The brainstem is thus the stalk that extends from the brain to meet the spinal cord, and is clearly visible when looking at the brain from any perspective that allows the base of the brain to be seen. ![]() At about this point, the cord merges with the medulla oblongata, which is the lowest part of the brainstem. The spinal cord enters the skull through an opening known as the foramen magnum. Before the signal is sent to our muscles, however, it is sent to the cerebellum. When we make a voluntary movement, the signal to initiate that movement originates in the motor cortices. It is best known for its part in the modulation of movement. It protrudes from the back and bottom of the cerebral cortex. Cerebellum is Latin for "little brain", and indeed the cerebellum looks a bit like a smaller version of our brain. The cerebellum is hard to miss when you're looking at a brain. The cerebellum integrates this information and sends signals back to the rest of the brain, thereby enabling accurate and well-coordinated movements. The cerebellar cortex receives information from most parts of the body, and from many other regions of the brain. The primary visual cortex is contained in the occipital lobe. It receives information from the lateral geniculate nucleus of the thalamus, and aids in the processing of visual information. The occipital lobe is dedicated to vision. For example, visual information from your retina travels to the lateral geniculate nucleus of the thalamus, which is specialized to handle visual information, before being sent on to the primary visual cortex (the main area for visual processing in the brain). This is because almost all sensory information (with the exception of smell) that proceeds to the cortex first stops in the thalamus before being sent on to its destination. The thalamus is often described as a relay station. A large number of pathways travel through the thalamus, including all of the sensory pathways other than those devoted to olfaction (smell). The thalamus is a large, symmetrical (meaning there is one in each cerebral hemisphere) structure that makes up most of the mass of the diencephalon. The parietal lobe also contains areas responsible for the dorsal or "where" pathway of visual processing and spatial orientation. The primary somatosensory cortex receives sensory input from the opposite side of the body. ![]() The central sulcus is a prominent landmark of the brain, separating the parietal lobe from the frontal lobe Parietal LobeĪ large portion of the parietal lobe is dedicated to sensation. As a means of simplification, the cerebral cortex is often characterized as being made up of three types of areas: sensory, motor, and association areas. The cerebral cortex forms extensive connections and is involved in multitudinous brain functions. It is the most prominent visible feature of the human brain, and although it is only a few millimeters thick, it comprises about half of the weight of the brain. Cerebral CortexĬortex means "bark" in Latin and appropriately the cerebral cortex is the outermost layer of the brain, made up primarily of grey matter. The frontal lobe also contains Broca's area (expressive language area) which is controls speech and the frontal eye fields that help direct eye movements. The medial prefrontal cortex, orbitofrontal area, and the medial frontal area are responsible for motivation and social information processing and regulating emotions, behavior, and personality. The main crossing location of these motor fibers occurs in the brainstem. The left side of the brain controls movement for the right side of the body, and vice-versa. The primary motor cortex controls the majority of movement. It is primarily responsible for the planning and execution of actions as well as inhibition. ![]() The frontal lobe is the largest area of the brain. The occipital lobe is critical for vision and visual processing. The parietal lobe is critical for sensory processing. The temporal lobe is critical for auditory processing and visual and language memory. The frontal lobe is critical for motor execution and eye movement. On a broad level, the cerebral cortex is divided into four main areas (termed lobes). The "brain" as we tend to refer to it is a structure of densely packed nerve cells (neurons) called the cerebral cortex.
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