Modulo Mento Flashcards
Which are the aims of EEG in Cognitive Psychology?
- To understand how cognitive processes work
- To depict the timing of cognitive processes
- Few interest for the brain by itself (networks, dynamics, etc)
Which are the aims of EEG in Cognitive Neuroscience?
- To understand how the brain supports cognition (the mind/brain problem)
- To depict the spatiotemporal Neurodynamics
- Focus on the brain by itself (networks, dynamics, etc)
THE BRAIN ELECTRICAL ACTIVITY CAN BE EXPRESSED/MEASURED ACROSS
2 Modalities, 4 Domains
Which are the modalities?
- TIME-LOCKED: HOW THE SIGNAL CHANGES AS COMPARED TO A DISCRETE EVENT (EP/ERP)
- SPONTANEOUS: HOW THE SIGNAL CHANGES IN THE ABSENCE OF DISCRETE EVENTS
(I.E., RESTING STATE, TASK-FREE)
Which are the domains of EEG?
- TIME: HOW THE SIGNAL (EEG /ERP) EVOLVES ACROSS TIME
- SPACE: HOW THE SIGNAL (EEG /ERP) EVOLVES ACROSS SPACE
- FREQUENCY: HOW THE EEG SIGNAL IS REPRESENTED IN TERMS OF FREQUENCIES
- TIME/FREQUENCY : HOW THE FREQUENCY CHANGES ACROSS TIME
Which domain of EEG is the most accurate?
THE MAIN FEATURE OF THE EEG IS THE SUPER FINE TEMPORAL RESOLUTION (IN THE ORDER OF ms)
FOR THIS REASON IT HAS BEEN TRADITIONALLY USED TO DEPICT TIME COURSE OF NEURAL SIGNAL PROCESSING
FOR EXAMPLE, THE PEAK LATENCY OF SENSORY/MOTOR EVOKED RESPONSES IS CURRENTLY CONSIDERED A DIAGNOSTIC MARKER IN MANY CASES (E.G., MULTIPLE SCLEROSIS, ETC)
THE «TEMPORAL OVER SPATIAL SUPREMACY» HAS PREVENTED FOR MANY DECADES THE EEG FROM BEING
CONSIDERED AS A NEUROIMAGING TECHNIQUE…BUT THINGS CHANGED IN THE LAST YEAR
Which type of montage can improve spatial resolution?
BIPOLAR MONTAGES CAN IMPROVE SPATIAL LOCALIZATION BUT IT STILL REMAINS LOW
How ERPs are obtained from EEG?
ERP’ s are obtained after averaging EEG signals obtained over multiple trials (trials are aligned by stimulus onset)
Which is the difference between Evoked Potentials and Event Related Potentials?
EVOKED POTENTIALS= exogenous, Independent of Whether the subject is attentive or interested in the stimulus. They can be recorded even during sleep
EVENT-RELATED POTENTIALS= endogenous, Require stimulus active analysis, cognitive
How are ERPs divided depending on the latency?
SHORT LATENCY (<10 ms)
MIDDLE LATENCY (10-50/80 ms)
LONG LATENCY (>80 ms)
MIDDLE LATENCY IS USEFUL TO…
ASSESS THE FUNCTIONAL INTEGRITY OF AUDITORY PATHWAY
What’s P50 morphology and latency?
positive deflection, sharp, 50 ms
What’s P50 scalp location?
Vertex (Cz)
Which stimuli can elicit a P50?
obbligatorily elicited by fast auditory stimuli (e.g., paired-click paradigm, first auditory click
followed by a second click 500 ms later)
Which are the anatomical generators of P50?
frontal lobe suggesting a contribution of prefrontal processes in the sensory-gating
What’s the functional meaning of P50?
to evaluate the sensory gating (i.e., the capacity of the brain to automatically filter unnecessary or redundant stimuli). The sensory gating induces a reduction of the second P50. This reduction is altered in brain damaged or schizophrenic patients (Smith et al)
How does the P50 change in schizophrenia patients?
A sensory gating deficit, as reflected by P50 suppression, has been repeatedly shown in schizophrenia patients, which may be associated with cognitive deficits in this disorder.
Describe the study about P50 suppression in schizofrenic patients
Method: they recruited 38 chronic schizophrenia patients and 32 matched healthy controls, and assessed their cognition with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and P50 suppression with the electroencephalography system.
Results: The total and its 4 index scores (all p < 0.05) except for the visuospatial/ constructional index of RBANS were significantly lower in patients compared with healthy controls. Patients displayed a significantly higher P50 ratio, higher S2 amplitude, and lower S1 amplitude (all p < 0.05) than healthy controls. Interestingly, only in the patients, the S1 amplitude was associated with both language and attention, and the S2 amplitude with both visuospatial/ constructional and language (all p < 0.05), although all of these significances did not pass the Bonferroni corrections. The P50 ratio was not associated with any of the RBANS scores (all p > 0.05).
Conclusions: Our results suggest the P50 suppression deficits in Chinese patients with schizophrenia, which may be associated with cognitive impairments of this illness. Moreover, the amplitude of S1 and the amplitude of S2 may be involved in the different cognitive domain deficits in schizophrenia patients.
Significance: This study suggests that the P50 components may possibly be effective biomarkers for cognitive deficits in patients with schizophre
What’s the morphology and latency of P1?
positive deflection, sharp, latency of 100 130 ms (< 200 in infants/toddlers)
What’s scalp location of P1?
occipital sites bilaterally (Oz, O1, O2)
Which type of stimuli elicit the P1?
obbligatorily elicited by visual stimuli (e.g. black/white contrast)
What’s the anatomical source of the P1?
extra-striate cortex
What’s the functional meaning of P1?
low-level visual processes, but it is modulated by top-down processing (i.e., levels of selective attention, and arousal It has greater amplitude for stimuli towards which the subject’s spatial attention is oriented and the subject’s arousal is greater.
How does the mielin maturation influence the P1 latency?
P1 peak time decreases with age as myelination progresses in infants. Initially, P1 latency is high (~300 ms), but it drops rapidly in the first 20-30 weeks, reflecting faster neural transmission due to myelin development. After this period, the decline slows, stabilizing around 100 ms, indicating mature neural conduction. Multiple studies confirm this trend, showing that early myelination enhances visual processing efficiency in infants.
What does the comparison between normal vs. abnormal P100 wave latencies highlights?
It highlights the effects of demyelination, for istance in multiple sclerosis.In the normal condition, the P100 wave latency is 107 ms. In the abnormal (demyelinated) condition, the P100 latency is delayed to 134 ms, indicating slower neural conduction due to myelin loss. This delay is a hallmark of demyelinating diseases like multiple sclerosis, where impaired myelination disrupts signal transmission in the visual pathways.
Which are the evidences about the P1 amplitude?
Vogel and Luck (2000) found that P1 amplitude is sensitive to low-level visual features (e.g., brightness, contrast, spatial frequency) because it reflects early sensory processing in the extrastriate visual cortex. Stronger, more salient stimuli elicit larger P1 responses, indicating that P1 is influenced by stimulus-driven arousal rather than detailed feature discrimination. While attention can enhance P1, it primarily acts as an index of early visual processing and sensory gain control rather than cognitive-level analysis.
Which are the evidences about P1 in dysphoric people?
Reaction times for to neutral shapes (squares and diamonds) and the event-related potentials to emotional faces were recorded in 18 dysphoric people and 18 healthy controls.
Control participants exhibit a right occipital lateralization of the P100 component—an indication of early attention-related sensory facilitation for faces expressing emotions (rather than the target shape diamond or square, which they had to identify by pressing two different buttons).
Attentional-related sensory facilitation refers to the process by which directing attention to a particular stimulus or location enhances early sensory processing. In other words, when you focus your attention on a visual stimulus, the neural responses in early visual areas (reflected in early ERP components like the P100) become stronger or more pronounced. This enhancement means that the brain is “primed” to process the attended stimulus more effectively, making it more likely that relevant details are detected quickly and accurately.)
In contrast, dysphoric individuals did not show this lateralization, suggesting they may have reduced sensory facilitation when processing facial stimuli. (Buodo, Mento et. al)
What is the effect of proactive and reactive control on P1?
The use of proactive or reactive control of the block task doesn’t affect the P100 (bottom-up processes), but later components (P300) are affected by both top-down (instruction) and bottom up (block type). The Go-NoGo task have a small effect on P1 amplitude.
What’s the morphology and latency of N1?
negative deflection, sharp, latency of 100 200 ms (< 300 in infants/toddlers)
Which stimuli elicit the N1?
both visual and auditory
Which are the scalp locations of N1?
parieto-occipital (visual) and fronto-central (auditory) electrodes
Which is the anatomical source of N1?
extra-striate cortex
What’s the functional meaning of N1?
low-level sensory processes, but can be modulated by top-down processing
(i.e., levels of selective attention, and arousal It has greater amplitude for stimuli towards which the
subject’s spatial attention is oriented and the subject’s arousal is greater . Its amplitude is linked to the orientation of spatial attention but also to the discrimination of the stimulus
What is the effect of attention on N1 and P1?
Both increase the amplitude when the stimulus is presented in the expected hemispace
A similar effect (in dichotic listening) occurs for the auditory, centrally located N100
What is the classical effect of Posner paradigm?
BETTER PERFORMANCE (FASTER RTs) FOR CUED THAN UNCUED TARGETS
What is the effect of Posner paradigm on N1?
N1 amplitude is larger for unexpected stimuli and reduced when a stimulus is preceded by an attended one, suggesting efficient processing of predicted stimuli. This supports the idea that attention enhances sensory processing, while prediction reduces neural effort for expected events.
N1 is affected by top-down predictability
What’s N170 morphology and latency?
negative deflection, sharp, with a latency 150 - 220 ms (< 400 in infants/toddlers)
What’s N170 scalp location?
temporo-occipital (only visual)
Which stimuli elicit N170?
Faces
What is N170 anatomical source?
extra-striate cortex, fusiform gyrus, posterior superior temporal sulcus
What’s N170 functional meaning?
face-specific component, modulated by both local and global structural feature
N170 for inverted faces
Larger and more delayed (in peak) for inverted compared to upright faces.
Which specific processes does N170 reflect?
It does not reflect sensory processes by themselves, but rather the structural coding and processing of the configuration of the face, for instance access to its prototypical representation. Its latency is delayed if the face image is upside down or deprived of the eyes but the component is still present
N170 is linked to higher or lower processes?
THE N170 (BUT NOT P1) IS MODULATED BY FACE EXPRESSION, IT PROBABLY REFLECTS THE STRUCTURAL PROPERTIES OR THE AROUSAL RATHER THAN OTHER HIGHER COMPUTATONAL
PROCESSES. N170 IS SENSITIVE TO THE STRUCTURAL PROPERTIES OF STIMULI
Is the N170 evoked only by human faces?
No, it seems that N170 is evoked more in general by socially relevant stimuli, such as bodies.
THE N170 IS SPECIFICALLY MODULATED BY THE SOCIAL CONTENT (BOTH FACES AND BODIES)
Which are the commonalities and differences between human bodies and human faces in terms of N170?
Both of them provide social cues relevant for communication and interaction and are processed configurally. Moreover both of them show the inversion effect in N170 (Face Inversion effect and Body Inversion Effect). THE N170 “INVERSION EFFECT” IS PRESENT FOR BOTH FACES AND
BODIES, HOWEVER, IT IS SUBSERVED BY TWO DISTICT CORTICAL NETWORKS
However they are processed in different specialized brain areas in adults:
- human faces by FFA (fusiform face area) and OFA (occipital face area)
- human bodies by EBA (extriate body area) and FBA (fusiform body area)
THE SCALP DISTRIBUTION IS SIMILAR FOR FACES AND BODIES BUT NOT EXACTLY THE SAME
THIS PROBABLY REFLECTS THE INVOLVEMENT OF DISTINCT NEURAL GENERATORS FOR FACES AND BODIES. ANYWAY, THE MODULATION GOES INTO THE VERY SAME DIRECTION, THAT IS, LARGER AMPLITUDE TO INVERTED STIMULI, THAT REFLECTS HIGHER EFFORT FOR STRUCTURAL DECODING
How does the N170 change while observing human faces human bodies and houses (objects)?
In the two post clusters the N170 was larger for inverted faceas and bodies as compared to the up-right ones (p < .05). The N170 modulation effect is larger for faces than for bodies (p < .05).
This effect was not present for houses.
How does the N170 change while observing human faces human bodies and houses (objects)?
In the two post clusters the N170 was larger for inverted faceas and bodies as compared to the up-right ones (p < .05). The N170 modulation effect is larger for faces than for bodies (p < .05).
This effect was not present for houses.
What’s the Brainstorm Pipeline?
It is a workflow for EEG/ERP analysis and source localization. It follows these steps:
- EEG/ERP Measurements – Record brain activity and analyze event-related potentials (ERPs)
like N170. - Head Model – Create a model to predict how brain signals reach the scalp (forward problem).
- EEG Source Localization – Use mathematical methods (e.g., sLORETA, MN) to estimate brain
activity sources (inverse problem). - Structural MRI Integration – Align EEG data with anatomical brain images for better
spatial accuracy. - Cortical Meshes – Generate a 3D brain model for visualization.
- Source Activation – Identify and display brain regions involved in processing stimuli.
This process helps localize neural activity from EEG recordings, improving understanding of brain function.
Which types of filtering there are?
- Low-pass filter: Filter frequencies above the given threshold (e.g., 30 Hz)
- High-pass filter: Filter frequencies below the given threshold (e.g., 0.1 Hz)
- Band-pass filter: Filter frequencies outside a give range (0.1-100 cut all frequencies outside this range)
What are the findings about face perception with TMS?
Pitcher et al. (2011) conducted a transcranial magnetic stimulation (TMS) study to investigate the neural mechanisms of face perception. Their main goal was to determine whether different regions of the brain contribute uniquely to face processing.
Three Key Face-Selective Areas:
• Occipital Face Area (OFA)
• Fusiform Face Area (FFA)
• Superior Temporal Sulcus (STS)
Functional Specialization:
1. Occipital Face Area (OFA) – Processes individual face parts (e.g., eyes, nose, mouth). Configural processing, perceptual level
2. Fusiform Face Area (FFA) – Supports holistic face perception. Semantic level
3. Superior Temporal Sulcus (STS) – Involved in recognizing facial expressions and movements.
• OFA and FFA process static facial identity, while STS processes dynamic facial cues. • This supports a hierarchical and parallel processing model of face perception.
Conclusion: Face perception relies on a network of specialized brain regions, each responsible for different aspects of face processing.
Which are the findings about face and body perception through fMRI?
Peelen and Downing (2006) explored how the brain processes faces and bodies using fMRI. Their study focused on whether brain regions selective for faces (like the fusiform face area, FFA) also respond to bodies and vice versa.
Key Findings:
1. FFA (Fusiform Face Area) is Face-Specific: Responds strongly to faces but not to bodies.
2. EBA (Extrastriate Body Area) and FBA (Fusiform Body Area) are Body-Specific: respond more to bodies than faces.
3. Overlapping Activation in Social Perception: While face and body processing areas are distinct, they are close to each other, suggesting a shared network for recognizing social stimuli.
Conclusion: Faces and bodies are processed by separate but neighboring brain regions, supporting the idea of specialized neural mechanisms for different socially relevant stimuli.
How is the hierarchical functional model of face processing organized in fusiform cortex?
An fMRI study by Grill-Spector et al. (2004) investigated how the fusiform gyrus processes different types of visual stimuli, particularly faces, objects, and words. The researchers aimed to understand whether the fusiform face area (FFA) is specialized for face recognition or if it responds to other stimuli as well.
Key Findings:
1. Category Selectivity in the Fusiform Cortex: The fusiform cortex contains distinct, yet overlapping, regions that respond to faces, objects, and words. The FFA responds most strongly to faces but also shows weaker activation for objects.
2. Graded Organization: Rather than having completely separate areas, the fusiform gyrus shows a gradient of selectivity, with face, object, and word-processing regions arranged next to each other.
3. Face Recognition is Strongest in the Mid-Fusiform: The central fusiform gyrus (mid-fusiform sulcus) shows the highest face-selectivity, supporting the idea of a specialized face-processing region.
Conclusion: Face, object, and word processing regions in the fusiform cortex are not entirely distinct but form a graded, overlapping organization. This supports a continuum model rather than strict modularity in visual processing.
What’s MMN morphology and latency?
negative deflection, sharp, latency of 180 - 250 ms (< 400 in infants/toddlers)
What’s MMN scalp location?
fronto-central (only visual)
Which type of stimuli elicit the MMN?
both auditory and visual.
MMNs can be elicited by differences in sound frequency, duration, amplitude or interstimulus interval (ISI).
MMN is evoked by an infrequently presented stimulus (“deviant”), differing from the frequently-occurring stimuli (“standards”) in one or several physical parameters like duration, intensity, or frequency.
In addition, it is generated by a change in spectrally complex stimuli like phonemes, in synthesised instrumental tones, or in the spectral component of tone timbre. Also the temporal order reversals elicit an MMN when successive sound elements differ either in frequency, intensity, or duration
The MMN is not elicited by deviant stimuli alone. The MMN has, therefore, been suggested to reflect a change detection when a memory trace representing the constant standard stimulus and the neural code of the stimulus with deviant parameter(s) are discrepant
What’s MMN’s anatomical source?
primary cortex (i.e., planum temporale), frontal areas (DLPFC)
What’s MMN functional meaning?
It is associated to stimuli discrimination. Different interpretations: sensory memory, pre-attentive allocation, error prediction. The difference in the responses evoked by deviants and standards takes the form of a broadly negative waveform at the top of the scalp, which peaks between 180 and 250 ms after the onset of the sound.
How do differences in sound frequency, duration, amplitude, or interstimulus interval (ISI) affect MMN?
- Näätänen et al. (1987) - Amplitude Changes:
This study demonstrated that the mismatch negativity (MMN) can be elicited by amplitude deviations in auditory stimuli. When a sound’s intensity deviates from the expected norm, it generates an MMN, indicating that the brain automatically detects changes in sound intensity, even when the listener is not consciously focused on the stimulus. - Näätänen et al. (1989) - Frequency and Duration Changes:
This study showed that MMNs can also be elicited by changes in sound frequency and duration. The research confirmed that the brain responds to these deviations in the auditory environment in an automatic and pre-attentive manner. It demonstrated that both frequency (e.g., pitch changes) and duration (e.g., length of a sound) deviations can trigger an MMN response, reflecting the brain’s sensitivity to these auditory characteristics. - Ford and Hillyard (1981) - Interstimulus Interval (ISI) Changes:
This study explored how changes in the interstimulus interval (ISI), the time gap between consecutive sounds, can also elicit an MMN. It suggested that the brain can detect irregularities in timing (such as shorter or longer intervals between sounds), triggering a mismatch negativity. This finding showed that the brain is sensitive not just to the properties of the sounds themselves but also to their temporal relationships.
In summary, MMN can be elicited by changes in the loudness or intensity of sounds, by changes in sound frequency (pitch) and duration (length of the sound) and by deviations in the timing or spacing of sounds (ISI).
Are there analogs of auditory MMN ?
MMN analogs are found in visual, olfactory, and somatosensory modalities, supporting the idea that MMN is part of a shared automatic brain mechanism that detects novel stimuli across different sensory systems
Does manipulation of attention an states of wakefulness affect MMN?
MMN is resistant to manipulations of attention and states of wakefulness, meaning it can be elicited even if the subject is not actively paying attention to the auditory stimuli or is in different states of alertness. However, while MMN is robust in these contexts, the amplitude of the MMN can still be modulated by factors such as attention and wakefulness.
How to elicit MMN?
Through the Oddball Paradigm: In the oddball paradigm for eliciting Mismatch Negativity (MMN), a sequence of standard stimuli (identical or similar) is presented (80%), with occasional deviant stimuli that differ in properties like frequency or duration (20%). The brain automatically detects these deviations and generates the MMN, a negative ERP component, typically within 100-250 ms after the deviant stimulus. This response occurs even if the person is not paying attention, reflecting the brain’s automatic processing of sensory novelty. The MMN is usually recorded through EEG, providing insights into pre-attentive sensory processing.
Amplitude of MMN is proportional to the difference between standard sound and deviant sound
Max amplitude over central and parietal scalp sites Cz
Which are the typical Oddball tasks?
- Do nothing (sounds are presented during reading a book), just listen
- Count oddballs
- Press only for oddballs
- Press different buttons for standard and oddball
Which are the typical Oddball tasks?
- Do nothing (sounds are presented during reading a book), just listen
- Count oddballs
- Press only for oddballs
- Press different buttons for standard and oddball
Why can we say that MMN is a derived ERP component?
Because it is a difference wave, obtained subtracting the standard from the deviant.
How is MMN a marker of auditory sensory memory?
The MMN data provide evidence that stimulus features are separately analysed and stored in the vicinity of auditory cortex. The close resemblance of the behaviour of the MMN to that of the previously behaviourally observed “echoic” memory system strongly suggests that the MMN provides a non-invasive, objective, task-independently measurable physiological correlate of stimulus-feature representations in auditory sensory memory.
Näätänen et al. (1993b) demonstrated that Mismatch Negativity (MMN) is an automatic brain response to auditory deviations, occurring without focused attention. The study highlighted that MMN reflects the brain’s use of memory templates to detect changes in the auditory environment, signaling when a stimulus does not match expectations. MMN typically appears 100-250 ms after a deviant sound and is most prominent over frontal and central brain regions. The study also suggested that impaired MMN responses could be linked to cognitive disorders, like schizophrenia, making MMN a valuable tool for studying sensory processing.
How is MMN a marker of cortical plasticity?
Since the MMN can be easily elicited withouth active engagement (tasks) and attention (passive stimulation) it is an excellent candidate for studying neuropshysiological mechanisms underlying cortical plasticity since birth (or even before…)
How is MMN related to learning mechanisms?
Winkler et al. (1999b) showed that MMN is linked to auditory memory and the brain’s ability to detect deviations from learned auditory patterns. They found that MMN is more pronounced when a sound deviates from a pattern the brain has recently encountered or learned. The study highlighted the role of context and timing in eliciting MMN, with stronger responses occurring when the deviant sound closely follows standard stimuli. These findings emphasize MMN’s role in auditory discrimination, pattern learning, and sensory processing.
No MMN was elicited in “naive” Hungarians by vowel /ä/(/ae/), which is relevant for Finns but not for Hungarians. However, very similar MMNs were elicited by this vowel both in Finns and Hungarians fluent in Finnish. In contrast, vowel /y/, present in both languages, elicited similar MMNs in all groups.
Moreover, Cheour et al. (2002) showed that MMN can be measured in infants, even as young as a few months old, indicating early auditory pattern recognition and the ability to detect deviations from learned sounds. The study found that infants show language-specific MMN responses, distinguishing between native and non-native speech sounds, which marks the onset of language processing. These findings suggest that MMN plays a key role in the maturation of auditory processing and may be a precursor to language development and cognitive skills.
In the study, newborns showed no MMN response to the /y/i/–/y/ contrast in the evening (while sleeping). However, after receiving nocturnal training with this contrast, they exhibited a significant MMN the following morning, indicating the brain’s ability to learn during sleep. In contrast, control groups with no training or different training (/a/–/e/ contrast) did not show MMN in either the evening or morning, suggesting the effect was specific to the training.
What’s the relationship between MMN and language development?
Friedrich, Weber, and Friederici (2004) found that MMN plays a key role in language development by reflecting the brain’s ability to discriminate speech sounds. Their study showed that infants exhibit language-specific MMN responses, indicating early sensitivity to phonetic contrasts in their native language. MMN can serve as an early indicator of phonological processing abilities, which are crucial for language acquisition. Additionally, changes in MMN over time are associated with the development of language skills like phoneme recognition.
What’s the automatic syllable duration discrimination (MMN)?
Friederici, Friedrich, and Weber (2002) showed that MMN can be elicited by changes in syllable duration, indicating that the brain automatically detects temporal deviations in speech sounds. This finding suggests that the brain processes syllable duration pre-attentively, without requiring focused attention, and highlights the brain’s ability to detect important temporal features for speech perception.
MMN in speech processing
Dehaene-Lambertz (2000) found that infants can detect phonetic contrasts through MMN, even before they begin speaking, indicating early language-specific processing. The study highlighted MMN as an early marker of auditory discrimination and emphasized the role of pre-attentive auditory processing in the development of speech perception and language skills.
The objective of Dehaene-Lambertz (2000) was to examine the development of the functional organization of the auditory cortex in infants. The study found that infants’ auditory systems are capable of processing speech sounds early on, with the brain specialized for detecting phonetic contrasts. This early maturation of the auditory cortex is essential for the development of speech perception and language acquisition. Tones and syllables activate different neural networks
What’s the Positive Mismatch? (MMR, mismatch response)
a positive deflection prior to MMN, still in frontocentral areas, found in infants in response to mismatch in long duration stimuli both in sleeping and awake subject→ adult like MMN was present in awake infants only
positve mismatch response also used to explain functional organization of some processes— for istance auditory cortex (Cerebral Specialization for Speech and Non-Speech Stimuli in Infants G. Dehaene-Lambertz 2000): early cerebral specialization and lateralization for auditory processing in 4-month-old infants was studied by recording high-density evoked potentials to acoustical and phonetic changes in a series of repeated stimuli (either tones or syllables). Mismatch responses to these stimuli exhibit a distinct topography suggesting that different neural networks within the temporal lobe are involved in the perception and representation of the different features of an auditory stimulus.
Deviance-Probability debate
The MMN in not only dependent on the different probability of the deviant stimulus, but also stimulus characteristic.
This is supported by Pakarinen et al. (2007) study, they used a multi-feature oddball paradigm to examine how the brain processes deviant auditory features like frequency, duration, and intensity in MMN responses. Their findings showed that the brain can independently detect frequency deviations and that MMN reflects the processing of multiple auditory features. This study helped disentangle the brain’s response to different auditory features, providing insight into how it processes complex auditory stimuli.
In the oddball paradigm, both conditional probability and adaptation influence MMN responses. The probability of deviant stimuli affects MMN amplitude, with rarer deviants eliciting stronger responses. Adaptation occurs when the brain’s response to repeated standard stimuli decreases, influencing MMN. To control for these effects, researchers manipulate stimulus frequency, intervals, and presentation timing, ensuring that MMN reflects novelty detection rather than habituation. Studies like Pakarinen et al. (2007) have shown how controlling these factors allows clearer interpretation of MMN as a marker of novelty.
MMN and complex tasks
The study on attentional monitoring during a complex driving simulation found that MMN responses reflect the brain’s ability to detect unexpected stimuli while driving. Increased cognitive load reduced MMN amplitudes, suggesting that when attention is overburdened, the brain struggles to process novel events. This highlights that limited attentional resources can impair driving performance and safety, especially under complex conditions.
As participants learn to drive safely, more attentional resources are available to process the deviant oddball stimuli, as shown by the increase in the amplitude of MMN in the second block of driving
POTENTIAL CLINICAL MEANING OF MMN?
The study on neurocognitive development in preterm infants highlights early differences in brain function and structure using electrophysiological, neuroimaging, and behavioral approaches. Findings show that preterm infants may have altered auditory processing, cognitive development, and brain connectivity, affecting language and executive functions. Early detection and intervention are crucial for improving outcomes.
Mismatch Negativity (MMN) is also a marker of auditory processing deficits in aging and various clinical conditions. MMN declines with age and is impaired in neurodegenerative, psychiatric, and developmental disorders, reflecting cognitive and sensory processing deficits. It serves as a non-invasive tool for early diagnosis and monitoring of brain dysfunction.
WHAT IS THE IMPACT OF EARLY EXPOSURE ENVIRONMENTAL IN THE PREMATURE (which reflects in MMN)?
In deRegnier et al. (2002), the study compared three groups of infants to examine the impact of early environmental exposure on Mismatch Negativity (MMN) responses and auditory development in preterm infants.
Group Differences:
1. Preterm NICU Infants (High-Risk Environment)
• Born very prematurely and spent extended time in the Neonatal Intensive Care Unit (NICU).
• Experienced high levels of noise and stress, with less exposure to natural maternal sounds.
• Showed weaker MMN responses, suggesting delayed auditory discrimination and possible neurodevelopmental risks.
2. Preterm Infants with More Natural Caregiving (Low-Risk Environment) • Also born prematurely but received more maternal interaction and less harsh NICU conditions. • Displayed stronger MMN responses than the high-risk NICU group, indicating better auditory processing. • This suggests that early auditory experiences play a role in neural development. 3. Full-Term Infants (Control Group) • Born at full term with typical postnatal sensory experiences. • Had the strongest MMN responses, reflecting normal auditory development. • Served as a baseline to compare the effects of premature birth and early environmental exposure.
Summary of Differences:
• High-risk NICU preterm infants had weaker MMN responses, likely due to excessive noise, stress, and limited maternal exposure.
• Low-risk preterm infants showed better MMN responses, suggesting that early caregiving environments help mitigate risks.
• Full-term infants had the strongest MMN responses, reinforcing the importance of a natural auditory environment for healthy brain development.
This study highlights how early sensory environments shape auditory processing in infancy, with potential long-term effects on neurodevelopment.
WHAT IS THE IMPACT OF EARLY EXPOSURE ENVIRONMENTAL IN THE PREMATURE (which reflects in MMN)? (Mento)
Mento & Bisiacchi (2012) investigated how Mismatch Negativity (MMN) responses differ between preterm and full-term infants, providing insights into early auditory processing and neurodevelopmental outcomes.
Key Findings:
1. Weaker MMN Responses in Preterm Infants
• Preterm infants exhibited reduced MMN amplitudes compared to full-term infants.
• This suggests immature auditory discrimination abilities, likely due to early birth and altered sensory experiences.
- Delayed Neural Maturation
• The latency of MMN responses was longer in preterm infants, indicating slower neural processing.
• This delay could reflect immature cortical networks and neurodevelopmental risks. - Early Predictors of Cognitive Development
• The study suggests that MMN amplitude and latency could serve as biomarkers for later language and cognitive development.
• Infants with weaker MMN responses might be at higher risk for developmental delays.
Mento & Bisiacchi (2012) found that preterm infants show weaker and delayed MMN responses compared to full-term infants, reflecting immature auditory processing. These findings highlight the potential of MMN as an early marker for neurodevelopmental outcomes in preterm babies.
What impact do early extra uterine experiences have on brain development and MMN?
Extra-uterine exposure has no effect “compensatory”. Intra-uterine development is more important. THE MMR (MISMATCH RESPONSE, SAME THAN MMN) IS SENSITIVE TO THE INTRA RATHER THAN EXTRA UTERINE TIME EXPOSURE.
ERP RESPONSES ARE GREATER IN THE RIGHT HEMISPHERE ONLY IN THOSE BORN AFTER 30 WEEKS OF GESTATION.
THE MOST ENVIRONMENTAL EXPOSURE IN <30 NON COMPENSATES FOR CEREBRAL IMMATURITY.
-Very premature newborns (<30 GWs) show a different cortical maturation (auditory areas) compared to less premature newborns (>30 GWs), in particular they do not show hemispheric lateralization of ERP responses
-Early extra-uterine exposure does not exert “compensatory” effects.
What’s N2-P3 morphology and latency?
negative deflections followed by positive deflection, latency 200-300 ms
What’s N2 scalp location?
fronto-central
Which type of stimuli elicit N2?
both auditory and visual
Which are the anatomical sources of N2?
anterior cingulate cortex, frontal areas (DLPFC)
What’s N2-P3 functional meaning?
USUALLY THE N2-P3 COMPLEX IS ASSOCIATED TO STIMULI INDUCING SURPRISE/SALIENCY/CONFLICT (N2) AND AUTOMATIC ATTENTIONAL RIALLOCATION (P3A)
Which types of tasks elicit the N2-P3?
CONFLICT TASKS, TASKS THAT REQUIRE TO PROCESS COMPLEX INFORMATION AND/OR OPERATE IN A “CONTROLLED” MANNER, OVERCOMING AUTOMATION (I.E., WITHDRAWING AN URGENT RESPONSE OR MANAGING INTERFERENCE)
- Antisaccade: Stop a reflexive eye movement to a brief cue and instead look in the opposite direction in time to identify a briefly appearing target stimulus before it is masked.
- Stop-signal: Stop a prepotent categorization response on rare trials during which a stop signal occurs after the trial starts.
- Stroop: Name font color, resolving conflict from more dominant word reading response.
- Flanker: Indicate the identity of central letter, resolving response interference from flanking letters that may have different (but not prepotent) response associations.
- Go/NoGo: A Go/No-Go task is a psychological test used to measure response inhibition and attention. In this task, participants are required to perform an action (usually a button press) when a “Go” stimulus is presented and to withhold the action when a “No-Go” stimulus appears. This task helps researchers assess how well individuals can control impulsive responses and monitor their attention, and it is often used in studies of executive function, cognitive control, and disorders characterized by impulsivity.
Go/NoGo task on obese patients: effect of N2-P3?
Tarantino et al. (Biological Psychology) investigated inhibitory control in obese patients using a Go/NoGo task and analyzed the associated ERP components—specifically, the N2 and P3 waves.
N2 Component:
- The N2, typically linked to conflict detection and early cognitive control, was found to be altered in obese patients. This suggests that these individuals may have difficulties with early detection of conflicting information or the need to inhibit a prepotent response.
P3 Component:
- The P3, associated with the evaluation and execution of response inhibition, also showed differences in obese patients. Changes in the P3 amplitude and/or latency point to potential impairments in the later stages of inhibitory processing.
Implications:
The altered N2 and P3 responses in obese patients indicate deficits in the neural mechanisms underlying inhibitory control. Such impairments may contribute to impulsivity and maladaptive behaviors, such as overeating, by affecting the ability to properly regulate responses to food-related or other stimuli. More pronounced NoGo-N2 revealed higher involvement of conflict monitoring. HIGHER N2 BUT LOWER P3 IN PATIENTS THAN CONTROLS DISSOCIATION BETWEEN CONFLICT DETECTION AND ATTENTIONAL RIALLOCATION
In summary, the study by Tarantino et al. provides evidence that obese patients exhibit distinct electrophysiological patterns (in the N2 and P3 ERP components) during a Go/NoGo task, reflecting potential impairments in conflict detection and response inhibition. These findings help to elucidate the neurocognitive mechanisms that may underlie impulsive behaviors associated with obesity.
What are the evindeces about modulation of inhibitory processes in emotional Go-NoGo task?
Threat stimuli typically elicit a psychophysiological response pattern supporting the organism’s preparation for active defence. Differently, blood stimuli prompt a distinctive autonomic response pattern and sustained processing, which do not call for clear-cut mobilisation for action. However, the contribution of motor disposition in these response patterns remains unclear. One way to address this issue is to investigate whether threat and blood stimuli differentially affect the active suppression of an ongoing motor activity. Thirty-two undergraduates were presented with threat, mutilation, pleasant, and neutral pictures in an emotional Go/NoGo task. The amplitudes of the NoGo-N2 and NoGo-P3 components of the event-related potentials were analysed as indices of conflict monitoring and inhibition of motor response, respectively. Reaction times to Go trials were significantly faster for threat than for mutilations. The NoGo-N2 was significantly larger to threat than to mutilations, whereas the NoGo-P3amplitude did not differ between the two conditions. These findings suggest that threat stimuli facilitated the execution of a prepotent response and enhanced conflict monitoring when action must be withheld. In contrast, blood stimuli did not either promote action in the Go trials or increase conflict in the NoGo condition, suggesting a response pattern compatible with defensive immobility.
What’s the P3 morphology and latency?
positive deflection, broad, latency 250 - 600 ms. Its latency increases in relation to the difficulty of the categorization.
What’s P3 scalp location?
centro-parietal
Which type of stimuli elicit P3?
both auditory and visual
Which are the anatomical sources of P3?
fronto-parietal areas
What’s P3(A-B) functional meaning?
WORKING MEMORY ENCODING/UPDATING, TARGET DETECTION/SELECTION. It is an ENDOGENOUS component in all respects because it is not influenced by the physical characteristics of the stimuli but only by the demands of the task
When does the P3 amplitude decrease?
The amplitude of the P3 decreases when the subject is engaged in a second task, therefore when the attentional resources are distributed, or when the cognitive load of the task increases.
What’s the difference between P3a and P3b?
The P3a and P3b components of event-related potentials (ERPs) represent distinct neurophysiological responses associated with distinct cognitive processes.
The P3a is typically observed in response to novel or unexpected stimuli and is linked to the automatic orienting of attention. It is usually evoked by rare items (like deviant oddball stimuli)
It tends to peak earlier than the P3b, usually around 250 to 280 milliseconds after stimulus onset.
The P3b, on the other hand, is associated with the processing of target or task-relevant stimuli in a more controlled and discriminative manner. It typically peaks later than the P3a, around 300 to 600 milliseconds after stimulus onset.
While both components are part of the broader P300 complex, their differential timing and functional significance highlight their roles in distinct aspects of cognitive processing, with the P3a reflecting attentional capture by salient stimuli and the P3b reflecting higher-level cognitive processes related to target detection and decision-making.
In a task where the target stimuli are rare and mixed with distractor stimuli with characteristics
similar to the target and also rare, two types of P3 emerge:
- an earlier latency component, with frontal distribution, the P3a
- a later and sustained component, with parietal distribution, P3b.
Both support target/non-target categorization processes, but the P3a is more linked to
attentional processes, while P3b is more linked to mnestic processes
What’s N400 morphology and latency?
negative deflection, broad, latency 350-500 ms
What’s N400 scalp location?
fronto-central
Which stimuli elicit N400?
both auditory and visual
Which are the anatomical sources of N400?
fronto-parietal areas
What’s the functional meaning of N400?
The N400 reflects the detection of semantic inconsistency/violation when listening or reading sentences. The greater the semantic distance between words, the wider its width.
N400 across development
The N400 component, which reflects the brain’s processing of semantic incongruities, shows developmental changes across these age groups. At 12 months, infants show little to no N400 response, while by 19 months, they exhibit a more developed N400 effect. In adults, the N400 is fully matured, demonstrating the complete development of semantic processing in lexical tasks. This progression reflects the gradual development of language and semantic memory as children grow.
N400 - race categorical perception and linguistic labels
The N400 component is key to understanding how language influences race categorical perception. When children are exposed to specific linguistic labels related to race, their neural processing of race-related stimuli (like faces) is modulated. The N400 shows that the brain responds more strongly to semantic incongruities (e.g., when a face doesn’t fit the expected racial category based on prior linguistic labeling), providing evidence that linguistic exposure during early childhood plays a crucial role in shaping the neural architecture that underlies race perception.
This study supports the idea that semantic networks—which include race-related categories—are influenced by language and can be measured by the N400 response, reflecting the developmental and linguistic influences on racial categorization.
• Block 1 (Familiar Labels): Likely minimal or no N400 response as face-label congruency supports typical processing.
• Block 2 (Incongruent Labels): Larger N400 response due to semantic violation, reflecting the brain’s sensitivity to mismatched racial categories. (For istance black face labeled as Asian)
• Block 3 (Neutral/Unlabeled Faces): A neutral or smaller N400 response, indicating that without race-related labels, the brain’s processing is less focused on racial categorization.
These differences reveal how linguistic labels modulate neural processing of race, with stronger N400 effects emerging when the brain encounters unexpected or incongruent race-related information. The study would use these blocks to assess how childhood exposure to race labels influences neural perception of racial categories across different contexts.
LANGUAGE «BUILDS UP» THE CATEGORIAL PERCEPTION OF FACES. HAVING ETHNIC LINGUISTIC LABELS HELPS TO CATEGORIZE FACES BY ACTIVATING CERTAIN BRAIN AREAs
WHEN DO ERROR-RELATED NEGATIVITY (ENR) AND ERROR POSITIVITY (PE) ARE GENERATED?
These components are generated when we make a mistake. Soon after error commission (50-100 ms) a negative deflection emerges (ERN) over fronto-central sites. Later on (200-400 ms) a positive deflection (Pe) emerged, which reflects error awareness. Its amplitude is maximal over more posterior sites
The averaging for ERN and PE is locked to…?
The 0 point represents an error commission (e.g., pressing of a wrong button), so the averaging is locked to response, NOT to a stimulus!
Contingent Negative Variation (CNV)
It is a slow ERP component, evoked during tasks where a target stimulus (imperative stimulus or probe) is always anticipated by a cue (warning stimuls) that allow the brain to prepare in advance. Preparation processes are reflected by negative potentials, developed over fronto-central sites. These potentials reflect non only motor preparation but also cognitive expectations.
Automatic temporal expectancy and CNV
The study “Automatic Temporal Expectancy: A High-Density Event-Related Potential Study” investigates how the brain prepares for future events through temporal expectancy, which is reflected in the Contingent Negative Variation (CNV). The CNV occurs between an anticipatory cue and an expected target stimulus, showing the brain’s cognitive processes related to attention and preparation.
The research uses high-density EEG to capture detailed brain activity and examines whether temporal expectancy operates automatically, without conscious awareness, based on environmental cues. The study likely finds that the CNV increases in amplitude as the time of the expected stimulus approaches, showing that the brain adjusts its preparation and expectancy. These findings provide insights into how the brain anticipates events and prepares for them, which has clinical relevance for conditions involving attention and response preparation.
THE ONTOGENETIC ORIGIN OF THE CNV
A study on 9-month-old infants examines the development of automatic temporal expectancy through the Contingent Negative Variation (CNV), which reflects the brain’s preparation for upcoming events. Findings show that infants display an early CNV response, indicating they can automatically anticipate when a stimulus will occur. The CNV is observed in frontal and central brain regions, suggesting these areas are involved in early cognitive preparation. This study highlights that predictive processing and temporal expectancy begin to emerge in infancy, marking the early development of anticipatory mechanisms in the brain.
Another study explores how children generate and update expectations over time, using high-density EEG to examine the Contingent Negative Variation (CNV). The findings show spatiotemporally dissociable CNV responses: early CNV components in frontal regions reflect the generation of expectations, while later components in posterior regions are linked to updating expectations. The study also shows that older children have stronger and more distinct CNV responses, suggesting that the ability to update expectations improves with age. This provides insights into how children’s brains process temporal expectancy over development.
Study of CNV with Oddball paradigm
A passive temporal oddball task requiring neither time-based motor response nor explicit decision was specifically designed and delivered to participants during high-density, event-related potentials recording. Participants were presented with pairs of audiovisual stimuli (S1 and S2) interspersed with an Inter-Stimulus Interval (ISI) that was manipulated. Participants automatically and progressively created an implicit temporal expectation of S2 onset, reflected by the time course of the Contingent Negative Variation response, which always peaked in correspondence to the point of S2 maximum expectation and afterwards inverted in polarity towards the baseline.
According to such a rule, the maximum probability of occurrence of a specific event (i.e., the S2 onset) was at a precise time point, here defined as S2 Maximum Expectation Time-Point or S2 METP. The fact that CNV slope inversion for deviant ISis occurred at S2 METP suggests that participants implicity learned the temporal rule, and that S2 onset was maximally expected at the same time point, regardless of the actual duration of the ongoing ISI. This hypothesis was further confirmed by the presence of a significant time-on-task effect on the CNV morphological pattern, as it became more negative and steeper block-by-block.
Bereitschaftspotential (BP) or Readiness Potential (RP) functional meaning?
The RP is evoked by motor preparation processes, therefore it is observed in advance of the execution of a movement (pressing a button with the finger) and reflects the functioning of cortical areas linked to the movement.
It is a negative slow wave related to preparation of a movement, with max amplitude over central sites (early bilateral, later controlateral)
When does the RP amplitude increase?
Its amplitude increases as the moment in which the movement is performed approaches. It reaches maximum amplitudes immediately before the movement (time 0 of the potential).
Difference between the early and later part of RP?
The first part of the component (early) has a central-frontal distribution on the midline and reflects the activity of premotor areas and SMA
The second (late, the one immediately before the movement) instead reflects the activity of primary motor areas, and is therefore lateralized (lateralized readiness potential, LRP)
Which areas are implicated in RP?
SMA and primary motor cortex
What is the difference between CNV and RP?
Compared to the CNV, RP necessarily precedes an action, CNV reflect just the preparation
What’s a Spontaneous EEG?
Spontaneous EEG is characterized by neural oscillations at certain frequencies, which are fluctuations in the excitability of populations of neurons
EEG Rythmic activity
The EEG signal, like any oscillatory signal, can be divided into frequency bands and represented as the sum of many sine waves
What’s the usefulness of Fourier transform?
Through Fourier analysis, it is possible to quantify the amplitude (spectral power) of the oscillations for each constituent frequency of the signal
Time-frequency analysis: how does it works?
Time-frequency analysis allows to quantify spectral activity variations over time associated with a stimulus.
From the preprocessed and epoched EEG, the signal from all the epochs and all the channels is analyzed through either:
- Sparse Fast Fourier Transform (SFFT)
- Wavelet transform → the most common
In output we will obtain a perturbation map in which:
- in the X axis is represented the time
- in the Y axis is represented the frequency
- the color indicates the increase/decrease in power spectrum
What are Event-related synchronization/desynchronization (ERS/ERD)?
short-lasting and localized amplitude increase/decrease of rhythmic activity, time-locked to a stimulus
ERS = power increase
ERD = power decrease
What does time-frequency analysis tell us?
It tells us how the power spectrum of each frequency band present in the signal vary in time
Time-frequency analysis: how to perform it?
EEGLab, FieldTrip, Brainstorm, etc…
The four domains
1) TIME (ERPs): TO DEPICT THE TIMING OF MENTAL PROCESSES FROM EARLY (SENSORY-PERCEPTUAL) TO LATE (COGNITIVE, DECISION MAKING, STIMULUS EVALUATION) COMPONENTS
2) SPACE (BRAIN SOURCE ANALYSIS): TO IDENTIFY THE NEURAL GENERATORS OF SCALP RECORDED EEG/ERP ACTIVITY (MANDATORY FOR ADVANCED CONNECTIVITY INVESTIGATIONS)
3) FREQUENCY (POWER SPECTRUM): TO DECOMPOSE THE EEG SIGNAL INTO THE MAIN CONSTITUENT BANDS AND TO QUANTIFY THEIR ABSOLUTE OR RELATIVE POWER
4) TIME-FREQUENCY (ERS/D): TO IDENTIFY HOW THE SPECTRAL PROPERTIES OF THE SCALP/SOURCE SIGNAL CHANGE OVER TIME IN RELATION TO A GIVEN EVENT
THESE DOMAINS ARE NOT MUTUALLY EXCLUSIVE, RATHER, THEY ALLOW ANSWERING
DIFFERENT/COMPLEMENTARY QUESTIONS ABOUT HUMAN BRAIN-MIND INTERACTION
