n165 quiz 4

Hickok-Poeppel model

a model of brain areas involved in language comprehension and speech production; describes dorsal pathway for production and ventral pathway for comprehension

Aphasia

not a result of deficits in sensory, intellectual, or psychiatric functioning, nor muscle weakness; deficit arises from damage to language-specific cortical regions

Broca's aphasia

aphasia characterized by slow, effortful speech output lacking function words, problems with grammar and articulation, in which patients rely on high-frequency content words. Patients have deficits in repetition, naming, and fluency, but can comprehend normally.

Wernicke's aphasia

aphasia characterized by fluent, meaningless speech with many semantic errors and little understanding (often with anosognosia). Patients have deficits in repetition, naming, comprehension, and have paraphasic fluency. In severe cases, patients appear to have no concept of what language is for.

Paraphasia

a notable feature of aphasia in which one loses the ability of speaking correctly, substitutes one word for another, and changes words and sentences in an inappropriate way. The patient's speech is fluent but is error-prone, e.g. 'treen' instead of 'train'.

'Word salad'

apparently fluent speech, but meaningless; seen in Wernicke's aphasia

Anosognosia

a deficit of self-awareness; a condition in which a person who suffers a certain disability seems unaware of the existence of his or her disability

Arcuate fasciculus

The neural white matter pathway connecting Broca's area and Wernicke's areas

Conduction aphasia

phasia due to damage to the arcuate fasciculus resulting in poor repetition and naming, but normal comprehension and fluency

Transcortical sensory aphasia

aphasia that is similar to Wernicke's aphasia, except that patients are able to repeat language they have just heard (but still do not comprehend it)

Transcortical motor aphasia

aphasia associated with right hemiparesis (paralysis or inability to move) that is similar to Broca's aphasia, except patients are able to repeat

Global aphasia

aphasia, associated with right hemiparesis, characterized by severe communication difficulties in both speech and comprehension; Patients may have no concept of language as communication.

Transcortical mixed aphasia

similar to global aphasia, but patients are still able to repeat

Anomic aphasia

aphasia in which word-finding is severely impaired, usually from damage to parietal and/or temporal lobes, and patients resort to circumlocution

Averbia

specific aphasia in which patient loses ability to use verbs

Color anomia

specific aphasia in which patient loses ability to use color words

Circumlocution

the use of other words to describe a specific word or idea which cannot be remembered (means ‘talking around’ something)

Speech entrainment therapy

patients practice mimicking audio-visual speech stimuli; this therapy can enable them to produce fluent speech in real time.

Subsystems of speech

Respiration
Phonation
Resonance
Articulation

Respiration

the process of breathing

Phonation

is the process by which the vocal folds produce certain sounds through

quasi-periodic vibration

Resonance

the prolongation of sound during speech

Articulation

the movement of the tongue, lips, jaw, and other speech organs to

make speech sounds

Dysarthria

Motor disorder affecting any or all of the 4 subsystems of speech

Spastic dysarthria

motor disorder caused by damage to the upper motor neurons.

•   Causes: Cerebral palsy, stroke, multiple sclerosis

•   Symptoms: Harsh, strained voice; vocal pitch breaks; reduced speed of articulation

Flaccid dysarthria

motor disorder caused by damage to the lower motor neurons.

•   Causes: Brainstem stroke, cranial nerve palsy, myasthenia gravis (a chronic autoimmune neuromuscular disorder that is characterized by fluctuating weakness of the voluntary muscle groups)

•   Symptoms: Reduced lip closure and strength of articulatory; hyper-nasality, breathy voice

• Speech apraxia

a developmental or acquired problem with speech production not associated with muscle weakness. Its symptoms include difficulty putting sounds and syllables together in the correct order to form words.

• Stuttering

• a speech disorder in which the flow of speech is disrupted by involuntary repetitions and prolongations of sounds, syllables, words or phrases, and involuntary silent pauses. It may be caused by genetic mutations and/or head trauma. Therapy includes relaxation techniques, singing, and choral reading.

• Cluttering

• a fluency disorder in which the patient has a problem with rate, word confusion, and disorganized thoughts. Language is most clear at the start of utterances, but rate increases and intelligibility decreases towards the end. Patients are often not aware of the disorder, but can improve with therapy that focuses on attending to speech details. The cause is not known.

Spoonerisms

phonemic substitution

Malapropisms

wrong word substitution

Freudian slips

error in speech from ‘unconscious mind’

• Odorant molecul

• any substance capable of stimulating the sense of smell by binding

  to an olfactory receptor; substance must be volatile (able to vaporize)

• Olfactory epithelium

• a sheet of cells that contains the olfactory receptors and that lines the upper part of the nasal passages. The epithelium is covered by a mucous layer through which odorants must be absorbed before activating the olfactory receptors.

• Olfactory receptors

• are expressed in the dendrites of the olfactory receptor neurons and are responsible for the detection of odorant molecules.

• Olfactory receptor neurons

• bipolar neurons with dendrites facing the nasal cavity and axons that pass through the openings in the (bone) to synapse in the olfactory bulb. These neurons make up the ‘olfactory nerve’ , and are one of only ~3 structures in the brain that have been found to undergo continuing neurogenesis in adult mammals.

• Olfactory nerve

• he first cranial nerve (CN I) is actually the many small nerve fascicles of the olfactory receptor neurons. \ is unique among cranial nerves, because it is capable of some regeneration if damaged

• Cribriform plate

• section of the bone that separates the nasal cavity from the brain. contains many small holes through which the olfactory receptor neurons project axons. Clinical significance: (i) afracture can result in leaking of CSF into the nose and loss of sense of smell. (ii) The tiny holes can become the entry point for a pathogenic amoeba (Naegleria fowleri).

• Trigeminal sense

• sensation of touch, pressure, pain, temperature (hot chili peppers!) in mouth, eye, nasal cavity that is carried by the trigeminal nerve (the fifth cranial nerve, CN V).

• Olfactory bulb

• is a multi-layered structure located on the ventral surface of the brain that receives inputs from olfactory receptor neurons and sends output to cortex via mitral cell axons.

• Olfactory glomerulus

• pherical structures located in the olfactory bulb where synapses form between the axon terminals of the olfactory nerve and the dendrites of mitral cells.

• Mitral cells

• neurons located in the olfactory bulb that receive inputs from the olfactory receptor neurons within the glomeruli, along with inputs from modulatory cells, and then project axons to several cortical areas including the olfactory tubercle and piriform cortex and regions in the limbic system

• Olfactory tract

• the bundle of axons including those from the mitral cells that connects the olfactory bulb to several target regions in the brain

• Olfactory tubercle and piriform cortex

• ventral regions that together are considered ‘primary’ olfactory cortex. . Both regions are involved in identification of odor type and concentration.

• Orbitofrontal cortex for olfaction

• ventral region of the frontal lobes that is located just above the orbits of the eyes. Contains secondary olfactory cortex which is involved in odor identification and determining the reward value of an odor.

• Limbic system

• includes several interconnected regions in the medial temporal lobe that play important roles in processing emotion and memory. One function is higher-order olfactory processing – tying odors to emotion and memory.

• Anosmia

• ack of ability to smell; associated with trauma to olfactory neurons projecting through the cribriform plate bone.

• Hyposmia

• decreased ability to smell; often associated with clogged nasal sinuses (e.g., stuffiness from a head cold can block odorants from reaching olfactory receptors), or from nerve damage from trauma/infection

• Dysosmia

• things smell differently than they should; often associated with hormonal changes like pregnancy, with clogged sinuses as seen in colds, or with nerve damage from trauma, infection

• Hyperosmia

• an abnormally acute sense of smell; often associated with hormonal changes like pregnancy

• Phantosmia

• "hallucinated smell", often unpleasant; commonly seen as an aura (i.e., early symptom) of a seizure in temporal lobe epilepsy

• Tastant molecule

• any substance capable of stimulating the sense of taste

• Papillae

• The majority of taste buds on the tongue sit on raised protrusions of the tongue surface called

Filiform papillae

these are thin, long papillae "V"-shaped cones that don't contain taste buds but are the most numerous. These papillae are mechanical and not involved in gustation.

Fungiform papillae

slightly mushroom-shaped if looked at in section. These are present mostly at the apex (tip) of the tongue, as well as at the sides.

Foliate papillae

ridges and grooves towards the posterior part of the tongue found on lateral margins.

Circumvallate papillae

there are only about 3-14 of these papillae on most people, and they are present at the back of the oral part of the tongue. They are arranged in a circular-shaped row just in front of the sulcus terminalis of the tongue.

• Taste bud

• structure on the tongue that contains several taste receptor cells. A young tongue contains ~10,000

• Taste receptor cells

• provide taste information. They are located throughout the tongue in the taste buds, have areas of higher sensitivity, and have a very short life span

• Microvilli

• microscopic cellular membrane protrusions that increase the surface area of cells and minimize any increase in volume and are involved in a wide variety of functions

• Taste pore

• any of numerous spherical clusters of receptor cells found mainly in the epithelium of the tongue and constituting the end organs of the sense of taste.

• Supertasters

• eople who have a genetic mutation producing extra fungiform papillae and an increase of gustatory nerve fibers per papilla. They therefore experience a greater intensity of taste than normal, and may be especially sensitive to bitter tastes and the texture of fat

• Gustatory nerves

• nerve fibers at each taste bud that receive information from the taste receptor cells. Their axons join three different cranial nerves to carry taste information to cortex (

• Anterior insula & frontal operculum

• djacent cortical regions involved in taste processing; considered to be primary gustatory cortex. Plays a primary role in taste identification and evaluation of taste intensity.

• Orbitofrontal cortex for taste

• ventral region of the frontal lobes that is located just above the orbits of the eyes. Contains secondary gustatory cortex , which is involved in identifying taste, determining the reward value of a taste, combining multisensory information to determine flavor, and signaling satiety (fullness).

Ageusia

he complete loss of taste; patients will not be able to discriminate

differences among sweetness, sourness, bitterness, saltiness, and umami

Hypogeusia

partial loss of taste; taste sensitivity is reduced

Dysgeusia

istortion or alteration of taste; food tastes abnormal

medication side effects, vitamin deficiencies, respiratory illnesses Trauma

Causes of ageusia, hypogeusia, dysgeusia

Geographical tongue

an inflammatory condition of the mucous membrane of the tongue in which the loss of fungiform papillae produce smooth, red, painful regions that change location over time; May result from other infections or medications like antibiotics

Fissured tongue

benign condition characterized by deep grooves (fissures) in the top surface of the tongue; associated with geographical tongue, aging, environmental factors, and genetic conditions like Down’s syndrome

• Cross-modal perception

• occurs where perception involves interactions between two or

  more different sensory modalities.

• Synesthesia
  

• A phenomenon where stimulation of one sensory or cognitive
  pathway leads to automatic, involuntary experiences in a second sensory or
  cognitive pathway; a type of cross-modal perception. May be associated with improved memory and faster reaction times on certain tasks

differences in white matter connections (decrease in synaptic pruning), drugs, or trauma

synesthesia causes

• Graphemecolor

• [written letters/numbers evoke colors]

• Soundcolor

• [sounds evoke colors; also called chromesthesia]

• Lexicalgustatory

• [spoken or written words evoke tastes (and often also temperature, textures of food)]

• Number-form & spatial-sequence

• [numbers and sequences evoke shapes and forms]; these types may overlap significantly

• Ordinal-linguistic personification

• [ordered sequences like numbers and letters are associated with personalities and/or genders]

• Misophonia

• [possible synesthesia vs. neurological disorder; sounds evoke strong negative emotions; also associated with anxiety, obsessive- compulsive disorder, Tourrette’s syndrome, and maybe autism

X is the “inducing stimulus”, Y is the “concurrent sensory experience”

XY notation

• Projector synesthetes

• these people experience their synesthetic percepts as similar in quality to real-world perceptions. For example, synesthetic colors might appear as projected onto external objects and be difficult to dissociate from real-world colors. These synesthetes might not be able to tell whether letter are in black/white or color

• Associator synesthetes

• hese people experience their synesthetic sensations within their internal mental space. For example, they would see letters as appearing black/white, but would automatically associate the letters with colors in their mind/memory.

Visual search task

, it takes longer to find the number 2 hidden among 5’s when they are all the same color. Reaction time is much faster when there is a color difference. Grapheme-color synesthetes have a reaction time like there is a clear color difference when the numbers used match their synesthetic perceptions, even when the written text is all in black.