There is a long-standing interest in exploring the factors related to student achievement. As a newly explored personality trait, grit is defined as a person's tendency to pursue long-term goals with continual perseverance and passion, and grit plays a critical role in student achievement. Increasing evidence has shown that growth mindset, the belief that one's basic abilities are malleable and can be developed through effort, is a potential factor for cultivating grit. However, less is known about the association between grit and the brain and the role of growth mindset in this association. Here, we utilized voxel-based morphometry to examine the neuroanatomical correlates of grit in 231 healthy adolescent students by performing structural magnetic resonance imaging. The whole-brain regression analyses revealed that the regional gray matter volume (rGMV) in the left dorsolateral prefrontal cortex (DLPFC) negatively predicted grit. In contrast, the rGMV in the right putamen positively predicted grit. Furthermore, mediating analyses suggested that growth mindset served as a mediator in the association between left DLPFC volume and grit. Our results persisted even after controlling for the influences of self-control and delayed gratification. Overall, our study presents novel evidence for the neuroanatomical basis of grit and highlights that growth mindset might play an essential role in cultivating a student's grit level.
The mesencephalon (or midbrain) consists of several structures around the cerebral aqueduct such as the periaqueductal gray (or central gray), the mesencephalic reticular formation, the substantia nigra, the red nucleus (Figure 1.4), the superior and inferior colliculi, the cerebral peduncles, some cranial nerve nuclei, and the projection of sensory and motor pathways.
Gray 039 s-Anatomy-For-Students -3rd-Edition-pdf
The caudal end of the myelencephalon develops into the spinal cord. The spinal cord is an elongated cylindrical structure lying within the vertebral canal, which includes the central canal and the surrounding gray matter. The gray matter is composed of neurons and their supporting cells and is enclosed by the white matter that is composed of a dense layer of ascending and descending nerve fibers. The spinal cord is an essential link between the peripheral nervous system and the brain; it conveys sensory information originating from different external and internal sites via 31 pairs of spinal nerves (Figure 1.5). These nerves make synaptic connections in the spinal cord or in the medulla oblongata and ascend to subcortical nuclei.
The largest and most obvious parts of the human brain are the cerebral hemispheres. The cerebrum has an outer layer - the cortex, which is composed of neurons and their supporting cells, and in living brain, has a gray color thus called the gray matter. Under the gray matter is the white matter, which is composed of myelinated ascending and descending nerve fibers, and in living brain have a white color. Embedded deep within the white matter are aggregates of neurons exhibiting gray color and known as subcortical nuclei. The cerebral hemispheres are partially separate from each other along the midline by the interhemispheric fissure (deep groove) the falx cerebri (Figure 1.8A); Posteriorly, there is a transverse fissure that separates the cerebral hemisphere from the cerebellum, and contains the tentorium cerebellum. The hemispheres are connected by a large C-shaped fiber bundle, the corpus callosum, which carries information between the two hemispheres.
Transverse Section through the Spinal Cord. Figure 1.17A illustrates a section taken at the level of the thoracic spinal cord. The spinal cord neuron (gray matter) form a central core taking a butterfly configuration that is surrounded by nerve fibers (white matter). In the left and right halves of the spinal cord, the gray matter is organized into a dorsal horn and ventral horn with the intermediate gray located between them. In the thoracic spinal cord, which is illustrated in this figure, a lateral horn extends laterally from the intermediate gray (Figure 1.17A). The spinal cord white matter is subdivided into the posterior white column, the anterior white column and the lateral white column. The anterior white commissure joins the two halves of the spinal cord and is located ventral to the intermediate gray. The dorsal root fibers enter the spinal cord at the dorsolateral sulcus and the fibers of the ventral root fibers exit the spinal cord in numerous fine bundles through the ventral funiculus (see Figure 1.5).
Section through the Midbrain. Figure 1.17F is a section that shows the main midbrain nuclei which include the tectum (superior colliculi) the periaqueductal gray, the red nuclei, substantia nigra and the cerebral peduncles.
Meditation group participants reported spending an average of 27 minutes each day practicing mindfulness exercises, and their responses to a mindfulness questionnaire indicated significant improvements compared with pre-participation responses. The analysis of MR images, which focused on areas where meditation-associated differences were seen in earlier studies, found increased gray-matter density in the hippocampus, known to be important for learning and memory, and in structures associated with self-awareness, compassion, and introspection.
Participant-reported reductions in stress also were correlated with decreased gray-matter density in the amygdala, which is known to play an important role in anxiety and stress. Although no change was seen in a self-awareness-associated structure called the insula, which had been identified in earlier studies, the authors suggest that longer-term meditation practice might be needed to produce changes in that area. None of these changes were seen in the control group, indicating that they had not resulted merely from the passage of time.
The terms white matter and gray matter refer to different components of nervous tissue found in the brain and spinal cord, which make up the central nervous system (CNS). Neurons, specialized cells which send and respond to electrical impulses, make up a large portion of the nervous system and are responsible for forming the basis of the CNS. Neurons arrange themselves in very distinct ways within the CNS, which makes the brain and spinal cord appear as areas of either gray or white color. These differences are due to the presence or absence of myelin, a fatty covering on the axons of neurons. Gray matter refers to tissue which is made up of nonmyelinated neurons, while white matter refers to areas of myelinated neurons.
Within the CNS, gray and white matter are localized in distinct regions. The gray matter of the spinal cord is found deep to the white matter, and in cross section, resembles a butterfly or the letter H. The brain stem shows a similar organization, with additional gray matter nuclei, or neuron cell bodies, distributed within the white matter. In the cerebrum, the organization is switched, with white matter being interior to gray matter.
Along with differences in myelination, gray and white matter in the brain and spinal cord have different functions. The cerebrum consists of an outer layer of grey matter called the cerebral cortex, which surrounds an inner mass of white matter. The cerebral cortex is referred to as the "executive suite," where the conscious mind is found, and it consists entirely of gray matter containing neuron cell bodies, dendrites, glia cells, and blood vessels. There are no fiber tracts, or axons, in this region. There are three general functional areas of the cerebral cortex:
The white matter of the cerebrum allows for communication between the gray matter and the lower CNS centers. The nervous tissue here consists of myelinated fibers, or axons, which are bundled into tracts. These fibers and tracts are classified based on the direction that they run:
The main function of the spinal cord is to relay messages to the brain from the body and vice versa. As a result, gray and white matter function differently in this region of the CNS. The gray matter of the spinal cord contains cell bodies that are responsible for receiving information that must travel to the brain, and sending information to elicit responses in the body. Information is highly organized in the posterior and anterior horns. Some regions of the spinal column also have lateral horns (Figure 1). The posterior horns contain neurons which receive incoming sensory information from the body and viscera. These signals may travel up to the brain or to other regions of the spinal cord. The anterior horns contain motor neurons, which send outgoing signals to the body and viscera to elicit responses. The lateral horns contain neurons that mostly serve the viscera.
Figure 1: The spinal cord. This cross-sectional diagram shows the organization of the gray and white matter of the spinal cord. The gray matter forms three horns, the posterior (top of image), anterior (bottom) and some regions contain lateral horns (center).
White matter vs. gray matter, what does it matter? What's the big difference between these two? Where can we find them? And, why the color difference? Well, you'll learn about that right now. Firstly, let's define white matter vs. gray matter.
White matter is the whitish nerve tissue of the central nervous system that is mainly composed of myelinated nerve fibers (or axons). The central nervous system is the brain and spinal cord. And gray matter is grayish nerve tissue of the central nervous system mainly composed of nerve cell bodies and dendrites.
The color differences seen between gray and white matter has to do with a fatty material called myelin. In the CNS, myelin is formed by cells called oligodendrocytes. These cells have flat processes which wrap themselves around the axons of neurons. Myelin sheaths serve to insulate the axon while leaving small exposed regions, or gaps, that are known as Nodes of Ranvier (Figure 2). This increases the conductivity of neurons and allows electrical impulses to travel quickly down the axon in a method known as saltatory conduction. In gross dissection, myelinated areas of the CNS look white, thus leading them to be referred to as white matter. Gray matter contains neuron cell bodies, glia cells, and other nervous tissue, all of which is nonmyelinated and thus appears gray in color. 2ff7e9595c
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