02/25/16 FG_Growth of the Cranium and the Cranial Base

Central sulcus

A fold in the cerebral cortex in the brains of vertebrates. It is sometimes confused with the medial longitudinal fissure. It is a prominent landmark of the brain, separating the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex.

Inferior frontal sulcus

A sulcus between the middle frontal gyrus and the inferior frontal gyrus. A feature of the frontal lobe.

Insula

A portion of the cerebral cortex folded deep within the lateral sulcus (the fissure separating the temporal lobe from the parietal and frontal lobes). These regions are believed to be involved in consciousness and play a role in diverse functions usually linked to emotion or the regulation of the body's homeostasis. These functions include perception, motor control, self-awareness, cognitive functioning, and interpersonal experience. In relation to these, it is involved in psychopathology. The cortical area overlying the insula toward the lateral surface of the brain is the operculum (meaning lid). The opercula are formed from parts of the enclosing frontal, temporal, and parietal lobes.

Supramarginal gyrus

A portion of the parietal lobe. It is probably involved with language perception and processing, and lesions in it may cause receptive aphasia. It is located just ventral to the angular gyrus allowing these two structures to form a multimodal complex that receives somatosensory, visual, and auditory inputs from the brain.[7] Although the supramarginal gyrus isn't considered a major portion of the language circuit, it still works with the angular gyrus to attempt to link words with meanings. It is also bound caudally by the lateral sulcus, one of the most prominent structures found in the brain. A feature of the parietal lobe.

Orbitofrontal cortex / Orbital surface

A prefrontal cortex region in the frontal lobes in the brain which is involved in the cognitive processing of decision-making. This feature is considered anatomically synonymous with the ventromedial prefrontal cortex, therefore the region is distinguished due to the distinct neural connections and the distinct functions it performs. It is defined as the part of the prefrontal cortex that receives projections from the magnocellular, medial nucleus of the mediodorsal thalamus, and is thought to represent emotion and reward in decision making. A feature of the frontal lobe.

Inferior occipital gyrus

A stubby, knuckle-shaped gyrus on the lateral surface of the occipital lobe of each cerebral hemisphere, just below the lateral occipital sulcus. The occipital lobe is divided into several functional visual areas. Each visual area contains a full map of the visual world. Although there are no anatomical markers distinguishing these areas (except for the prominent striations in the striate cortex), physiologists have used electrode recordings to divide the cortex into different functional regions.

Superior frontal sulcus

A sulcus between the superior frontal gyrus and the middle frontal gyrus. A feature of the frontal lobe.

Paracentral sulcus

A sulcus of the brain. It forms the paracentral lobule's anterior border. It is a part of the frontal lobe.

Preoccipital notch

About 5 cm. in front of the occipital pole on the infero-lateral border is an indentation or notch. It is considered a landmark because the occipital lobe is located just behind the line that connects that notch with the parietoccipital sulcus.

Superior frontal gyrus / Gyrus frontalis superior

Feature of the brain that makes up about one third of the frontal lobe of the human brain. It is bounded laterally by the superior frontal sulcus. This structure, like the inferior frontal gyrus and the middle frontal gyrus, is more of a region than a true gyrus. A feature of the frontal lobe.

Temporal lobe

One of the four major lobes of the cerebral cortex in the brain of mammals. This lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. This lobe is involved in processing sensory input into derived meanings for the appropriate retention of visual memories, language comprehension, and emotion association.

Frontal lobe

One of the four major lobes of the cerebral cortex in the mammalian brain. Located at the front of each cerebral hemisphere and positioned in front of the parietal lobe and above and in front of the temporal lobe. It is separated from the parietal lobe by a space between tissues called the central sulcus, and from the temporal lobe by a deep fold called the lateral sulcus also called the Sylvian fissure. The precentral gyrus, forming the posterior border of the frontal lobe, contains the primary motor cortex, which controls voluntary movements of specific body parts. Contains most of the dopamine-sensitive neurons in the cerebral cortex. The dopamine system is associated with reward, attention, short-term memory tasks, planning, and motivation. Dopamine tends to limit and select sensory information arriving from the thalamus to the forebrain.

Lateral sulcus / Sylvian fissure / Lateral fissure

One of the most prominent structures of the human brain, it divides both the frontal lobe and parietal lobe above from the temporal lobe below. It is in both hemispheres of the brain but is longer in the left hemisphere in most people. It is one of the earliest-developing sulci of the human brain.

Superior temporal gyrus

One of three (sometimes two) gyri in the temporal lobe of the human brain, which is located laterally to the head, situated somewhat above the external ear. Bounded by: -the lateral sulcus above; the superior temporal sulcus (not always present or visible) below; -an imaginary line drawn from the preoccipital notch to the lateral sulcus posteriorly. -The superior temporal gyrus contains several important structures of the brain, including: This structure contains the primary auditory cortex, which is responsible for processing sounds. Specific sound frequencies map precisely onto the primary auditory cortex. This auditory (or tonotopic) map is similar to the homunculus map of the primary motor cortex.

Temporal pole

The anterior end of the temporal lobe.

Anterior paracentral gyrus

The anterior portion of the paracentral lobule; the medial continuation of the primary somatomotor cortex (precentral gyrus) in which the thigh, leg, and foot are represented. It is a part of the frontal lobe.

Cingulate sulcus

The cingulate sulcus is a sulcus (brain fold) on the medial wall of the cerebral cortex. The frontal and parietal lobes are separated from the cingulate gyrus by the cingulate sulcus.

Pars orbitalis

The orbital part of the inferior frontal gyrus. In the human, this region is bordered by the triangular part of the inferior frontal gyrus (pars triangularis) and, surrounding the anterior horizontal limb of the lateral sulcus, a portion of the opercular part of the inferior frontal gyrus (pars opercularis). Bounded caudally by the anterior ascending limb of the lateral sulcus, it borders on the insula in the depth of the lateral sulcus. It is bordered anteriorly/inferiorly by the lateral orbital sulcus. A feature of the frontal lobe.

Cuneus

(Latin for "wedge") A smaller lobe in the occipital lobe of the brain that is bounded anteriorly by the parieto-occipital sulcus, inferiorly by the calcarine sulcus. This structure receives visual information from the same-sided superior quandrantic retina (corresponding to contralateral inferior visual field). It is most known for its involvement in basic visual processing. Mid-level visual processing that occurs in the extrastriate projection fields of the cuneus are modulated by extraretinal effects, like attention, working memory, and reward expectation. A structure of the occipital lobe.

What are the gyri of the frontal lobe?

1) Gyrus frontalis superior 2) Gyrus frontalis medius 3) Gyrus frontalis interior

Lingual gyrus

A brain structure that is linked to processing vision, especially related to letters. It is thought to also play a role in analysis of logical conditions (i.e. logical order of events) and encoding visual memories. This structure is named after the shape it most closely resembles - the tongue.[1] Contrary to the name, the region has little to do with speech. This structure in the occipital lobe lies between the calcarine sulcus and the posterior part of the collateral sulcus; behind, it reaches the occipital pole; in front, it is continued on to the tentorial surface of the temporal lobe, and joins the parahippocampal gyrus. A structure of the occipital lobe.

Intraparietal sulcus

A feature of the brain located on the lateral surface of the parietal lobe, and consists of an oblique and a horizontal portion. This feature contains a series of functionally distinct subregions. Its principal functions are related to perceptual-motor coordination (e.g., directing eye movements and reaching) and visual attention, which allows for visually-guided pointing, grasping, and object manipulation that can produce a desired effect. A feature of the parietal lobe.

Middle temporal gyrus

A gyrus in the brain on the Temporal lobe. It is located between the superior temporal gyrus and inferior temporal gyrus. The middle temporal gyrus is bounded by: -the superior temporal sulcus above; -the inferior temporal sulcus below; -an imaginary line drawn from the preoccipital notch to the lateral sulcus posteriorly. Its exact function is unknown, but it has been connected with processes as different as contemplating distance, recognition of known faces, and accessing word meaning while reading. Some studies indicate that lesions of the posterior region of this structure in the left cerebral hemisphere, may result in alexia and agraphia for kanji characters (characters of Chinese origin used in Japanese writing).

Superior occipital gyrus

A gyrus lying above the lateral occipital sulcus on the lateral surface of the occipital lobe. The occipital lobe is divided into several functional visual areas. Each visual area contains a full map of the visual world. Although there are no anatomical markers distinguishing these areas (except for the prominent striations in the striate cortex), physiologists have used electrode recordings to divide the cortex into different functional regions.

Gyrus frontalis inferior / Inferior frontal gyrus

A gyrus of the frontal lobe (the red area of the human brain image to the right). Its superior border is the inferior frontal sulcus (which divides it from the gyrus frontalis medius), its inferior border the lateral fissure (which divides it from the gyrus temporalis superior in the green area), and its posterior border is the inferior precentral sulcus. Above it is the middle frontal gyrus (the gyrus frontalis medius), behind it the precentral gyrus (the gyrus praecentralis). This structure, like the middle frontal gyrus and the superior frontal gyrus, is more of a region than a true gyrus. It can be subdivided into the following macroanatomical structures, shown in yellow in the top image, just below the label gyrus frontalis inferior: 1) Pars opercularis (cortex posterior to the ascending ramus of the lateral fissure). 2) Pars triangularis (cortex between the ascending ramus and the horizontal ramus of the lateral fissure). 3) Pars orbitalis (cortex inferior and anterior to the horizontal ramus of the lateral fissure). A feature of the frontal lobe.

Precuneus

A part of the superior parietal lobule forward of the occipital lobe (cuneus). It is hidden in the medial longitudinal fissure between the two cerebral hemispheres. It is sometimes described as the medial area of the superior parietal cortex. The _____ is bounded anteriorly by the marginal branch of the cingulate sulcus, posteriorly by the parietooccipital sulcus, and inferiorly by the subparietal sulcus. It is involved with episodic memory, visuospatial processing, reflections upon self, and aspects of consciousness. The location of the ________ makes it difficult to study. Furthermore, it is rarely subject to isolated injury due to strokes, or trauma such as gunshot wounds. This has resulted in it being "one of the less accurately mapped areas of the whole cortical surface". Part of the parietal lobe.

Postcentral gyrus

A prominent structure in the parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory areas, there is a map of sensory space in this location, called the sensory homunculus. A feature of the parietal lobe.

Angular gyrus

A region of the brain in the parietal lobe, that lies near the superior edge of the temporal lobe, and immediately posterior to the supramarginal gyrus; it is involved in a number of processes related to language, number processing and spatial cognition, memory retrieval, attention, and theory of mind. It is the part of the brain associated with complex language functions (i.e. reading, writing and interpretation of what is written). A feature of the parietal lobe.

Cerebellum

A region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established. This structure does not initiate movement, but it contributes to coordination, precision, and accurate timing. It receives input from sensory systems of the spinal cord and from other parts of the brain, and integrates these inputs to fine-tune motor activity. Damage to this region produces disorders in fine movement, equilibrium, posture, and motor learning. Anatomically, this structure has the appearance of a separate structure attached to the bottom of the brain, tucked underneath the cerebral hemispheres. Its cortical surface is covered with finely spaced parallel grooves, in striking contrast to the broad irregular convolutions of the cerebral cortex. These parallel grooves conceal the fact that the cerebellar cortex is actually a continuous thin layer of tissue tightly folded in the style of an accordion. Within this thin layer are several types of neurons with a highly regular arrangement, the most important being Purkinje cells and granule cells. This complex neural organization gives rise to a massive signal-processing capability, but almost all of its output passes through a set of small deep cerebellar nuclei lying in the interior of this structure.

Transverse occipital sulcus

A structure in the occipital lobe. It is continuous with the posterior end of the occipital ramus of the intraparietal sulcus, and runs across the upper part of the lobe, a short distance behind the parietooccipital fissure.

Calcarine sulcus

An anatomical landmark located at the caudal end of the medial surface of the brain. Its name comes from the Latin meaning "spur." This landmark begins near the occipital pole in two converging rami and runs forward to a point a little below the splenium of the corpus callosum, where it is joined at an acute angle by the medial part of the parieto-occipital sulcus. The anterior part of this sulcus gives rise to the prominence of the calcar avis in the posterior cornu of the lateral ventricle. This landmark is where the primary visual cortex (V1) is concentrated. The central visual field is located in the posterior portion of the calcarine sulcus and the peripheral visual field in the anterior portion. A structure of the occipital lobe.

Sulcus

In neuroanatomy, a furrow/depression or groove in the cerebral cortex. It surrounds a gyrus, creating the characteristic folded appearance of the brain. One of three parts of the cerebral cortex, the others being the gyri and the fissures. The three different parts create a larger surface area for the human brain and other mammalian brains. When looking at the human brain, two-thirds of the surface are hidden in the grooves. This feature along with grooves in the cortex are both linear depressions in the cortex but they are differentiated by size. This structure is a shallower groove that surrounds a gyrus. A fissure is a large furrow that divides the brain into lobes, and also into the two hemispheres as the medial longitudinal fissure does. As the surface area of the brain increases more functions are made possible. A smooth-surfaced brain is only able to grow to a certain extent. A depression in the surface area allows for continued growth. This in turn allows for the functions of the brain to continue growing.

Precentral sulcus

Lies parallel to, and in front of, the central sulcus. This feature divides the inferior, middle and superior frontal gyri from the precentral gyrus. In the majority of brains, this feature is divided into two parts: the inferior ___ ___ and the superior ___ ___. However, the ___ ___ may also be divided into three parts or form one continuous ___. A feature of the frontal lobe.

Occipital lobe

One of the four major lobes of the cerebral cortex in the brain of mammals. The visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex. The primary visual cortex is Brodmann area 17, commonly called V1 (visual one). Human V1 is located on the medial side of the occipital lobe within the calcarine sulcus; the full extent of V1 often continues onto the posterior pole of the occipital lobe. V1 is often also called striate cortex because it can be identified by a large stripe of myelin, the Stria of Gennari. The name derives from the overlying bone, which is named from the Latin ob, behind, and caput, the head. Bilateral lesions of this lobe can lead to cortical blindness (See Anton's syndrome).

Parietal lobe

One of the four major lobes of the cerebral cortex in the brain of mammals. This lobe is positioned above the occipital lobe and behind the frontal lobe and central sulcus. This lobe integrates sensory information among various modalities, including spatial sense and navigation (proprioception), the main sensory receptive area for the sense of touch (mechanoreception) in the somatosensory cortex which is just posterior to the central sulcus in the postcentral gyrus, and the dorsal stream of the visual system. The major sensory inputs from the skin (touch, temperature, and pain receptors), relay through the thalamus to this lobe. This lobe is named for the bone above it.

Parieto-occipital sulcus

Only a small part of this structure is seen on the lateral surface of the hemisphere, its chief part being on the medial surface. The lateral part of this structure is situated about 5 centimeters (cm) in front of the occipital pole of the hemisphere, and measures about 1.25 cm. in length. This sulcus marks the boundary between the cuneus and precuneus, and also between the parietal and occipital lobes. It has been found in various neuroimaging studies to be involved along with the dorsolateral prefrontal cortex during planning.

Pars opercularis

Part of the frontal cortex in the human brain. Situated just anterior to premotor cortex and on the lateral surface. This area is part of the inferior frontal gyrus, and it refers to a subdivision of the cytoarchitecturally defined frontal region of cerebral cortex. In the human it corresponds approximately to the opercular part of inferior frontal gyrus. Thus, it is bounded caudally by the inferior precentral sulcus and rostrally by the anterior ascending limb of lateral sulcus. It surrounds the diagonal sulcus. In the depth of the lateral sulcus it borders on the insula. A feature of the frontal lobe.

Pars triangularis

Part of the frontal cortex in the human brain. Situated on the lateral surface it occupies the triangular part of inferior frontal gyrus and, surrounding the anterior horizontal limb of lateral sulcus, a portion of the orbital part of inferior frontal gyrus. Bounded caudally by the anterior ascending limb of lateral sulcus, it borders on the insula in the depth of the lateral sulcus. A feature of the frontal lobe.

Precentral gyrus

Prominent structure on the surface of the posterior frontal lobe. It is the site of the primary motor cortex. It lies in front of the postcentral gyrus - mostly on the lateral (convex) side of the cerebral hemispheres - from which it is separated by the central sulcus. Its anterior border is represented by the precentral sulcus, while inferiorly it borders to the lateral fissure (Sylvian fissure). Medially, it is contiguous with the paracentral lobule. A feature of the frontal lobe.

Frontal pole

The anterior end of the hemisphere.

Cingulate gyrus

The cingulate cortex, a part of the limbic cortex, is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus. The cingulate cortex is usually considered part of the limbic lobe. It receives inputs from the thalamus and the neocortex, and projects to the entorhinal cortex via the cingulum. It is an integral part of the limbic system, which is involved with emotion formation and processing,[1] learning,[2] and memory.[3][4] The combination of these three functions makes the cingulate gyrus highly influential in linking behavioral outcomes to motivation (e.g. a certain action induced a positive emotional response, which results in learning).[5] This role makes the cingulate cortex highly important in disorders such as depression[6] and schizophrenia.[7] It also plays a role in executive function and respiratory control.

Inferior temporal sulcus

The inferior surface of the temporal lobe is concave, and is continuous posteriorly with the tentorial surface of the occipital lobe. It is traversed by this structure, which extends from near the occipital pole behind, to within a short distance of the temporal pole in front, but is frequently subdivided by bridging gyri.

Hippocampal commissure

The lateral portions of the body of the fornix are joined by a thin triangular lamina, named the psalterium (lyra). This lamina contains some transverse fibers that connect the two hippocampi across the middle line and constitute the commissure of fornix also called the (______ _______). The terminal lamina creates the _______ plate. This structure gives existence to the corpus callosum, the septum pellucidum, and the fornix. The fornix splits into two columns at the front, (anterior pillars) and then splits into two posterior crura. These two crura are joined together through the ______ ________. The beginning of the splitting is called the psalterium or Lyra Davidis. The latter name is used because the structure resembles a lyra (or triangular harp): The two crura are the "chassis" of the lyra, and the ________ connections are the fibers.

Marginal sulcus

The portion of the cingulate sulcus adjacent to the paracentral lobule and the precuneus. Part of the parietal lobe.

Occipital pole

The posterior end of the hemisphere.

Brainstem

The posterior part of the brain, adjoining and structurally continuous with the spinal cord. In humans it is usually described as including the medulla oblongata (myelencephalon), pons (part of metencephalon), and midbrain (mesencephalon). Less frequently, parts of the diencephalon are included. Provides the main motor and sensory innervation to the face and neck via the cranial nerves. Of the twelve pairs of cranial nerves, ten pairs come from the brainstem. Though small, this is an extremely important part of the brain as the nerve connections of the motor and sensory systems from the main part of the brain to the rest of the body pass through this structure. This includes the corticospinal tract (motor), the posterior column-medial lemniscus pathway (fine touch, vibration sensation, and proprioception), and the spinothalamic tract (pain, temperature, itch, and crude touch). This section of the brain also plays an important role in the regulation of cardiac and respiratory function. It also regulates the central nervous system, and is pivotal in maintaining consciousness and regulating the sleep cycle. The brainstem has many basic functions including heart rate, breathing, sleeping, and eating.

Middle temporal sulcus

The sulcus between the middle temporal gyrus and inferior temporal gyrus.

Superior temporal sulcus

The sulcus separating the superior temporal gyrus from the middle temporal gyrus in the temporal lobe of the brain. The superior temporal sulcus is the first sulcus inferior to the lateral fissure. Research has documented activation in this feature as a result of five specific social inputs, and thus this feature is assumed to be implicated in social perception. It showed increased activation related to: voices versus environmental sounds, stories versus nonsense speech, moving faces versus moving objects, biological motion,and theory of mind (false belief stories versus false physical stories). It is involved in the perception of where others are gazing (joint attention) and is thus important in determining where others' emotions are being directed.

Middle frontal gyrus / Gyrus frontalis medius

This feature makes up about one-third of the frontal lobe of the human brain. (A gyrus is one of the prominent "bumps" or "ridges" on the surface of the human brain.) Like the inferior frontal gyrus and the superior frontal gyrus, this is more of a region than a true gyrus. The borders of this feature are the inferior frontal sulcus below; the superior frontal sulcus above; and the precentral sulcus behind. A feature of the frontal lobe.

Postcentral sulcus

This feature of the parietal lobe lies parallel to, and behind, the central sulcus in the human brain. This structure divides the postcentral gyrus from the remainder of the parietal lobe. A feature of the parietal lobe.

Superior parietal lobule

This structure is involved with spatial orientation, and receives a great deal of visual input as well as sensory input from one's hand. It is also involved with other functions of the parietal lobe in general. There are major white matter pathway connections with this structure. It is bounded in front by the upper part of the postcentral sulcus, but is usually connected with the postcentral gyrus above the end of the sulcus.. Behind it is the lateral part of the parietooccipital fissure, around the end of which it is joined to the occipital lobe by a curved gyrus, the arcus parietooccipitalis. Below, it is separated from the inferior parietal lobule by the horizontal portion of the intraparietal sulcus. A feature of the parietal lobe.