Neuropsychology, Brain Development, and Brain Damage: Key Concepts and Structures

What is Neuropsychology?

The study of the relationship between the nervous system and behavior.

How is Neuropsychology related to Cognitive Neuroscience?

Both study how the brain supports thinking and behavior, but Neuropsychology focuses on how brain damage affects behavior.

What is the distinction between clinical and experimental neuropsychologists?

Clinical neuropsychologists work directly with patients, while experimental neuropsychologists conduct research.

What is trephination?

An ancient surgical procedure where a hole was drilled or scraped into the skull.

Why was trephination performed?

To relieve pressure or swelling in the brain.

What were the two theories about where behavior originates?

Cardiac hypothesis (behavior originates in the heart) and Brain hypothesis (behavior originates in the brain).

Which theory did Hippocrates support?

The brain hypothesis.

Which theory did Aristotle support?

The cardiac hypothesis.

What is the Humor Theory?

The belief that behavior was caused by the balance of four bodily fluids: blood, mucus, yellow bile, and black bile.

Who held the Humor Theory?

Hippocrates and Galen.

What is the Ventricular Theory?

The belief that mental functions were located in the ventricles of the brain.

What did Galen's knowledge of anatomy rely on?

Animal dissections, not human bodies.

Why did anatomical knowledge not advance for 14 centuries after Galen?

Human dissection was restricted, so Galen's writings were accepted without challenge.

How did Andreas Vesalius improve anatomical knowledge?

By performing careful human dissections and directly observing the human body.

What is phrenology?

A pseudoscientific theory claiming that different mental abilities and personality traits are localized in specific areas of the brain.

Who were the first two men famous for promoting localization of function in its pseudoscientific form?

Franz Joseph Gall and Johann Spurzheim.

Who provided scientific evidence for localization of function?

Paul Broca and Carl Wernicke.

What is equipotentiality?

The idea that all parts of the brain contribute equally to behavior.

What led Flourens to hold the view of equipotentiality?

Lesion experiments on animals showed that removing different cortical areas did not produce specific deficits.

What is mass action?

The idea that the brain works as a whole for complex behaviors, and impairment depends on the amount of cortex removed.

What view did Hughlings Jackson propose regarding the nervous system?

That the nervous system is organized hierarchically.

What was Luria's view on the organization of the nervous system?

That the brain works as a functional system, not as isolated centers.

What are Luria's three functional units of the brain?

1. Arousal/Attention Unit, 2. Information Processing Unit, 3. Planning and Regulation Unit.

What is the distinction between the central and peripheral nervous system?

The CNS consists of the brain and spinal cord; the PNS consists of all nerves outside the CNS.

What parts comprise the central nervous system?

The brain and the spinal cord.

What is the difference between the somatic and autonomic nervous system?

The somatic nervous system controls voluntary movements, while the autonomic nervous system regulates involuntary functions.

What does the somatic nervous system control?

Voluntary movements of skeletal muscles and sensory information to the CNS.

What does the autonomic nervous system control?

Involuntary functions such as heart rate, digestion, and gland activity.

What do afferent fibers do?

Carry sensory information toward the central nervous system (CNS).

What do efferent fibers do?

Carry motor commands away from the CNS to muscles and glands.

What does ventral mean?

Toward the front (belly side).

What does dorsal mean?

Toward the back.

What does rostral mean?

Toward the nose/front of the brain.

What does caudal mean?

Toward the tail/back of the brain.

What does medial mean?

Toward the midline.

What does lateral mean?

Away from the midline.

What does superior mean?

Above.

What does inferior mean?

Below.

What does anterior mean?

Front.

What does posterior mean?

Back.

How are dorsal, ventral, rostral, and caudal different for the trunk?

Dorsal = back, Ventral = front, Rostral = toward the head, Caudal = toward the feet.

How are dorsal, ventral, rostral, and caudal different for the head?

Dorsal = top, Ventral = bottom, Rostral = front (toward the face), Caudal = back (toward the back of the head).

What is the sagittal plane?

Divides the brain/body into left and right portions.

What is the midsagittal plane?

Divides the brain into equal left and right halves.

What is the frontal (coronal) plane?

Divides the brain/body into front (anterior) and back (posterior) sections.

What is the horizontal (transverse) plane?

Divides the brain/body into top (superior) and bottom (inferior) sections.

What are the two general classes of cells in the nervous system?

Neurons and glial cells.

What is the estimate for the number of neurons?

Approximately 86 billion.

What are the parts of a neuron?

Dendrites, cell body (soma), axon.

What is the main function of a neuron?

Process and transmit information.

What is a myelin sheath?

A fatty wrapping around the axon.

What difference does it make if an axon is myelinated?

Transmission is about 4 times faster.

What are the types of glial cells?

Microglia, astrocytes, oligodendrocytes, Schwann cells.

What is the function of microglia?

Clean debris and bacteria.

What is the function of astrocytes?

Provide nutrients, maintain ionic balance, help repair, support blood-brain barrier.

What is the function of oligodendrocytes?

Produce myelin in the CNS.

What is the function of Schwann cells?

Produce myelin in the PNS.

How do oligodendrocytes and Schwann cells differ?

Oligodendrocytes wrap multiple axons in the CNS; Schwann cells wrap one segment of one axon in the PNS.

What is the difference in composition between white and gray matter?

White matter is mostly axons; gray matter is mostly cell bodies.

Where is gray matter found in the brain?

In the cerebral cortex and other areas containing neuron cell bodies.

What are fibers, tracts, and pathways?

Fibers are individual axons; tracts are bundles of axons within the CNS; pathways are functional connections made up of multiple tracts.

What is multiple sclerosis (MS)?

A demyelinating disorder in which myelin in the central nervous system is damaged.

What is the general disease mechanism in MS?

Demyelination due to the immune system attacking oligodendrocytes.

What is the proximal cause of MS?

Autoimmune attack on the body's own cells.

What is the distal cause of MS?

Likely genetic susceptibility plus an environmental trigger.

What categories of symptoms occur in MS?

Sensory, motor, cognitive, emotional.

What is the incidence of MS in the US?

About 1 in 2000 people.

What is the usual age of onset of MS?

Common onset is 20-40 years old.

What is the gender difference in incidence of MS?

More common in women.

What are the three characteristics of MS that get treated?

Attacks (relapses), disease progression, symptoms.

What is neurogenesis?

Creation of new neurons.

When does most neurogenesis take place?

Prenatally.

What is migration in the context of neurodevelopment?

Movement of neurons to their proper location.

When does migration take place?

Prenatally, mainly during early brain development.

What is synaptogenesis?

Formation of synapses between neurons.

When does synaptogenesis start and how long does it continue?

Begins before birth, increases rapidly after birth, and continues through development.

What is myelination?

Formation of the myelin sheath around axons.

When does myelination start and how long does it continue?

Begins before birth and continues into adolescence and early adulthood.

What is synaptic pruning?

Elimination of unused synapses.

When does synaptic pruning start and how long does it continue?

Begins in infancy and continues into adolescence.

What three layers does the embryonic plate develop into?

Ectoderm, mesoderm, endoderm.

What does the ectoderm develop into?

Nervous tissue and epidermis (skin).

What does the mesoderm develop into?

Muscles and skeleton.

What does the endoderm develop into?

Gut and internal organs.

When does the neural tube close on average at the anterior and posterior pores?

Around day 24-28 of development.

What defects result when the neural pores do not close?

Serious defects can occur, particularly with nonclosure of the anterior pore.

What happens when the anterior pore fails to close?

Anencephaly

What happens when the posterior pore fails to close?

Spina bifida

What is lissencephaly?

A condition characterized by a smooth brain due to defective neuronal migration.

What is microcephaly?

A condition of small head circumference, with causes including genetic factors, viral infections, and hypoxia.

Which virus is associated with microcephaly?

Zika virus

What are the 7 CNS structures from caudal to rostral?

Spinal cord, medulla oblongata, pons, cerebellum, midbrain, diencephalon, corpus callosum.

Which structure in the adult human brain comes from the vertebrate myelencephalon?

Medulla oblongata

Which structures in the adult human brain come from the vertebrate metencephalon?

Cerebellum, pons, fourth ventricle, brainstem.

What is another name for the vertebrate mesencephalon?

Midbrain

Which structures in the adult human brain come from the vertebrate diencephalon?

Thalamus, hypothalamus, pineal body, third ventricle.

What structures in the adult human brain come from the vertebrate telencephalon?

Neocortex, basal ganglia, limbic system, olfactory bulb, lateral ventricles, forebrain.

What are the names of the meningeal membranes?

Dura mater, arachnoid, pia mater.

What is the result of folding of the dura in the skull?

It divides the brain into two hemispheres and separates the cerebrum from the cerebellum.

What is the subarachnoid space?

The space underneath the arachnoid that contains arteries and cerebrospinal fluid.