Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
CNS Physiology For Bio 260 Regions and Organization of the CNS • Adult brain regions 1. 2. 3. 4. Cerebral hemispheres Diencephalon Brain stem (midbrain, pons, and medulla) Cerebellum Precentral gyrus Frontal lobe Central sulcus Postcentral gyrus Parietal lobe Parieto-occipital sulcus (on medial surface of hemisphere) Lateral sulcus Occipital lobe Temporal lobe Transverse cerebral fissure Cerebellum Pons Medulla oblongata Spinal cord Fissure (a deep sulcus) Gyrus Cortex (gray matter) Sulcus White matter (a) Figure 12.6a Motor areas Central sulcus Primary motor cortex Premotor cortex Frontal eye field Broca’s area (outlined by dashes) Prefrontal cortex Working memory for spatial tasks Executive area for task management Working memory for object-recall tasks Solving complex, multitask problems (a) Lateral view, left cerebral hemisphere Sensory areas and related association areas Primary somatosensory cortex Somatic Somatosensory sensation association cortex Gustatory cortex (in insula) Taste Wernicke’s area (outlined by dashes) Primary visual cortex Visual association area Auditory association area Primary auditory cortex Vision Hearing Motor association cortex Primary sensory cortex Primary motor cortex Sensory association cortex Multimodal association cortex Figure 12.8a Primary Somatosensory Cortex • In the postcentral gyri • Receives sensory information from the skin, skeletal muscles, and joints • Capable of spatial discrimination: identification of body region being stimulated Multimodal Association Areas • Receive inputs from multiple sensory areas • Send outputs to multiple areas, including the premotor cortex • Allow us to give meaning to information received, store it as memory, compare it to previous experience, and decide on action to take Premotor cortex Corpus callosum Cingulate gyrus Primary motor cortex Frontal eye field Prefrontal cortex Processes emotions related to personal and social interactions Orbitofrontal cortex Olfactory bulb Olfactory tract Fornix Temporal lobe (b) Parasagittal view, right hemisphere Uncus Primary olfactory cortex Central sulcus Primary somatosensory cortex Parietal lobe Somatosensory association cortex Parieto-occipital sulcus Occipital lobe Visual association area Primary visual cortex Calcarine sulcus Parahippocampal gyrus Motor association cortex Primary sensory cortex Primary motor cortex Sensory association cortex Multimodal association cortex Figure 12.8b Anterior Association Area (Prefrontal Cortex) • Most complicated cortical region • Involved with intellect, cognition, recall, and personality • Contains working memory needed for judgment, reasoning, persistence, and conscience • Development depends on feedback from social environment Posterior Association Area • Large region in temporal, parietal, and occipital lobes • Plays a role in recognizing patterns and faces and localizing us in space • Involved in understanding written and spoken language (Wernicke’s area) Lateralization of Cortical Function • Left hemisphere – Controls language, math, and logic • Right hemisphere – Insight, visual-spatial skills, intuition, and artistic skills • Left and right hemispheres communicate via fiber tracts in the cerebral white matter Basal Nuclei (Ganglia) • Subcortical nuclei • Consists of the corpus striatum – Caudate nucleus – Lentiform nucleus (putamen + globus pallidus) • Functionally associated with the subthalamic nuclei (diencephalon) and the substantia nigra (midbrain) Functions of Basal Nuclei • Though somewhat elusive, the following are thought to be functions of basal nuclei – Influence muscular control – Help regulate attention and cognition – Regulate intensity of slow or stereotyped movements – Inhibit antagonistic and unnecessary movements Thalamic Function • Gateway to the cerebral cortex • Sorts, edits, and relays information – Afferent impulses from all senses and all parts of the body – Impulses from the hypothalamus for regulation of emotion and visceral function – Impulses from the cerebellum and basal nuclei to help direct the motor cortices • Mediates sensation, motor activities, cortical arousal, learning, and memory Cerebral hemisphere Septum pellucidum Interthalamic adhesion (intermediate mass of thalamus) Interventricular foramen Anterior commissure Hypothalamus Optic chiasma Pituitary gland Mammillary body Pons Medulla oblongata Corpus callosum Fornix Choroid plexus Thalamus (encloses third ventricle) Posterior commissure Pineal gland (part of epithalamus) Corpora quadrigemina MidCerebral brain aqueduct Arbor vitae (of cerebellum) Fourth ventricle Choroid plexus Cerebellum Spinal cord Figure 12.12 Hypothalamic Function • Autonomic control center for many visceral functions (e.g., blood pressure, rate and force of heartbeat, digestive tract motility) • Center for emotional response: Involved in perception of pleasure, fear, and rage and in biological rhythms and drives Hypothalamic Function • Regulates body temperature, food intake, water balance, and thirst • Regulates sleep and the sleep cycle • Controls release of hormones by the anterior pituitary • Produces posterior pituitary hormones View (a) Optic chiasma Optic nerve (II) Crus cerebri of cerebral peduncles (midbrain) Diencephalon • Thalamus • Hypothalamus Mammillary body Thalamus Hypothalamus Diencephalon Midbrain Oculomotor nerve (III) Trochlear nerve (IV) Pons Brainstem Medulla oblongata Trigeminal nerve (V) Pons Facial nerve (VII) Middle cerebellar peduncle Abducens nerve (VI) Vestibulocochlear nerve (VIII) Pyramid Glossopharyngeal nerve (IX) Hypoglossal nerve (XII) Vagus nerve (X) Ventral root of first cervical nerve Decussation of pyramids Accessory nerve (XI) Spinal cord (a) Ventral view Figure 12.15a Spinal Cord Physiology Dorsal root (sensory) Dorsal root ganglion Dorsal horn (interneurons) Somatic sensory neuron Visceral sensory neuron Visceral motor neuron Somatic motor neuron Spinal nerve Ventral root (motor) Ventral horn (motor neurons) Interneurons receiving input from somatic sensory neurons Interneurons receiving input from visceral sensory neurons Visceral motor (autonomic) neurons Somatic motor neurons Figure 12.32 Ascending tracts Fasciculus gracilis Dorsal white Fasciculus cuneatus column Dorsal spinocerebellar tract Ventral spinocerebellar tract Lateral spinothalamic tract Ventral spinothalamic tract Descending tracts Ventral white commissure Lateral reticulospinal tract Lateral corticospinal tract Rubrospinal tract Medial reticulospinal tract Ventral corticospinal tract Vestibulospinal tract Tectospinal tract Figure 12.33 Example of a tract Anterolateral Pathways • Lateral and ventral spinothalamic tracts • Transmit pain, temperature, and coarse touch impulses within the lateral spinothalamic tract Lateral spinothalamic tract (axons of second-order neurons) Medulla oblongata Pain receptors Cervical spinal cord Lumbar spinal cord Axons of first-order neurons Temperature receptors (b) Spinothalamic pathway Figure 12.34b (2 of 2) Primary somatosensory cortex Axons of third-order neurons Thalamus Cerebrum Midbrain Cerebellum Pons (b) Spinothalamic pathway Figure 12.34b (1 of 2) Example of Clinical Consideration Spinal Cord Trauma • Spastic paralysis—damage to upper motor neurons of the primary motor cortex – Spinal neurons remain intact; muscles are stimulated by reflex activity – No voluntary control of muscles Spinal Cord Trauma • Flaccid paralysis—severe damage to the ventral root or ventral horn cells – Impulses do not reach muscles; there is no voluntary or involuntary control of muscles – Muscles atrophy