What is a sensory homunculus?
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A representation of the sensory areas of the body in the brain.
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What is a sensory homunculus?
A representation of the sensory areas of the body in the brain.
What do loss of function experiments test?
Whether a missing component is necessary for a function.
What is the function of Broca's area?
It is responsible for our ability to speak and have good understanding.
What is the role of Wernicke's area?
It is associated with difficulty understanding language.
What do gain of function experiments involve?
Adding a specific component to the system.
What does the motor homunculus represent?
It represents the body map of motor control in the brain.
What is an example of a perturbation experiment?
Putting prisms on a barn owl.
Who was Camillo Golgi?
A scientist who believed in the reticular theory and discovered the Golgi apparatus.
What is the most commonly encountered neuron in the mammalian cerebral cortex?
The pyramidal neuron.
What does the neuron doctrine state?
Neuronal processes do not fuse together to form a continuous reticulum; neurons communicate at distinct contact sites called synapses.
What significant invention did Camillo Golgi create?
The Golgi stain.
Describe the structure of a pyramidal neuron.
It has a pyramid-shaped cell body with an apical dendrite and several extensively branching basal dendrites.
What is the length of the synaptic cleft?
20-100 nm.
What does the Golgi stain allow scientists to visualize?
The entire morphology of individualized neurons.
Who coined the term 'synapses'?
Charles Sherrington.
What are basket cells known for?
They wrap their axon terminals around the cell bodies of pyramidal cells in the cerebral cortex and Purkinje cells in the cerebellum.
What structure leads axons and changes shape dynamically?
Growth cone.
What technique did Ramon y Cajal use to support the neuron doctrine?
The Golgi stain.
How is the Golgi stain applied to neural tissue?
By soaking it in a solution of silver nitrate and potassium dichromate in the dark for several weeks.
Where is the action potential initiated in sensory neurons?
At the junction between terminal endings and the peripheral axon.
What are the four subtypes of glial cells?
Oligodendrocytes, Schwann cells, Astrocytes, and Microglia.
What characterizes a multipolar neuron?
It has both dendrites and an axon leaving the cell body.
What are neurons considered according to Ramon y Cajal?
Functionally, structurally, and embryonically independent units of the nervous system.
What technique cannot resolve structures less than 200 nm apart?
Light microscopy.
What happens when the Golgi stain is applied to nerve cells?
Black precipitates form, rendering the cells visible against an unstained background.
How is information transmitted in sensory neurons?
By the peripheral and central axon to the spinal cord across a long distance.
What role do astrocytes play in the nervous system?
They are involved in neural development and regulation of neuronal communication.
What type of neuron are somatosensory neurons classified as?
Pseudounipolar neurons.
What happens during the development of neurons?
Neurons start with only cell bodies, and axons grow out from the cell bodies to their final destinations.
What do presynaptic terminals contain that is crucial for neurotransmission?
Small synaptic vesicles filled with neurotransmitters.
What is the result of the autocatalytic reaction in stained cells?
The majority of the cell can be visualized in its native tissue.
Where does action potential initiation likely occur in invertebrate neurons?
At the junction between the dendritic and axonal compartments.
What initiates the avoidance response in zebrafish larvae?
A sensory neuron detects a splash of water.
What is the function of microglia?
They act as immune cells, engulfing damaged cells and debris, and help reorganize neuronal connections.
What experimental technique allowed observation of axon growth?
In vitro experiments made possible by tissue culturing techniques.
What is unique about pseudounipolar neurons?
They have one process leaving the cell body that gives rise to both peripheral and central branches.
What are the specialized structures on postsynaptic target cells enriched with?
Neurotransmitter receptors.
How is information transmitted at electrical synapses?
By a membrane potential change in ions across the gap junction.
What is the role of the motor neuron in the zebrafish larvae's response?
It communicates impulses to run.
What do oligodendrocytes and Schwann cells do?
They wrap axons with myelin sheaths in their respective parts of the nervous system.
Who proposed the theory of dynamic polarization?
Ramon y Cajal.
What type of synapses are commonly referred to as chemical synapses?
Regular synapses.
Who first coined the phrase 'nature vs. nurture'?
Francis Galton in the 1800s.
What triggers neurotransmitter release at chemical synapses?
Arrival of action potentials at presynaptic terminals.
What is electron microscopy used for?
To visualize structures at nanometer resolution.
What comprises spinal reflexes in vertebrates?
A sensory neuron that receives external stimuli and a motor neuron that controls muscle contraction.
How do myelin sheaths affect information propagation?
They increase the speed at which information is propagated along axons.
What does the theory of dynamic polarization state?
Transmission of neuronal signals proceeds from dendrites to cell bodies to axons.
How do neurons communicate via electrical synapses?
Through gap junctions.
What are identical twins also known as?
Monozygotic twins.
What is neuroplasticity?
Changes in the nervous system in response to experience and learning.
What is synaptic transmission?
The process of neurotransmitter release from the presynaptic neuron and neurotransmitter reception at the postsynaptic neuron.
What specialized apparatus do sensory neurons embed their endings in for the knee jerk reflex?
Muscle spindles.
What is gray matter composed of in the CNS?
Astrocytes, neuronal cell bodies, dendrites, axon terminals, and connections between neurons.
What do gap junctions allow to travel between adjacent neurons?
Ions and small molecules.
How did barn owls adapt to the prisms in the experiment?
They adjusted their auditory map to match their visual map.
What is white matter composed of in the CNS?
Oligodendrocytes and myelinated axons.
What is the correlation between identical twins and IQ?
0.86.
How is intraneuronal communication achieved?
By membrane potential changes in the form of graded potentials and action potentials.
How do sensory neurons detect the stretching of muscle spindles?
By converting the physical impact of the hammer into electrical signals (receptor potentials).
What type of neuron extends a single process that bifurcates in the somatosensory system?
Sensory neuron.
What is neuroethology?
The field of study that emphasizes observing animal behavior in their natural environments.
What does interneuronal communication rely on?
Neurotransmitter release and reception at chemical synapses.
What did Mathias Schleiden and Theodor Schwann propose in 1839?
The cell theory: all living organisms are composed of cells as their basic units.
What happens after sensory neurons propagate electrical signals to the spinal cord?
They release neurotransmitters onto the dendrites of motor neurons.
What are nerves?
Discrete bundles of axons.
What are nonidentical twins also known as?
Dizygotic twins.
What are fixed action patterns?
Instinctive behaviors.
What does the spinal cord motor neuron project its axon into?
Muscle.
What was the reticular theory regarding the nervous system?
It proposed that nerve cells were linked together to form a giant net, or reticulum, constituting the unit of the nervous system.
What are neural circuits?
Ensembles of interconnected neurons that work together to perform a specific function.
What is the correlation between dizygotic twins and IQ?
0.60.
What is the function of the axons of motor neurons in the knee jerk reflex?
They extend outwards from the spinal cord and terminate in the same extensor muscle.
What are ganglia?
Clusters of cell bodies of nerve cells.
What are releasers in the context of fixed action patterns?
The essential features of the stimulus that activate the fixed action pattern.
How is heritability defined?
The contribution of genetic differences to trait differences.
What are circuit motifs in the nervous system?
Common configurations of neural circuits that allow specific functions.
What are the two sides of the brain called?
Hemispheres.
How does neuroplasticity change with age?
It declines with age; juvenile owls adapt more quickly than adult owls.
What is the heritability of IQ calculated from the twin studies?
0.52.
What is convergent excitation?
When several neurons synapse onto a postsynaptic neuron.
How is the nervous system traditionally examined?
In three sections: transverse, sagittal, and horizontal.
What are the main components of the central nervous system (CNS)?
The brain and spinal cord.
What are epigenetic modifications?
Changes made to DNA and chromatin that alter gene expression without modifying DNA sequences.
What does the neuraxis refer to?
The rostral-caudal axis or CNS axis.
What are axonal branches also known as?
Collaterals.
How is the mammalian brain organized?
It consists of the cerebral cortex, basal ganglia, hippocampus, amygdala, thalamus, hypothalamus, cerebellum, and brainstem.
What is an example of instinctive behavior in animals?
A baby penguin nudging the beak of its parent for food.
What are the two major categories of cells in the CNS?
Neurons and glial cells.
What are the three developmental regions of the brain?
Forebrain, midbrain, and hindbrain.
What does 'innate' refer to in the context of behavior?
Something genetically programmed within an organism from birth.
What are typical neurons characterized by?
Having two neuronal processes (cytoplasmic extensions).
What segments make up the spinal cord?
Cervical, thoracic, lumbar, and sacral groups.
What was the purpose of putting prism glasses on barn owls in the experiment?
To distort their vision and study the correlation between auditory and visual systems.
What are axons?
Long, thin processes that extend far beyond the cell body.
What does the peripheral nervous system (PNS) include?
Nerves and ganglia.
What are presynaptic terminals?
The ends of axons that specialize in the transmission of information between neurons.
What are dendrites?
Thick, bushy processes that receive information.
What are the three main components of a neuron?
What are dendritic spines?
Protrusions on dendrites that specialize in information transfer.
What is the function of dendrites in a neuron?
Dendrites receive information.
What is the cell body of a neuron?
The center of the neuron.
What is the role of axons in a neuron?
Axons send information.
What type of neurons are usually found in invertebrates?
Unipolar neurons, which extend a single process giving rise to both dendritic and axonal branches.
Who discovered that electric current could generate muscle twitches in frogs?
Luigi Galvani.
What is an action potential?
The elementary unit of nerve impulses propagated along axons.
How do neurons convey the intensity of signals?
By using the frequencies of action potentials.
What are graded potentials?
Membrane potentials that vary continuously in magnitude, induced by sensory stimuli.
What are synaptic potentials?
A type of graded potential produced at postsynaptic sites in response to neurotransmitter release.
What is the axon initial segment (axon hillock)?
The site of action potential initiation.
