scholarly journals Behavioural and electrophysiological correlates of lightness contrast and assimilation

Author(s):  
Stephanie L. Acaster ◽  
Naira A. Taroyan ◽  
Alessandro Soranzo ◽  
John G. Reidy

AbstractLightness contrast and assimilation are opposite phenomena: in contrast grey targets appear darker when bordering bright rather than dark surfaces; in assimilation grey targets appear lighter when bordering bright rather than dark surfaces. The underlying neurophysiological mechanisms of these phenomena are not known. The aim of this study was to investigate the relationship between contrast and assimilation, and the timing and levels of perceptual and cognitive processing using combined behavioural and electrophysiological methods. Thirty undergraduate students (23 female, age range 18–48 years) participated in a forced-choice (grey target is lighter/darker than a comparison square) task, using stimuli designed such that the inducers were in two configurations (small and large) and two shades (white and black). The behavioural data (more consistent and faster responses) corroborated previous findings of stronger contrast effects with white inducers and stronger assimilation effects with black inducers. According to the Event-Related Potentials (ERP) results the mean amplitude was larger in conditions with less consistent and slower behavioural responses. Thus, with contrast responses P1 amplitude was larger with black than white inducers, and N1 amplitude was larger to assimilation than contrast when the configuration of the stimulus was held constant. These results suggest contrast may occur as early as P1 (~ 110 ms) and assimilation may occur later in N2 (~ 220 ms), whereas in some conditions, differences in ERPs associated with contrast vs assimilation may happen as early as in N1 (~ 170 m), in occipital and parietal cortical sites.

2002 ◽  
Vol 16 (1) ◽  
pp. 56-66 ◽  
Author(s):  
Marc Antony Serfaty ◽  
Robert Bothwell ◽  
Richard Marsh ◽  
Heather Ashton ◽  
Robert Blizard ◽  
...  

Abstract Background: Depressed subjects and euthymic controls demonstrate differences in cognitive processing and brain electrophysiology. Contingent negative variation (CNV) and postimperative negative variation (PINV) was used to investigate the relationship between cognition and cortical event related potentials. Method: Electrophysiological responses and memory of different personality trait adjectives were measured in 15 patients with major depressive disorder and 15 euthymic controls. The words were presented acoustically to elicit event-related potentials. The subjects were asked to indicate whether the words were self-referential. Responses were measured separately for self referential and non-self referential, neutral, positively and negatively toned words. Results: Depressed patients chose more negative and fewer positive words as self-referential, though no significant differences between groups in CNV magnitude for any of the words were found. Persistence of cortical negativity after the motor response (PINV) was significantly (P < 0.02) greater in patients for all non-self-referential words, and reaction times were significantly longer for all words. Recall of positive words and recognition of all words were significantly impaired in patients. Conclusions: Both electrophysiological measures and memory tests found differences between depressed patients and controls, suggesting that the PINV wave may be a useful electrophysiological probe to clarify the neurophysiological basis of cognitive processes.


2006 ◽  
Vol 20 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Bruce D. Dick ◽  
John F. Connolly ◽  
Michael E. Houlihan ◽  
Patrick J. McGrath ◽  
G. Allen Finley ◽  
...  

Abstract: Previous research has found that pain can exert a disruptive effect on cognitive processing. This experiment was conducted to extend previous research with participants with chronic pain. This report examines pain's effects on early processing of auditory stimulus differences using the Mismatch Negativity (MMN) in healthy participants while they experienced experimentally induced pain. Event-related potentials (ERPs) were recorded using target and standard tones whose pitch differences were easy- or difficult-to-detect in conditions where participants attended to (active attention) or ignored (passive attention) the stimuli. Both attention manipulations were conducted in no pain and pain conditions. Experimentally induced ischemic pain did not disrupt the MMN. However, MMN amplitudes were larger to difficult-to-detect deviant tones during painful stimulation when they were attended than when they were ignored. Also, MMN amplitudes were larger to the difficult- than to the easy-to-detect tones in the active attention condition regardless of pain condition. It appears that rather than exerting a disruptive effect, the presence of experimentally induced pain enhanced early processing of small stimulus differences in these healthy participants.


2021 ◽  
Vol 11 (7) ◽  
pp. 835
Author(s):  
Alexander Rokos ◽  
Richard Mah ◽  
Rober Boshra ◽  
Amabilis Harrison ◽  
Tsee Leng Choy ◽  
...  

A consistent limitation when designing event-related potential paradigms and interpreting results is a lack of consideration of the multivariate factors that affect their elicitation and detection in behaviorally unresponsive individuals. This paper provides a retrospective commentary on three factors that influence the presence and morphology of long-latency event-related potentials—the P3b and N400. We analyze event-related potentials derived from electroencephalographic (EEG) data collected from small groups of healthy youth and healthy elderly to illustrate the effect of paradigm strength and subject age; we analyze ERPs collected from an individual with severe traumatic brain injury to illustrate the effect of stimulus presentation speed. Based on these critical factors, we support that: (1) the strongest paradigms should be used to elicit event-related potentials in unresponsive populations; (2) interpretation of event-related potential results should account for participant age; and (3) speed of stimulus presentation should be slower in unresponsive individuals. The application of these practices when eliciting and recording event-related potentials in unresponsive individuals will help to minimize result interpretation ambiguity, increase confidence in conclusions, and advance the understanding of the relationship between long-latency event-related potentials and states of consciousness.


2002 ◽  
Vol 13 (01) ◽  
pp. 001-013 ◽  
Author(s):  
James Jerger ◽  
Rebecca Estes

We studied auditory evoked responses to the apparent movement of a burst of noise in the horizontal plane. Event-related potentials (ERPs) were measured in three groups of participants: children in the age range from 9 to 12 years, young adults in the age range from 18 to 34 years, and seniors in the age range from 65 to 80 years. The topographic distribution of grand-averaged ERP activity was substantially greater over the right hemisphere in children and seniors but slightly greater over the left hemisphere in young adults. This finding may be related to age-related differences in the extent to which judgments of sound movement are based on displacement versus velocity information.


2008 ◽  
Vol 20 (10) ◽  
pp. 1753-1761 ◽  
Author(s):  
Vera Ferrari ◽  
Maurizio Codispoti ◽  
Rossella Cardinale ◽  
Margaret M. Bradley

Visual attention can be voluntarily oriented to detect target stimuli in order to facilitate goal-directed behaviors. Other visual stimuli capture attention because of motivational significance. The aim of the present study was to investigate the relationship between directed and motivated attention using event-related potentials. Affectively engaging pictures were presented either as target stimuli or as nontargets in a categorization task. Results indicated that both task relevance and emotional significance modulated the late positive potential (LPP) over centro-parietal sensors. Effects of directed and motivated attention on the LPP were additive, with the largest centro-parietal positivity found for emotional pictures that were targets of directed attention, and the least for neutral pictures that were nontargets. Taken together, the data provide new information regarding the relationship between motivated and directed attention, and suggest that the LPP reflects the operation of attentional neural circuits that are utilized by both top-down and bottom-up processes.


2005 ◽  
Vol 100 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Michela Balconi

The present research compared the semantic information processing of linguistic stimuli with semantic elaboration of nonlinguistic facial stimuli. To explore brain potentials (ERPs, event-related potentials) related to decoding facial expressions and the effect of semantic valence of the stimulus, we analyzed data for 20 normal subjects ( M age = 23.6 yr., SD = 0.2). Faces with three basic emotional expressions (fear, happiness, and sadness from the 1976 Ekman and Friesen database), with three semantically anomalous expressions (with respect to their emotional content), and the neutral stimuli (face without an emotional content) were presented in a random order. Differences in peak amplitude of ERP were observed later for anomalous expressions compared with congruous expressions. In fact, the results demonstrated that the emotional anomalous faces elicited a higher negative peak at about 360 msec., distributed mainly over the posterior sites. The observed electrophysiological activity may represent specific cognitive processing underlying the comprehension of facial expressions in detection of semantic anomaly. The evidence is in favour of comparability of this negative deflection with the N400 ERP effect elicited by linguistic anomalies.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yutong Liu ◽  
Huini Peng ◽  
Jianhui Wu ◽  
Hongxia Duan

Background: Individuals exposed to childhood maltreatment present with a deficiency in emotional processing in later life. Most studies have focused mainly on childhood physical or sexual abuse; however, childhood emotional abuse, a core issue underlying different forms of childhood maltreatment, has received relatively little attention. The current study explored whether childhood emotional abuse is related to the impaired processing of emotional facial expressions in healthy young men.Methods: The emotional facial processing was investigated in a classical gender discrimination task while the event-related potentials (ERPs) data were collected. Childhood emotional abuse was assessed by a Childhood Trauma Questionnaire (CTQ) among 60 healthy young men. The relationship between the score of emotional abuse and the behavioral and the ERP index of emotional facial expression (angry, disgust, and happy) were explored.Results: Participants with a higher score of childhood emotional abuse responded faster on the behavioral level and had a smaller P2 amplitude on the neural level when processing disgust faces compared to neutral faces.Discussion: Individuals with a higher level of childhood emotional abuse may quickly identify negative faces with less cognitive resources consumed, suggesting altered processing of emotional facial expressions in young men with a higher level of childhood emotional abuse.


2020 ◽  
Author(s):  
Mareike J. Hülsemann ◽  
Björn Rasch

AbstractOur thoughts, plans and intentions can influence physiological sleep, but the underlying mechanisms are unknown. According to the theoretical framework of “embodied cognition”, the semantic content of cognitive processes is represented by multimodal networks in the brain which also include body-related functions. Such multimodal representation could offer a mechanism which explains mutual influences between cognition and sleep. In the current study we tested whether sleep-related words are represented in multimodal networks by examining the effect of congruent vs. incongruent body positions on word processing during wakefulness.We experimentally manipulated the body position of 66 subjects (50 females, 16 males, 19-40 years old) between standing upright and lying down. Sleep- and activity-related words were presented around the individual speech recognition threshold to increase task difficulty. Our results show that word processing is facilitated in congruent body positions (sleep words: lying down and activity words: standing upright) compared with incongruent body positions, as indicated by a reduced N400 of the event-related potential (ERP) in the congruent condition with the lowest volume. In addition, early sensory components of the ERP (N180 and P280) were enhanced, suggesting that words were also acoustically better understood when the body position was congruent with the semantic meaning of the word. However, the difference in ERPs did not translate to differences on a behavioural level.Our results support the prediction of embodied processing of sleep- and activity-related words. Body position potentially induces a pre-activation of multimodal networks, thereby enhancing the access to the semantic concepts of words related to current the body position. The mutual link between semantic meaning and body-related function could be a key element in explaining influences of cognitive processing on sleep.


2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
C. Silveira ◽  
F. Santos ◽  
F. Barbosa ◽  
A. Pedro ◽  
A. Palha ◽  
...  

Background/Objective:Despite the well established genetic basis of schizophrenia, the relationship between genes and the disorder itself is still elusive. Individual endophenotypes, which reduce the complexity of genetic analyses, allow statistical approaches with quantitative trait methodologies. P200 abnormalities of event-related potentials have been reported in schizophrenia with conflicting results. The present study aims to characterize the P200 in first-episode patients and to compare it with that of first-degree relatives and controls.Methods:ERPs were recorded at 19 sites with an auditory oddball for 21 first-episode patients with schizophrenia (mean age=25.14; SD=6.20), 41 of their first degree relatives (mean age=47.65; SD=15.53) and 19 healthy controls (mean age=26.32; SD=7.16). Potentials were averaged for frequent stimuli and P200 amplitude and latency measures were obtained.Results:Analysis of midline electrodes revealed significant group effects for P200 peak amplitudes (F(2, 78)=3.315, p=.042), but not for peak latencies. Post-hoc analyses revealed that patients with schizophrenia present significantly lower P200 amplitudes (M=2.466; SD=1.564) than controls (M=5.037; SD=2.500) at Pz (T(38)=3.851, p=.003). No other significant differences were found.Conclusion:The results obtained do not straight-forwardly support the P200 peak amplitude nor peak latency as an endophenotype of schizophrenia. However, the trends of our results may suggest that the P200 amplitudes of relatives may present intermediate values between healthy controls (with higher amplitudes) and patients (with lower amplitudes). Further statistical analyses will be required in order to disentangle the effects of possible confounding variables.


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