Central Nervous System Part 2 Cerebrum: lobes, functions, ventricles Specialization Areas Cerebral dominance Disorders

Functions: Sensory: interprets signals so we “know: what we are seeing, hearing, tasting, smelling … Motor: responsible for all voluntary movement (somatic) / some involuntary (autonomic) Association: all intellectual activities of cerebral cortex: learning, reasoning, memory storage, recall, language abilities, even consciousness

Cerebral cortex: gray matter = cell bodies of neurons involved in hemisphere functions Fissure or sulci Gyri or gyrus

Ventricles/CSF:

Cerebral white matter:axons 1. association (within hemispheres) 2. commissure –connects neoccortex of hemispheres (corpus callosum) 3. projection

Fig Speech Occipital lobe Vision Temporal lobe Frontal lobe Parietal lobe Somatosensory association area Frontal association area Visual association area Reading Taste Hearing Auditory association area Speech Smell Motor cortex Somatosensory cortex Central and Limbic lobes

Frontal: primary motor area allows conscious movement of skeletal muscles, higher intellectual reasoning, complex memory Parietal lobe: somatic sensory area : impulses from sensory receptors are localized and interpreted; path are X’d, able to interpret characteristics of objects feel with hand and to comprehend spoken and written language Occipital lobe: visual cortex, receives visual info via thalamus (primary visual area)integrates info to formulate response (visual association area) Temporal lobe: emotion, personality, memory behavior, auditory and olfactory area, complex memory (both neo and old cortex) Limbic Lobe: (linked with temporal) ring of cortex around cerebral ventricles, connections between emotional and cognitive mechanism, emotional, autonomic, subconscious motor and sensory drives, sexual behavior, biological rhythms Motivation=pleasure or punishment Limbic is the connection between emotional and cognitive mechanisms

Basal Nuclei: grey matter deep within white matter surrounding 3rd ventricle they influence: monitoring, starting, stopping of stereotyped motor movement (voluntary) 1. subconscious movement 2. humans: planning, programming movement, information feedback with cortex, 3. help decisions about sensory input

Amygdala nucleus : part of the limbic system located deep within each hemisphere/ important part of emotional feelings linked to cognitive input (pleasure and fear emotions) Fear conditioning sends input to hypothalamus to signal the sympathetic NS to act

Complex polysynaptic path in brainstem and thalamus RF Receives messages from neurons on spine and other parts and communicates with cerebral cortex with complex circuits Ultimately responsible for consciousness Extent of RAS activity determines state of alertness (focus) Slow stimulation get sleepy and bored Toss and turn at night due to RAS Effects the way we react to stimuli If damaged= deep permanent coma Reticular Activating System: nuclei axons connect hypothalamus, thalamus, cerebellum and spinal cord to keep the cortex alert and conscious. Also acts as a filter for sensory input to the cortex … filters out 99% of sensory input as unimportant. RAS: arousal system

Specialization areas: *p 249 primary motor in precentral gyrus,: motor cortex: control voluntary skeletal movment primary sensory in postcentral gyrus somatosensory area:: receives info from skin, joint via thalamus somatosensory association cortex Primary somatosensory cortex Visual association area Auditory association area primary visual cortex primary auditory cortex auditory association area olfactory cortex gustatory cortex

Wernicke’s language area primary somatic motor cortex: axons from the primary motor area in the frontal lobe form major voluntary motor tract which descends into the cord, paths are crossed and body is represented upside down. Most neurons are dedicated to fine motor control of face, moth and hands. premotor cortex primary motor area Spatial Discrimination: Speech area: junction of parietal and occipital and temporal lobes: allows us to understand words, make connections between words, in one hemisphere Broca’s area: base of precentral gyrus (usually inleft hemisphere) ability to speak Prefrontal

Cerebral dominance: (L) language abilities, mathematics, intellectual functions with language (R) spatiotemporal matter, recognize face, appreciates and recognizes music

DISORDERS: Alzheimers disease Parkinson’s disease Stroke Aphasia Concussion Contussion Cerebral contusion

Disorders and Clinical Applications Lumbar puncture Spinal tap vs epidural Spina Bifida Anencaphaply Paralysis Spinal Shock ALS Poliomyelitis