29 Questions
What type of attention is characterized by a bottom-up, stimulus-driven process?
Exogenous attention
In the lunch-line effect, what does the perceptual system track in the environment?
Salient stimuli
Which model of attention determines what will undergo additional processing and be represented in awareness?
Early selection
What effect is described as the ability to focus voluntarily on what we choose to perceive and process?
Cocktail-party effect
When a sensory event captures our attention, it is an example of which type of attention process?
Exogenous attention
What is the goal of estimating the contribution of various frequencies to a measured EEG signal?
To quantify the different frequency components present in the EEG signal
Why is absolute power preferred over relative power in EEG spectral analysis?
It allows for easier interpretation of the amount of a specific frequency within the EEG signal
What role does the length of the segment play in determining frequency resolution in Fast Fourier Transform (FFT) analysis?
It limits the number of different frequencies that can be resolved
Why is it important to use artifact-free EEG segments in spectral analysis?
To avoid distortions in the estimation of spectral features
In time-frequency analysis, what does Short-time Fourier Transform (STFT) help to compute?
The time-dependent spectrum, known as a spectrogram
How are EEG signals viewed in wavelet analyses?
As shifted and scaled versions of a mathematical function
What assumption is made in the context of pure insertion?
Adding an extra component affects the operation of earlier components
What is the purpose of a cognitive conjunction in experimental design?
To identify regions of activation shared across different subtractions
Why is the choice of baseline task considered crucial in experimental design?
To avoid interaction effects that could make data ambiguous
In the context of neuroimaging experiments, what does comparing (A-B)-(C-D) aim to determine?
The effect of touch compared to self-movement
Why is a factorial design useful in neuroimaging experiments?
To isolate specific regions involved in different cognitive processes
Why should the baseline task ideally be as similar to the experimental task as possible?
To ensure a clear distinction between baseline and experimental task
What is the primary characteristic of the alpha band in EEG recordings?
Lower and upper alpha sub-bands have distinct functional roles.
Which of the following statements about the beta band is correct?
It replaces the alpha rhythm during cognitive activity.
What is the primary characteristic of the gamma band in EEG recordings?
It reflects large-scale integration and synchrony among widely distributed neurons.
What is the typical amplitude and distribution of the beta band in EEG recordings?
Small amplitude (10-20 μV) with a symmetric fronto-central distribution.
Which of the following statements about alpha desynchronization is correct?
Upper alpha desynchronization is linked to processing sensory-semantic information.
Which of the following statements about alpha blockage/desynchronization is correct?
It is greatly diminished by eye opening, sudden alerting, and mental concentration.
What was the purpose of the 'resting' measurements in the experiment?
To measure baseline brain activity without any task
According to the discussion, what cognitive process is associated with activation of the inferior parietal lobule during the syllable counting task?
Phonetic segmentation and short-term memory
What is the primary approach used in the first-level analysis of the experiment?
Cognitive subtraction
Which brain region is specifically mentioned as being associated with attentional demand and mental imagery in the discussion?
Prefrontal cortex
According to the discussion, what cognitive process is associated with activation of posterior parietal areas?
Spatial transformation of visual stimuli
Based on the information provided, what can be inferred about the nature of the 'pre-processing' steps mentioned in the experiment?
They were time-consuming and 'ridiculous'
Study Notes
Cognitive Conjunctions and Factorial Designs
- Cognitive conjunction: identify a set of tasks that share a particular component
- Look for regions of activation that are shared across different subtractions
- Factorial design: baseline task still required
- Example: A-B & C-D = isolate regions involved in tactile sensation; A-C & B-D = isolate regions involved in motor production
- (A-B)-(C-D) = difference between A & B vs. difference between C & D = effect of touch greater in presence of self-movement?
Alpha, Beta, and Gamma Bands
- Alpha band:
- Desynchronization/suppression associated with stimulus- and task-unspecific increases in attentional demands (lower alpha, 8-10Hz)
- Associated with processing of sensory-semantic information, better semantic memory performance, and stimulus-specific expectancy (upper alpha, 10-12Hz)
- Beta band:
- High frequency, small amplitude (13-30Hz)
- Replaces alpha rhythm during cognitive activity
- Increased excitatory activity related to focused attention, diffuse arousal, and vigilance
- Gamma band:
- Directly associated with brain activation (36-44Hz)
- Reflects large-scale integration and synchrony among widely distributed neurons
- Associated with exogenous attention, top-down modulation of sensory processes, and the "cocktail-party effect"
Attention and Selection Models
- Early selection: stimulus can be discarded before perceptual analysis
- Late selection: stimulus is fully processed before being selected or rejected
- Reflexive attention: bottom-up, stimulus-driven process in which a sensory event captures attention
- Voluntary attention: ability to intentionally attend to something
EEG Analysis
- Spectral/Frequency Analyses:
- Based on the notion that any oscillatory activity can be characterized by the sum of different sinusoidal waves with distinct frequencies and amplitudes
- Estimates the contribution of various frequencies to the measured EEG signal
- Uses Fast Fourier Transform (FFT) and assumes stationarity of the EEG signal
- Time-Frequency Analysis:
- Shows when in time frequency shifts occur
- Uses Short-time Fourier Transform (STFT) or wavelet analyses
Application of EEG in Social Cognitive and Affective Neuroscience (SCAN)
- Experiment 2:
- Spatial imagery: same as in Experiment 1
- Perception condition: saw actual clock faces
- Syllable counting condition: count the syllables of auditorily presented pairs of times and report whether the total syllable number was odd or even
- 72 measurements for each subject
- Complicated pre-processing and first-level analysis
Discussion
- Reverse inference: mental state is inferred from brain activation
- Activation of prefrontal cortex associated with attentional demand involved in different kinds of mental imagery and working memory
- Activation of inferior parietal lobule associated with phonetic segmentation and short-term memory
- Activation of posterior parietal areas associated with spatial transformation of visually presented stimuli and orientation discrimination of tactile stimuli
Learn about different types of attention including exogenous attention and endogenous attention. Explore how exogenous attention is reflexive and stimulus-driven, while endogenous attention is voluntary and intentional.
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