Neuro pt 2 Flashcards
wernickes area
comprehension is stated here
brocas area
speech articulation
dorsal stream
Conveys phonological information for articulation
Ventral Stream
conveys semantic information (i.e., assigning meaning)
what hemisphere does language reside in
left hemisphere
left hemisphere does what
Identifies “words” – PET shows temporal activity to FROOP but no activity for FZNQT
¤ Maps graphemes to phonemes
¤ Understands syntax
¤ Produces speech
¤ Converts phonemes to graphemes
right hemispheres
Determines overall theme of discourse
¤ Responsible for humour
¤ Interprets body language and non-verbal sounds to provide additional meaning to speech
¤ Sarcasm, emotional intention, prosody
Brain Stimulation and Surgical Lesions
Electrodes implanted in the brain to determine function of certain areas before surgery
aphasia
Language disorder in speech
agraphia
Language disorder in writing
alexia
language disorder in reading
Broca’s Aphasia
Inability to produce fluent speech, despite relatively intact speech comprehension and intact voice
Wernicke’s Aphasia
First observed by Carl Wernicke in 1885
¤ Damage to left temporal/parietal lobe
¤ Production of fluent, but nonsensical, speech (word salad) ¤ Patients seem completely unaware of their deficit
Conduction aphasia
Damage resulting in an inability to shuttle information between Broca’s and Wernicke’s areas
Transcortical Motor Aphasia
Normal (spontaneous) speech production is impaired
Echolalia
Compulsion to repeat something just heard
Pure Word Deafness
Inability to comprehend speech
¤ Able to perceive and recognize other non-verbal sounds
¤ Speech sounds like a foreign language
Phonological Method:
Uses grapheme-to-
phoneme correspondence rules
Whole-Word Method:
“Sight reading”
Allows for recognition of word from memory
Irregular words (yacht, colonel) can only use direct route
phonological alexia
Disruption of phonological route
¤Inability to map phonemes onto graphemes
¤ Cannot sound out unfamiliar words, but can recognize familiar words
¤Familiar words can be read correctly using intact whole-word route
¤Damage to dorsal brain regions
surface alexia
Disruption of whole-word route
¤ Impaired reading of irregular words (e.g., yacht)
¤ Reading of regular words and non-words is preserved
¤ Regular words can be read correctly using intact phonological route
¤ Damage to ventral brain regions
Aprosodia
Loss of ability to produce or comprehend prosody in speech
¤ RH Broca’s area produces prosody
¤ RH Wernicke’s area comprehends prosody
`
Double dissociation
Some patients can’t produce
prosody but can understand it
¤ Other patients can produce prosody but can’t understand it
what is emotion?
Internal state and involuntary physiological response to object or situation
Emotional states have two components:
Physical sensation of the emotion
¤ Cognitive experience, or feeling, of the emotion itself
what is emotion (compared to mood)
Sudden, intense reactions to events
what is mood
More diffuse and tend to last longer
Allostasis?
maintaining internal stability despite
changing conditions
Somatic Marker Hypothesis
Emotion results from change in the body following evaluation of a stimulus or event
“Somatic markers” are feelings in the body associated with emotions (e.g., rapid heartbeat with anxiety)
classical conditioning
Type of learning by association
¤ Associate a neutral stimulus with a positive or
negative outcome
¤ E.g.,) Fear Conditioning - Neutral stimulus is paired with stimulus that induces fear (e.g., electric shock)
Right Hemisphere Hypothesis suggests…
RH is dominant for all emotions
Valence Hypothesis suggests…
LH is dominant for positive emotions and RH is dominant for negative emotions
valence hypothesis
Asymmetry for expression or perception of emotions depends on valence
¤ RH – Negative emotion ¤ LH – Positive emotion
right hemisphere hypothesis
RH responsible for expression or perception of all emotional information regardless of valence
¤ Support from studies on healthy controls:
¤ Faster to identify emotion in left visual field
¤ No difference for positive or negative emotions
Chimeric faces
Visual tests examine facial emotional processing
Left Ear Advantage (LEA)
Identifying emotional tones in speech
¤ Non-speech emotional tones (e.g., crying, laughing)
¤ RH lesion patients showed greater impairment than LH lesion patients
¤ Dichotic listening tasks
Auditory tests examine emotional
prosody processing
Right Ear Advantage (REA)
Identifying specific words
insula roles?
empathy, love, disgust, fear and phobias
prefrontal cortex
Regulation emotional behaviour
¤ Anticipating consequences of action
cingulate cortex
Attention to emotional states
¤ Resolving conflict between physical and emotional states
hippocampus
Personal or “episodic” memories that include
emotional content
amygdala
Negative emotions, especially fear
hypothalamus
Physiological component of emotional state release hormones
olfactory bulb
Carries messages about
smell directly to limbic areas
Amygdala becomes activated before
conscious perception of fearful faces
hatred activates…
Amygdala (negative
emotion)
¤ Insula (disgust and rejection)
Lower activation in regions associated with emotion processing are associated with…
psychopaths
Klüver–Bucy Syndrome
Lack of affect and no response to previously threatening stimuli
¤ Reduced fear, heightened aggression, and changes in emotion of disgust
Klüver–Bucy Syndrome caused by
lesions of medial temporal lobe
¤ Caused by stroke, encephalitis, tumours, or lobotomy
Capgras Syndrome
Person thinks a loved one has been replaced by an imposter
Patients do not show normal emotional response to seeing a loved one
¤ They do show normal response when talking over the phone
whats depression?
¤Extended periods (>2 weeks) of depressed mood
Evidence of genetic contribution:
¤ 50-70% concordance for monozygotic twins ¤ 13-20% concordance for dizygotic twins
Depression Neurobiology:
Loss of cortical mass in frontal and temporal
areas
¤10-30% show enlarged ventricles
¤Increased right hemisphere activity
Bipolar Disorder
¤Alternate between depressive and manic states
BPD Neurobiology
Decreased levels of serotonin & GABA
¤ Hyperactivity in limbic system
¤ Abnormal connections between frontal lobes and basal ganglia
Anxiety
disorder characterized by sense of danger, distress, or fear:
¤ Generalized Anxiety Disorder
Feelings of anxious somatic sensations in the absence of an identifiable stimulus
Posttraumatic Stress Disorder
Anxious somatic sensations in response to reminders of traumatic event
Obsessive Compulsive Disorder
Unwanted obsessions and recurrent behaviours accompanied by urge to do something to alleviate discomfort caused by the obsession
what is a phobia?
Anxious somatic sensations in response to specific stimuli
Dysfunction of the amygdala
what is attention
State of focused awareness on a subset of the available perceptual information
what are the 3 stages of attention
Disengage, Shift, Engage
disengage shift
Take attention away from current focus
Shift stage
Move attention from one item to another
Engage stage
Lock attentional focus onto new item
whats selective attention
Process that allows selection of inputs, thoughts, or actions while other ones are ignored
whats voluntary attention
Attention is shifted between inputs
intentionally (reading the textbook)
whats reflexive
Shifts in attention occur in response to an external event ie. textbook falling and making loud noise
overt attention
Attention to information being looked at directly
¤ Involves eye movements
covert attention
Attention to a location
not directly being looked at
¤ Not associated with eye movements
cocktail party effect
The cocktail party effect refers to the ability of people to focus on a single talker or conversation in a noisy environment.
Endogenous Control:
Voluntary
¤Cue usually needs interpretation
exogenous control
Reflexive
¤Cue automatically draws attention
Posterior Attentional System (PAS)
Responsible for
orienting of attention – where do we focus?
Anterior Attentional System (AAS)
Conscious control of attention – what do we need to focus on?
Vigilance System (VS)
Prepares and sustains alertness toward signals that demand high priority
Parietal lobe in response to attention
Shifts of attention in
space
¤ ‘Where’ information DISENGAGE
Superior Colliculi in response to attention
Visual processing
and eye movements MOVE
Pulvinar Nucleus of the Thalamus in response to attention
Filtering/suppressing irrelevant stimuli ENHANCE
Dorsolateral Prefrontal Cortex
Decision making
¤ Maintaining attention away from irrelevant information
Cingulate Cortex
Selective attention
Inattentional Blindness
A failure to notice — or at least to report — a stimulus that would be easily reportable if it were attended.
if the right side of the brain is damaged what happens to attention
Right frontal damage compromises ability to maintain alert state or perform vigilance tasks (e.g., watching for danger)
neglect in the brain
Inability to attend to or respond to stimuli in contralesional visual field
¤ Typically, neglect of left visual field after damage to right parietal lobe
Change Blindness
A change in a visual stimulus is introduced that the observer does not notice
Patients tend to not see left side of their own body and of world
¤ Only copy right side of picture
¤ Only dress right side of body
¤ Ignore tactile stimulation to left side of body
what does this person suffer from
neglect
Simultaneous Extinction
subject is presented with two objects at same time, but notice and report only one of the objects
adhd
Deficits in selective attention
3 types of adhd
¤ Inattentive
¤ Hyperactive/impulsive ¤ Combined
cause of adhd
Genetics
¤ Environment (e.g., alcohol during pregnancy)
¤ Problems with CNS at key moments in development (e.g., premature delivery)
what is consciousness
Level of responsiveness of the mind to impressions made by the senses
Awareness
¤ “The process of knowing
what one knows”
¤ Opposite of unconscious, anaesthetized, comatose
is consciousness dichotomous
no
consciousness scale is determined by what two things
awareness and wakefulness
3 facts abt consciousness
Consciousness is the privileged role of particular neural structures, the state of integration between otherwise distinct brain systems, and is a graded property of neural information processing
what is responsible for consciousness
Frontal lobe, pineal gland, and cingulate cortex
what happens in your brain when you suffer lack of awareness
disconnection of brain regions that make up the ‘consciousness network’
is Consciousness all-or-nothing?
no
what determines how likely it is to become consciously aware
how much you’re paying attention to something
Sleep and wakefulness
Despite the body resting, the brain is still very active
rem sleep effect on the brain
Low-voltage, fast changes in EEG
¤ Accompanied by dreams
¤ Paralyzed except eyes, ears, and vegetative functions (e.g., breathing)
when does sleepwalking happen
Most often occurs during deep, non-REM sleep
early in the night
what is lucid dreaming
dreamer aware of dreaming some degree of control over the dream characters
what allows the dreamer to be conscious when lucid dreaming
Prefrontal cortex and parietal lobe
what do psychoactive frugs do
Chemical that changes states of consciousness, particularly perceptions and moods
Influence how neurotransmitters operate at synapses of CNS
Network cross-linking at a dramatically higher rate when you take…
psiocybin
_________ in brain activity appeared to reflect a
deeper and richer conscious state
Randomness
what is Transcendental Meditation
Mind settles inward until you transcend to a state of pure consciousness
what is a trance state
Altered state of consciousness that may be induced by hypnosis, drugs, or ritual
what is Slain in the Spirit
Individual falls to the floor while experiencing religious ecstasy
what is ouija board
Board with symbols, and a pointer
¤ Supposedly answers questions from spirits at a séance
¤ Move the pointer around in a circle on the board for a moment or two to get it “warmed up”
whats the Ideomotor Effect
Ones muscles move subconsciously when the
movement is an expected one
Faraday determined movements were result of unconscious muscular action
what is the claustrum
Possible neural region for coordination of conscious awareness
¤ Perhaps not functioning properly in individuals in minimally conscious state (e.g., coma or vegetative state)
what is a vegetative state
Normal responsiveness to sound and speech input
¤ Auditory cortex activated by true speech and nonsense sentences
¤ Frontal-temporal activation consistent with language processing
how does a tbi happen
when an external force injures the brain
what is a tbi classified on?
Severity
¤ Mechanism (closed or
penetrating head injury)
¤ Other features (e.g., occurring in a specific location or over a widespread area)
patients with tbis have difficulties with
Executive skills
¤ Short-term memory
¤ Concentration
closed vs open head injury
NO penetration to the skull Penetration to the skull
whats a coup injury
when Damage occurs on the same side of impact
whats a contrecoup injury
when damage occur on the side opposite of the impact
whats the Glasgow Coma Scale used for
to quantify consciousness: Eye opening
2) Motor response
3) Verbal response
what are the care steps for tbi
Emergency care
¤ E.g.,) Oxygen/blood supply in brain
¤ Medication
¤ E.g.,) Reduce pressure, anti-seizure
¤ Surgery
¤ E.g.,) Removing clots, repairing skull fracture
¤ Rehabilitation
¤ E.g.,) Re-learning basic skills
whats a tumour
An abnormal mass of tissue in which cells grow and multiply uncontrollably.
what are the charcateristics of a benign tumour?
Not cancer
¤ Slow growing
¤ Encapsulated
¤ Non-invasive, do not metastasize, well differentiated
what are the characteristics of a maligant tumour?
Cancer
¤ Fast growing
¤ Non-encapsulated ¤ Metastasize
¤ Poorly differentiated
whats an encapsulated tumour
if a malignant tumor remains compact and does not have roots, it is encapsulated.
whats an infiltrating tumour
Listen to pronunciation. (IN-fil-TRAY-ting KAN-ser) Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues
Characteristics of Glioma
Most common type of brain tumour ¤ Form within brain and spinal cord
Characteristics of meningioma
Forms in the meninges ¤ Most are benign
characteristics of Metastatic (Secondary) tumour
¤Begin elsewhere in the
body
Metastatic tumours
¤Spread to the brain (via blood stream)
¤Usually originate in lung, breast, and skin
what do the symptoms and signs depend on based off tumours
depending on the tumour’s size and location
Cerebrovascular Disorders cause and characteristics
Occurs when blood supply to brain (or spinal cord) is interrupted
¤ Sudden or gradual
¤ Complete or partial
¤ Permanent or transient
other name for cerebrovascular disorder
common term for cerebrovascular disorders is stroke
whats an ischemic stroke
ischemic stroke occurs when a blood clot, known as a thrombus, blocks or plugs an artery leading to the brain
whats an infarct
An infarct is an area of necrosis (tissue death) due to the blood vessel blockage
whats a Thrombotic stroke
strokes caused by a thrombus (blood clot) that develops in the arteries supplying blood to the brain.
whats a Embolic stroke
usually caused by a blood clot that forms elsewhere in the body (embolus) and travels through the bloodstream to the brain
whats a Hemorrhagic Stroke
due to bleeding into the brain by the rupture of a blood vessel.
can a Hemorrhagic stroke be two different things
Hemorrhagic stroke may be further subdivided into intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH). Hemorrhagic stroke is associated with severe morbidity and high mortality.
what are the symptoms of a stroke
Sudden:
¤ Numbness or weakness of limbs
¤ Confusion, trouble speaking or understanding
¤ Trouble seeing in one or both eyes
¤ Trouble walking, dizziness, loss of balance or coordination
¤ Severe headache with no known cause
what is the treatment for ischemic stroke
Tissue plasminogen activator (tPA) and Mechanical devices
whats a Mechanical devices for ischemic stroke
Tool traps the clot, and either breaks it up or pulls out of the brain, reopening the blocked blood vessel
whats a tPA for ischemic stroke
Dissolves clot and improves blood flow to the part of
brain being deprived of blood flow
whats the Treatment for Hemorrhagic Stroke
Find cause of bleeding and control it
¤ Surgical clips or coils inserted in aneurysms (weaknesses in the blood vessel wall)
¤ Surgery to remove the bleeding vessel and blood that has spilled into the brain
whats a Arteriovenous Malformations (AVM)
Tangle of blood vessels in the brain or abnormal connection between arteries and veins
what is the treatment for AVM
Surgery and Cerebrovascular embolization
what are characteristics of infections in the brain
Invasion of a microorganisms to the CNS Releases toxins that skill surrounding tissue
What is Meningitis and symptoms
Bacterial infection of the meninges
¤ Fever, headache, vomiting, muscle pain and fever with cold hands and feet
what Substances destroy the nervous system tissue?
Pesticides
¤ Fuels
¤Heavy metals (e.g., mercury, lead, aluminum)
AKA NEUROTOXINS
what is epilepsy?
Characterized by spontaneous, unpredictable, recurrent seizures
¤Excessive excitatory neural activity
whats the difference between a seizure and convulsions?
Confirmed by electroencephalography (EEG) ¤Seizure: Electrical activity of the brain ¤Convulsions: Behavioural manifestation
what are some common symptoms of seizures?
Aura: Subjective sensation, perception, or motor experience associated with seizure onset
¤ Loss of consciousness
¤ Ranging from staring into space to complete
loss
¤ Movement: Many seizures include full body movements or repetitive behaviors
What is a focal seizure
Begin in one location in brain and electrical activity spreads to other regions
what is a generalized seizure
Seizure activity occurs in both hemispheres without a clear focus
whats the treatment for epilepsy?
Antiepileptic drugs ¤Enhance GABAergic
neurotransmission ¤ Surgery
¤If focus is localized, neurosurgeon may opt to remove source
What is narcolepsy
Individual has overwhelming urge to sleep or collapses asleep
Sleep attacks are brief, irresistible sleep episodes ¤Incidences is about 0.02% of the population
¤ Runs in families
¤Stimulants and antidepressants have been used for treatment
What is cataplexy?
Loss of muscle tone or sudden paralysis during which patient is conscious
what is insomnia?
Difficulty falling asleep or remaining asleep
¤ Patients have less REM sleep and more movement during sleep
¤ Incidence claimed to be as high as 14%
whats sleep paralysis
Person is conscious but unable to move during the transition from sleep to wakefulness
whats Hypnagogic hallucination
Hallucinations that occur while falling asleep or waking up
whats parkinson disease?
Degenerative disorder of central nervous system that mainly affects the motor system
what are the symptoms of parkinsons disease
Tremor at rest
¤ Slowed movement (bradykinesia) ¤ Rigidity
¤ Disturbance of posture
What is the neuropathology behind parkinsons disease?
Neural degeneration (dopamine depletion) in substantia nigra
what are the causes behind parkinsons disease
Genetics
¤ Toxins
¤ Carbon monoxide ¤ Pesticides
¤ Free radicals
Treatment for parkinsons disease
Drug therapy
¤ Dopamine – cannot cross BBB
¤ L-dopa – precursor to dopamine
¤ Surgery
¤ Thalamotomy
¤ Pallidotomy
¤ Cell transplant
¤ Deep brain stimulation (DBS)
Huntington’s Disease?
Cortex of patients shows shrinkage and thinning, particularly the basal ganglia
symptoms of huntingtons disease
Jerky, coordinated yet
involuntary, movements
¤ Speech, and any purposeful movement, is very hard
¤ Changes in personality, memory
causes behind genetics
Inherited defect in a single gene
¤ Dominant gene – 50% chance of passing onto child
¤Chromosome 4
¤ Normal copy of the gene produces huntingtin,
a protein
¤ Faulty gene is larger than it should be and produces a larger form of huntingtin
what do treatment for tbi patients depend on
Neuroplasticity: Brain’s capacity to form new connections and change how its circuits are wired
