Chapter 14: The Brain and Cranial Nerves

a brain wave is a measure of the activity in the cells of the brain

Electrical

Migraine headache

Recurring headaches often accompanied by nausea, vomiting, dizziness, and aversion to light, often triggered by such factors as weather changes, stress, hunger, red wine, or noise; more common in women and sometimes running in families

The function of the cardiac center is to:

Regulate autonomic reflexes for controlling the rate of the heartbeat, Regulate autonomic reflexes for controlling the strength of the heartbeat

temporal lobe

The temporal lobe is a lateral, horizontal lobe deep to the temporal bone, separated from the parietal lobe above it by a deep lateral sulcus. It is concerned with hearing, smell, learning, memory, and some aspects of vision and emotion.

meninges

The three-layer fibrous membranes surrounding the brain and spinal cord are collectively called the ____.

cerebral cortex

a layer covering the surface of the hemispheres - superficial gray matter of the cerebrum - only 2 to 3 mm thick, the cortex constitutes about 40% of the mass of the brain and contains 14 to 16 billion neurons - possesses two principal types of neurons (fig. 14.15) called stellate cells and pyramidal cells.

midbrain

a short segment of brainstem that connects the hindbrain and forebrain

respiratory centers

a vasomotor center, which regulates blood pressure and flow by dilating and constricting blood vessels; two respiratory centers, which regulate the rhythm and depth of breathing; and other nuclei involved in the aforementioned motor functions.

epithalamus

a very small mass of tissue composed mainly of the pineal gland (an endocrine gland discussed in chapter 17), the habenula (a relay from the limbic system to the midbrain), and a thin roof over the third ventricle

Hydrocephalus

abnormal accumulation of CSF in the brain, usually resulting from a blockage in its route of flow and reabsorption

Sleep

can be defined as a temporary state of unconsciousness from which one can awaken when stimulated

posterior spinocerebellar tract

carries sensory signals to the cerebellum

a fetus has a blocked interventricular foramen what are the likely effects

hydrocephalus and impaired circulation of csf

The _____ region of the brain forms the floor and part of the walls of the third ventricle.

hypothalamus

nuclei

clusters of cell bodies in CNS

Association tracts

connect different regions within the same cerebral hemisphere. Long association fibers connect different lobes of a hemisphere to each other, whereas short association fibers connect different gyri within a single lobe. Among their roles, association tracts link perceptual and memory centers of the brain; for example, they enable you to smell a rose, name it, and imagine what it looks like.

blood-brain barrier (BBB)

consists of tight junctions between the endothelial cells that form the capillary walls

rostral

"toward the nose"

caudal

"toward the tail"

Name the prominent C-shaped band of nerve tracts that connect the right and left cerebral hemispheres to each other.

Corpus callosum

Memory

one of the cognitive functions

tectospinal tract

originates in the midbrain, passes through the medulla, and controls muscles of the neck.

sulcus or sulci

(anatomy) any of the narrow grooves in an organ or tissue especially those that mark the convolutions on the surface of the brain

V-VIII

- Cranial nerves V-VIII begin and end in pons.

suprachiasmatic nucleus (SCN)

- control center for sleep - located just above the optic chiasm in the anterior hypothalamus

electroencephalogram (EEG)

- records brain waves - useful in studying normal brain functions such as sleep and consciousness, and in diagnosing degenerative brain diseases, metabolic abnormalities, brain tumors, trauma, and so forth - frequency and amplitude distinguishes the various types of brain eaves

Cerebrospinal fluid (CSF)

-a clear, colorless liquid that fills the ventricles and canals of the CNS and bathes its external surface. The brain produces about 500 mL of CSF per day, but the fluid is constantly reabsorbed at the same rate and only 100 to 160 mL is normally present at one time Cerebrospinal fluid serves three purposes: 1. Buoyancy. Because the brain and CSF are similar in density, the brain neither sinks nor floats in the CSF. It hangs from delicate specialized fibroblasts of the arachnoid meninx. A human brain removed from the body weighs about 1,500 g, but when suspended in CSF its effective weight is only about 50 g. By analogy, consider how much easier it is to lift another person when you are standing in a lake than it is on land. This buoyancy allows the brain to attain considerable size without being impaired by its own weight. If the brain rested heavily on the floor of the cranium, the pressure would kill the nervous tissue. 2. Protection. CSF also protects the brain from striking the cranium when the head is jolted. If the jolt is severe, however, the brain still may strike the inside of the cranium or suffer shearing injury from contact with the angular surfaces of the cranial floor. This is one of the common findings in child abuse (shaken child syndrome) and in head injuries (concussions) from auto accidents, boxing, and the like. 3. Chemical stability. The flow of CSF rinses metabolic wastes from the nervous tissue and homeostatically regulates its chemical environment. Slight changes in CSF composition can cause malfunctions of the nervous system. For example, a high glycine concentration disrupts the control of body temperature and blood pressure, and a high pH causes dizziness and fainting.

the putamen and globus pallidus form a lens-shaped mass, the lentiform nucleus

...

commissure

1. A bundle of nerve fibers that crosses from one side of the brain or spinal cord to the other. 2. A corner or angle at which the eyelids, lips, or genital labia meet; in the eye, also called the canthus.

order in which the CSF flows:

1. the lateral ventricle 2. interventricular foramina 3. third ventricle 4. cerebral aqueduct 5. fourth ventricle

The ____ ventricle is a narrow median space inferior to the corpus callosum and reveives fluid from the interventricular foramen.

3rd

basal nuclei

= masses of cerebral gray matter buried deep in the white matter, lateral to the thalamus - often called basal ganglia, but the word ganglion is best restricted to clusters of neurons outside the CNS. - three brain centers: the caudate nucleus, putamen, and globus pallidus. (collectively called the corpus striatum because of their striped appearance)

pons

A brain structure that relays information from the cerebellum to the rest of the brain - measures about 2.5 cm long

neural tube

A dorsal hollow tube in the embryo that develops into the central nervous system.

ventricle

A fluid-filled chamber of the brain or heart.

vasomotor center

A nucleus in the medulla oblongata that transmits efferent signals to the blood vessels and regulates vasomotion.

Schizophrenia

A thought disorder involving delusions, hallucinations, inappropriate emotional responses to situations, incoherent speech, and withdrawal from society, resulting from hereditary or developmental abnormalities in neural networks

cranial nerve

Any of 12 pairs of nerves connected to the base of the brain and passing through foramina of the cranium.

The nerve fibers connecting the brain to the spinal cord passing through the medulla are:

Ascending sensory and descending motor

blood-CSF barrier

At the choroid plexuses, the brain is protected by a similar blood-CSF barrier formed by tight junctions between the ependymal cells.

Which area is responsible for the formation of spoken words?

Broca's area

arachnoid granulations

CSF is reabsorbed by arachnoid granulations, extensions of the arachnoid meninx shaped like little sprigs of cauliflower, protruding through the dura mater into the superior sagittal sinus. CSF penetrates the walls of the granulations and mixes with blood in the sinus.

Which of the following can freely pass through the blood-brain barrier?

Caffeine, glucose, oxygen

_____ functions to protect the brain and spinal cord from chemical and physical injury?

Cerebrosphinal fluid

Which three of the following structures are agreed upon by all sources as components of the limbic system?

Cingulate gyrus, Amygdala, Hippocampus

Concussion

Damage to the brain typically resulting from a blow, often with loss of consciousness, disturbances of vision or equilibrium, and short-term amnesia

The pyramids of the medulla oblongata are the sites of

Decussation of nerve tracts

List, from rostral to caudal, the components of the brainstem.

Diencephalon, Midbrain, Pons, Medulla oblangata.

Epilepsy

Disorder causing sudden, massive discharge of neurons (seizures) resulting in motor convulsions, sensory and psychic disturbances, and often impaired consciousness; may result from birth trauma, tumors, infections, drug or alcohol abuse, or congenital brain malformation

True or False: The hypothalamic thermostat responds to changes in the osmolarity of the extracellular fluid.

False

List structures located in the diencephalon.

Hypothalamus, epithalamus, thalamus

Encephalitis

Inflammation of the brain, accompanied by fever, usually caused by mosquito-borne viruses or herpes simplex virus; causes neuronal degeneration and necrosis; can lead to delirium, seizures, and death

The primary auditory cortex is distributed between two lobes of each cerebral hemisphere. Identify these two lobes.

Insula, Superior region of the temporal lobe.

olive

Lateral to each pyramid is a prominent bulge

The thalamus is involved in:

Memory and emotional functions of the limbic system

Another term describing the midbrain is:

Mesencephalon

Cerebral palsy

Muscular incoordination resulting from damage to the motor areas of the brain during fetal development, birth, or infancy; causes include prenatal rubella infection, drugs, or radiation exposure; oxygen deficiency during birth; and hydrocephalus

Name the embryonic structure that gives rise to most neurons and all glial cells except microglia.

Neural plate

Sensory receptors for equilibrium send signals to:

Nuclei in the brainstem, the cerebellum

choroid plexus

On the floor or wall of each ventricle is a spongy mass of blood capillaries called a choroid (CO-royd) plexus, named for its histological resemblance to a fetal membrane called the chorion.

The _____ lobe starts at the central sulcus and extends caudally to the parieto-occipital sulcus.

Parietal

The primary somesthetic association area is located in the ______ lobe and the ______.

Parietal lobe, Roof of the lateral sulcus

Wernicke's area is located in the left _____ and ____ lobes, and is responsible for interpreting the meaning of written and spoken language.

Parietal, temporal

gracile and cuneate fasciculi

Posteriorly, the gracile and cuneate fasciculi of the spinal cord continue as two pairs of ridges on the medulla.

Which structures are involved with emotional feelings and memories.

Prefrontal cortex, diencephalon

Stages of Sleep

Stage 1. One feels drowsy, closes the eyes, and begins to relax. Thoughts come and go, often accompanied by a drifting sensation. One awakens easily if stimulated. The EEG is dominated by alpha waves. Stage 2. One passes into light sleep. The EEG declines in frequency but increases in amplitude. Occasionally it exhibits 1 or 2 seconds of sleep spindles, high spikes resulting from interactions between neurons of the thalamus and cerebral cortex. Stage 3. This is moderate to deep sleep, typically beginning about 20 minutes after stage 1. Sleep spindles occur less often, and theta and delta waves appear. The muscles relax, and the vital signs (body temperature, blood pressure, and heart and respiratory rates) fall. Page 537 Stage 4. This is also called slow-wave sleep (SWS), because the EEG is dominated by low-frequency, high-amplitude delta waves. The muscles are now very relaxed, vital signs are at their lowest levels, and one becomes difficult to awaken.

Which of the following are the main components of the cerebral peduncles.

Substantia nigra, cerebral crus, tegmentum

cerebellum

The ______ is responsible for equilibrium, motor coordination, and memory of learned motor skills.

gracile and cuneate nuclei

The ascending fibers include first-order sensory fibers of the gracile and cuneate fasciculi, which end in the gracile and cuneate nuclei seen in Figure 14.9c, a cross section of the medulla. Here, they synapse with second-order fibers that decussate and form the ribbonlike medial lemniscus on each side.

frontal lobe

The frontal lobe lies immediately behind the frontal bone, superior to the eyes. From the forehead, it extends caudally to a wavy vertical groove, the central sulcus. It is chiefly concerned with voluntary motor functions, motivation, foresight, planning, memory, mood, emotion, social judgment, and aggression.

inferior and superior colliculi

The inferior colliculi (auditory) of the midbrain are located just below the visual processing centers known as the superior colliculi.

hypothalamus

The inferior portion of the diencephalon of the brain, forming the walls and floor of the third ventricle and giving rise to the posterior pituitary gland; controls many fundamental physiological functions such as appetite, thirst, and body temperature and exerts many of its effects through the endocrine and autonomic nervous systems. -- Hormone secretion. The hypothalamus secretes hormones that control the anterior pituitary gland. Acting through the pituitary, it regulates growth, metabolism, reproduction, and stress responses. The hypothalamus also produces two hormones that are stored in the posterior pituitary gland, concerned with labor contractions, lactation, and water conservation. These relationships are explored especially in chapter 17. -- Autonomic effects. The hypothalamus is a major integrating center for the autonomic nervous system. It sends descending fibers to lower brainstem nuclei that influence heart rate, blood pressure, gastro-intestinal secretion and motility, and pupillary diameter, among other functions. -- Thermoregulation. The hypothalamic thermostat consists of a collection of neurons, concentrated especially in the preoptic nucleus, that monitor body temperature. When the temperature deviates too much from its set point, this center activates either a heat-loss center in the anterior hypothalamus or a heat-promoting center in the posterior hypothalamus. Those centers activate mechanisms for lowering or raising the body temperature. These mechanisms are detailed at the end of chapter 26. -- Food and water intake. The hypothalamus regulates sensations of hunger and satiety. One nucleus in particular, the arcuate nucleus, contains receptors for hormones that increase hunger and energy expenditure, other hormones that reduce both, and hormones that exert long-term control over body mass. These are further discussed in chapter 26. Hypothalamic neurons called osmoreceptors monitor the osmolarity of the blood and stimulate water-seeking and drinking behavior when the body is dehydrated. Dehydration also stimulates the hypothalamus to produce antidiuretic hormone, which conserves water by reducing urine output. -- Sleep and circadian rhythms. The caudal part of the hypothalamus is part of the reticular formation. It contains nuclei that regulate the rhythm of sleep and waking. Superior to the optic chiasm, the hypothalamus contains a suprachiasmatic nucleus that controls our 24-hour (circadian) rhythm of activity. -- Memory. The mammillary nuclei lie in the pathway of signals traveling from the hippocampus, an important memory center of the brain, to the thalamus. Thus, they are important in memory, and lesions to the mammillary nuclei cause memory deficits. (Memory is discussed more fully on p. 538.) -- Emotional behavior and sexual response. Hypothalamic centers are involved in a variety of emotional responses including anger, aggression, fear, pleasure, and contentment; and in sexual drive, copulation, and orgasm.

insula

The insula is a small mass of cortex deep to the lateral sulcus, made visible only by retracting or cutting away some of the overlying cerebrum. It is less understood than the other lobes because it is less accessible to testing in living subjects, but it apparently plays roles in understanding spoken language, in the sense of taste, and in integrating sensory information from visceral receptors.

thalamus

The largest part of the diencephalon, located immediately inferior to the corpus callosum and bulging into each lateral ventricle; a point of synaptic relay of nearly all signals passing from lower levels of the CNS to the cerebrum.

medulla oblongata

The most caudal part of the brainstem, immediately superior to the foramen magnum of the skull, connecting the spinal cord to the rest of the brain.

occipital lobe

The occipital lobe is at the rear of the head, caudal to the parieto-occipital sulcus and underlying the occipital bone. It is the principal visual center of the brain.

cortex

The outer layer of some organs such as the adrenal gland, cerebrum, lymph node, and ovary; usually covers or encloses tissue called the medulla.

parietal lobe

The parietal lobe forms the uppermost part of the brain and underlies the parietal bone. Starting at the central sulcus, it extends caudally to the parieto-occipital sulcus, visible on the medial surface of each hemisphere. It is the primary site for receiving and interpreting signals of the general senses described later; for taste (one of the special senses); and for some visual processing.

Folia

The slender, transverse, parallel folds of the cerebellum are specifically called _____.

reticular formation

a loose network of nuclei extending throughout the medulla, pons, and midbrain - a loosely organized web of gray matter that runs vertically through all levels of the brainstem -- Somatic motor control. Some motor neurons of the cerebral cortex send their axons to reticular formation nuclei, which then give rise to the reticulospinal tracts of the spinal cord. These tracts adjust muscle tension to maintain tone, balance, and posture, especially during body movements. The reticular formation also relays signals from the eyes and ears to the cerebellum so the cerebellum can integrate visual, auditory, and vestibular (balance and motion) stimuli into its role in motor coordination. Other motor nuclei include gaze centers, which enable the eyes to track and fixate objects, and central pattern generators—neural pools that produce rhythmic signals to the muscles of breathing and swallowing. -- Cardiovascular control. The reticular formation includes the previously mentioned cardiac and vasomotor centers of the medulla oblongata. -- Pain modulation. The reticular formation is one route by which pain signals from the lower body reach the cerebral cortex. It is also the origin of the descending analgesic pathways mentioned in the description of the reticulospinal tracts on page 486. Under certain circumstances, the nerve fibers in these pathways act in the spinal cord to deaden one's awareness of pain (see chapter 16). -- Sleep and consciousness. The reticular formation has projections to the thalamus and cerebral cortex that allow it some control over what sensory signals reach the cerebrum and come to our conscious attention. It plays a central role in states of consciousness such as alertness and sleep. Injury to the reticular formation can result in irreversible coma. -- Habituation. This is a process in which the brain learns to ignore repetitive, inconsequential stimuli while remaining sensitive to others. In a noisy city, for example, a person can sleep through traffic sounds but wake promptly to the sound of an alarm clock or a crying baby. Reticular formation nuclei that modulate activity of the cerebral cortex are called the reticular activating system or extrathalamic cortical modulatory system.

inferior olivary nucleus

a major relay center for signals going from many levels of the brain and spinal cord to the cerebellum

cerebral hemispheres

a pair of half globes in the cerebrum

pyramids

a pair of ridges on the anterior surface resembling side-by-side baseball bats, these are wider at the rostral end, taper caudally, and are separated by a groove, the anterior median fissure continuous with that of the spinal cord.

limbic system

an important center of emotion and learning

cerebrum

anterior portion of the brain consisting of two hemispheres, , area of the brain responsible for all voluntary activities of the body - 83% of the brain's volume

Aphasia

any language deficit resulting from lesions in the hemisphere (usually the left) containing the Wernicke and Broca areas.

tracts

bundles of axons in the white matter of the CNS that share common origins, destinations and functions

diencephalon

between cerebrum and midbrain, 2 main parts thalamus and hypothalamus - A portion of the brain between the midbrain and corpus callosum; composed of the thalamus, epithalamus, and hypothalamus.

Association areas are regions of the _____ ______ where sensory perception, thought, reasoning, judgement, memory, imagination and intuition occurs.

cerebral cortex

Basal nuclei reveive signals from the:

cerebral cortex, midbrain

Commissural tracts

cross from one cerebral hemisphere to the other through bridges called commissures (COM-ih-shurs). The great majority of commissural tracts pass through the large corpus callosum (see fig. 14.2). A few tracts pass through the much smaller anterior and posterior commissures. Commissural tracts enable the two sides of the cerebrum to communicate with each other.

The ____ is the region of the brain between the midbrain and corpus callosum.

diencephalon

gyri

elevated ridges on cortical surface of the cerebral hemisphere, which increase the surface area and provide space for additional cortical neurons

Which structures produce CSF?

ependymal cells, choroid plexus

Projection tracts

extend vertically between higher and lower brain and spinal cord centers, and carry information between the cerebrum and the rest of the body. The corticospinal tracts, for example, carry motor signals from the cerebrum to the brainstem and spinal cord. Other projection tracts carry signals upward to the cerebral cortex. Superior to the brainstem, such tracts form a broad, dense sheet called the internal capsule between the thalamus and basal nuclei (described shortly), then radiate in a diverging, fanlike array (the corona radiata34) to specific areas of the cortex.

Beta (β) waves

have a frequency of 14 to 30 Hz and occur in the frontal to parietal region. They are accentuated during mental activity and sensory stimulation.

Theta (θ) waves

have a frequency of 4 to 7 Hz. They are normal in children and in drowsy or sleeping adults, but a predominance of theta waves in awake adults suggests emotional stress or brain disorders.

Alpha (α) waves

have a frequency of 8 to 13 Hz and are recorded especially in the parieto-occipital area. They dominate the EEG when a person is awake and resting, with the eyes closed and the mind wandering. They are suppressed when a person opens the eyes, receives specific sensory stimulation, or engages in a mental task such as performing mathematical calculations. They are absent during deep sleep.

Delta (δ) waves

high-amplitude "slow waves" with a frequency of less than 3.5 Hz. Infants exhibit delta waves when awake, and adults exhibit them in deep sleep. A predominance of delta waves in awake adults indicates serious brain damage.

circumventricular organs (CVOs)

in the third and fourth ventricles where the barrier is absent and the blood has direct access to brain neurons. These enable the brain to monitor and respond to fluctuations in blood glucose, pH, osmolarity, and other variables.

general (somatosensory, somesthetic, or somatic) senses

include such senses as touch, pressure, stretch, movement, heat, cold, and pain

Meningitis

inflammation of the meninges—is one of the most serious diseases of infancy and childhood. It occurs especially between 3 months and 2 years of age. Meningitis is caused by a variety of bacteria and viruses that invade the CNS by way of the nose and throat, often following respiratory, throat, or ear infections.

the _____ system is part of the brain involved with coordination of motor input, and emotion.

limbic

special senses

limited to the head and employ relatively complex sense organs - Vision. Visual signals are received by the primary visual cortex in the far posterior region of the occipital lobe. This is bordered anteriorly by the visual association area, which includes all the remainder of the occipital lobe, some of the posterior parietal lobe (concerned with spatial perception), and much of the inferior temporal lobe, where we recognize faces and other familiar objects. - Hearing. Auditory signals are received by the primary auditory cortex in the superior region of the temporal lobe and in the nearby insula. The auditory association area occupies areas of temporal lobe inferior to the primary auditory cortex and deep within the lateral sulcus. This is where we become capable of recognizing spoken words, a familiar piece of music, or a voice on the telephone. - Equilibrium. Signals from the inner ear for equilibrium project mainly to the cerebellum and several brainstem nuclei concerned with head and eye movements and visceral functions. Some fibers of this system, however, are routed through the thalamus to areas of association cortex in the roof of the lateral sulcus and near the lower end of the central sulcus. This is the seat of consciousness of our body movements and orientation in space. - Taste and smell. Gustatory (taste) signals (gustation) are received by the primary gustatory cortex in the inferior end of the postcentral gyrus of the parietal lobe (discussed shortly) and an anterior region of the insula. Olfactory (smell) signals are received by the primary olfactory cortex in the medial surface of the temporal lobe and inferior surface of the frontal lobe. The orbitofrontal cortex mentioned earlier serves as a multimodal association area for both of these senses.

During embryonic development, the midbrain does not divide and retains the name____.

mesencephalon.

the pons develops from an embryonic ssecondary brain vesicle called the _____.

metencephalon.

The primary visual cortex, which recieves visual stimuli is located in the posterior region of the occipital lobe.

occipital

cardiac center

regulates the rate and force of the heartbeat

Wernicke area

responsible for the recognition of spoken and written language

After an injury to the head, Hans cannot remember the past several years of his life. Hans has _____ amnesia.

retrograde

brain waves

rhythmic voltage changes resulting predominantly from synchronized postsynaptic potentials in the superficial layers of the cerebral cortex

transverse cerebral fissure

separates the cerebellum from the cerebrum

longitudinal fissure

separates the two cerebral hemispheres

circadian rhythms

so named because they are marked by events that reoccur at intervals of about 24 hours

Stellate cells

spheroidal somas with dendrites projecting for short distances in all directions. They are concerned largely with receiving sensory input and processing information on a local level.

brain barrier system

strictly regulates what substances can get from the bloodstream into the tissue fluid of the brain - highly permeable to water, glucose, and lipid-soluble substances such as oxygen, carbon dioxide, alcohol, caffeine, nicotine, and anesthetics. It is slightly permeable to sodium, potassium, chloride, and the waste products urea and creatinine. While the BBS is an important protective device, it is an obstacle to the delivery of medications such as antibiotics and cancer drugs, and thus complicates the treatment of brain diseases.

cerebral crura

structures which consist of axons that transmit motor impulses from the cerebral cortex to the pons, medulla oblongata, and spinal cord

Pyramidal cells

tall and conical (triangular in tissue sections). Their apex points toward the brain surface and has a thick dendrite with many branches and small, knobby dendritic spines. The base gives rise to horizontally oriented dendrites and an axon that passes into the white matter. Pyramidal cells include the output neurons of the cerebrum—the only cerebral neurons whose fibers leave the cortex and connect with other parts of the CNS. Pyramidal cell axons have collaterals that synapse with other neurons in the cortex or in deeper regions of the brain.

The ____ is located in the diencephalon on each side of the brain at the superior end of the brainstem beneath the cerebral hemispheres.

thalamus

cerebellum

the "little brain" attached to the rear of the brainstem; its functions include processing sensory input and coordinating movement output and balance - A large portion of the brain posterior to the brainstem and inferior to the cerebrum, responsible for equilibrium, motor coordination, and memory of learned motor skills.

rapid eye movement (REM) sleep

the eyes oscillate back and forth as if watching a movie. It is also called paradoxical sleep because the EEG resembles the waking state, yet the sleeper is harder to arouse than in any other stage. The vital signs increase and the brain consumes even more oxygen than when awake - Dreams occur in both REM and non-REM sleep, but REM dreams tend to be longer, more vivid, and more emotional than non-REM dreams.

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

purkije cells

the most distinctive, unsusially large cells of the cerebellum with thick dendrites compressed into a single plane

brainstem

the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus, responsible for automatic survival functions - The stalklike lower portion of the brain, composed of all of the brain except the cerebrum and cerebellum. (Many authorities also exclude the diencephalon and regard only the medulla oblongata, pons, and midbrain as the brainstem.

vermis

the portion of the cerebellum that connects the right and left cerebellar hemispheres

Cognition

the range of mental processes by which we acquire and use knowledge—sensory perception, thought, reasoning, judgment, memory, imagination, and intuition

Prefrontal cortex

the seat of judgement, intent, and control over the expression of our emotions

primary sensory cortex

the sites where sensory input is first received and one becomes conscious of a stimulus

arbor vitae

the white matter located in the deep aspects of the cerebellum exhibiting a branching fern-like pattern

True or false: There are three types of tracts in the cerebral white matter.

true (projection, commissural and association tracts)

The perception of visual stimulus by the primary visual cortex is called ______.

vision