The Brain

rhinencephalon

"nose brain"), which includes all parts of the cerebrum that receive olfactory signals

corpus callosum

"thickened body," The largest commissure, lies superior to the lateral ventricles, deep within the longitudinal fissure

gyri

"twisters" elevated ridges of tissue

mammillary bodies

( "little breast"), paired pealike nuclei that bulge anteriorly from the hypothalamus, are relay stations in the olfactory pathways

metencephalon

("afterbrain")

telencephalon ("endbrain")

("endbrain")

diencephalon

("interbrain"),

myelencephalon

("spinal brain")

form three broad columns along the length of the brain stem

(1) the midline raphe nuclei (raphe = seam or crease), which are flanked laterally by (2) the medial (large cell) group and then (3) the lateral (small cell) group of nuclei.

Various other centers found in the medulla

Additional centers regulate such activities as vomiting, hiccuping, swallowing, coughing, and sneezing

The multimodal association areas are divided into 3 areas

Anterior association area,Posterior association area,Limbic association area

Premotor cortex

Anterior to the precentral gyrus,Controls learned, repetitious, or patterned motor skills

Sensory Areas

Areas concerned with conscious awareness of sensation, occur in the parietal, insular, temporal, and occipital lobes

internal capsule

At the top of the brain stem, the projection fibers on each side form a compact band, that passes between the thalamus and some of the basal nuclei.

primary auditory cortex

Auditory areas. is located in the superior margin of the temporal lobe abutting the lateral sulcus. Sound energy exciting the inner ear hearing receptors causes impulses to be transmitted to the primary auditory cortex, where they are interpreted as pitch, loudness, and location

infundibulum

Between the optic chiasma and mammillary bodies...a stalk of hypothalamic tissue that connects the pituitary gland to the base of the hypothalamus

corpus striatum

Collectively, the lentiform and caudate nuclei...because the fibers of the internal capsule that course past and through them give them a striped appearance

Premotor cortex

Coordinates simultaneous or sequential actions, Involved in the planning of movements that depend on sensory feedback

Primary somatosensory cortex

Neurons in this gyrus receive information from the general (somatic) sensory receptors in the skin and from proprioceptors (position sense receptors) in skeletal muscles, joints, and tendons

Frontal eye field

The frontal eye field is located partially in and anterior to the premotor cortex and superior to Broca's area. This cortical region controls voluntary movement of the eyes.

Respiratory centers

These control the rate and depth of breathing and (in concert with pons centers) maintain respiratory rhythm

Projection fibers

They tie the cortex to the rest of the nervous system and to the body's receptors and effectors. In contrast to commissural and association fibers, which run horizontally, projection fibers run vertically

corona radiata ("radiating crown").

This distinctive arrangement of projection tract fibers...fibers radiate fanlike through the cerebral white matter to the cortex.

Cardiovascular center

This includes the cardiac center, which adjusts the force and rate of heart contraction to meet the body's needs, and the vasomotor center, which changes blood vessel diameter to regulate blood pressure.

primary visual (striate) cortex

Visual areas,on the extreme posterior tip of the occipital lobe. The largest of all cortical sensory areas, the primary visual cortex receives visual information that originates on the retina of the eye.

cerebellum ("small brain"),

cauliflower-like; protrudes under occipital lobes; 2 hemispheres connected by vermis; is responsible for subconscious activity location: dorsal to pons/medulla; protrudes under occipital lobes

Brain Stem

centers produce the rigidly programmed, automatic behaviors necessary for survival. Positioned between the cerebrum and the spinal cord, also provides a pathway for fiber tracts running between higher and lower neural centers.

Commissures

composed of commissural fibers, connect corresponding gray areas of the two hemispheres, enabling them to function as a coordinated whole

Association fibers

connect different parts of the same hemisphere. Short association fibers connect adjacent gyri. Long association fibers are bundled into tracts and connect different cortical lobes

inferior cerebellar peduncles

connect medulla and cerebellum. These peduncles convey sensory information to the cerebellum from (1) muscle proprioceptors throughout the body and (2) the vestibular nuclei of the brain stem, which are concerned with equilibrium and balance.

superior cerebellar peduncles

connecting cerebellum and midbrain carry instructions from neurons in the deep cerebellar nuclei to the cerebral motor cortex via thalamic relays

Diencephalon

consists largely of three paired structures—the thalamus, hypothalamus, and epithalamus. These gray matter areas collectively enclose the third ventricle

thalamus

consists of bilateral egg-shaped nuclei, which form the superolateral walls of the third ventricle - plays a key role in mediating sensation, motor activities, cortical arousal, learning, and memory. It is truly the gateway to the cerebral cortex.

Motor Areas

control voluntary movement, lie in the posterior part of the frontal lobes: primary motor cortex, premotor cortex, Broca's area, and the frontal eye field.

Somatosensory association cortex

cortex lies just posterior to the primary somatosensory cortex and has many connections with it.

Primary somatosensory cortex

cortex resides in the postcentral gyrus of the parietal lobe, just posterior to the primary motor cortex (Brodmann areas 1-3)

basal nuclei or basal ganglia.

deep within the cerebral white matter is the third basic region of each hemisphere, a group of subcortical nuclei

fissures

deeper grooves which seperate large regions of the brain

The reticular formation

extends through the central core of the medulla oblongata, pons, and midbrain

temporal

flaplike lobe; separated from overlying parietal and frontal lobes by deep lateral sulcus

prosencephalon

forbrain

cerebral hemispheres

form the superior part of the brain

cerebral peduncles

form vertical pillars that seem to hold up the cerebrum, hence their name meaning "little feet of the cerebrum." contain the large pyramidal (corticospinal) motor tracts descending toward the spinal cord

ipsilateral (ipsi = same)

from and to the same side of the body

sulci divide each hemisphere into five lobes

frontal, parietal, temporal, occipital, and insula

The Limbic System

group of structures located on the medial aspect of each cerebral hemisphere and diencephalon. Its cerebral structures encircle (limbus = ring) the upper part of the brain stem and include parts of the rhinencephalon

rhombencephalon

hindbrain.

psychosomatic illnesses

illnesses emotion-induced illnesses

Anterior association area

in frontal lobe, also called prefrontal cortex

Cerebral Cortex

is composed of gray matter: neuron cell bodies, dendrites, associated glia and blood vessels, but no fiber tracts.

midbrain

is located between the diencephalon and the pons.The portion of the brain responsible for visual and auditory startle reflexes.

Primary (somatic) motor cortex

is located in the precentral gyrus of the frontal lobe of each hemisphere (Brodmann area 4).

Cerebral Cortex

is the "executive suite" of the nervous system, where our conscious mind is found. It enables us to be aware of ourselves and our sensations, to communicate, remember, and understand, and to initiate voluntary movements.

pons

is the bulging brain stem region wedged between the midbrain and the medulla oblongata. Dorsally, it forms part of the anterior wall of the fourth ventricle.

transverse cerebral fissure

large fissure, separates the cerebral hemispheres from the cerebellum below

Purkinje cells

large, with their extensively branched dendrites, are the only cortical neurons that send axons through the white matter to synapse with the central nuclei of the cerebellum

Broca's area-

lies anterior to the inferior region of the premotor area and overlaps Brodmann areas 44 and 45. It has long been considered to be (1) present in one hemisphere only (usually the left) and (2) a special motor speech area that directs the muscles involved in speech production

central sulcus

lies in the frontal plane, separates the frontal lobe from the parietal lobe

Olfactory (smell) cortex

lies on the medial aspect of the temporal lobe in a small region called the piriform lobe which is dominated by the hooklike uncus

pyramidal tracts, or corticospinal tracts

long axons, project to the spinal cord, form the massive voluntary motor tracts

Somatosensory association cortex

major function of this area is to integrate sensory inputs (temperature, pressure, and so forth) relayed to it via the primary somatosensory cortex to produce an understanding of an object being felt: its size, texture, and the relationship of its parts.

somatotopy

mapping the body in CNS structures

Vestibular (equilibrium) cortex.

medical imaging studies now locate this region in the posterior part of the insula, deep to the temporal lobe.

mesencephalon

midbrain

The cerebral cortex contains three kinds of functional areas

motor areas, sensory areas, and association areas

cerebral dominance

one cerebral hemisphere or the other "dominates" each task, designates the hemisphere that is dominant for language.

olives

oval swellings produced mainly by the underlying inferior olivary nuclei, wavy folds of gray matter

reticular activating system (RAS)

part of reticular formation that keeps it active and alert

diencephalon

part of the forebrain specializes to form the hypothalamus, thalamus, epithalamus, and retina of the eye

auditory association area

permits the perception of the sound stimulus, which we "hear" as speech, a scream, music, thunder, noise, and so on

interthalamic adhesion (intermediate mass).

plays a key role in mediating sensation, motor activities, cortical arousal, learning, and memory. It is truly the gateway to the cerebral cortex.

three primary brain vesicles

prosencephalon mesencephalon rhombencephalon

Limbic association area

provides the emotional impact, which makes a scene important to us, which includes the cingulate gyrus, the parahippocampal gyrus, and the hippocampus, is part of the limbic system

pineal gland or body ("pine cone shaped")-

secretes the hormone melatonin (a sleep-inducing signal and antioxidant; and, along with hypothalamic nuclei, helps regulate the sleep-wake cycle.

parietal

separated from frontal lobe by central sulcus and from occipital by parietooccipital sulcus

occipital lobe

separated from parietal lobe by parieto-occipital sulcus

lateral sulcus

separates temporal lobe from parietal and frontal lobes

longitudinal fissure

separates the cerebral hemispheres

nucleus gracilis and nucleus cuneatus

serve as relay nuclei in a pathway by which general somatic sensory information ascends from the spinal cord to the somatosensory cortex.

sulcus

shallow grooves separating gyri

three paired fiber tracts—the cerebellar peduncles

superior cerebellar peduncles,middle cerebellar peduncles,inferior cerebellar peduncles

visual association area

surrounds the primary visual cortex and covers much of the occipital lobe. Communicating with the primary visual cortex, uses past visual experiences to interpret visual stimuli (color, form, and movement), enabling us to recognize a flower or a person's face and to appreciate what we are seeing.

secondary brain vesicles

telencephalon diencephalon metencephalon myelencephalon

prefrontal cortex

the most complicated cortical region of all; involved with intellect, complex learning abilities, recall, and personality; contains working memory needed for judgment, reasoning, persistence, and conscience; development depends on feedback from social enviornment

Epithalamus

the most dorsal portion of the diencephalon and forms the roof of the third ventricle

Medulla Oblongata

the most inferior part of the brain stem

brain stem

the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus

lentiform nucleus

the putamen ("pod") and globus pallidus ("pale globe") form a lens-shaped mass, that flanks the internal capsule laterally.

lateralization

there is a division of labor, and each hemisphere has unique abilities not shared by its partner... means that each hemisphere is better than the other at certain functions, neither side is better at everything.

Projection fibers

those that enter the cerebral hemispheres from lower brain or cord centers, and those that leave the cortex to travel to lower areas

motor homunculi

upside - down caricatures representing the motor innervation of body regions

corpora quadrigemina -( "quadruplets")

which raise four domelike protrusions on the dorsal midbrain surface - superior colliculi,inferior colliculi,substantia nigra,red nucleus

Cerebral White Matter

white matter is responsible for communication between cerebral areas and between the cerebral cortex and lower CNS centers. White matter consists largely of myelinated fibers bundled into large tracts.

Medulla Oblongata

It blends imperceptibly into the spinal cord at the level of the foramen magnum of the skull

The reticular formation

It is composed of loosely clustered neurons in what is otherwise white matter.

decussation of the pyramids

Just above the medulla-spinal cord junction, most of the pyramidal tract fibers cross over to the opposite side before continuing into the spinal cord at this point

pyramidal cells

Large neurons, in these gyri allow us to consciously control the precise or skilled voluntary movements of our skeletal muscles

Multimodal Association Areas

Most of the cortex, though, is more complexly connected, receiving inputs from multiple senses and sending outputs to multiple areas

cephalization

During the course of animal evolution, an elaboration of the rostral ("toward the snout"), or anterior, portion of the CNS, along with an increase in the number of neurons in the head.

pyramids

Flanking the midline on the medulla's ventral aspect are two longitudinal ridges called, formed by the large pyramidal (corticospinal) tracts descending from the motor cortex

parieto-occipital sulcus

Separates parietal and occipital lobes

cingulate gyrus

The former recognizes angry or fearful facial expressions, assesses danger, and elicits the fear response. The latter plays a role in expressing our emotions through gestures and in resolving mental conflicts when we are frustrated.

substantia nigra

The bandlike- is located deep to the cerebral peduncle. Its dark (black) color reflects a high content of melanin pigment, a precursor of the neurotransmitter (dopamine) released by these neurons

Visceral sensory area

The cortex of the insula just posterior to the gustatory cortex is involved in conscious perception of visceral sensations. These include upset stomach, full bladder, and the feeling that your lungs will burst when you hold your breath too long.

arbor vitae ("tree of life")

The distinctive pattern of white matter in the cerebellum resembles a branching tree, a pattern fancifully

red nucleus

The oval...lies deep to the substantia nigra. Its reddish hue is due to its rich blood supply and to the presence of iron pigment in its neurons.

Posterior association area

a large region encompassing parts of the temporal, parietal, and occipital lobes. This area plays a role in recognizing patterns and faces, localizing us and our surroundings in space, and in binding different sensory inputs into a coherent whole.

hippocampus

a neural center located in the limbic system that helps process explicit memories for storage

Gustatory (taste) cortex

a region involved in the perception of taste stimuli, is located in the insula just deep to the temporal lobe

interthalamic adhesion (intermediate mass).

a small, midline commissure connecting the right and left thalamus

spatial discrimination-

an ability, the neurons then identify the body region being stimulated

amygdala

an almond-shaped nucleus that sits on the tail of the caudate nucleus

Brodmann areas

an elaborate numbered mosaic of 52 cortical areas, mapped subtle variations in the thickness and structure of the cerebral cortex

fornix ("arch")

and other fiber tracts link these limbic system regions together

cerebrum

anterior portion of the brain consisting of two hemispheres

Functional brain systems

are networks of neurons that work together but span relatively large distances in the brain, so they cannot be localized to specific brain regions. The limbic system and the reticular formation

inferior colliculi

are part of the auditory relay from the hearing receptors of the ear to the sensory cortex. They also act in reflexive responses to sound, such as in the startle reflex, which causes you to turn your head toward an unexpected sound.

superior colliculi

are visual reflex centers that coordinate head and eye movements when we visually follow a moving object, even if we are not consciously looking at the object.

cochlear nuclei

auditory relays

precentral gyrus

borders the central sulcus anteriorly

postcentral gyrus

borders the central sulcus posteriorly

central nervous system (CNS)

brain and spinal cord

insula

buried deep w/in lateral sulcus; covered by parietal, temporal, and frontal lobes

Hypothalamus

caps the brain stem and forms the inferolateral walls of the third ventricle, extends from the optic chiasma (crossover point of the optic nerves) to the posterior margin of the mammillary bodies

middle cerebellar peduncles

carry one-way communication from the pons to the cerebellum, advising the cerebellum of voluntary motor activities initiated by the motor cortex (via relays in the pontine nuclei).

constitute most of the mass of each group of basal nuclei

caudate nucleus, putamen, and globus pallidus