THE BIG BRAIN EBOOK By The Visible Body Team & Professor Blythe Nilson Located inside the skull, the brain is an organ of the central nervous system that receives sensory input and information to form perception and thought. It controls activities such as speech, movement, and maintaining homeostasis. Forebrain REGIONS OF THE BRAIN The brain can be split into three regions: forebrain, brainstem, and cerebellum. Cerebellum Brainstem 2 | Brain Regions Basal Ganglia Cerebral Cortex Corpus Callosum FOREBRAIN The forebrain is made up of the cerebrum (cerebral cortex and basal ganglia), corpus callosum, diencephalon, and the limbic system. Diencephalon Limbic system Brain Regions>Forebrain | 3 CEREBRUM OVERVIEW The cerebrum is the largest part of the brain. It is responsible for higher intellectual functions and conscious thought. The cerebrum is made up of the cerebral cortex and the basal ganglia. 4 | Brain Regions> Forebrain> Cerebrum Neuron diagram CEREBRAL CORTEX OVERVIEW The cerebral cortex is the surface of the cerebrum. The cortex contains around 16 billion neurons (cells that relay sensory sulcus information and motor commands as electric signals throughout the body). In order for the cerebral cortex to fit inside the skull, the cerebral cortex has folds called gyri and grooves called sulci. gyrus Brain Regions> Forebrain> Cerebrum> Cerebral Cortex | 5 CEREBRAL CORTEX HEMISPHERES The cerebral cortex consists of a left and a right hemisphere. The left is typically responsible for language, calculation, comprehension, and writing. The right is generally responsible for creativity, visual, emotional, and artistic awareness. Each hemisphere controls the opposite side of the body. Left hemisphere Right hemisphere 6 | Brain Regions> Forebrain> Cerebrum> Cerebral Cortex Frontal Lobe Parietal Lobe LOBES OF THE CEREBRAL CORTEX Each hemisphere has four lobes: frontal, parietal, temporal, and occipital lobe. Each lobe is responsible for different brain functions. Temporal Lobe Occipital Lobe Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes | 7 Prefrontal association area Supplementary motor area (SMA) FRONTAL LOBE Premotor cortex Prefrontal association area: Executive function (thought, cognition, planning, and personality) Premotor cortex: Planning movement Supplementary motor area: Planning limb and eye movement Broca’s area: Speech production and Primary motor area language processing Gustatory cortex: Receives and processes taste signals Broca’s area Gustatory cortex Primary motor area: Voluntary movement control 8 | Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes Primary somatosensory cortex PARIETAL LOBE Secondary somatosensory cortex Primary somatosensory cortex: Processes tactile information (for the opposite side of the body) Secondary somatosensory cortex: Processes tactile information (including pain) Somatosensory association area: Integrates sensory input (perceives temperature, pressure, size, texture, and relationships between touched objects) Somatosensory association area Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes | 9 TEMPORAL LOBE Secondary auditory cortex Auditory association area Auditory association area: Interprets Wernicke’s area auditory information such as speech, music, or other sounds Primary auditory cortex Primary auditory cortex: Interprets pitch and rhythm of sounds Wernicke’s area: Comprehension of written and spoken language Primary olfactory cortex: Receives and processes olfaction signals Secondary auditory cortex: Processes auditory information and plays a role in Primary olfactory cortex Visual association area speech perception Visual association area: Participates in 10 | Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes object and pattern recognition OCCIPITAL LOBE Primary visual cortex Primary visual cortex: Receives and processes visual signals from the Secondary visual cortex opposite visual field via the thalamus Secondary visual cortex: Interprets visual signals and contributes to visual mapping Tertiary visual cortex: Participates in Tertiary object recognition and motion sensing visual cortex Brain Regions>Forebrain>Cerebrum>Cerebral Cortex> Lobes | 11 BASAL GANGLIA The basal ganglia contain nuclei inside the cerebrum that influence body movement and muscle tone. 12 | Brain Regions> Forebrain> Cerebrum> Basal Ganglia CORPUS CALLOSUM The corpus callosum is a c-shaped structure that straddles the midline of the brain. This connects the two hemispheres to allow communication between them. Brain Regions> Forebrain> Corpus Callosum | 13 DIENCEPHALON OVERVIEW The diencephalon is a region of the brain that consists of the hypothalamus, thalamus and epithalamus (main structure is the pineal gland). Thalamus Epithalamus Hypothalamus 14 | Brain Regions> Forebrain> Diencephalon HYPOTHALAMUS The hypothalamus regulates autonomic nervous functions, emotions, behavior, food consumption, circadian rhythms, and body temperature. It also produces hormones that influence the pituitary gland and regulate endocrine functions. At the base of the hypothalamus, the optic chiasm is the crossing point of the optic nerves. Brain Regions> Forebrain> Diencephalon> Hypothalamus | 15 THALAMUS The thalamus plays a role in learning and memory. It consists of several nuclei that pass sensory information to different regions of the cerebral cortex. The thalamus also determines what sensory information is important enough to send to the cerebral cortex to allow for conscious awareness of the sensory input. 16 | Brain Regions> Forebrain> Diencephalon> Thalamus PITUITARY Hormones secreted by the hypothalamus activate hormone secretion by the pituitary gland. These hormones drive endocrine functions (like sexual development and promotion of bone and muscle growth) by targeting glands and tissues. Brain Regions> Forebrain> Diencephalon> Pituitary | 17 Cingulate gyrus LIMBIC SYSTEM The limbic system is located on the inner border of the cerebrum, above the diencephalon, forming a pair of rings between the two cerebral hemispheres. It manages a range of emotions and contributes to the processing of smell memory. Amygdala = memory and emotion Hippocampus = long term memory Septal nucleus Mammillary body = smell memory Hippocampus Septal nucleus = feeling of pleasure Amygdala Mammillary body Cingulate gyrus = expressing emotions through gestures 18 | Brain Regions> Forebrain> Limbic System Midbrain BRAINSTEM Pons The brainstem (consisting of the midbrain, pons, and medulla oblongata) connects the brain to the spinal cord. Medulla oblongata The brainstem controls the involuntary functions of the respiratory, digestive, and circulatory systems, while also contributing to hearing, balance, and gustation. Brain Regions> Brainstem | 19 MIDBRAIN The midbrain contains nuclei, called colliculi, which control visual and auditory reflexes. It also contains nuclei for the oculomotor (CN03) and trochlear (CN04) nerves. Both help control eye movement. 20 | Brain Regions> Brain Stem> Midbrain PONS The pons connects the brain to the brain stem through tracts of white fibers that carry signals between them. It houses pontine nuclei, which affect breathing rhythms. Brain Regions> Brain Stem> Pons | 21 MEDULLA OBLONGATA The medulla oblongata controls involuntary functions of the respiratory, digestive, and circulatory system and contributes to hearing, balance, and taste. The medulla plays a role in homeostatis, acting as the autonomic reflex center for heart contraction, vasomotor control, respiratory rate and depth, as well as other reflexes such as swallowing, coughing, vomiting, and sneezing. 22 | Brain Regions> Brain Stem> Medulla Oblongata CEREBELLUM The cerebellum is mostly considered to be a motor structure. Even though motor commands do not directly come from the cerebellum, it modifies the commands to make the movements more accurate. This is why cerebellar damage leads to impairment in motor control. Other functions of the cerebellum include: maintaining balance and posture, coordination of voluntary movements, and motor learning, as well as some cognitive functions related to word association and puzzle solving. Brain Regions> Cerebellum | 23 Central nervous system PARTS OF THE NERVOUS SYSTEM Peripheral nervous The brain is connected with the rest of system the body via the nervous system. The nervous system is responsible for the correlation and integration of various bodily processes, producing reactions and adjustments based on the current environment. The nervous system can be split into two different regions: the central nervous system (CNS) and the peripheral nervous system (PNS). 24 | Nervous System> Overview CENTRAL NERVOUS Brain SYSTEM The central nervous system (CNS) consists of the brain and the spinal cord. The average length of a male spinal cord is 45 cm and for females, it is around 43 Spinal cord cm. The spinal cord carries incoming and outgoing messages between the brain and the rest of the body. Nervous System> Central Nervous System | 25 PERIPHERAL NERVOUS SYSTEM The peripheral nervous system (PNS) consists of all the nerves and ganglia outside of the central nervous system connecting it to all the regions of the body. The PNS can be split into two different divisions: the somatic nervous system (SNS) and the autonomic nervous system (ANS). The somatic nervous system - controls all voluntary movement plus somatic reflexes The autonomic nervous system - regulates involuntary movement such as heartbeat and smooth muscle contraction. 26 | Nervous System> Peripheral Nervous