Cerebrum – Anatomy, Types, Structure, Functions

Cerebrum – Anatomy, Types, Structure, Functions

The cerebrum is the uppermost part of the brain. It contains two hemispheres split by a central fissure. The cerebrum itself contains the major lobes of the brain and is responsible for receiving and giving meaning to information from the sense organs, as well as controlling the body.

The cerebrumtelencephalon, or endbrain is the largest part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In the human brain, the cerebrum is the uppermost region of the central nervous system. The cerebrum develops prenatally from the forebrain (prosencephalon). In mammals, the dorsal telencephalon, or pallium, develops into the cerebral cortex, and the ventral telencephalon, or subpallium, becomes the basal ganglia. The cerebrum is also divided into approximately symmetric left and right cerebral hemispheres.

Structure

Location of the human cerebrum (red).

The cerebrum is the largest part of the brain. Depending upon the position of the animal it lies either in front or on top of the brainstem. In humans, the cerebrum is the largest and best-developed of the five major divisions of the brain.

The cerebrum is made up of the two cerebral hemispheres and their cerebral cortex cortices (the outer layers of grey matter), and the underlying regions of white matter.[rx] Its subcortical structures include the hippocampus, basal ganglia, and olfactory bulb. The cerebrum consists of two C-shaped cerebral hemispheres, separated from each other by a deep fissure called the longitudinal fissure.

Cerebral cortex

The cerebral cortex, the outer layer of the grey matter of the cerebrum, is found only in mammals. In larger mammals, including humans, the surface of the cerebral cortex folds to create gyrus gyri (ridges) and sulci (furrows) which increase the surface area.[rx]

The cerebral cortex is generally classified into four lobes: the frontal, parietal, occipital, and temporal lobes. The lobes are classified based on their overlying neurocranial bones.[rx]

Cerebral hemispheres

The cerebrum is divided by the medial longitudinal fissure into two cerebral hemispheres, the right and the left. The cerebrum is contralaterally organized, i.e., the right hemisphere controls and processes signals from the left side of the body, while the left hemisphere controls and processes signals from the right side of the body.[rx] There is a strong but not complete bilateral symmetry between the hemispheres. The lateralization of brain function looks at the known and possible differences between the two.

Overview of the Cerebrum

With the assistance of the cerebellum, the cerebrum controls all voluntary actions in the body.

Key Points

The cerebrum is the largest and most developed of the five major divisions of the brain.

The brain contains two hemispheres, the left and the right, connected by a bundle of nerve fibers called the corpus callosum.

The cerebrum directs the conscious or volitional motor functions of the body. Damage to this area of the brain can result in loss of muscular power and precision rather than total paralysis.

The primary sensory areas of the cerebral cortex receive and process visual, auditory, somatosensory, gustatory, and olfactory information.

Each hemisphere of the mammalian cerebral cortex can be broken down into four functionally and spatially defined lobes: frontal, parietal, temporal, and occipital.

Key Terms

sulci: Any of the grooves that mark the convolutions of the surface of the brain (plural of sulcus).

cerebral cortex: The cerebrum’s outer layer of neural tissuecomposed of folded gray matter. The cerebral cortex plays a key role in memory, attention, perception, awareness, thought, language, and consciousness.

olfactory bulb: A neural structure of the vertebrate forebrain involved in olfaction (sense of smell).

Broca’s area: A region in the frontal lobe of the dominant hemisphere of the human brain with functions linked to speech production.

Wernicke’s area: Involved in the comprehension or understanding of written and spoken language.

aphasia: A combination speech and language disorder often caused by a stroke.

gyri: A ridge on the cerebral cortex (plural of gyrus).

Cerebrum Animation

Cerebrum Animation: Location of the cerebrum (in red).

The cerebrum, which lies in front or on top of the brainstem, comprises a large portion of the brain. In humans, it is the largest and best-developed of the brain’s five major divisions. The cerebrum is the newest structure in the phylogenetic sense, with mammals having the largest and most developed among all species.

The cerebrum contains the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In larger mammals, the cerebral cortex is folded into many gyri and sulci, which allows it to expand in a surface area without taking up the much greater volume. With the assistance of the cerebellum, the cerebrum controls all voluntary actions in the body.

Cerebral Cortex

The cerebral cortex

The cerebral cortex: The cerebral cortex is the outer layer depicted in dark violet. Notice the folded structure of the cortex: the “valleys” of the cortex are known as sulci.

The cortex is composed of two hemispheres, right and left, separated by a large sulcus. A thick fiber bundle, the corpus callosum, connects the two hemispheres, allowing information to be passed from one side to the other. The right hemisphere controls and processes signals from the left side of the body, while the left hemisphere controls and processes signals from the right side of the body.

The Four Brain Lobes

Each hemisphere of the mammalian cerebral cortex can be broken down into four functionally and spatially defined lobes: frontal, parietal, temporal, and occipital.

The frontal lobe is located at the front of the brain, over the eyes, and contains the olfactory bulb. The frontal lobe also contains the motor cortex, which is important for planning and implementing movement.

This diagram of the cerebral lobes delineates the frontal lobe, temporal lobe, medulla oblongata, spinal cord, cerebellum, occipital lobe, parietal lobe, somatosensory cortex, and somatomotor cortex.

Cerebral Lobes: Locations of the cerebral lobes

 

Two of the parietal lobe’s main functions are processing somatosensation (touch sensations such as pressure, pain, heat, cold) and proprioception (the sense of how parts of the body are oriented in space).

The temporal lobe is located at the base of the brain by the ears. It is primarily involved in processing and interpreting sounds. It also contains the hippocampus, which processes memory formation.

The occipital lobe is located at the back of the brain. It is primarily involved in vision: seeing, recognizing, and identifying the visual world.

Cerebrum Function

The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the primary motor cortex and other frontal lobe motor areas where actions are planned. Upper motor neurons in the primary motor cortex send their axons to the brainstem and spinal cord to synapse on the lower motor neurons, which innervate the muscles. Damage to motor areas of the cortex can lead to certain types of motor neuron disease. This kind of damage results in loss of muscular power and precision rather than total paralysis.

The olfactory sensory system is unique in that neurons in the olfactory bulb send their axons directly to the olfactory cortex, rather than to the thalamus first. Damage to the olfactory bulb results in a loss of the sense of smell. The olfactory bulb also receives “top-down” information from such brain areas as the amygdala, neocortex, hippocampus, locus coeruleus, and substantia nigra. Its potential functions can be placed into four non-exclusive categories: discriminating among odors, enhancing the sensitivity of odor detection, filtering out background odors, and permitting higher brain areas involved in arousal and attention to modify the detection or the discrimination of odors.

Speech and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to Broca’s area within the frontal lobe. Speech comprehension is attributed to Wernicke’s area, at the temporal-parietal lobe junction. Damage to the Broca’s area results in expressive aphasia (non-fluent aphasia) while damage to Wernicke’s area results in receptive aphasia.

The cerebrum itself houses the four major lobes, and each lobe as its own set of functions. So although the cerebrum as a whole controls numerous functions in the body, this is mainly due to the function of each individual lobe and the interplay between them.

In general, the cerebrum controls all voluntary actions. It is also the control center for:

  • sensory processing
  • emotional control
  • motor control
  • personality
  • learning
  • problem solving
  • language and speech
  • visual information
  • spatial information
  • cognition and higher thought
  • imagination
  • creativity
  • music interpretation

Areas in the cerebrum are responsible for receiving and interpreting much of the physical world around the body.

The sections below will detail which lobe controls which processes.

Frontal lobe

  • speech
  • behavior and personality
  • emotions
  • body movement
  • intelligence and self-awareness

Parietal lobe

  • language and symbol use
  • visual perception
  • sense of touch, pressure, and pain
  • giving meaning to signals from other sensory information

Temporal lobe

  • memory
  • hearing
  • understanding language
  • organization and patterns

Occipital lobe

  • light
  • color
  • movement
  • spatial orientation

Insular lobe

  • homeostasis
  • compassion and empathy
  • self-awareness
  • cognitive function
  • social experience

Cerebral Lobes

The cortex is divided into four main lobes: frontal, parietal, occipital, temporal.

Key Points

Each lobe contributes to overall functionality of the brain and each lobe has many different roles.

The frontal lobe is involved in conscious thought.

The parietal lobe is important for spatial reasoning.

The occipital lobe is required for visual processing.

The temporal lobe contributes to language and face recognition.

Key Terms

frontal lobe: The frontal lobe is an area in the brain of mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes. In humans, it contributes to a number of higher cognitive functions including attention, planning, and motivation.

temporal lobe: A region of the cerebral cortex that is located behind the temples and beneath the Sylvian fissure on both cerebral hemispheres of the human brain. This region is involved in auditory perception, speech and vision processing, and the formation of long-term memory as it houses the hippocampus.

parietal lobe: A part of the brain positioned superior to the occipital lobe and posterior to the frontal lobe that integrates sensory information from different modalities, particularly spatial sense and navigation.

occipital lobe: Located at the back of the head, this is the visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex.

Cerebral lobes: The four lobes (frontal, parietal, occipital, and temporal) of the human brain are depicted along with the cerebellum.

Brain lobes were originally a purely anatomical classification, but we now know they are also associated with specific brain functions. The telencephalon (cerebrum), the largest portion of the human brain, is divided into lobes like the cerebellum. If not specified, the expression “lobes of the brain” refers to the telencephalon. There are four uncontested lobes of the telencephalon:

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The Frontal Lobe

The frontal lobe is an area in the mammalian brain located at the front of each cerebral hemisphere and positioned anterior to (in front of) the parietal lobe and superior and anterior to the temporal lobes. 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 (Sylvian) sulcus. The precentral gyrus, forming the posterior border of the frontal lobe, contains the primary motor cortex, which controls voluntary movements of specific body parts.

The frontal lobe 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 that the thalamus sends to the forebrain. A report from the National Institute of Mental Health indicates that a gene variant that reduces dopamine activity in the prefrontal cortex is related to poorer performance in that region during memory tasks; this gene variant is also related to a slightly increased risk for schizophrenia.

The frontal lobe is considered to contribute to our most human qualities. Damage to the frontal lobe can result in changes in personality and difficulty planning. The frontal lobes are the most uniquely human of all the brain structures.

The Parietal Lobe

The parietal lobe is a part of the brain positioned above (superior to) the occipital lobe and behind (posterior to) the frontal lobe. The parietal lobe integrates sensory information from different modalities, particularly spatial sense and navigation. For example, it comprises the somatosensory cortex and the dorsal stream of the visual system. This enables regions of the parietal cortex to map objects perceived visually into body coordinate positions.

Several portions of the parietal lobe are also important in language processing. Also, this lobe integrates information from various senses and assists in the manipulation of objects. Portions of the parietal lobe are involved with visuospatial processing.

The Occipital Lobe

The two occipital lobes are the smallest of the four paired lobes in the human cerebral cortex. Located in the rearmost portion of the skull, the occipital lobes are part of the forebrain. At the front edge of the occipital there are several lateral occipital gyri separated by lateral occipital sulci. The occipital lobe is involved in the sense of sight; lesions in this area can produce hallucinations.

The Temporal Lobe

The temporal lobe is a region of the cerebral cortex located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobes are involved in many functions, such as retaining visual memories, processing sensory input, comprehending language, storing new memories, feeling and expressing emotion, and deriving meaning. The temporal lobe contains the hippocampus and plays a key role in the formation of explicit long-term memory, modulated by the amygdala. It is involved in the senses of smell and sound as well as in the processing of complex stimuli.

Adjacent areas in the superior, posterior, and lateral parts of the temporal lobes are involved in high-level auditory processing. The temporal lobe is involved in primary auditory perception such as hearing and holds the primary auditory cortex. The superior temporal gyrus includes an area where auditory signals from the ear first reach the cerebral cortex and are processed by the primary auditory cortex in the left temporal lobe.

The areas associated with vision in the temporal lobe interpret the meaning of visual stimuli and establish object recognition. The central part of the temporal cortices appears to be involved in the high-level visual processing of complex stimuli such as faces (fusiform gyrus) and scenes (parahippocampal gyrus). Anterior parts of this ventral stream for visual processing are involved in object perception and recognition.

White Matter of the Cerebrum

White matter is composed of myelinated axons and glia and connects distinct areas of the cortex.

Key Points

White matter modulates the distribution of action potentials, acting as a relay and coordinating communication between different brain regions.

There are three main kinds of white matter tracts: projection, commissural, and association.

The largest white matter structure of the brain is the corpus callosum, a form of the commissural tract that connects the right and left hemispheres.

Key Terms

Corpus callosum: A wide, flat bundle of neural fibers beneath the cortex that connects the left and right cerebral hemispheres and facilitates interhemispheric communication.

grey matter: A major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astroglia and oligodendrocytes), and capillaries.

gyri: Ridges on the cerebral cortex, generally surrounded by one or more sulci.

A lateral cross-section of the human brain

A lateral cross-section of the human brain: White matter appears white in this dissected human brain, while gray matter appears darker. White matter is composed largely of myelinated axons.

White matter is one of the two components of the central nervous system (CNS). It consists mostly of glial cells and myelinated axons and forms the bulk of the deep parts of the cerebrum and the superficial parts of the spinal cord. In a freshly cut brain, the tissue of white matter appears pinkish white to the naked eye because myelin is composed largely of lipid tissue containing capillaries. The axons of white matter transmit signals from various grey matter areas (the locations of nerve cell bodies) of the cerebrum to each other and carry nerve impulses between neurons. While grey matter is primarily associated with processing and cognition, white matter modulates the distribution of action potentials, acting as a relay and coordinating communication between different brain regions.

Tracts

There are three different kinds of tracts (bundles of axons) that connect one part of the brain to another within the white matter:

  • Projection tracts extend vertically between higher and lower brain areas and spinal cord centers, and carry information between the cerebrum and the rest of the body. 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, then radiate in a diverging, fanlike array to specific areas of the cortex.
  • Commissural tracts cross from one cerebral hemisphere to the other through bridges called commissures. The great majority of commissural tracts pass through the large corpus callosum. A few tracts pass through the much smaller anterior and posterior commissures. Commissural tracts enable the left and right sides of the cerebrum to communicate with each other.
  • Association tracts connect different regions within the same hemisphere of the brain. 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.

Corpus Callosum

The corpus callosum (Latin: “tough body”), also known as the colossal commissure, is a wide, flat bundle of neural fibers beneath the cortex in the eutherian brain at the longitudinal fissure. It connects the left and right cerebral hemispheres and facilitates interhemispheric communication. It is the largest white matter structure in the brain, consisting of 200 to 250 million contralateral axonal projections.

Corpus Callosum: Location of the corpus callosum in the cerebrum.

The posterior portion of the corpus callosum is called the splenium, the anterior is called the genu (or “knee”), and the area between the two is the truncus or body of the corpus callosum. The part between the body and the splenium is often markedly thin and thus called the isthmus. The rostrum is the part of the corpus callosum that projects posteriorly and inferiorly from the anteriormost genu. The rostrum is so named for its resemblance to a bird’s beak.

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Agenesis of the corpus callosum (ACC) is a rare congenital disorder in which the corpus callosum is partially or completely absent. It is usually diagnosed within the first two years of life and may manifest as a severe syndrome in infancy or childhood, as a milder condition in young adults, or as an asymptomatic incidental finding. Initial symptoms of ACC usually include seizures that may be followed by feeding problems and delays in holding the head erect, sitting, standing, and walking. Hydrocephaly may also occur.

Other possible symptoms include impairments in mental and physical development, hand-eye coordination, and visual and auditory memory. In mild cases, symptoms such as seizures, repetitive speech, or headaches may not appear for years.

Basal Ganglia

The basal ganglia is important for the control of movement and forming habits, and each of its components has a complex internal anatomical and neurochemical organization.

Key Points

The basal ganglia are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit.

The basal ganglia are associated with a variety of functions including voluntary motor control, procedural learning relating to routine behaviors or “habits” such as bruxism, eye movements, cognitive, and emotional functions.

The basal ganglia are composed of the striatum, the pallidum, the substantia nigra, and the subthalamic nucleus.

The basal ganglia play a central role in a number of neurological conditions including Parkinson’s disease and Huntington’s disease.

Key Terms

Huntington’s disease: A neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and psychiatric problems.

Parkinson’s disease: A chronic neurological disorder resulting in lack of control over movement; poor balance and coordination; and similar symptoms.

executive functions: Also known as cognitive control and supervisory attentional system. Refers to a set of cognitive processes, including attentional control, inhibitory control, working memory, and cognitive flexibility, reasoning, problem-solving, and planning.

bruxism: Excessive grinding and clenching of the teeth.

The basal ganglia (or basal nuclei) are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit. They are situated at the base of the forebrain and are strongly connected with the cerebral cortex, thalamus, and other brain areas. The components of the basal ganglia include the striatum, pallidum, substantia nigra, and subthalamic nucleus. Each of these components has a complex internal anatomical and neurochemical organization.

Structure

This diagram of the basal ganglia indicates the structure itself as well as the global pallides, thalamus, substantia nigra, and cerebellum.

The Basal Ganglia: The basal nuclei are often referred to as the basal ganglia. The main components of the basal nuclei are labeled in purple.

The main components of the basal ganglia are:

  • The striatum, or neostriatum: This component consists of 3 divisions: the caudate, putamen, and ventral striatum (includes the nucleus accumbens). The striatum receives input from many brain areas but sends output only to other components of the basal ganglia.
  • Globus pallidus, or pallidum: This component is composed of the globus pallidus external (GPe) and globus pallidus internal (GPi). The pallidum receives its most important input from the striatum (either directly or indirectly), and sends inhibitory output to a number of motor-related areas, including the part of the thalamus that projects to the motor-related areas of the cortex.
  • Substantia nigra: This component consists of the substantia nigra pars compacta (SNc) and substantia nigra pars reticulate (SNr). The SNr functions similarly to the pallidum, and the SNc cells contain neuromelanin and produce dopamine (a neurotransmitter) for input to the striatum.
  • The subthalamic nucleus (STN): The STN receives input mainly from the striatum and cortex, and projects to a portion of the pallidum (internal portion or GPi). It is the only portion of the ganglia that produces an excitatory neurotransmitter, glutamate. The role of the subthalamic nucleus is to stimulate the SNr-GPi complex, and it receives inhibitory input from the GPe and sends excitatory signals to the GPi.

Function

The basal ganglia are associated with a variety of functions, including voluntary motor control, procedural learning relating to routine behaviors or habits such as bruxism, eye movements, and cognitive, emotional functions. Currently, popular theories implicate the basal ganglia primarily in action selection, that is, the decision of which several possible behaviors to execute at a given time. Experimental studies show that the basal ganglia exert an inhibitory influence on a number of motor systems and that a release of this inhibition permits a motor system to become active. The behavior switching that takes place within the basal ganglia is influenced by signals from many parts of the brain, including the prefrontal cortex, which plays a key role in executive functions.

The basal ganglia play a central role in a number of neurological conditions, including several movement disorders. The most notable are Parkinson’s disease, which involves degeneration of the melanin-pigmented dopamine-producing cells in the substantia nigra pars compacta (SNc), and Huntington’s disease, which primarily involves damage to the striatum. Basal ganglia dysfunction is also implicated in some other disorders of behavior control such as Tourette’s syndrome, ballismus (particularly hemibalismus), obsessive-compulsive disorder, and Wilson’s disease (hepatolenticular degeneration). With the exception of Wilson’s disease and hemiballismus, the neuropathological mechanisms underlying diseases of ganglia such as Parkinson’s’ and Huntington’s are not very well understood or are at best still developing theories.

The basal ganglia have a limbic sector whose components are the nucleus accumbens, ventral pallidum, and ventral tegmental area (VTA). This limbic sector is thought to play a central role in reward learning, particularly a pathway from the VTA to the nucleus accumbens that uses the neurotransmitter dopamine. A number of highly addictive drugs, including cocaine, amphetamine, and nicotine, are thought to work by increasing the efficacy of this dopamine signal.

Limbic System

The limbic system makes up the inner border of the cortex and is vital for emotion, motivation, and memory.

Key Points

The lymbic system includes the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex, and fornix, which together support a variety of functions including emotion, behavior, motivation, long-term memory, and olfaction.

The limbic system operates by influencing the endocrine system and the autonomic nervous system. It is highly interconnected with the nucleus accumbens, the brain’s pleasure center, which plays a role in sexual arousal and the “high” derived from certain recreational drugs.

The limbic system is also tightly connected to the prefrontal cortex. Some scientists contend that this connection is related to the pleasure obtained from solving problems.

Key Terms

nucleus accumbens: A collection of neurons that forms the main part of the ventral striatum. It is thought to play an important role in reward, pleasure, laughter, addiction, aggression, fear, and the placebo effect.

hippocampus: A part of the brain located inside the temporal lobe consisting mainly of gray matter. It is a component of the limbic system and plays a role in memory and emotion.

mammillary bodies: Act as a relay for impulses coming from the amygdalae and hippocampi.

prefrontal cortex: The anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas. This brain region has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior, but its primary function is the orchestration of thoughts and actions in accordance with internal goals.

septal nuclei: Play a role in reward and reinforcement along with the nucleus accumbens.

The limbic system, or paleomammalian brain, is a set of brain structures in the cortex and subcortex of the brain. It includes the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex, and fornix, and supports a variety of functions including emotion, behavior, motivation, long-term memory, and olfaction. The term “limbic” comes from the Latin limbus, for “border” or “edge,” because the limbic system forms the inner border of the cortex.

Limbic System Anatomy

This diagram of the limbic system delineates the corpus callosum, fornix, pineal gland, cingulate gyrus, hippocampus, parahippocampal gyrus, amygdaloid body, hypothalamus, mamillary body, and anterior group of thalamic nuclei.

The Limbic System: This diagram of the limbic system delineates components of the diencephalon and cerebrum.

The limbic system consists of various structures that each support distinctive brain functions.

Hippocampus and Associated Structures

  • Hippocampus: Required for the formation of long-term memories and implicated in the maintenance of cognitive maps for navigation.
  • Amygdala: Involved in signaling the cortex of motivationally significant stimuli, such as those related to reward and fear, and in social functions, such as mating.
  • Fornix: A white matter structure that carries signals from the hippocampus to the mammillary bodies and septal nuclei.
  • Mammillary body: Important for the formation of memory.
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Septal Nuclei

  • These lie below the rostrum of the corpus callosum and anterior to the lamina terminalis. The septal nuclei receive reciprocal connections from the olfactory bulb, hippocampus, amygdala, hypothalamus, midbrain, habenula, cingulate gyrus, and thalamus.

Limbic Lobe

A phylogenetically old structure consisting of the following structures:

  • Parahippocampal gyrus: Plays a role in the formation of spatial memory
  • Cingulate gyrus: Conducts autonomic functions regulating heart rate, blood pressure, and cognitive and attentional processing
  • Dentate gyrus: Thought to contribute to the formation of new memories

Additional Structures

  • Entorhinal cortex: Important memory and associative components
  • Piriform cortex: Processes olfactory information
  • Fornicate gyrus: Region encompassing the cingulate and parahippocampal gyrus
  • Nucleus accumbens: Involved in reward, pleasure, and addiction
  • Orbitofrontal cortex: Involved in cognitive processing during decision-making

Limbic System Function

The limbic system operates by influencing the endocrine system and the autonomic nervous system. It is highly interconnected with the nucleus accumbens, the brain’s pleasure center, which plays a role in sexual arousal and the “high” derived from certain recreational drugs.

The structures of the limbic system are involved in motivation, emotion, learning, and memory.

The limbic system is also tightly connected to the prefrontal cortex. Some scientists contend that this connection is related to the pleasure obtained from solving problems. To cure severe emotional disorders, this connection was sometimes surgically severed, a procedure of psychosurgery called a prefrontal lobotomy. Patients who underwent this procedure often became passive and lacked motivation.

Vasculature

The blood supply to the cerebrum can be simply classified into 3 distinct paired arterial branches:

  • Anterior Cerebral Arteries – branches of internal carotid arteries, supplying the anteromedial aspect of the cerebrum.
  • Middle Cerebral Arteries – continuation of internal carotid arteries, supplying most of the lateral portions of the cerebrum.
  • Posterior Cerebral Arteries – branches of the basilar arteries, supplying both the medial and lateral sides of the cerebrum posteriorly.

Venous drainage of the cerebrum is via a network of small cerebral veins. These vessels empty into the dural venous sinuses – endothelial lined spaces between the outer and inner layers of dura mater.

Anatomy: Brain

  • brain
    • grey matter
    • white matter
    • cerebrum
      • cerebral hemisphere (telencephalon)
        • cerebral lobes and gyri
          • frontal lobe
            • frontal pole
            • frontopolar cortex
            • superior frontal gyrus
            • middle frontal gyrus
            • inferior frontal gyrus
              • pars orbitalis
              • pars triangularis
              • pars opercularis
            • precentral gyrus
            • medial frontal gyrus
              • supplementary motor area
            • paracentral lobule
            • cingulate gyrus
              • anterior cingulate cortex
            • orbital gyrus
            • gyrus rectus
            • rostral gyrus
            • septal area
          • parietal lobe
            • postcentral gyrus
            • superior parietal lobule
            • inferior parietal lobule
              • supramarginal gyrus
              • angular gyrus
            • precuneus
          • occipital lobe
            • occipital pole
            • lingual gyrus
            • fusiform gyrus (Brodmann area 37)
            • calcarine (visual) cortex
            • cuneus
          • temporal lobe
            • temporal pole
            • Heschl gyrus
            • superior temporal gyrus
            • middle temporal gyrus
            • inferior temporal gyrus
            • fusiform gyrus
            • mesial temporal lobe
              • amygdala
              • hippocampus
                • malrotation of the hippocampus
              • uncus
              • dentate gyrus
                • band of Giacomini
              • parahippocampal gyrus
              • medial occipitotemporal gyrus
              • subiculum
              • entorhinal cortex
            • lateral parietotemporal line
          • basal forebrain
            • anterior perforated substance
            • substantia innominata
              • basal nucleus of Meynert
          • limbic system
            • limbic lobe
            • parahippocampus
            • septal nuclei
            • nucleus accumbens
            • Papez circuit
          • insula
            • limen insulae
            • operculum
        • cerebral sulci and fissures (A-Z)
          • calcarine fissure
          • callosal sulcus
          • central (Rolandic) sulcus
          • cingulate sulcus
          • collateral sulcus
          • inferior frontal sulcus
          • inferior occipital sulcus
          • inferior temporal sulcus
          • interhemispheric fissure
          • intraparietal sulcus
          • lateral (Sylvian) sulcus
            • anterior ramus of the lateral sulcus
            • ascending ramus of the lateral sulcus
            • circular sulcus
          • lateral occipital sulcus
          • marginal sulcus
          • occipitotemporal sulcus
          • olfactory sulcus
          • paracentral sulcus
          • paraolfactory sulcus
          • parieto-occipital fissure
          • posterior parolfactory sulcus
          • precentral sulcus
          • preoccipital notch
          • postcentral sulcus
          • rhinal sulcus
          • rostral sulcus
          • subparietal sulcus
          • superior frontal sulcus
          • superior occipital sulcus
          • superior temporal sulcus
        • cortical histology
          • Betz cells
      • white matter tracts
        • commissures
          • corpus callosum
            • indusium griseum
            • callososeptal interface
            • Probst bundles
          • anterior commissure
          • hippocampal commissure
            • psalterium
          • habenular commissure
          • posterior commissure
          • supraoptic commissure
            • Gudden commissure
            • Meynert commissure
            • Gasner commissure
        • fornix
        • forceps major
        • forceps minor
        • internal capsule
        • external capsule
        • extreme capsule
        • corona radiata
        • centrum semiovale
        • corticobulbar
        • medial lemniscus
        • optic radiation
          • Meyer loop
          • superior geniculocalcarine tract
        • subcortical U-fibers
        • terminal zones of myelination
        • uncinate fasciculus
      • deep grey matter
        • basal ganglia claustrum
          • caudate nucleus
            • caudothalamic groove
          • corpus striatum
          • lentiform nucleus
            • globus pallidus
            • putamen
          • neostriatum
          • nucleus accumbens
      • pituitary gland
        • posterior pituitary and stalk (part of diencephalon)
          • ectopic posterior pituitary
        • anterior pituitary
        • inferior hypophyseal arterial circle
      • diencephalon
        • thalamencephalon
          • thalamus
            • interthalamic adhesion
            • lateral geniculate nucleus
            • medial geniculate nucleus
          • metathalamus
          • epithalamus
            • habenula
            • stria medullaris
            • pineal gland
        • subthalamus
          • subthalamic nuclei
        • hypothalamus
          • supraoptic nucleus
          • mammillary bodies
          • tuber cinereum
    • brainstem
      • midbrain (mesencephalon)
        • tectal plate
        • tegmentum
        • cerebral peduncles
        • corpora quadrigemina
        • posterior perforated substance
        • periaqueductal grey matter
      • pons (part of metencephalon)
        • facial colliculus
        • superior olivary nucleus
      • medulla oblongata (myelencephalon)
        • olive
        • inferior olivary nucleus
        • nucleus of the tractus solitarius
        • nucleus ambiguus
        • dorsal vagal motor nucleus
      • white matter
      • grey matter
        • ​non-cranial nerve
          • substantia nigra
          • red nucleus
          • superior colliculi
          • inferior colliculi
        • cranial nerve nuclei
          • oculomotor nucleus
          • Edinger-Westphal nucleus
          • trochlear nucleus
          • motor nucleus of CN V
          • ​mesencephalic nucleus of CN V
          • main sensory nucleus of CN V
          • spinal nucleus of CN V
          • abducent nucleus
          • facial nucleus
          • superior salivatory nucleus
          • cochlear nuclei
          • vestibular nuclei
          • inferior salivatory nucleus
          • solitary tract nucleus
          • ambiguus nucleus
          • dorsal vagal motor nucleus
          • hypoglossal nucleus
    • cerebellum (part of metencephalon)
      • vermis
      • cerebellar hemisphere
        • cerebellar tonsil
        • dentate nucleus
      • cerebellar peduncles
        • superior cerebellar peduncle
        • middle cerebellar peduncle
        • inferior cerebellar peduncle
    • cranial meninges (meninx primitiva)
      • dura mater (pachymeninx)
        • falx cerebri
        • tentorium cerebelli
        • falx cerebelli
        • petroclinoid ligaments
        • diaphragma sellae
        • carotid cave
      • leptomeninges
        • arachnoid mater
          • Liliequest membrane
          • arachnoid granulations
            • aberrant arachnoid granulations
        • pia mater
          • velum interpositum
            • cavum velum interpositum
      • extradural space
      • subdural space
      • subarachnoid space
      • blood supply of the meninges
      • innervation of the meninges
    • CSF spaces
      • ventricular system
        • lateral ventricles
          • septum pellucidum
            • cavum septum pellucidum
            • cavum vergae
        • interventricular foramen (of Monro)
          • choroidal fissure
        • third ventricle
          • lamina terminalis
          • supraoptic recess
          • infundibular recess
          • pineal recess
          • suprapineal recess
        • aqueduct of Sylvius
        • fourth ventricle
          • superior medullary velum
          • inferior medullary velum
          • obex
          • area postrema
          • rhomboid fossa
        • calcar avis
        • foramen of Magendie
        • foramina of Lushka
        • tela choroidea
        • cerebrospinal fluid
          • choroid plexus
            • Bochdalek’s flower basket
      • subarachnoid cisterns
        • suprasellar cistern
          • empty sella sign
        • interpeduncular cistern
        • ambient cistern
          • transverse fissure
        • quadrigeminal cistern
        • pericallosal cistern
        • prepontine cistern
        • cerebellopontine cistern
        • premedullary cistern
        • Sylvian cistern
        • cisterna magna
          • mega cisterna magna
        • Meckel cave
    • cranial nerves (mnemonic)
      • olfactory nerve (CN I)
      • optic nerve (CN II)
        • optic chiasm
        • optic tract
      • oculomotor nerve (CN III)
      • trochlear nerve (CN IV)
      • trigeminal nerve (CN V) (mnemonic)
        • trigeminal ganglion
      • abducens nerve (CN VI)
      • facial nerve (CN VII) (segments mnemonic | branches mnemonic)
        • geniculate ganglion
          • greater (superficial) petrosal nerve
            • Vidian nerve
          • external petrosal nerve
          • nerve to stapedius
        • nervus intermedius
      • vestibulocochlear nerve (CN VIII)
        • vestibular ganglion (Scarpa’s ganglion)
      • glossopharyngeal nerve (CN IX)
        • Jacobson nerve
        • lesser petrosal nerve
      • vagus nerve (CN X)
        • Arnold’s nerve
      • spinal accessory nerve (CN XI)
      • hypoglossal nerve (CN XII)
    • functional neuroanatomy
      • Brodmann areas
      • cortical motor system
        • extrapyramidal system
      • cortical sensory system
        • pain and temperature sensation
        • vibration and proprioception sensation
      • auditory/speech system
        • Broca’s area (Brodmann area 44)
        • Wernicke’s area (Brodmann area 22)
      • visual system
      • olfactory system
      • default mode network
    • CNS development
      • brain development
        • neural plate
          • neural tube
        • prosencephalon
          • telencephalon
            • paraphysis elements
            • Rathke pouch
          • diencephalon
        • mesencephalon
        • rhombencephalon
          • metencephalon
          • myelencephalon
    • cerebral vascular supply
      • arteries
        • vascular territories
          • anterior circulation
          • posterior circulation
        • circle of Willis
          • internal carotid artery (ICA) (segments)
            • inferolateral trunk
            • meningohypophyseal trunk
              • inferior hypophyseal artery
            • capsular arteries (of McConnell) (variable)
            • superior hypophyseal artery
            • anterior cerebral artery (ACA)
              • anterior communicating artery (ACOM)
              • medial lenticulostriate arteries
              • recurrent artery of Heubner
              • medial frontobasal artery
              • frontopolar artery
              • orbitofrontal artery
              • pericallosal artery
                • callosomarginal artery
                • pericallosal moustache
            • middle cerebral artery (MCA)
              • M1 branches
                • lenticulostriate arteries
                  • medial lenticulostriate arteries
                  • lateral lenticulostriate arteries
                • anterior temporal artery
                • temporopolar artery
              • M2 branches
            • posterior communicating artery (PCOM)
            • ophthalmic artery
              • lacrimal artery
              • supraorbital artery
              • posterior ethmoidal artery
              • anterior ethmoidal artery
              • internal palpebral artery
              • supratrochlear artery (frontal artery)
              • dorsal nasal artery
            • anterior choroidal artery
          • vertebral artery
            • posterior inferior cerebellar artery (PICA)
            • basilar artery
              • anterior inferior cerebellar artery (AICA)
                • labyrinthine artery
              • pontine arteries
              • superior cerebellar artery (SCA)
              • posterior cerebral artery (PCA)
                • calcarine artery
                • splenial artery
                • posterior choroidal artery
                  • medial posterior choroidal artery
                  • lateral posterior choroidal artery
          • normal variants
            • intracranial arterial fenestration
            • internal carotid artery (ICA)
              • absent ICA
              • aberrant ICA
            • anterior cerebral artery (ACA)
              • azygos ACA
            • middle cerebral artery (MCA)
              • accessory MCA
              • duplicated MCA
              • MCA fenestration
            • posterior cerebral artery (PCA)
              • fetal origin of PCA / fetal PCOM
              • artery of Percheron
            • basilar artery
              • basilar artery fenestration
              • basilar artery hypoplasia
            • persistent carotid-vertebrobasilar artery anastomoses (mnemonic)
              • persistent primitive trigeminal artery
              • persistent otic artery
              • persistent hypoglossal artery
              • persistent proatlantal artery
                • persistent proatlantal intersegmental artery
            • vertebral artery
              • vertebral artery hypoplasia
            • ophthalmic artery
      • cerebral venous system
        • dural venous sinuses
          • basilar venous plexus
          • cavernous sinus (mnemonic)
          • clival diploic veins
          • inferior petro-occipital vein
          • inferior petrosal sinus
          • inferior sagittal sinus
          • intercavernous sinus
          • internal carotid artery venous plexus of Rektorzik
          • jugular bulb
          • marginal sinus
          • occipital sinus
          • sigmoid sinus
          • sphenoparietal sinus
          • straight sinus
          • superior petrosal sinus
            • superior petrosal vein
          • superior sagittal sinus
          • torcula herophili
          • transverse sinus
        • cerebral veins
          • superficial veins of the brain
            • superior cerebral veins (superficial cerebral veins)
            • inferior cerebral veins
            • superficial middle cerebral vein
            • superior anastomotic vein (of Trolard)
            • inferior anastomotic vein (of Labbe)
        • deep veins of the brain
          • vein of Galen (median prosencephalic vein)
            • basal vein of Rosenthal
            • internal cerebral vein
              • thalamostriate vein
              • septal cerebral vein
          • venous circle of Trolard
        • normal variants
          • persistent falcine sinus
    • glymphatic pathway

References

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