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Electrophys Exam 1
Question | Answer |
---|---|
What are the three basic kinds of neurons? Primary purpose? | 1) Unipolar - dendrites & axons emerge from same process 2) Bipolar - dendrites & axon emerge from opposite sides of soma - imp. for relaying info 3) Multipolar - < than 2 dendrites, single axon; most common - imp. for divergence & convergence of info |
What are the two primary types of neurotransmitters? | 1) Excitatory - lowers postsynaptic membrane pot./thresh. (inside neuron becomes less neg./depolarizes - more likely to fire) 2) Inhibatory - raises postsyn. membrane pot./thresh. inside neuron becomes more neg./hyperdepolarizes - less likely to fire) |
Describe post-synaptic potentials. | 1) Come from cell body. 2) Slow graded potentials (most later AEP) 3) Electrical potentials that happens beforehand while it is building up to get ready to fire - there is a lot of variability b/c they are slower potentials (cortical potentials) |
Describe action potentials. | 1) Come from the axon 2) Fast potentials 3) Most earlier potentials 4) Happen quickly and not a lot of variability |
How does the CANS tract form dipoles? | When an excitatory input goes into one end of a dendrite it results in the extracellular environment becoming more negative (negative ions flow out of cell and positive ions come into cell). The opposite end of the dendrite goes to the opposite polarity. |
What is being measured when we do electrophysiologic testing? | Chemical changes in the nerve fibers that result in voltage changes (depolarization). The voltage is measured. |
What are the three MAIN acoustic characteristics of speech (as laid out by Delgutte in 1997)? | 1) Relatively strong vowels alternate with relatively weak consonants - modulation of waveform at 3-4kHz (syllables) 2) Spectral envelope of speech exhibits maxima corresponding to formants 3) Speech has periodic and aperiodic components |
Summarize (general principles of) the auditory nerve function. | Function: Break down incoming input into fundamental components for RELAY and further processing by higher CANS levels. |
Summarize (general principles of) the auditory nerve characteristics. | 1) Respond in a relatively homogenous and PREDICTABLE manner 2) Input is faithfully represented - pathologies affecting synchrony can lead to severe effects b/c the CANS is relying on info being transmitted |
Summarize (general principles of) the brainstem function. | Function: Neurons at various levels of brainstem extract/enhance various characteristics for speech |
Summarize (general principles of) the brainstem characteristics. | Characteristics: - as signal ascends, phase-locking decreases - responses of individual neurons become more differentiated and less predictable |
Summarize (general principles of) the thalamus function. | Function: Serves as PRIMARY WAY-STATION for all info b/w brainstem and cortex 2) a lot of MULTI-MODAL info; coding of SLOWLY CHANGING acoustic parameters (vowels, syllabic structure) 3) additional feature extraction/enhancement & complex signal processi |
Summarize (general principles of) the thalamus characteristics. | Characteristics: decrease in phase-locking; feature extraction/enhancement and multi-modal integration increases |
Summarize (general principles of) the primary auditory cortex function. | Functions: 1) coding of rapid acoustic events (fine-grained temporal resolution and discrimination...like da vs. ga) 2) Development of concept of "auditory space" 3) Final integration |
Summarize (general principles of) the primary auditory cortex characteristics. | Characteristics: 1) Continued tonotopicity (multiple auditory "maps" and integration 2) Fine timing and decreased phase-locking ability |
Summarize (general principles of) the primary auditory association cortex function. | Functions: Recognition of linguistic stimuli comprehension of spoken lang.; some lang. formulation ability |
Summarize (general principles of) the primary auditory association cortex characteristics. | Characteristics: Integrative in nature rather than focusing on representation of spectro-temporal features of the signal. |