[Music] [The Human Brain] [A Dynamic View of Its Structure and Organs] [Copyright MCMLXXVI by The Regents of The University of California] [Based Upon Research At the University of California, San Diego] [Robert B. Livingston, M.D. Professor of Neurosciences, Institute for Information Systems, University of California, San Diego] [Associate, Neurosciences Research Program Massachusetts Institute of Technology] [Kent R. Wilson, Ph.D. Associate Professor of Chemistry, University of Caifornia, San Diego] [Music] [Narrator:] The adult human brain. Average weight: three pounds. Three-quarters water, composed of a few thousand known chemical compounds, designed into a dozen billion nerve cells. The brain burns oxygen and glucose at rates ten times the average of other tissues at rest, day and night, night and day, for a lifetime. The human brain. Site of trillions of electrical events and tiny jets of chemicals that signal messages between nerve cells. The control center of the body, storehouse of memories, the seat of consciousness. Awesome in function. Yet after three centuries of increasingly intensive study, still largely unknown. At the University of California San Diego, two new techniques for exploring brains have been developed. The first is the cinemorphology. By means of cinemorphology, thousands of sections of a brain are photographed and displayed in smooth succession. Structures appear and succeed one another, as if in continuous flow. Blood vessels can be injected to trace the details of the vascular plan. Cinemorphology on frozen brains permits staining that will distinguish white and gray matter. To achieve these unique records, a fixed brain is first embedded in plastic. Then the plastic block is placed on a giant microtome. By means of elaborate mechanical and electronic controls, this instrument is programmed to cut away a very thin section of the brain, as little as 25 microns. Following each cut, the brain is automatically moved in front of a motion picture camera. The cut surface of the brain is illuminated, and the camera photographs the new surface that has been exposed by the removal of the thin slice by the microtome. A typical cinemorphology film for an entire brain depicts more than 10,000 surfaces. Each anatomical part is photographed in its natural position, in its exact relations with all other parts. The resulting motion picture films can be studied frame by frame, or viewed in smooth succession, forwards or backwards, at fast or slow motion speeds. Since 1967, some 60 cinemorphology films have been created at the University of California San Diego. This cinemorphology film shows a brain that has been sliced in the horizontal plane. Some 7000 individual surfaces appear from crown to spinal cord. Without staining, the cerebral cortex appears cream-colored, and the white matter looks slightly pinkish. The cinemicrotome is now cutting through the corpus callosum, a dense bundle of fibers which bridges between the two cerebral hemispheres. On each side appear the two lateral ventricles. The basal ganglia, which contribute to posture and locomotion, now emerge. Then the thalamus, surrounding the third ventricle. The hypothalamus separates from the brain stem. The brain stem contains a narrow ventricular aqueduct, which interconnects the third and fourth ventricles. The cerebellum reveals its beautiful fan-like structures. The cortex of the cerebellum shows hundreds of repeated identical folia, which seem to succeed one another in cinemorphology like the opening of petals in a awakening flower. The cerebellum can be seen to rise out the brain stem on three stout peduncular attachments on each side. The brainstem contains connections between the forebrain, cerebellum, and spinal cord. It also embodies the sites and origins and relays for the cranial nerves. Now the same images can be reversed in order to view the brain from spinal cord to crown. The film is now seen at twice the previous viewing speed. [Music] Cinemorphology has revealed that every brain is found to be unique, just as our faces are. [Music] In this brain, the ventricle opens up before the corpus callosum appears. [Music] In this particular brain, the thalamus is comparatively squared off and not so smoothly rounded as in most other brains. The form of the cortex, the shape of each individual nucleus, the configuration of each functional system, all are each recognizably somewhat different in one brain from any other. A second technique for studying the brain, also developed at the University of California San Diego, converts cinemorphology films to computer graphic display. Individual frames of cinemorphology films are projected onto large sheets of paper, and any desired structures of the human brain are then carefully traced. [Music] These tracings are of course unique to the individual brain. [Music] Each of these tracings is placed on a special easel. [Music] When an electronic pen touches any point on the tracing, the exact location of this point is transferred to the memory of a computer. The locations of many thousands of points from each tracing provides a replica of that tracing in the computer. Point by point, tracing by tracing, the information committed by camera to cinemorphology is preserved in the computer. The computer, a wonderful assistant to the human brain, can be programmed to call up and display the pinpoints of neuroanatomy so laboriously traced, either to assemble a whole brain or to erect individual structures on demand. Ideas, generated in the brain of the programmer, excited by that nimble process called imagination, transferred by nerves to muscles, to finger movements, to the electrical mechanical complex of the machine, interact dynamically within the computer. The hand of the programmer and the calculations of the computer enable the human eye to visualize brain structures as they have never been seen before. [Music] Now, a specially constructed motion picture camera can photograph the images generated on the face of the computer display, and by the use of three primary color filters superimpose any color of choice on any selected still or moving neuroanatomical structures. [Music] Here the cerebral ventricles are shown in blue. They represent the cephalic elaboration of the original neural tube around which all of the structures of the brain are organized during embyrogenesis. The two lateral ventricles penetrate each lobe of the cerebral hemispheres. The rounded anterior horns of the lateral ventricles reach into the frontal lobes. The posterior horns occupy the central axis of the occipital lobes. The temporal horns curve beneath to invade the temporal lobes. The lateral ventricles connect by narrow channels with a single midline third ventricle. In this particular brain, the third ventricle has a hole in its central region, another of the many variable features of the construction of the human brain. The third ventricle connects a still narrower channel, the cerebral aqueduct, with the fourth ventricle. [Music] The thalamus occupies both sides of the third ventricle. The thalamus provides mainly for relaying information to and from the cerebral cortex. The hypothalamus embraces the lower anterior portion of the third ventricle. The pineal gland, which Descartes supposed to be the seat of the soul, lies directly behind the roof of the third ventricle and above the brain stem. Here a brain has been dissected in order to show the combination of thalamus, pineal gland, and hypothalamus in a natural post-mortem condition. Any such structures, after suitable preparation, can be sliced on the cinemicrotome, photographed, traced, digitized, and programmed into the computer. [Music] The brain stem is continuous with the thalamus and the hypothalamus. It connects these diencephalic structures to and from the spinal cord. [Music] One of the major motor control systems of the brain is called the basal ganglia. Downstream components of the basal ganglia include the subthalamic nucleus, depicted in mauve color, the red nucleus, which looks reddish in freshly cut brains, and the substantia nigra, so called because of its tendency to accumulate black pigment. Here it appears white, in orientation among other structures. [Music] The basal ganglia in the forebrain include the globus pallidus, named because of its natural pallor in the fresh state, the putamen, which has been likened to a seashell, and the caudate nucleus, which is named for its long, curving tail. The basal ganglia in the forebrain, and in the diencephalon and mesenphalic brain stem, have to do principally with postural and gestural control of body musculature. The characteristic shape of the basal ganglia is visible in this dissected specimen. [Music] The basal ganglia receive projections from all regions of the cerebral cortex which activate mainly the putamen and caudate nuclei. [Music] The putaman and caudate nuclei project in turn to the globus pallidus. The globus pallidus sends projections to and receives impulses from the subthalamic nucleus. [Music] The globus pallidus also sends fibers forward to nuclei which lie deep within the thalamus. [Music] From the thalamus, impulses are relayed up the motor cortex. [Music] The motor cortex receives an integrated message from two major motor control systems: the basal ganglia and the cerebellum. Signals from the basal ganglia also course downward into the basal ganglia nuclei in the diencephalon and mesencephalon, [Music] the subthalmic nucleus, the red nucleus, and the substantia nigra. [Music] Such signals are also transmitted to the diffusely projecting brain stem reticular formation. The cerebellum, the so-called "little brain," sits on stout stalks which arise from the brain stem. The gross anatomical relations between cerebellum and brain stem can be seen in this dissection. The brain stem is truncated at the level of the red nucleus. The cerebellum is thought to regulate sensory and motor coordination of a relatively automatic kind. For example, it is concerned with adjusting the body in recovery from displacement in space and to coordinate the body within the gravitational field. The cerebellum receives impulses from all areas of the cerebral cortex. It projects downward into the brain stem and upward into the thalamus by way of the red nucleus. The thalamus, which relays impulses from basal ganglia to motor cortex, also receives and relays impulses via the same nuclei from cerebellum to motor cortex. [Music] The limbic system governs visceral functions. It is generally considered to be the seat of emotional experience and emotional expression. The amygdala was thought to resemble an almond. It lies directly in front of the temporal horn of the lateral ventricle on each side. [Music] The hippocampus, shown in purple, looks like a seahorse, lying on the floor of the lateral ventricles. The two hippocampi are interconnected across the midline by the hippocampal commissure. [Music] Each hippocampus gives rise to a distinctive bundle of fibers, the fornix, here yellow-orange. [Music] The fornix passes both to and beyond the septum and by relays to the mammillary bodies in the posterior part of the hypothalamus. From the mamillary bodies, impulses travel upwards along the mamillo-thalamic tract. [Music] This tract connects the mamillary bodies with the anterior nucleus of the thalamus bilaterally. [Music] From this region of the thalamus, signals are distributed to a magnificent ring of primitive cortex, which forms a complete circlet, bounding the margins of each hemisphere. [Music] The limbic system consists, then, of a array of cortical and subcortical gray matter structures that ultimately project to the anterior superior portion of the brain stem. In this dissection, the limbic system has been preserved in its entirety along with some additional structures which help to support the limbic system's natural shape. The amygdala receives olfactory signals. It also shares projections to and from the hypothalamus and back and forth with neighboring limbic cortex. [Music] The hippocampus also connects with the hypothalamus and with the local limbic cortex. It receives visual, auditory, and somatic sensory input. The hippocampus also receives signals from the hypothalamus and from the brain stem. These signals relate to bodily needs. The thalamus plays a very involved role by interacting with all regions of the cerebral cortex and conveying to the cortex the outcome of activities in such systems as the basal ganglia and the limbic system. One of the main outputs of the hippocampus is by way of the fornix to the septum and via additional relays to the mamillary bodies. From the mamillary bodies, impulses travel to the anterior nucleus of the thalamus and on from there to the bordering rim of limbic cortex. [Music] The limbic system completes this circuit of communications like a crocodile biting its own tail. [Music] The limbic system and the basal ganglia fit intimately together. Both of these distinctive functional systems are neatly packaged within each cerebral hemisphere. [Music] A computer has taken data from one person's brain and has revealed that brain's most important systems in three-dimensional space. [Music] Underlying all are membranes loaded with specialized structures for discriminative reactions to neurotransmitters, electrical signals, and hormonal messages. [Music] We do not yet know why the anatomy of the brain is so different from one person to another. By taking advantage of the marvelous projective capabilities of the computer, which can represent and measure exactly volumes, configurations, and topologies, a new precision for quantitative neurology of the human brain can be obtained. [Music] Mankind needs to know a great deal more about the human brain, not only at the biochemical and cellular levels,but also at the level of quantitative comparisons relating to the sizes and the topologies of human brain structures. Cinemorphology, aided by the computer, can now provide an exciting opportunity to explore many aspects of what makes humankind human. [Music] [Project Organization: Bill AtkinsonCinemorphology Operations: Roy E. Mills] [Computer Programming: David M. Rempel,John S. MacGregor III, Guy E. Tribble III] [Computer Facilities: John F. Cornelius, Arthur D. Olson] [Original Art: Frank ArmitageMusical Composition: Bernhard A. Batschelet, Russell W. Lieblich] [Narration: Robert B. Livingston] [Technical Assistance: C. Noel Bartlett, H. Paul Savage, Dana R. LivingstonAdministrative Assistance: Maureen H. Wood] [Cinemorphology Development Supported by The National Library of Medicine] [and The National Institute of Neurological Diseases and Blindness, Grant No. PH-43-66-597] [Computer Development Sponsored by: The National Institutes of Health, Grant No. RR 00757] [and The National Science Foundation, Grant No. GK 36356] [Presented by Roche LaboratoriesDivision of Hoffmann-La Roche, Inc., Nutley, New Jersey] [Wexler Films, Los Angeles]