Ch14pt2-language and sleep and the brain
Last Modified: 2016-03-08
– Receive input from all neighboring regions.
– Recognize spoken and written language.
– important in the ability to read and write.
• Broca area transmits the program to the primary motor cortex, which issues commands to the lower motor neurons that supply the relevant muscles; larynx, tongue, cheeks, and lips to produce speech.
Lesions here can result in such problems as inability to understand a joke.
– results in slow speech, difficulty choosing words, or use words that approximate the correct word; example say “tssair” instead of chair.
– In extreme cases, the person's entire vocabulary consists of two or three words, the patient feels frustrated and often reluctant to talk.
– The person speaks normally or excessively, but uses jargon and invented words that make little sense (example, choss for chair).
– cannot comprehend written and spoken words.
– Anomic aphasia, a person can speak normally and understand speech, but cannot identify written words or pictures. Know an object in a picture but unable to name it
– In left-handed people, left frontal, parietal, and occipital lobes are usually wider than those on the right
– Adult males exhibit more lateralization than females and suffer more functional loss when one hemisphere is damaged.
– When the left hemisphere is damaged, men are three times as likely as women to become aphasic.
– Neither hemisphere is dominant. each is specialized in certain tasks
– Lateralization develops with age.
– In young children, if one cerebral hemisphere is damaged or removed, the other can take over its functions.
– specialized in spoken and written language, analysis
– More integrated holistic way of perception.
– For imagination, insight, music, artistic skill, spatial relationships, compare sights, sounds, smells, and tastes.
– Left hemisphere categorical in 96%, and the right hemisphere in 4%.
• left-handed people
– right hemisphere is categorical in 15% and the left in 70%,
– in 15%, neither hemisphere is distinctly specialized.
• Rhythmic voltage changes resulting from synchronized postsynaptic potentials in the superficial layers of the cerebral cortex.
• Useful in studying normal functions and diagnosing brain diseases.
• Brain waves change with age, sensory stimuli, brain disease, and the chemical state of the body
– Regular, rhythmic, low-amplitude
– occur in healthy, awake at rest adults with their eyes closed and the mind wandering
– Absent in deep sleep
– Suppressed when engaged in mental task or receive sensory stimulation
– rhythmic, more irregular waves
– In frontal to parietal region.
– Occur during awake and mentally alert state
– more irregular than alpha waves
– normal in children and in drowsy or sleeping adults
– Predominance of theta waves in awake adults suggests emotional stress or brain disorders.
– Frequency less than 3.5 Hz.
– Seen in awake infants adults in deep sleep
– predominance of delta waves in awake adults indicates serious brain damage.
• Epilepsy is not associated with, nor does it cause, intellectual impairments
• Epilepsy occurs in 1% of the population
• Associated with changes in the pattern of EEG
• Valproic acid, a nonsedating drug, enhances GABA and is a drug of choice
• Vagus nerve stimulators can be implanted under the skin of the chest and can keep electrical activity of the brain from becoming chaotic
• occur in cycles called circadian rhythms
– One feels drowsy, eyes closed, and begins to relax.
– Thoughts come and go, one awakens easily if stimulated.
– Vital signs are normal
– One passes into light sleep. arousal is more difficult
– Occasionally 1 or 2 seconds of sleep spindles, which are high spikes resulting from interactions between neurons of the thalamus and cerebral cortex.
– typically beginning about 20 minutes after stage 1.
– Sleep spindles occur less often
– The muscles relax, and the vital signs decline.
– difficult to awaken
– EEG dominated by low-frequency, high-amplitude delta waves.
– vital signs are at their lowest levels
– skeletal muscles are relaxed but GI motility increase
– Bed wetting and sleep walking may occur
• they are harder to arouse than in any other stage.
• brain consumes more oxygen than when awake. and vital signs are increased
• Sleep paralysis strong during REM sleep.
• Nuclei in the upper reticular formation induce arousal while nuclei below the pons induce sleep
• a person experiences excessive daytime sleepiness and fatigue and may often fall asleep at work or school, with abnormally quick onset of REM sleep.
• There is evidence that narcolepsy is usually an autoimmune disease caused by antibody mediated
destruction of the orexin-producing neurons.
– replenish energy sources such as glycogen and ATP.
– purges superfluous information from memory by weakening or eliminating other synapses.
– learns from sensory input while an experience is happening, but it has a short memory. Later, it plays this memory repeatedly to the cerebral cortex, to form longer-memories (memory consolidation).
– Lesions of hippocampus can cause profound anterograde amnesia.
– vocabulary and memory of faces and familiar objects reside in superior temporal lobe
– memories of plans and social roles are in the prefrontal cortex.
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