Essay Flashcards
What are the dorsal and the ventral streams? Describe their functional contributions and why do we need both of them?
Both are pathways responsible for a part of visual processing.
Dorsal stream
-guidance of movements
-Visual relationships between objects (including the body and the environment).
-The dorsal stream provides the needed visual information guiding the body in navigation and skilled movements directed toward objects.
-Informs bodily movement toward objects
-Locations, speed, direction, movement
Specialized areas:
a. orientation and movement – perception of movement; responds to complex patterns of movement and optic flow (analysis of relative movement of visual objects in our environment to allow moving toward or away, or avoid/contact an object
b. motion sensitive
c. optic flow sensitive
d. form from motion sensitivity
e. biological motion (involves experience) - extrastriate body area (EBA) sensitivity to body parts
f. compensation for eye moments - head or body movements vis-à-vis environment and stability of object perception
Ventral stream
-object perception
- The ventral stream processes an object’s size, shape, color, texture.
-Involved in detailed perception (size, shape, color, texture) and identification of visual stimuli
-Includes superior temporal sulcus pathway to medial temporal lobe
-Primary inferior temporal cortex
specialized areas:
a. Shape recognition
b. differentiation of categories of objects
c. Fusiform face area (FFA): face recognition
d. recognition of photographs, silhouettes and stick figures in the extrastriate body area (EBA)
e. spatial perception and memory (recognizing sights and scenes)
reason for both:
The ventral stream perceives what an object or person is, while the dorsal stream processes where the object is located in space, its movement, its speed and direction.
Purposeful existence in the visual world requires an integrated and synchronized (well connected) information by both streams.
spacial information is needed for object recognition
You are a neuropsychologist administering neuropsychological tests to several individuals. In response to a presentation of a pencil and your question “What is this object?” both Person A and B responded: “I don’t know.” Upon further inquiry you determined that Person A suffers from associative visual agnosia, while Person B suffers from apperceptive visual agnosia
*Describe and explain what you did (your line of inquiry) with each of them - and their reactions - to reach these diagnostic conclusions.
Inability to recognize objects in a specific modality (cannot be explained by other things such as memory, language problems, attention deficits, etc)
apperceptive agnosia - unable to form a percept, or differentiate, or recognize it
associative agnosia - can perceive, recognize, recreate, differentiate, but unable to associate it (from simple to complex) to some meaning; no semantic associations (can define it if spoken about—visual agnostic)
- if testing, check all modalities
- ask to draw the object
- ask to copy the figure
- ask to describe the object
- ask to mime the object
- ask to pick up the object with other objects there
- ask to select the correct match in a set of images
- ask to categorize the object
- apperceptive visual agnosia will not be able to do his
- associative can draw or copy, but do not know what they are drawing
- They correctly perceive the form and know the object when tested with verbal or tactile information, but cannot identify the object. They are unable to link the fully perceived visual stimulus to prior experience to help them recognize the stimulus
Describe the classical syndromes of Broca’s aphasia and Wernicke’s aphasia from a classical psycholinguistic point of view.
Phonology – sounds that compose a language and the rules governing their combination; sounds of speech are conceptualized phonemically and phonetically (units of sound that have meaning vs. units of speech/production of sound)
•Broca
–difficulties with phonetic representation of speech and correct variants of phonemes
– problems with word production (orofacial movements intact) with intact comprehension; telegraphic speech, content words (nouns, verbs) with very limited function words and endings; syndrome transient if limited to Broca area;
•Wernicke
–difficulties with production of correct phonemes
– dysfunction of language comprehension, fluent, lacking awareness of problems, jumbled/word salad, structurally correct nonsensical speech, multiple paraphasias; (semantic: barn for house, phonemic: table for fable, and neologisms);
Based on recent research, the Integrated System-Based Approach to language (network perspective) disagrees with classical neurology and psycholinguistics regarding language processing. Briefly, describe the three areas of “insights about language” promoting the network perspective regarding language processing. (Read pages 232-238 and slides 23-28)
Three General Insights about Language (i.e., as gleaned from recent studies on language processing; taken from text):
1) The provision of more specific information about the localization of brain tissue that is activated when individuals are engaged in language-related processing
slides: localizers of brain tissue found that activation of these “traditional” language processing extend beyond the “traditional” language areas (including the Right hemisphere), and these “language specific” areas might be involved in other types pf information processes
a) Classic model is founded upon the notion that specific language-related processes were bound to specific pieces of neural tissue (i.e., the posterior region of the superior temporal gyrus is specialized for processing language-related sounds)
b) Research suggests that the area of activation extends far beyond that of regions of the brain typically associated with “language” (e.g., Broca’s and Wernicke’s areas)
c) Areas that have been considered to be “language-specific” historically may also serve the purpose of processing additional information as well
d) Summary: As compared to the initial idea that language-related processing occurs within a definitive region of the brain, emerging research suggests that “distinct types and streams of information contained in speech are likely to be processed in parallel across the brain, whether it be through separate bands of neural oscillations or in parallel across the hemispheres”
2) Language subsystems are not as distinct as originally assumed
slides: Language subsystems not as distinct as we thought, and more overlapping, because they share domain-general computations (pointing toward some ‘central’ organization)
a) Classic psycholinguistic theory: an individual first creates a syntactic frame (e.g., subject-verb-object) and then inputs the corresponding semantic values into the frame (e.g., “The cat sat on the windowsill”)
i) Within this view, syntax and semantics are distinct entities that can be separated AND syntax must precede semantics
b) Conversely, neural organization for processing phonology, syntax, and semantics demonstrate a certain degree of overlap
i) This overlap is thought to occur as a result of different components of language relying upon domain-general computations that are required by two different processes (e.g., syntax and semantics, phonology and syntax, etc.)
ii) Degree of overlap thought to depend upon the demands of a particular language-related situation
c) Neuroimaging findings also support this idea of overlap
d) Authors suggest that the classical model is not all wrong, but rather just needs some refinement
i) Long-term storage of phonological and semantic production depends upon posterior regions of the brain
ii) Conversely, frontal regions support the short-term maintenance and control over phonological and semantic information (i.e., which then support language comprehension)
3) Language appears to be supported by interactions between various brain regions that are reliant upon the white-matter connectivity between them
slides: Language appears to be supported by interactions between brain regions, reliant on white-matter connectivity between them
a) Classical theorists proposed conduction aphasia results via the disconnection between posterior and anterior regions of the brain
b) Contemporary neuroanatomy has found that the connection (i.e., arcuate fasciculus) between the anterior and posterior language regions is not observed within other primates, suggesting that this pathway may play a significant role in language processing within the human brain specifically
c) Processing of language is believed to rely upon two streams of info: dorsal stream (i.e., phonological and motoric processing) and ventral stream (i.e., lexical and semantic processing)
a. Describe the functional aspects of language
b. Present at least two examples (per aspect) to demonstrate their significance in social situations.
Pragmatics: the social appropriate use of language or use of language that follows the rules of social language; knowing what to say, how to say it, and when to say it
Ex 1: Talking to a teacher versus talking to a baby: knowing that we have to simplify language, change tone of our voice and facial expressions etc. to effectively communicate w children
Ex 2: Continuing the same topic as the other speaker: vital for social interaction and verbal communication
ex general: dealing with indirect requests, reading in-between the lines
Discourse processing: the ability to go beyond the single sentence and comprehend both narratives and explanations; using cognitive processes to build meaning out of linguistic events and make connections within and across linguistic contexts
Ex 1: the goal or intention influences how readers process and understand information and thus make it meaningful. For example, are individuals reading to acquire knowledge, be entertained, pass time, brainstorm, evaluate arguments, or judge others’ understandings?
Ex 2: organizing, monitoring, and activating information from memory: For instance, a student might actively search memory for details about particular historical events while attempting to complete an assignment or share their opinion on the event in class.This student is engaged in a targeted search for meaning from memories related to the concepts presented in the moment. This is influenced by the individual’s personal experience, religion, ethnic-racial background, cultural background, regional background etc.
-ex general: understanding metaphors, following a storyline, inferences (not clearly stated)
“Hemispheric functional differences are actually process-specific and not stimulus specific.” Explain this sentence. Offer specific examples (at least two) to indicate the pragmatic value of the differences between the functional contributions of each hemisphere.
“Hemispheric functional differences are actually process-specific and not stimulus specific.” Explain this sentence:
The “verbal or nonverbal “ dichotomy of the hemispheres became an oversimplification; the original idea was mostly based on studies of pathology.
Both hemispheres are engaged in most tasks, differences however are due to division of labor amongst the hemispheres, which are determined by the neuropsychological process needed, not by input (stimulus) or output (response). Hemispheres are interconnected, working together and dividing the tasks based on the complexity and processes requiring activation.
does not depend on what you’re doing or what is happening, but instead, the process of how it is occurring
Offer specific examples (at least two) to indicate the pragmatic value of the differences between the functional contributions of each hemisphere:
RH: The Right hemisphere is better equipped to deal with multimodal representations and informational complexity; With novelty and complexity , RH will predominate; gets the “big picture;” essay questions; processes novelty, global information and discordant information; responsible for following story lines and inference (filling in the blanks or make assumptions not explicitly stated, reading between the lines), understanding metaphors, jokes, understanding indirect requests (Will you pass the salt? means that the person wants salt not whether you are physically able to pass the salt to them)
LH: The Left hemisphere is better equipped to deal with single modal representations; routinized or coded information will require the predominance of the LH; iLH more concerned about rote, detailed, local, and concordant information
; multiple choice questions ;dentifies intonation patterns; organization or semantic information (integrating words in a sentence); responsible for understanding grammar, vocabulary, and literal meaning of words and phrases
Describe the Default Network and its systemic relations with other neurological areas. What are the significant clinical ramifications for this network existence?
The default mode network is a separate network that is active when the brain is not actively involved in attentional processes which is therefore a “default mode”. It is a group of brain regions that shows lower levels of activity when we are engaged in a particular task like paying attention, but higher levels of activity when we are awake but not involved in any specific mental exercise. This network includes the medial orbitofrontal, superior frontal, posterior cingulate, parts of the parietal lobe, parts of the medial temporal lobe and hippocampal connections. Part of the clinical dilemma in regards to the default mode network is that there may be a difference between faulty attention and lack of attention, evidence suggests that the engagement of attentional systems requires the actual disengagement of the default mode network.
We discussed in class 6 (six) prerequisites for executive functions. Choose 3 (three) of them, explain why do you think they are necessary prerequisites for having intact executive functions.
Specific executive skills:
1) Planning – a road map for action; what’s important (a hierarchy of needs and desires)
2) Organizing – designing a system for keeping track of information, materials and methods
3) Time management – estimation and allocation of time, according to the plan; a sense of what’s important; a sense of time (staying within the limits of deadlines)
4) Working memory – ability to hold information while performing complex tasks; ability to rely on past learning/experiences and apply to situation at hand or project into future
5) Metacognition (includes verification capacity, or quality control) – the ability to stand back and look at self in the situation from a bird’s eye view; ability to observe “how I” solve a problem; includes self-monitoring and skills of evaluation
Three prerequisites for executive function include response inhibition, emotional control and flexibility. Response inhibition is the ability to think before acting, the ability to resist urges, allowing time to evaluate situations and exploring alternatives. This allows us to think before we act to mediate the time between thinking and responds and to think ahead of how an action will impact ourselves. Emotional control provides us with the ability of self regulation of emotions and allows us to manage emotions in service of goal-directed actions which allows us to regulate emotions in service of our broader goals and desires.
- Response inhibition – think before action; resist urges; allow time to evaluate situation, explore alternatives, think ahead how action will affect “me” (gamblers have issues with this).
- Emotional control – self regulation of emotions; manage emotions in the service of goal directed action
- Sustained attention – ability to be task oriented in spite of distractibility, fatigue or boredom
- Task initiation – ability to begin a task without procrastination, in a timely manner
- Flexibility – ability to revise plans, actions, or intentions, in face of obstacles, setbacks, new information, mistakes; adaptability to changing conditions (set shifting and modifying strategies)
- Goal directed persistence = capacity or drive to follow through, to reach a goal, and not be put off by other demands or competing interests (important for initiation of behavior, creation and maintenance of goals, and sequence/planning)
Describe the Fight-Flight mechanism. Your description has to include the main anatomical structures and physiological processes involved (both the CNS and the body)
The Fight –Flight Mechanism is a normal and needed mechanism allowing the organism to respond adaptively to potential danger or stressful situations; a complex chain of events involving various neurochemical and hormonal reactions, preparing the body for rapid action, while shutting down digestion and reproductive systems. Perception of danger (stress), activates “limbic alert.” If such alert brings the system to a conclusion of “danger” the system activates the f-f mechanism.
Mechanisms:
- Perceived stressful event – cortex and amygdala perceive event and “decide” that the system is in imminent danger;
- Locus coeruleus (LC) provides a burst of excitation (mediated by NE), projecting to the LS; LC arousal is also mediated by 5-HT (receptors are inhibitory; serotonin depletion can result in disinhibition)
- LS and hypothalamus become very excited and activate the pituitary gland and the sympathetic system to go into alert;
- The SNS stimulates the adrenal medulla to secrete adrenaline and noradrenaline (elevating NE levels in the entire body)
- Pituitary gland secretes ACTH to stimulate the adrenal cortex to secrete cortisol, and TSH to stimulate secretion of thyroxine/triiodothyronine by the thyroid gland
- LS also stimulates the parabrachial nucleus to increase respiration, and the periaquaductal gray area to trigger freeze/avoid/escape reactions; LS continues to demand from LC continuous NE stimulation
Restoration to Homeostatic State:
•When the cortical subcortical appraisal of the event changes (no more stress), the Fight-or- Flight response is brought to a stop:
•LC stops the infusion of NE;
•chloride ion channels open to allow negative ions to flood neurons and reduce their excitability (hyperpolarizing neurons)
•Hypothalamus stops SNS activity and stimulates PNS; anterior pituitary gland stops secreting ACTH and TSH;
•Amygdala stops activating brain-stem and tegmentum nuclei
Empathy is considered by researchers as having three main components.
a. Describe these components and how each of these components might influence the person experiencing empathy toward another.
b. Which of these components can be related to the concept of Theory of Mind?
Describe these components and how each of these components might influence the person experiencing empathy toward another.
- Emotional cognition (feeling like others)
- Cognitive perspective-taking or understanding other’s POV
- Pro-social action or acting on the above
Which of these components can be related to the concept of Theory of Mind?:
theory of mind: The capacity to cognitively represent another person’s mental states, and even to understand that they may be different than one’s own
Cognitive perspective taking is related to theory of mind
Taking other’s perspective without judging it, understanding that other’s views are different than your own
the ability to do two things simultaneously 1. Understanding what’s going on with you, but 2. Understanding that you think/act/do differently; have to do theory of mind with empathy (understand without contaminating [e.g., stereotypes, prejudice, etc] others perceptions)
