ME03 - Higher Cortical Functions Flashcards
Portion of anterior end of diencephalon that lies below the hypothalamic sulcus and in front of the interpeduncular nuclei
Divided into a variety of nuclei and nuclear areas
Hypothalamus - links the nervous system to the endocrine system via the pituitary gland
Important Functions of the Hypothalamus
ENDOCRINE FUNCTIONS
AUTONOMIC FUNCTIONS
LIMBIC FUNCTIONS
What are the Endocrine Functions of the Hypothalamus
Cardiovascular regulation_- involves control of blood pressure and heart rate
Body temperature regulation hypothalamus signal appropriate cells to activate body temperature-lowering or temperature-elevating mechanisms
Regulation of body water intake (thirst)- controls urinary excretion of water
Uterine Contraction and Milk Ejection - causes contraction of the smooth muscle of the uterus and milk let down
Gastrointestinal and feeding regulation
Anterior pituitary gland regulation
Increase BP and HR
Posterior and Lateral hypothalamus
Decreases BP and HR
Preoptic Area
Cardiovascular Regulation is mediated by
Cardiovascular centers in pontine and medullary reticular formation
Controls the set-point of human body temperature
Hypothalamus
Controls the body temperature regulation
Neurons in the preoptic area
What is the thirst center?
Lateral hypothalamus
Release antidiuretic hormone (ADH) into posterior pituitary
Magnocellular cells in supraoptic nuclei
In Uterine Contraction and Milk Ejection, this is responsible for the release of oxytocin
Magnocellular cells in paraventricular nuclei
MNEMONICS Paraventricular nuclei
Oxytocin = Para sa Voobs
What is responsible for hunger?
Lateral hypothalamus
Lesion in the lateral hypothalamus results to:
Starvation
What inhibits the Lateral Hypothalamus?
Leptin
This is the satiety center | activity produces a stop eating signal
Ventromedial nucleus
Lesion in the Ventromedial nucleus results to:
Uncontrolled vo- racious appetite
What stimulates the Ventromedial nucleus?
Leptin
Involved in re- flexes related to food intake like lip licking and swallowing
Mamillary nuclei
Responsible for the releasing and inhibitory factors that modulate anterior pituitary function
Periventricular zone, Arcuate nucleus and Ventromedial nucleus
“Head Ganglion” of autonomic nervous system
Autonomic Functions of the Hypothalamus
Stimulation of the hypothalamus produces autonomic responses. True or False?
True.
What are the different autonomic functions of the Hypothalamus
Sympathetic: posterior hypothalamus»_space; has a warming function
Parasympathetic: anterior hypothalamus»_space; has a cooling function
Stimulation of hypothalamus affects behavioral control functions
Limbic Functions of the Hypothalamus
Causes increased general level of activity leading to rage and aggression
Lateral hypothalamus
Causes sense of tranquility, pleasure and reward
Ventromedial nucleus
Evokes fear and feel- ings of punishment and aversion
Periventricular nuclei
Sexual Arousal is stimulated from what portion of the hypothalamus?
From most anterior and most posterior portions of the hypothalamus
What are the Types of Biologic Periodicity
Ultradian Rhythms | Infradian Rhythms | Circadian Rhythms
Cycles of periodicity shorter than 24 hours
Ultradian Rhythms | Ex: heart beat, respiratory rhythm
Cycles of periodicity longer than 24 hours
INFRADIAN RHYTHMS | Ex: menstrual cycle, gestation
Cycles of periodicity that approximate Earth’s rotational period (24-hour day)
Circadian Rhythms | Ex: Sleep-Wake cycle, Hormone levels
Regulate activity of many physiological processes including heart rate, blood pressure, body core temperature and blood levels of hormones
Biologic Clock
External environmental clues influence strict 24- hour cycles. True or False
True.
Master clock of all biological clocks in the human body
Suprachiasmatic Nucleus
Function of SCN
Retain synchronized, rhythmical firing patterns even though they are isolated from the rest of the brain
Destruction of SCN will cause
Loss of circadian functions
Implicated in regulation of circadian rhythms
Pineal Gland
A hormone that is synthesized from serotonin; which is responsible for:
o increased during darkness
o inhibited by daylight
o controlled by sympathetic nerve activity, which is regulated by light signals from the retina
Melatonin
Also known as jet lag
Physiological condition which results from alterations of circadian rhythms
Desynchrosis
Reason behind when traveling across time zones, body clocks will
be out of synchronization with the destination time
Due to experience of daylight and darkness contrary to accustomed
rhythms
How do you treat Jet Lag/Desynchrosis?
Treated with melatonin or sunlight exposure
Unconsciousness from which the person can be aroused by sensory or other stimuli
Sleep
Distinguish coma from sleep?
Coma is unconsciousness from which the person cannot be aroused
2 Types of Sleep
Slow Wave/Non REM Sleep | REM Sleep
Describe Slow Wave Sleep/Non REM Sleep
o deep, restful type of sleep
o characterized by decreases in periph- eral vascular tone, blood pressure, respiratory rate and metabolic rate
o frequently called dreamless sleep
o however, dreams and sometimes even nightmares do occur during slow-wave sleep
Why is REM called the “Paradoxical Sleep”?
Because the brain is active and skeletal muscle con- tractions occur
Describe Rapid Eye Movement (REM) Sleep
active form of sleep associated with dreaming and active bodily muscle movements
o lasts 5 to 30 minutes
o repeats at 90 minute intervals
o may be absent in extremely tired individuals
REM is more difficult to arouse than slow-wave sleep. True or False?
True.
What are some of the Important Characteristics of REM sleep
Muscle tone is exceedingly depressed
irregular heart rate and respiratory rate (dream state)
irregular muscle movements do occur
brain is highly active in REM sleep
What are the sleep centers in a Slow-Wave Sleep?
raphe nuclei in lower pons and medulla
nucleus of the tractus solitarius
diencephalon
o rostral hypothalamus (suprachiasmal area)
o diffuse nuclei of thalamus
Most conspicuous stimulation area for causing almost natural sleep
Raphe nuclei in lower pons and medulla (SLOW-WAVE SLEEP)
What neurotransmitter is elaborated from raphe nuclei?
Serotonin
In relation to sleep, a drug that mimics Ach where people take this to have more REM sleep
Neostigmine
What are some of the Postulated Functions of Sleep
neural maturation
facilitation of learning or memory
cognition
conservation of metabolic energy
restoration of natural balance among neuronal centers
Measures voltage fluctuations resulting from ionic current flows within neurons
Recording the brains spontaneous electrical activi- ty from multiple electrodes placed on the scalp
Electroencephalography (EEG)
What are the Diagnositc Applications of EEG?
Epilepsy, Coma, Brain Death
4 Types of EEG Waves
Alpha waves, Beta waves, Theta waves and Delta waves
o rhythmical waves with a frequency of 8-12 Hz at about 50 mV
o found in normal, awake but resting (eyes closed) individuals
o disappear during deep sleep
Alpha waves
o occur at frequencies of 14 to 80 Hz with voltage less than 50 mV
o recorded mainly from parietal and frontal regions
o occur when the eyes are opened in the light
Beta waves
In Beta waves, what is required to be intact?
requires intact thalamocortical projetions and ascending reticular input to thalamus
o wave frequencies of 4 to 7 Hz
o occur mainly in the parietal and temporal areas in children but may appear in adults during emotional stress
Theta waves
Types of EEG Wave that is associated with brain disorders and degenerative brain states
Theta waves
o all of the waves below 3.5 Hz
o occur during deep sleep, organic brain disease and in infants
o persist in the absence of cortical input from the thalamus and lower brain centers
Delta waves
2 Common EEG Rhythms
Alpha Rhythm and Beta Rhythm
o fairly regular pattern of waves at a frequency of 813 Hz and amplitude of
50100 V (alpha waves)
o most marked in the parietal and occipital lobes
o associated with decreased levels of attention
Alpha Rhythm
o alpha rhythm is replaced by an irregu- lar 1330 Hz low-voltage activity (beta waves)
o also called alpha block, arousal re- sponse or desynchronization
o produced by any form of sensory stimu- lation or mental concentration
Beta Rhythm
Examples of Common Sleep Disorders
Narcolepsy | Somnambulism/Sleep Walking | Insomnia | Sleep Apnea
o Lapsing abruptly into REM sleep from awake state
o Sleep episodes last about 15 minutes without warning
o Often triggered by a pleasurable event
NARCOLEPSY
A sudden loss of voluntary muscle control in Narcoplepsy
Cataplexy
o Ssleepwalkers arise from slow wave sleep in a state of low consciousness and perform activities that are usually performed during full consciousness
o Little or no memory of the incident, as they are not truly conscious
Somnambulism/Sleep Walking
Chronic inability to obtain the amount or quality of sleep needed to function adequately during the day
Insomnia
Most common cause of Insomnia is?
Psychological Disturbance
o Ttemporary cessation of breathing dur- ing sleep
o Loss of muscle tone during sleep allows excess fatty tissue or other structural abnormalities to block the upper air- way
Sleep Apnea
Sleep Anea is associated with OBESITY and made worse by ALCOHOL. True or False?
True.
This refers to the entire neuronal circuitry that controls emotional behavior and motivational drives
Limbic System
What are the important communicating structures involved in Limbic System:
o brain stem via the medial forebrain bundle
o hippocampus to mammilary bodies via fornix
First pathway hypothesized to explain appreciation and expression of emotion
Responsible for linking the experience and the ex- pression of emotion
Papez circuit
The seat of emotional experience
Cingulate cortex
Pathway of Papez Circuit
Output from the cingulate cortex is conveyed via the fornix to the hypothalamus, where it is translated into the expression of emotion through the autonomic nervous system
MNEMONICS - Functions of Limbic System
5 Fs
Fighting |Fleeing|Feeding |Feeling Fucking/Fornicating
Responsible for stimulation evokes rage, passivity and excessive sexual drive
Provides signals for consolidation of memory
Highly hyperexcitable (weak stimuli can cause seizures)
Hippocampus
A lesion in the Hippocampal area can result to
Anterograde amnesia; Inability to form new memories
The window of the limbic system
o receives neuronal signals from all portions of the limbic cortex, as well as from the neocortex of the temporal, parietal, and occipital lobes
Amygdala
What are the functions of Amygdala
o Endocrine and vegetative functions
o Involuntary movements
o Rage, escape, punishment, severe pain and fear
o Sexual activity
Results from bilateral destruction of the amygdala
Kluver Bucy Syndrome
Manifestations of Kluver Bucy Syndrome
o Hyperorality
o Loss of fear
o Decreased aggressiveness o changes in eating behavior o psychic blindness
o Excessive sexual drive
Most poorly understood portion of the limbic sys- tem
Cerebral association area for control of behavior
Limbic Cortex
Lesions in the Limbic Cortex include the following:
o Bilateral anterior temporal cortex: Kluver-Bucy syndrome
o Bilateral posterior orbitofrontal cortex: insomnia, restlessness
o Bilateral anterior cingulate and subcal- losal gyri: extreme rage reaction
Acquisition of the information that gives an organ- ism the ability to alter behavior on the basis of experience
Learning
2 Types of Learning
ASSOCIATIVE LEARNING | NON-ASSOCIATIVE LEARNING
Also called simple learning
Modification of response to a repeated stimulus
Non-Associative Learning
Occurs when the response becomes weaker as the stimulus is perceived to have no particular importance
Habituation
Occurs when the response is enhanced in the even that an unpleasant or otherwise strong stimulus is given
Sensitization
Involves the ability to make a connection between a neutral stimulus and a second stimulus that is either rewarding or noxious
Associative Learning
2 Important example for Associative Learning
o CLASSICAL CONDITIONING Food response to Dogs salivation | Bell is used as neutral stimulation together with food | Dog salivates upon hearing the bell because it is perceived as with food
o OPERANT CONDITIONING Baby smiles | Father picks up baby | Baby keeps on smiling (There is reinforcement)
Ability to store, retain and recall information and past experiences
Memory
Type of Memory associated with consciousness
_ dependent on the hippocampus and other parts of the medial temporal lobes of the brain for its retention
Recall is automatic and does not require conscious attention
Acquired slowly through repetition
Includes motor skills and rules and procedures
Procedural memories can be demonstrated
EXPLICIT / DECLARATIVE MEMORY
Type of Memory that does not involve awareness
_ retention does not usually involve processing in the hippocampus.
Recall requires conscious attention.
Depends on higher-level thinking skills such as inference, comparison, and evaluation.
Memories can be reported verbally.
IMPLICIT / NONDECLARATIVE MEMORY
Stored in the brain by changing the basic sensitivity of synaptic transmission between neurons as a result of previous neural activity
Physiology of Memory
o Lasts seconds to hours
o Memory traces are subject to disrup- tion by trauma and various drugs
Short-Term Memory
Form of short-term memory that keeps information available, usually for very
short periods
Working Memory
o Stores memories for years and some- times for life
o Long-term memory traces are remarka- bly resistant to disruption
Long-Term Memory
What type of neuronal circuit is exemplified in short-term memory?
Reverberating Circuit
Initiation of chemical, physical, and anatomical changes in the synapses
Consolidation of Memory
Rehearsal enhances the transference of short-term memory into long-term memory. True or False?
True.
New memories are codified into different classes of information. True or False?
True.
Consolidation of Memory is postulated to be a function of the?
Hippocampus
What are some of the Physiologic Evidences of Long Term Memory
increase in vesicle release sites for secretion of transmitter substance
increase in number of transmitter vesicles released
increase in number of presynaptic terminals
changes in structures of the dendritic spines that permit transmission of stronger signals
Condition in which memory is disturbed or lost
Amnesia
Two basic types of Amnesia:
o ANTEROGRADE AMNESIA | o RETROGRADE AMNESIA
Loss of short-term memory
Impairment of the ability to form new memories through memorization
Anterograde Amnesia
What lesions cause Anterograde Amnesia?
Lesions to the Hippocampus
Loss of pre-existing memories to conscious recol- lection
Person may be able to memorize new things but is unable to recall events or identity prior to the onset
Retrograde Amnesia
What lesions cause Reterograde Amnesia?
Thalamus
Right hemisphere is dominant in ______________
Facial expression, intonation, body language, and spatial tasks
Left hemisphere is dominant in ______________
Respect to lan- guage, even in left-handed people
Information is transferred between the two hemi- spheres through the _______________
Corpus callosum
Human communication is distinguished by its range and subtlety of expression
Language
Production of sound that has no specific meaning
Vocalization
Language consists of a specific vocabulary and a set of rules of expression (syntax). True or False?
TRUE
o located in the inferior frontal lobe of the dominant hemisphere
o processes the information received from Wernicke’s area into a detailed and coordinated pattern for vocalization
BROCAS AREA (Brodmann Area 44)
o located in posterior superior temporal gyrus of the dominant hemisphere
o concerned with COMPREHENSION of auditory and visual information
WERNICKES AREA (Brodmann Area 22)
Bundle of the nerve fibers that connect Wernickes area to Brocas area
ARCUATE FASCICULUS
Appears to process information from words that are read in such a way that they can be converted into the auditory forms of the words in Wernicke’s area
ANGULAR GYRUS (Brodmann Area 39)
Abnormalities of language functions that are not due to defects of vision or hearing or to motor paralysis
APHASIA
Lesions in what part causes Aphasia?
Lesions in the categorical/dominant hemisphere
Most common cause of Aphasia
Cerbrovascular Disease
o Lesion in Brocas area
o Also called non-fluent aphasia or ex- pressive aphasia
o Speech is slow and words are hard to come by
o Patients with severe damage to this area are limited to two or three words
BROCA’S APHASIA
o Lesion in Wernickes area
o Also called fluent aphasia or receptive aphasia
o Speech is normal
o Patients talk excessively (jargon, neologisms)
o Fails to comprehend the meaning of spoken or written words
WERNICKE’S APHASIA
o Lesion in ARCUATE FASCICULUS
o Patients can speak relatively well and have good auditory comprehension but cannot put parts of words together or conjure up words
CONDUCTION APHASIA
o Lesion in ANGULAR GYRUS
o No difficulty with speech or the under- standing of auditory information
o Trouble understanding written language or pictures
o Visual information is not processed and transmitted to Wernicke’s area
ANOMIC APHASIA
o Due to generalized brain destruction
o More than one form of aphasia is often present
o Speech is scant as well as nonfluent
GLOBAL APHASIA
