classified as part of the primary cortical areas responsible for receiving information?
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Which of the following statements about the insular cortex is true? (Select all that apply)
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The primary somatosensory cortex is which of the following structures in the cerebrum?
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The primary motor cortex is which of the following structures in the cerebrum?
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The posterior horn of the lateral ventricles is located within which of the following lobes of the brain?
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The corpus callosum is considered a large band of projection fibers.
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Commissural fibers are considered tracts of fibers that link the two hemispheres of the brain.
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Which subcortical fibers listed below connect Wernicke's area to Broca's area?
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What is the primary function of the Broca area in the brain?
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Which hemisphere is dominant for language processing in the majority of right-handed individuals?
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What type of aphasia is characterized by deficits in the production of language?
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Which areas of the brain are connected by the arcuate fasciculus?
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What is the role of the non-dominant hemisphere in language processing?
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What is the primary function of the Wernicke area in the brain?
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Which part of the brain contains reciprocal connections with the frontal lobe for higher order motor aspects of speech?
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In which hemisphere is language predominantly processed in right-handed individuals?
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What type of aphasia is characterized by deficits in the production of language, leading to halting speech and impaired fluency?
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Which structure connects the left and right hemispheres of the brain and is involved in language processing?
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What is the function of the arachnoid layer in the meninges?
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What happens in the epidural space during certain pathological conditions?
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Which of the following accurately describes a potential space in relation to the meninges?
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Which structure is created by the dural reflections of the meningeal layer?
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In a healthy individual, what defines a real space in the context of the meninges?
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What primarily drains into the dural venous sinus from the subdural space?
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What characterizes the pia mater among the three meninges layers?
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What causes the subdural space to become a real space?
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What is the primary function of the periosteal layer of the dura mater?
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What distinguishes real spaces from potential spaces in the meninges?
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Which layer of the meninges is responsible for creating folds known as dural reflections?
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What is the potential space located between the skull and the periosteal layer of the dura mater?
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Which type of hemorrhage is associated with a rupture of bridging veins in the subdural space?
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What connects the arachnoid layer to the pia mater?
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Which layer of the meninges adheres tightly to the brain and is the innermost layer?
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Study Notes
Central Nervous System (CNS) Components
- The CNS is comprised of the brain and spinal cord.
Forebrain
- The cerebral cortex and deep gray matter nuclei comprise the forebrain.
Cerebral Cortex
- Covers the entire surface of the brain.
- Contains folds called gyri (ridges) which are named based on their function and location.
- Contains grooves called sulci (furrows) which are named based on their location.
- The central sulcus separates the frontal and parietal lobes.
- The parieto-occipital sulcus separates the occipital from parietal and temporal lobes.
- Contains large sulci known as fissures.
- The lateral fissure separates the frontal and parietal lobes from the temporal lobe.
Cerebral Cortex Lobes
- Frontal lobe: Involved in motor activity and higher-order thinking and cognition
- Parietal lobe: Involved in sensory processing
- Occipital lobe: Involved in vision
- Temporal lobe: Involved in hearing and memory
-
Limbic lobe: Involved in emotional processing, including arousal, fear, and anger
- Includes the cingulate gyrus and parahippocampal gyrus
Cerebral Cortex Matter
-
Gray matter: Consists of neuronal cell bodies, also known as ganglia, nuclei, or small groups of cell bodies.
- Gray matter is found on the outside of the brain and inside the spinal cord.
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White matter: Consists of myelinated axons.
- White matter is found on the inside of the brain and outside the spinal cord.
Brainstem
- Composed of the midbrain, pons, and medulla.
- The medulla becomes the spinal cord at the foramen magnum (base of the skull).
Cerebellum
- The cerebellum is a separate part of the brain.
Central Nervous System (CNS) Components
- Brain & Spinal Cord
-
Forebrain
-
Cerebral Cortex
- Covers entire surface of the brain
-
Sulci
-
Gyri
- Ridges
- Named based on function and/or location
-
Sulci
- Furrows
- Major sulci have specific names:
-
Central Sulcus
- Separates frontal lobe from parietal lobe
-
Parieto-occipital Sulcus
- Separates occipital lobe from parietal and temporal lobes
-
Central Sulcus
-
Fissures (large sulci)
-
Lateral Fissure
- Separates frontal and parietal lobes from temporal lobe
-
Lateral Fissure
-
Gyri
-
Lobes
-
Frontal Lobe
- Motor activity and higher-order thought/cognition
-
Parietal Lobe
- Sensory
-
Occipital Lobe
- Vision
-
Temporal Lobe
- Hearing and memory
-
Limbic Lobe
- Emotional center
- Contains cingulate gyrus and parahippocampal gyrus
-
Frontal Lobe
-
Matter
-
Gray Matter
- Primarily neuronal cell bodies (ganglia, nuclei, or small groups of cell bodies)
- In the brain: gray matter is on the outside
- In the spinal cord: gray matter is on the inside (used for processing before sending signals up or down)
-
White Matter
- Primarily myelinated axons (nerves can be myelinated or non-myelinated)
- In the brain: white matter is on the inside
- In the spinal cord: white matter is on the outside
-
Gray Matter
-
Cerebral Cortex
Brain Stem
- Midbrain
- Pons
-
Medulla
- Becomes spinal cord at the foramen magnum (base of the skull)
- Cerebellum
Neuron Anatomy
- Neurons have distinct parts, each with a specialized function, for transmitting signals.
- Dendrites receive stimuli and transmit signals to the cell body.
- Soma synthesizes neurotransmitters and acts as the neuron's control center.
- Myelin sheath is a fatty covering around the axon that increases signal transmission speed.
- Nodes of Ranvier are gaps between portions of the myelin sheath, enabling faster signal propagation.
- Axon is the long, slender projection that transmits the nerve impulse.
- Axon terminal synapses with other neurons, muscles, or glands to transmit signals.
Synaptic Connections
- Axo-dendritic synapse: Connects the axon terminal of one neuron to the dendrite of another, representing new learning or development.
- Axo-somatic synapse: Connects the axon terminal to the soma of another neuron, indicating a more established connection.
- Axo-axonic synapse: Connects the axon terminal of one neuron to the axon of another neuron, implying a very strong and well-established connection.
Resting Membrane Potential (RMP)
- RMP is the electrical charge difference across the neuron's membrane when it is at rest.
-
Electrochemical gradient: Drives the movement of ions across the membrane.
- Concentration gradient: Ions move from areas of high concentration to low concentration.
- Extracellular: High concentration of sodium (Na+) ions.
- Intracellular: High concentration of potassium (K+) ions.
Action Potential
- Action potential is a rapid change in the electrical charge across the neuron's membrane, enabling signal transmission.
- Depolarization: Na+ ions rush into the cell, making the intracellular environment more positive.
- Repolarization: K+ ions move out of the cell, restoring the negative charge inside the neuron.
- Hyperpolarization: The membrane potential becomes more negative than resting potential as K+ ions continue to flow out.
Channels
- Voltage-gated channels: Open and close based on changes in the membrane voltage.
- Ligand-gated channels: Open when a specific molecule binds to the channel.
- Leaky channels: Allow passive diffusion of specific ions across the membrane.
Neural Communication
- Post-synaptic potentials: Are graded potentials occurring at the dendrite of the receiving neuron.
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Excitatory post-synaptic potential (EPSP): Depolarizes the membrane, increasing the likelihood of an action potential.
- Glutamate: Is a common excitatory neurotransmitter.
-
Inhibitory post-synaptic potential (IPSP): Hyperpolarizes the membrane, decreasing the likelihood of an action potential.
- GABA: Is a common inhibitory neurotransmitter.
- Spatial summation: Multiple neurons release neurotransmitters onto the same dendrite simultaneously, causing additive effects.
- Temporal summation: Repeated neurotransmitter release from a single neuron in a short timeframe can produce a cumulative effect.
Axon
-
Myelination: The process of wrapping the axon with a myelin sheath.
- Schwann cells: Create myelin in the peripheral nervous system (PNS).
- Oligodendrocytes: Create myelin in the central nervous system (CNS).
- Action potential (all-or-none): The neuron either fires an action potential completely or not at all.
- Threshold potential: The minimum depolarization required to trigger an action potential (-55 mV).
-
Factors impacting action potential speed:
- Axon size: Larger axons conduct signals faster.
- Myelination: Myelination greatly increases signal speed.
- Temperature: Heat increases signal speed.
Axon Terminal
- Communication between neurons: Signals from one neuron are transmitted to the next across the synapse.
-
Steps of neurotransmitter release:
- Arrival of the action potential: Triggers calcium (Ca++) influx.
- Calcium influx: Opens Ca++ voltage-gated channels.
- Exocytosis: Neurotransmitter-containing vesicles fuse with the presynaptic membrane and release neurotransmitter into the synaptic cleft.
- Neurotransmitter binding: Neurotransmitter binds to receptors on the postsynaptic membrane.
- Sodium influx: Neurotransmitter binding opens ion channels, allowing Na+ to enter the postsynaptic neuron, potentially triggering an action potential.
- Generation of action potential: If enough EPSPs occur, the postsynaptic neuron reaches threshold and generates an action potential.
Neuron Anatomy
- Dendrites receive stimuli and transmit it to the soma.
- Soma is the cell body that synthesizes neurotransmitters.
- Myelin sheath speeds up signal transmission along the axon.
- Nodes of Ranvier are gaps between myelin sheaths.
- Axon is where the nerve impulse travels.
- Axon terminal synapses with muscle, gland, or another nerve to transmit the signal.
Types of Synapses
- Axo-dendritic synapse is involved in learning and developing a skill.
- Axo-somatic synapse is involved in performing a skill for an extended period.
- Axo-axonic synapse is involved in performing a skill for a lifetime.
Resting Membrane Potential (RMP)
- Electrochemical gradient is the driving force for ion movement.
- Concentration gradient is the difference in concentration of ions across the membrane.
- Sodium (Na+) is more concentrated outside the cell.
- Potassium (K+) is more concentrated inside the cell.
Action Potential
- Depolarization occurs when sodium ions (Na+) move into the cell, making the inside more positive.
- Repolarization occurs when potassium ions (K+) move out of the cell, making the inside more negative.
- Hyperpolarization occurs when the membrane potential becomes even more negative than the resting potential.
Types of Channels
- Voltage-gated channels open in response to changes in the membrane potential.
- Ligand-gated channels open when a specific molecule binds to them.
- Leaky channels allow for passive diffusion of specific ions.
Neural Communication
- Post-synaptic potentials (PSPs) are graded potentials generated at dendrites, proportional to the strength of the stimuli received.
- Excitatory post-synaptic potential (EPSP): Caused by glutamate, making the neuron more likely to fire an action potential.
- Inhibitory post-synaptic potential (IPSP): Caused by GABA, making the neuron less likely to fire an action potential.
- Spatial summation: Reception of stimuli from multiple neurons close together in the same timeframe.
- Temporal summation: Reception of repeated stimuli from one neuron in a small time frame.
Axon
- Myelin acts as an electrical insulator, improving signal transmission.
- Schwann cells create myelin in the peripheral nervous system (PNS).
- Oligodendrocytes create myelin in the central nervous system (CNS).
- Action potential: All or nothing response.
- Threshold of -55mV must be met to initiate an action potential.
Action Potential Steps
- Resting membrane potential (RMP): Both sodium (Na+) and potassium (K+) gates are closed.
- Graded potential: Sodium (Na+) gates open due to influx of Na+ through ligand-gated channels in the dendrite.
- Depolarization: Threshold is reached, more Na+ gates open, and a large influx of Na+ occurs.
- Repolarization: Sodium (Na+) gates close, potassium (K+) gates open, and potassium leaves the cell.
- Hyperpolarization: Potassium (K+) continues to leave the cell, leading to an overshoot.
Factors Affecting Axon Firing Rate
- Axon size: Larger axons have faster conduction velocity.
- Myelination: Myelinated axons have faster conduction velocity.
- Temperature: Increased temperature increases conduction velocity.
Axon Terminal
- Communication between neurons: Neurotransmitters are released from the axon terminal.
- Action potential arrives: Calcium (Ca++) channels open, allowing Ca++ to enter the terminal.
- Exocytosis: Neurotransmitter-containing vesicles fuse with the presynaptic membrane and release neurotransmitter into the synaptic cleft.
- Neurotransmitter binding: Neurotransmitter binds to receptors on the post-synaptic membrane, causing a change in the membrane potential.
- Ion influx: Sodium (Na+) ions enter the postsynaptic cell, potentially triggering an action potential.
- Generation of action potential: If the postsynaptic potential is strong enough, it triggers an action potential in the postsynaptic neuron.
The Cortex & its Lobes
- Frontal lobe: Higher order thought
-
Parietal lobe: Sensory functions
- Anterior part: Somatosensory (how we feel)
- Posterior part: Insulin cortex from the gut, Vestibular cortex for balance and processing
- Temporal lobe: Hearing & memory
- Occipital lobe: Vision
- Limbic lobe: Emotions
Cortical Organization
-
Primary cortical areas
- Receive information from peripheral receptors (e.g., thalamus).
- Limited interpretation of information meaning.
- Crucial for receiving sensory information and executing motor tasks.
- Examples: Primary motor, somatosensory, visual, auditory, and gustatory areas.
-
Association areas
- Receive information from primary areas and engage in higher-order processing, integration, and interpretation.
- Located adjacent to primary areas.
- Examples: Premotor, somatosensory, visual, auditory, frontal, parietal/sensory, and temporal association areas.
-
Classifications:
- Unimodal association cortex: Higher-order information processing for a single sensory or motor modality. Located adjacent to primary areas.
- Heteromodal association cortex: Integrates functions from multiple modalities.
Functional Areas
-
Motor
-
Primary motor areas:
- Located in the precentral gyrus of the frontal lobe.
- Responsible for motor output to the contralateral side of the body.
- Forms the corticospinal tract.
-
Supplementary motor area:
- Anterior to the primary motor area.
- Superior to the premotor area.
- Contains the motor map for posture.
-
Premotor association area:
- Anterior to the primary motor area.
- Inferior to the supplementary motor area.
- Involved in higher-order processing and integrating motor information.
-
Primary motor areas:
-
Motor-related
-
Frontal eye fields:
- Located in the supplementary motor area and extend anteriorly.
- Involved in eye movement.
-
Motor-hand area:
- Part of the precentral gyrus, just posterior to the frontal eye field.
- Responsible for motor-hand function.
-
Frontal eye fields:
-
Somatosensory
-
Primary somatosensory area:
- Located in the postcentral gyrus of the parietal lobe.
- Sensory afferents from contralateral peripheral receptors travel to the thalamus, then to this area.
- Forms the spinothalamic tract.
-
Somatosensory association area:
- Posterior to the primary somatosensory area.
- Interpretation of the significance of sensory information (touch, pressure, proprioceptive information).
-
Primary somatosensory area:
-
Visual
-
Primary visual area:
- Located on the banks of the calcarine sulcus on the medial occipital lobe.
- Fibers from the retina travel to the lateral geniculate nucleus of the thalamus, then to the primary visual cortex as optic radiations.
-
Primary visual cortex:
- Retinotopically organized.
- Upper visual field: Inferior bank of the calcarine sulcus.
- Lower visual field: Superior bank of the calcarine sulcus.
- Highest visual acuity of the retina (fovea): Near the occipital pole.
-
Visual association area:
- Surrounds the primary visual cortex on the medial side.
- Gives meaning and interpretation to visual information.
-
Primary visual area:
-
Auditory areas
-
Primary auditory area:
- Composed of:
- Transverse Heschl's gyri deep within the lateral fissure.
- Part of the superior surface of the superior temporal gyrus for the temporal lobe.
- Auditory information travels from the cochlea to the medial geniculate nucleus of the thalamus and then to the primary auditory area of the cortex.
- Information from the cochlea travels both ipsilaterally and contralaterally.
- Composed of:
-
Auditory association area:
- Adjacent to the primary auditory area, on the lateral surface of the superior temporal gyrus.
- Interprets sound and gives meaning.
-
Primary auditory area:
-
Insular cortex:
- Role in consciousness, emotion, self-awareness, and cognitive function.
-
Primary gustatory area:
- Taste.
Cortex
-
Lobes
- Frontal lobe: higher order thought
-
Parietal lobe: Sensory
- Anterior part: Somatosensory (how we feel)
- Posterior part: Insulin cortex from the gut; Vestibular cortex for balance and processing
- Temporal lobe: Hearing & memory
- Occipital lobe: Vision
- Limbic lobe: Emotional
Cortical Organization
-
Primary cortical areas
- Receive information from peripheral receptors (e.g., thalamus) with minimal interpretation
- Important for receiving sensory information and executing motor tasks
- Examples: Primary (motor, somatosensory, visual, auditory, gustatory) areas
-
Association areas
- Receive information from primary areas and are involved in higher order processing, integrating, and interpreting
- Located adjacent to primary areas
- Examples: (Premotor, somatosensory, visual, auditory, frontal, parietal/sensory, temporal) association areas
-
Classifications:
- Unimodal association cortex: Higher order information processing of a single sensory/motor modality; located adjacent to primary areas.
- Heteromodal association cortex: Integrating functions from multiple modalities.
Functional Areas
-
Motor
-
Primary motor areas:
- Located in the precentral gyrus of the frontal lobe
- Responsible for motor output to the contralateral side of the body
- Makes up the corticospinal tract
-
Supplementary motor area:
- Anterior to the primary motor area
- Superior to the premotor area
- Contains the motor map for posture
-
Premotor association area:
- Anterior to the primary motor area
- Inferior to the supplementary motor
- Involved in higher order processing and integrating motor information
-
Primary motor areas:
-
Motor-related
-
Frontal eye fields:
- Located in the supplementary motor area and extend anterior
- Involved in eye movement
-
Motor-hand area:
- Part of the precentral gyrus, just posterior to the frontal eye field
- Responsible for motor-hand function
-
Frontal eye fields:
-
Somatosensory
-
Primary somatosensory area:
- Located in the postcentral gyrus of the parietal lobe
- Sensory afferent from contralateral peripheral receptors travel to the thalamus and then end up in this area
- Makes up the spinothalamic tract
-
Somatosensory association area:
- Posterior to the primary somatosensory area
- Interpretation of the significance of sensory information (touch, pressure, proprioceptive information)
-
Primary somatosensory area:
-
Visual
-
Primary visual area:
- Located on the banks of the calcarine sulcus on the medial occipital lobe
- Fibers from retina -> lateral geniculate nucleus of thalamus -> primary visual cortex, travel as optic radiations
- Retinotopically organized
- Upper visual field: Inferior bank of the calcarine sulcus
- Lower visual field: Superior bank of the calcarine sulcus
- Highest visual acuity of the retina (fovea): Near occipital pole
-
Visual association area:
- Surrounds the primary visual cortex on the medial side
- Gives meaning and interpretation to visual information
-
Primary visual area:
-
Auditory areas
-
Primary auditory area:
- Composed of: Transverse Heschl's gyri deep within the lateral fissure; Part of the superior surface of the superior temporal gyrus for the temporal lobe
- Auditory information -> cochlea -> medial geniculate nucleus of thalamus -> primary auditory area cortex
- Information from the cochlea travels both ipsi and contralateral
-
Auditory association area:
- Adjacent to the primary auditory area, on the lateral surface of the superior temporal gyrus
- Interprets sound and gives meaning
-
Primary auditory area:
-
Insular cortex:
- Part of consciousness, emotion, self-awareness, and cognitive function
-
Primary gustatory area:
- Taste
Key Language Areas
- Broca's area: Located in the frontal lobe, anterior to the premotor association area and in the inferior frontal gyrus. Responsible for the production of all forms of language, including spoken, written, and signed communication.
- Wernicke's area: Situated in the parietal and temporal lobes, around the lateral fissure and the primary auditory area. Primarily responsible for language comprehension, encompassing both spoken and signed language.
Arcuate Fasciculus
- Connects Broca's and Wernicke's areas, facilitating communication between the two regions.
- A subcortical bundle of white matter, crucial for language processing.
Interacting Areas
- Broca's area: Has reciprocal connections with the frontal lobe to manage higher-order motor aspects of speech, including grammar and syntax.
- Wernicke's area: Has reciprocal connections with the parietal and temporal lobes, supporting vocabulary and mapping sounds to their meanings.
Hemisphere Specializations
- Dominant hemisphere: Usually the left hemisphere, responsible for language processing in the majority of individuals.
- Left hemisphere: Dominant in approximately 95% of right-handed people and 65% of left-handed people.
- Non-dominant hemisphere: Typically the right hemisphere, plays a role in non-verbal aspects of language like tone of voice, emotional significance, and melody.
- Corpus callosum: Connects the language areas of the left and right hemispheres, allowing for communication and coordination.
Aphasia
- A condition characterized by language impairment resulting from brain dysfunction, rather than disorders affecting language itself.
- Broca's aphasia: Also known as expressive or motor aphasia, it involves deficits in language production.
- Broca's aphasia symptoms: Halting and impaired fluency in speech, shortened speech length.
Key Language Areas
-
Broca's Area
- Located in the frontal lobe, anterior to the premotor association area, in the inferior frontal gyrus.
- Responsible for the production of all forms of language, including spoken, written, and signed.
-
Wernicke's Area
- Located in the parietal and temporal lobes, surrounding the lateral fissure and primary auditory area.
- Responsible for the comprehension of spoken and signed language.
Connections
-
Arcuate Fasciculus
- Subcortical bundle of white matter that connects Broca's and Wernicke's areas.
Interacting Areas
-
Broca's Area
- Contains reciprocal connections with the frontal lobe, which are used for the higher-order motor aspects of speech, grammar, and syntax.
-
Wernicke's Area
- Contains reciprocal connections with the parietal and temporal lobe, which are used for vocabulary and mapping sounds to meanings.
Hemisphere Specializations
- Language is primarily processed in the dominant hemisphere.
-
Left Hemisphere
- Dominant in approximately 95% of right-handed individuals and 65% of left-handed individuals.
-
Non-dominant Hemisphere
- Used for the non-verbal aspects of language, such as tone, emotional significance, and melody.
- The language areas of both hemispheres are connected via the corpus callosum.
Aphasia
-
Aphasia
- Language impairment caused by brain dysfunction, not by disorders that directly affect language.
-
Broca's Aphasia (Expressive/Motor Aphasia)
- Characterized by deficits in the production of language.
- Symptoms include halting language, impaired fluency, and shortened speech length.
Meninges
-
Layers: 3 membranes that protect the brain and spinal cord.
-
Dura mater: Outermost layer, directly connected to the skull.
- Composed of 2 fused layers:
- Periosteal layer: Attached to the skull.
-
Meningeal layer: Attached to the arachnoid, can form folds called dural reflections.
- Dural reflections include:
- Falx cerebri: Divides the two cerebral hemispheres.
- Tentorium cerebelli: Separates the cerebrum and cerebellum.
- Dural reflections include:
- Composed of 2 fused layers:
-
Arachnoid mater: Middle layer, web-like structure that adheres to the inner dural layer.
- Contains arachnoid granulations involved in CSF reabsorption.
- Arachnoid trabeculae connect arachnoid to pia mater.
- Pia mater: Innermost layer, tightly adheres to the brain.
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Dura mater: Outermost layer, directly connected to the skull.
Spaces
- Real spaces: Exist under normal conditions.
- Potential spaces: Become real spaces due to pathological conditions (e.g., accumulation of blood).
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Epidural space: Potential space between the skull and the periosteal layer of the dura.
- Contains meningeal arteries (branches of external carotid arteries) that supply the dura.
- Becomes a real space due to a bleed in the middle meningeal artery, often caused by a fracture of the temporal bone.
- Results in epidural hematoma.
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Subdural space: Potential space between the dura and arachnoid.
- Contains bridging veins that drain the cerebral hemispheres, travel in the subdural space, and drain into the dural venous sinus.
- Becomes a real space due to shear forces applied to the head, causing rupture of the bridging veins.
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Results in venous hemorrhage in the subdural space and a subdural hematoma (generally).
- Acute subdural hematoma: Occurs following significant head trauma.
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Results in venous hemorrhage in the subdural space and a subdural hematoma (generally).
Meninges
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Dura Mater: Outermost layer, connected to the skull; Composed of two fused layers:
- Periosteal layer: Connected to the skull
- Meningeal layer: Connected to arachnoid; Can create folds called dural reflections, these include the falx cerebri and tentorium cerebelli
- Arachnoid Mater: Middle layer; Spider-like, attaches to the inner layer of dura; Contains arachnoid granulations that are involved in reabsorbing cerebrospinal fluid (CSF); Arachnoid trabeculae connect the arachnoid to the pia mater
- Pia Mater: Innermost layer; Adheres tightly to the brain
Spaces
- Real spaces: Exist under normal conditions
- Potential spaces: Become real spaces pathologically with accumulation of blood
- Epidural space: Potential space between the skull and periosteal layer of the dura; Meningeal arteries (branches of external carotid arteries) run here and supply the dura; Becomes a real space due to a bleed in the middle meningeal artery from a fracture of the temporal bone, this results in an epidural hematoma
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Subdural space: Potential space between the dura and arachnoid; Bridging veins drain the cerebral hemispheres, travel in the subdural space, and drain into the dural venous sinus; Becomes a real space due to shear forces applied to the head causing a rupture of the bridging veins, this results in a venous hemorrhage in the subdural space known as a subdural hematoma, which can be acute or chronic
- Acute subdural hematoma: Following significant head trauma
Subarachnoid space
- Real space between arachnoid and pia mater
- Contains Cerebrospinal Fluid (CSF)
- This is the clinical space where CSF is sampled via lumbar puncture
- This is where blood is encountered in subarachnoid hemorrhage
- Subarachnoid hemorrhage typically occurs from a ruptured aneurysm
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Description
This quiz explores the components of the Central Nervous System, focusing on the forebrain and its key parts such as the cerebral cortex and its lobes. Participants will learn about the structure and functions of different brain regions, including the frontal, parietal, occipital, and temporal lobes. Test your knowledge on the intricate workings of the CNS!
