Midterm 3 Flashcards
Describe the Mental Lexicon
The mental lexicon is a mental store of information that includes semantic (word meaning) information, syntactic (how we combine words) information, and word form (sound patterns and spelling) information.
What is the Neighborhood effect?
We are slower to identify words with a large auditory neighborhood (more that differ on only a single phoneme)
What is auditory neighborhood?
The number of similar sounding words (differ from target by a single phoneme; late/rate/hate)
What is phoneme:
Smallest unit of sound that makes difference in meaning (L and R late vs. rate)
Describe Semantic Networks of Knowledge/Words
Our knowledge of words is organized into a semantic network, where words that are more closely related are represented more closely together in this network
What is the evidence behind Semantic Networks of Knowledge/Words
Evidence from studies of semantic priming; if subjects have to make a decision about a list of words, they are faster at making a decision about a word if the previously presented word is semantically related (“car” primes “truck”, but not “cloud”)
How are Semantic Networks organized?
Semantic Networks are categorically organized; words can be categorized by certain semantic properties (living, non-living)
Can brain damage destroy a particular category of words within the mental lexicon?
Yes; evidence from Category-Cpecific Word Deficits
Describe the Category-Specific Deficits
Warrington studied patients who had Category-Specific deficits for conceptual/semantic knowledge about certain categories of words: patients were fine at pointing to/naming pictures of living things, but they had great difficulty in pointing to/naming non-living, man-made objects like tools, other patient showed the opposite pattern (double dissociation)
How is Category-Specific deficit different from Visual Agnosia?
Can tell you that 2 objects are the same (i.e., can match 2
pictures of telephones), but don’t have access to what that object is for (not a problem of object recognition – deficit is in conceptual knowledge)
Describe Damasio et al. findings about Category-Specific Deficits
Locations of brain lesions are correlated with selective deficits in naming people (mostly anterior temporal lobe), animals, or tools (mostly posterior temporal lobe) anterior to posterior gradient for living to non-living things
Describe the similar pattern to Damasio in PET study of healthy subjects
Naming people activated mostly temporal pole (anterior portion of temporal lobe), naming animals activated middle portion of inferior temporal gyri, and naming tools activated mostly posterior portions of the inferior temporal gyrus
Why do we see this differentiable gradient of brain damage leading to different category-specific deficits?
Sensory-functional explanation
Describe the Sensory-functional explanation
Category-specific deficits due to brain damage can be attributed to differences in the processing of sensory/perceptual information vs processing of functional information
What is the compromise of the Sensory-functional explanation?
Organization of information within semantic memory network is a distributed network of specialized clusters
What is sound?
Pressure waves caused by vibration that vary in frequency
How does our speech system solve problems of speech perceptions?
Our speech system can solve these problems of speech perception by relying on higher order cues; prosody (tone of voice), syllable stress, and formant frequencies (complex sound waveforms that carry the most critical information about speech)
Describe Eric Ramsey and the results of the study conducted on him?
Eric Ramsey was in a vegetable state; can think of/imagine speech sounds, but cannot produce them; Kennedy and Guenther implanted electrodes in left premotor cortex (speech planning area) and measured activity; then they built a decoder that translates neural activity into formant frequencies, and output can drive a speech synthesizer
What is the key idea behind Kennedy and Guenther’s study?
Speech output areas represent intended speech sounds in terms of formant frequencies
What is aphasia?
Deficits in language comprehension or production following brain damage or disease
What is primary aphasia?
Problems in language due to direct disruption of language processing system
What is secondary aphasia?
Problems in language due to memory problems
Describe Lichtheim’s Classical Model of Language Processing
There is an auditory area that stores information about words sounds that you hear (Wernicke’s area) and another area for speech programming (motor) area that involves the motor component of word output, necessary for speaking (Broca’s area); these two are connected by a fiber tract; damage to these 2 areas result in different aphasias
What is Broca’s Aphasia, and who is Patient Tan?
Broca aphasia is a non-fluent aphasia in which the output of spontaneous speech is markedly diminished and there is a loss of normal grammatical structure. Patient Tan had Broca’s Aphasia; labored speech, repetition of words, can’t produce a full, fluent sentence. TMS to Broca’s area can disrupt fluent speech
Does damage to Broca’s area result in Broca’s aphasia?
No, not always. Damage to other white matter and subcortical structures is also important
What is Wernicke’s Aphasia?
Problems in word comprehension and producing meaningful sentences. Fluent speech but nonsensical sounds and/or sentences. Making up words
Does damage to Wernicke’s area result in Wernicke’s aphasia?
No, not always. There has to be damage to the surrounding posterior temporal lobe regions, or damage to white matter paths that connect this area to other parts of the brain.
Is Broca’s area = output and Wernicke’s Area = comprehension true?
No, it is too simplistic of a distinction. To some degree both areas are involved in both output and comprehension.
What is the Classical Economist’s approach to decision-making?
People are rational and should make the choice with the greatest expected outcome
What is Psychologist’s approach to decision-making?
People don’t behave rationally because there are psychological factors at play - they use certain heuristics or have biases when processing decisions
What is Neuroeconomics?
Combines classical economic theory, psychological theory, and neuroscience
What regions in the brain are correlated with Value Representation?
Two regions show a linear increase with subjective value: Striatum and Orbitofrontal Cortex
What do dopamine neurons in the striatum respond to?
“Reward Prediction Neurons”. Dopamine Response = Reward Occurred - Reward Predicted
Describe the Striatal-related monkey experiment
In the experiment, monkeys are either given an unexpected reward or trained to associate a light with a reward a few seconds later. Result 1: When a monkey receives a reward without an expectation of reward, the neurons fire. Result 2: Monkey is trained to associate a flash of light with a reward. when the light is turned on, the dopamine neuron fires. The dopamine neuron does not respond to the reward. Result 3: Same as result 2, but there is no reward, the dopamine neuron drops below baseline firing
What is the prediction error?
The discrepancy between the expectation or prediction of reward and receiving the actual reward
Summarize the Striatum
Striatum plays a key role in coding prediction error, allowing learning from feedback to influence future choices (across at least the domains of value and social reputation learning)
Describe the Orbitofrontal Cortex
OFC is an important structure for emotional decision making
Describe Patient Elliot
Damage to OFC; displayed dampened, dull emotional responses to situations; can generate solutions to social problems and consider the consequences, but can’t decide which solutions are most likely to be effective or which ones to choose
Describe Damasio’s Somatic Marker Hypothesis and OFC’s role
Our emotional response (physiological arousal) to a situation are “somatic markers” that can guide our decisions (“go with your gut”). OFC helps associate situations and somatic (bodily) changes - support from Iowa Gambling Task
Describe the Iowa Gambling Task
OFC patients continue to choose pile A (riskier pile), and do not show SCR (skin conductance) response from pile A. Suggests that failure to generate somatic marker impairs ability to learn from the task
Describe how Iowa Gambling Task supports Damasio’s Somatic Marker Hypothesis
Suggest that failure to generate somatic marker impairs the ability to learn from the task
Describe the evidence against Damasio’s Somatic Marker Hypothesis
Patients with spinal cord injuries don’t have physical feedback, and thus have no somatic markers; however, they learn the Iowa Gambling Task just fine - don’t need a physiological response to learn
How is the OFC related to Reward Value/Weighing Value?
OFC may track the relative value of choice; value in relation to social/emotional context, to previous value for the same choice, value relative to internal states, preferences, and long-term goals
What is the evidence behind OFC and Value?
Greater activity in OFC as pleasantness increases; OFC increases as pleasantness of temperature increases, water taste increases (different experiments)