* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 9 Part 3 Central Nervous System
Synaptic gating wikipedia , lookup
Neuroinformatics wikipedia , lookup
Brain morphometry wikipedia , lookup
Sensory substitution wikipedia , lookup
Environmental enrichment wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Haemodynamic response wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Cognitive neuroscience of music wikipedia , lookup
Selfish brain theory wikipedia , lookup
Neurolinguistics wikipedia , lookup
Nervous system network models wikipedia , lookup
Neuroesthetics wikipedia , lookup
Neurophilosophy wikipedia , lookup
Neuroscience in space wikipedia , lookup
History of neuroimaging wikipedia , lookup
Embodied language processing wikipedia , lookup
Sleep paralysis wikipedia , lookup
Aging brain wikipedia , lookup
Neuroeconomics wikipedia , lookup
Neuroscience of sleep wikipedia , lookup
Human brain wikipedia , lookup
Sleep deprivation wikipedia , lookup
Sleep medicine wikipedia , lookup
Obstructive sleep apnea wikipedia , lookup
Neuropsychology wikipedia , lookup
Brain Rules wikipedia , lookup
Sleep and memory wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Cognitive neuroscience wikipedia , lookup
Time perception wikipedia , lookup
Neuroanatomy wikipedia , lookup
Evoked potential wikipedia , lookup
Rapid eye movement sleep wikipedia , lookup
Neuroplasticity wikipedia , lookup
Embodied cognitive science wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Effects of sleep deprivation on cognitive performance wikipedia , lookup
Non-24-hour sleep–wake disorder wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Neuroprosthetics wikipedia , lookup
Metastability in the brain wikipedia , lookup
Start School Later movement wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Chapter 9 Part 3 Central Nervous System Processing Sensory Information into Perception (p. 315) Once sensory information has reached its appropriate spot in the cortex (e.g. visual information goes to visual cortex, etc.) Then, the information proceeds on to its association area (e.g. visual cortex sends visual information on to the visual association area, etc.) Association areas integrate all of the sensory information into perception Perception: the brain's interpretation of sensory stimuli In many cases, the perceived stimulus can be quite different from the actual stimulus – Photoreceptors in the eye receive light waves of many different frequencies – Brain perceives the different wavelengths as different colors Perception (continued) – Pressure waves hitting the ear – Brain translates these to sound – Chemicals binding to chemoreceptors – Brain translates these as taste or smell • Taste: taste buds in mouth • Smell: chemoreceptors in nose Perception (continued) Brain can often fill in missing information in order to get a more complete picture (fig. 9-18a) Brain can also translate a 2-dimensional (flat) drawing into a 3-dimensional object (fig. 9-18b) “Thus, we sometimes perceive what our brains expect to perceive.” (p. 316) Figure 9-18 Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Perceptual translation of sensory stimuli allows the information to be acted upon, used in voluntary motor control or complex cognitive functions like language Motor Output (3 parts): – Skeletal muscle movement • Controlled by somatic motor division – Neuroendocrine signals • Neurohormones secreted by hypothalamus and adrenal medulla – Visceral responses (see next slide) – Visceral responses • Governed by autonomic division • Actions of smooth and cardiac muscle; • Actions of endocrine and exocrine glands Figure 8-1 Copyright © 2010 Pearson Education, Inc. Motor Output (more details) Skeletal muscle movement – Can be processed in several areas: • Simple stimulus-response pathways are processed either in the spinal cord or in the brain stem • These responses do not require integration in the cerebral cortex, but can be modified or overridden by the cerebrum Motor Output (more details) Skeletal muscle movement – Voluntary movements • Initiated by cognitive system • Originate in primary motor cortex and motor association area (in frontal lobes of cerebrum) • See fig. 9-15, p. 315 • These areas receive input from sensory areas, cerebellum, basal ganglia Figure 9-15 Copyright © 2010 Pearson Education, Inc. Motor pathways Pyramidal cells, which are long output neurons, project axons from the motor areas down through the brain stem to the spinal cord Other pathways go from the cerebral cortex to the basal ganglia and lower brain regions Descending motor pathways cross over to the opposite side of the body Damage to a motor area manifests as paralysis or loss of function on the opposite side of the body Neuroendocrine and visceral responses – Coordinated in the hypothalamus and medulla – Brain Stem contains control centers for many automatic life functions: • Breathing • Blood pressure • Etc. • Brain Stem receives sensory information from body • Relays motor commands to peripheral muscles and glands Neuroendocrine and visceral responses – Coordinated in the hypothalamus and medulla – Hypothalamus contains centers for: • Temperature regulation • Eating • Control of body osmolarity, etc. • Response to stimulation of these centers can be in the form of neural or hormonal reflexes or a behavioral response • Hypothalamus also mediates stress, reproduction, and growth Sensory input not the only factor affecting motor output The behavioral state system can modulate reflex pathways and The cognitive system exerts both voluntary and involuntary control over motor functions Behavioral State system – Modulates sensory and cognitive processing – Many of the neurons of this system are located outside the cerebral cortex: • Some are found in the reticular formation (in the brain stem) • Some are found in the hypothalamus • Some are found in the limbic system Behavioral State system – Diffuse modulatory systems: • A group of neurons which originate in the reticular formation of the brain stem • These neurons project their axons to many brain areas (Table 9-3; fig. 9-19) Behavioral State system (continued) – The diffuse modulatory system regulates brain function by influencing: – Attention – Motivation – Wakefulness – Memory – Motor control – Mood – Metabolic homeostasis Table 9-3 Copyright © 2010 Pearson Education, Inc. Figure 9-19: Diffuse Modulatory System Copyright © 2010 Pearson Education, Inc. The behavioral state system controls both levels of consciousness and the sleep-wake cycle Consciousness: – Body's state of arousal or awareness of self and the environment Reticular Activating System – A “diffuse collection of neurons” in the reticular formation – Keeps the “conscious brain” awake – Blockage (surgical or drugs) of the ascending pathways from the RAS up to the cerebrum can result in unconsciousness Reticular Activating System: Reticular Activating System: Sleep vs Being Awake Can tell these apart by looking at an EEG or electroencephalogram (fig. 9-20, p. 319) • EEG records depolarizations of cortical neurons When awake, lots of neurons firing, little co-ordination among them In awake-resting (eyes closed), electrical activity of neurons begins to synchronize into waves with characteristic patterns Sleep and coma show further synchronization, etc. Sleep vs Being Awake As the state of arousal lessens (ie, slipping further in to sleep), wave frequency decreases The more synchronous the firing of cortical neurons, the larger the amplitude of the waves Awake-resting state has low amplitude, high frequency waves Deep sleep has high amplitude, low frequency waves Figure 9-20a Copyright © 2010 Pearson Education, Inc. Sleep Why we sleep: “One of the unsolved mysteries in neurophysiology” Very ancient, occurs in all birds and mammals (recently found to occur in some fish also) Most birds and mammals show the same stages of sleep as humans (REM sleep, etc.) Sleep is an active process, consumes as much or more oxygen as an awake brain Sleep Hypotheses (why sleep?): • To conserve energy • To avoid predators • To allow the body to repair itself • To process memories Sleep consists of 4 stages, based on somatic changes and brain wave patterns – REM (rapid eye movement) or stage 1 – Stage 2 – Stage 3 – Deep sleep (slow wave, non-REM) or stage 4 Sleep Two main sleep phases are REM and Deep or slowwave REM Sleep EEG similar to, but not the same as, that of an awake person (fig. 9-20a) Has low amplitude, high frequency waves During REM sleep, brain activity inhibits motor neurons to skeletal muscles This “paralyzes” most muscles, except muscles that move the eyes and muscles that control breathing Sleep Two main sleep phases are REM and Deep or slowwave REM Sleep Most dreaming occurs during this stage Eyes move back and forth behind closed lids (as if following the events in the dream) Sleepers are most likely to spontaneously wake up from REM sleep Sleep Two main sleep phases are REM and Deep or slowwave Deep sleep (slow wave, non-REM) or stage 4 Delta waves present High amplitude, low frequency waves; waves are of long duration Sleepers adjust body position without conscious commands from the brain Typical 8-hour sleep cycle Consists of repeating cycles (fig. 9-20b) Hour 1: – Person goes from wakefulness to deep sleep (stage 4—first blue area in figure) – Sleeper then cycles between deep sleep and REM sleep – Stages 2-3 occur in between these other ones – Near end of sleep cycle, alternate between stage 2 and REM, until sleeper awakes Figure 9-20b Copyright © 2010 Pearson Education, Inc. Figure 9-20a Copyright © 2010 Pearson Education, Inc. Next: Chapter 10 Sensory Physiology