– lies posterior to lateral sulcus. usually in left hemisphere, between visual, auditory, and somatosensory areas. – Receive input from all neighboring regions. – Recognize spoken and written language.
– Part of the parietal lobe caudal and superior to the Wernicke area – important in the ability to read and write.
Controls language expression - an area of the frontal lobe, usually in the left hemisphere, that directs the muscles movements involved in speech
how thoughts are turned into speech
When intend to speak, Wernicke area formulates phrases and transmits a plan of speech to the Broca area • 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.
emotional aspect of speech is controlled by
the region's that are opposite to broca's and wernicke's area on the other hemisphere
cortex opposite to Broca's area
is the affective language area. Lesions to this area result in aprosody (flat, emotionless speech).
cortex opposite to wernicke's area
is concerned with recognizing the emotional content of another person's speech. Lesions here can result in such problems as inability to understand a joke.
• language deficit resulting from lesions in Wernicke's and/or Broca's areas.
lesions to Broca's area
– Cause non fluent aphasia. – 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.
lesions to wernicke's area
– Cause fluent aphasia – 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
differences in left and right hemispheres
– in women, the left temporal lobe is longer than the right. – 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.
cerebral hemispheric lateralization
– The two hemispheres differ in some functions – 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.
lateralization: left hemisphere
(categorical hemisphere). – specialized in spoken and written language, analysis
lateralization: right hemisphere
(representational hemisphere). – More integrated holistic way of perception. – For imagination, insight, music, artistic skill, spatial relationships, compare sights, sounds, smells, and tastes.
left and right handed people
• Right-handed people – 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.
• EEG records brain activity with electrodes on the scalp and are called brain waves; each person’s brain waves are unique • 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
no activity on the EEG indicates
• A flat EEG (no electrical activity) is clinical evidence of death
– Frequency 8 to 13 Hz – 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
– Frequency of 14 to 30 Hz – rhythmic, more irregular waves – In frontal to parietal region. – Occur during awake and mentally alert state
– frequency of 4 to 7 Hz. – 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.
– High-amplitude, slow waves – 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.
• Epileptic patient may lose consciousness, fall stiffly, and have uncontrollable jerking, characteristic of epileptic seizure • 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
petit mal seizures
also called absence seizure, a minor seizure lasting only a few seconds. the person has a momentary clouding of consciousness, may have a blank facial expression and blink their eyes rapidly.
Grand Mal seizures
epileptic seizure characterized by sudden loss of consciousness and generalized involuntary muscular contraction. Vacillates between rigid body extension and an alternating contracting/ relaxing of muscle
control of epilepsy
• Epilepsy can usually be controlled with anticonvulsive drugs • 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
• temporary unconsciousness from which one can awaken when stimulated. • occur in cycles called circadian rhythms
sleep: stage 1
– EEG dominated by alpha waves. – One feels drowsy, eyes closed, and begins to relax. – Thoughts come and go, one awakens easily if stimulated. – Vital signs are normal
sleep: stage 2
– EEG declines in frequency and increases in amplitude. – 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.
sleep: stage 3
– moderate to deep sleep; theta and delta waves appear. – typically beginning about 20 minutes after stage 1. – Sleep spindles occur less often – The muscles relax, and the vital signs decline.
sleep: stage 4
– Also called slow-wave sleep (SWS) – 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
• About five times a night, a sleeper backtracks from stage 3 or 4 to stage 2 and exhibits bouts of rapid eye movement • 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.
sleep and waking cycle
• controlled by interaction between the cerebral cortex, thalamus, hypothalamus, and reticular formation. • Nuclei in the upper reticular formation induce arousal while nuclei below the pons induce sleep
vasolateral preoptic nucleus in hypothalamus induces sleep by
induce sleep by inhibiting arousal neurons of the upper reticular formation.
suprachiasmotic nucleus and sleep regulation
regulates the time of day that a person or animal sleeps. Destruction of SCN causes an animal to sleeps the same number of hours per day, but at random times with no relationship to night or day.
orexins and sleep
neuropeptides produced in lateral and posterior hypothalamus, strongly stimulate wakefulness and elevate metabolic rate. Blocking orexin induces sleep
• orexin levels are low or absent • 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.
function of non-REM sleep
– have a restorative effect on the body – replenish energy sources such as glycogen and ATP.
function of REM sleep
– consolidates and strengthens memories by reinforcing synaptic connections – purges superfluous information from memory by weakening or eliminating other synapses.
• Information management by the brain entails learning new information, store and retrieve information, forgetting trivial information.
defects in declarative memory (inability to describe past events), not procedural memory (ability to tie your shoes)
hippocampus and memory
– does not store memories, but organizes sensory and cognitive experiences into a unified long-term memory. – 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.
– held in various areas of cortex. – vocabulary and memory of faces and familiar objects reside in superior temporal lobe – memories of plans and social roles are in the prefrontal cortex.
helps learn motor skills
memory and amygdala
for emotional memory
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