Ms Time Window Research Articles

An investigation of listener envelopment utilizing a spherical microphone array and third-order ambisonics reproduction.

Listener envelopment (LEV), the sense of being surrounded by the sound field, is a perception that has been found to be related to the overall impression of a concert hall. The purpose of this study was to investigate the relationship between the perception of LEV and the direction and arrival time of energy from spatial room impulse responses (IRs). IRs were obtained in a 2000-seat concert hall using a 32-channel spherical microphone array and analyzed using a third-order plane wave decomposition. Additionally, the IRs were convolved with anechoic music and processed for third-order Ambisonic reproductions and presented to subjects over a 30-loudspeaker array. Instances were found in which the energy in the late sound field did not correlate with LEV ratings as well as energy in a 70-100 ms time window. Follow-up listening tests were conducted with hybrid IRs containing portions of an enveloping IR and an unenveloping IR with crossover times ranging from 40 to 140 ms. Additional hybrid IRs were studied wherein portions of the spatial IRs were collapsed into all frontal energy with crossover times ranging from 40 to 120 ms. The tests confirmed that much of the important LEV information exists in the early portion of these IRs.

Neurobiological basis of feeling of knowing in episodic memory.

Feeling of knowing (FOK) is a metacognitive process which allows individuals to predict the likelihood that they will be able to remember, in the future, information which they currently cannot recall. Although FOK provides evidence for the mechanisms of metacognitive systems, the neurobiological basis of FOK is still unclear. We investigated the neural correlates of FOK induced by an episodic memory task in 77 younger adult participants. Data were gathered using event-related potentials (ERPs). ERP components during high, low, extremely high and extremely low FOK judgments were analyzed. Stimulus-locked ERP analyses indicated that FOK judgment was associated with greater positivity for P200 component at frontal, central, and parietal electrode zones and greater negativity for the N200 component at parietal electrode zones. Furthermore, results revealed that amplitude of the ERP components for FOK judgments were affected by the level of FOK judgment. Results suggest that ERP components of FOK judgment observed within a 200ms time window support the perceptual fluency-based model.

Narrowly Confined and Glomerulus-Specific Onset Latencies of Odor-Evoked Calcium Transients in the Juxtaglomerular Cells of the Mouse Main Olfactory Bulb.

Odor information is transmitted from olfactory sensory neurons to principal neurons at the glomeruli of the olfactory bulb. The intraglomerular neuronal circuit also includes hundreds of interneurons referred to as juxtaglomerular (JG) cells. Stimulus selectivity is well correlated among many JG cells that are associated with the same glomerulus, consistent with their highly homogeneous sensory inputs. However, much less is known about the temporal aspects of their activity, including the temporal coordination of their odor-evoked responses. As many JG cells within a glomerular module respond to the same stimulus, the extent to which their activity is temporally aligned will affect the temporal profile of their population inhibitory inputs. Using random-access high-speed two-photon microscopy, we recorded the odor-evoked calcium transients of mouse JG cells and compared the onset latency and rise time among neurons putatively associated with the same and different glomeruli. Whereas the overall onset latencies of odor-evoked transients were distributed across a ∼150 ms time window, those from cells putatively associated with the same glomerulus were confined to a much narrower window of several tens of milliseconds. This result suggests that onset latency primarily depends on the associated glomerulus. We also observed glomerular specificity in the rise time. The glomerulus-specific temporal pattern of odor-evoked activity implies that the temporal patterns of inputs from the intraglomerular circuit are unique to individual glomerulus–odor pairs, which may contribute to efficient shaping of the temporal pattern of activity in the principal neurons.

Spontaneous pre-stimulus oscillatory activity shapes the way we look: A concurrent imaging and eye-movement study.

Previous behavioural studies have accrued evidence that response time plays a critical role in determining whether selection is influenced by stimulus saliency or target template. In the present work, we investigated to what extent the variations in timing and consequent oculomotor controls are influenced by spontaneous variations in pre-stimulus alpha oscillations. We recorded simultaneously brain activity using magnetoencephalography (MEG) and eye movements while participants performed a visual search task. Our results show that slower saccadic reaction times were predicted by an overall stronger alpha power in the 500ms time window preceding the stimulus onset, while weaker alpha power was a signature of faster responses. When looking separately at performance for fast and slow responses, we found evidence for two specific sources of alpha activity predicting correct versus incorrect responses. When saccades were quickly elicited, errors were predicted by stronger alpha activity in posterior areas, comprising the angular gyrus in the temporal-parietal junction (TPJ) and possibly the lateral intraparietal area (LIP). Instead, when participants were slower in responding, an increase of alpha power in frontal eye fields (FEF), supplementary eye fields (SEF) and dorsolateral pre-frontal cortex (DLPFC) predicted erroneous saccades. In other words, oculomotor accuracy in fast responses was predicted by alpha power differences in more posterior areas, while the accuracy in slow responses was predicted by alpha power differences in frontal areas, in line with the idea that these areas may be differentially related to stimulus-driven and goal-driven control of selection.

Hunger enhances automatic processing of food and non-food stimuli: A visual mismatch negativity study

Automatic detection of important and unexpected stimuli in the visual environment is crucial for survival. We sought to explore whether visual food stimuli are detected already in the pre-attentive stimulus processing phase, and whether hunger enhances such automatic detection. To attain these goals, we adapted an electroencephalography paradigm - visual mismatch negativity (vMMN). vMMN is a useful paradigm to study the processing of salient emotional stimuli which has not yet been applied in the context of eating behaviours. In our study, 18 right-handed women (25.2 ± 7.4 years) underwent two experimental sessions: hunger and fed conditions. Participants had to focus on a 2-back working memory task in the center of the computer screen, while stimuli depicting high fat savoury (HFSA) and high fat sweet (HFSW) foods were presented as deviants in a stream of neutral standard stimuli in the four corners of the screen. Automatic detection of foods was observed within 80–360 ms after stimulus onset, although some foods were better detected than the others. In HFSA, hunger enhanced the processing of all deviant stimuli in the early (100–160 ms) and mid-latency (160–220 ms) time windows. As the modulating effect of hunger was not food-specific, hunger may enhance automatic detection of changes in the visual environment, regardless of the type of input. Nevertheless, hamburger in HFSA was better detected than other stimuli, indicated by larger peak amplitudes, which supports the food-specificity of hunger modulation. In HFSW, the modulating effect of hunger was not observed, possibly due to suboptimally chosen stimuli within this block. In conclusion, we believe that after careful stimulus selection vMMN has a great potential to be a reliable measure of early food-cue processing.

Temporal expectations modulate face image repetition suppression of early stimulus evoked event-related potentials

Repeated exposure to a stimulus leads to reduced responses of stimulus-selective sensory neurons, an effect known as repetition suppression or stimulus-specific adaptation. Several influential models have been proposed to explain repetition suppression within hierarchically-organised sensory systems, with each specifying different mechanisms underlying repetition effects. We manipulated temporal expectations within a face repetition experiment to test a critical prediction of the predictive coding model of repetition suppression: that repetition effects will be larger following stimuli that appear at expected times compared to stimuli that appear at unexpected times. We recorded event-related potentials from 18 participants and mapped the spatiotemporal progression of repetition effects using mass univariate analyses. We then assessed whether the magnitudes of observed face image repetition effects were influenced by temporal expectations. In each trial participants saw an adapter face, followed by a 500 ms or 1000 ms interstimulus interval (ISI), and then a test face, which was the same or a different face identity to the adapter. Participants’ expectations for whether the test face would appear after a 500 ms ISI were cued by the sex of the adapter face. Our analyses revealed multiple repetition effects with distinct scalp topographies, extending until at least 800 ms from stimulus onset. An early (158–203 ms) repetition effect was larger for stimuli following surprising, rather than expected, 500 ms ISI durations, contrary to the model predictions of the predictive coding model of repetition suppression. During this time window temporal expectation effects were larger for alternating, compared to repeated, test stimuli. Statistically significant temporal expectation by stimulus repetition interactions were not found for later (230–609 ms) time windows. Our results provide further evidence that repetition suppression can reduce neural effects of expectation and surprise, indicating that there are multiple interactive mechanisms supporting sensory predictions within the visual hierarchy.

Neural Correlates of Conscious Motion Perception.

The nature of the proper neural signature of conscious perception remains a topic of active debate. Theoretical support from integrative theories of consciousness is consistent with such signature being P3b, one of the main candidates in the literature. Recent work has also put forward a mid-latency and more localized component, the Visual Awareness Negativity (VAN), as a proper Neural Correlate of Consciousness (NCC). Early local components like P1 have also been proposed. However, experiments exploring visual NCCs are conducted almost exclusively using static images as the content to be consciously perceived, favoring ventral stream processing, therefore limiting the scope of the NCCs that have been identified. Here we explored the visual NCCs isolating local motion, a dorsally processed feature, as the primary feature being consciously perceived. Physical equality between Seen and Unseen conditions in addition to a minimal contrast difference between target and no-target displays was employed. In agreement with previous literature, we found a P3b with a wide centro-parietal distribution that strongly correlated with the detection of the stimuli. P3b magnitude was larger for Seen vs. Unseen conditions, a result that was consistently observed at the single subject level. In contrast, we were unable to detect VAN in our data, regardless of whether the subject perceived or not the stimuli. In the 200–300 ms time window we found a N2pc component, consistent with the high attentional demands of our task. Early components like P1 were not observed in our data, in agreement with their proposed role in the processing of visual features, but not as proper NCCs. Our results extend the role of P3b as a content independent NCC to conscious visual motion perception.

The processing of animacy in noun-classifier combinations in reading Korean: An ERP study

A key issue in the area of language processing is the mechanism underlying the processing of animacy information during sentence comprehension. In this ERP study, we investigated the temporal dynamics of animacy processing in Korean noun-classifier combinations that do not involve verb-noun thematic processing. We manipulated semantic and animacy relationships between nouns and their following classifiers, and there were three conditions in our experiment: (a) correct, (b) semantic mismatch, or (c) animacy mismatch. The results showed that both noun-classifier mismatch conditions evoked a biphasic N400-P600 effect, but there was no P600 difference between the two mismatch conditions. However, further analyses indicated that the animacy mismatch condition evoked a less negative-going waveform than the semantic mismatch condition in the 400–500 ms time window. Our findings suggest that the brain processes animacy information differently from other semantic features in noun-classifier combinations in Korean, and additional animacy mismatch blocked further fine-grained semantic processing. The ERP evidence also suggests that the role of animacy in sentence comprehension varies according to language type and sentence structure. Whether animacy participates in the construction of verb-noun thematic relationships in sentences may be an important factor that influences the neural patterns of animacy processing in language comprehension.

How Dutch and Turkish-Dutch readers process morphologically complex words: An ERP study

Abstract To examine time-course differences between regularly and irregularly inflected, and productively and non-productively derived words, native Dutch speakers and Turkish-Dutch early bilinguals performed a visual lexical decision task combined with electroencephalography (EEG) recordings. Target items were presented in two types of nonword contexts to examine the effects of stimulus list composition and language background. We found similar negative brain responses for regularly and irregularly inflected words, and for productively and non-productively derived words, in the 200–350 ms time window for both participant groups. In the 350–500 ms time window, most negative brain responses were observed for the irregularly inflected verbs. We suggest that the negativities found in the 200–350 ms time window reflect early, form-based processing of complex words. In the 350–500 ms time window, this processing is affected by a discrepancy between orthography and morphology. Different results for the Dutch and Turkish-Dutch speakers in the nonword contexts show that, due to their language background, decomposition is more automatized in Turkish-Dutch speakers. Their processing strategy is thus less affected by the manipulation of stimulus list composition. In contrast, decomposition in our Dutch speakers is less automatized and thus more sensitive to the structure of nonwords.

S86. A framework for state-dependent TMS: Targeting the phase of cortical oscillations based on online EEG analysis

Introduction In recent years, there has been an increasing interest of using concurrent EEG-TMS to perform state informed brain stimulation to decrease the trial by trial variability. This is methodologically challenging because it requires real-time acquisition and fast analysis of EEG data. We present a framework for online analysis of EEG to enable state-informed TMS, more specifically, to trigger TMS pulses based on the phase of endogenous brain oscillations. The framework is based on open source software and written in Python and doesn’t require a specialized real-time computer. Methods We consider EEG data sampled at 5 kHz across 63-channels using a NeurOne EEG amplifier. The framework ensures minimal latency while circumventing issues of dropped samples by an efficient asynchronous analysis loop running in a separate process. In the current setting the analysis loop determines the phase of the pericentral μ -oscillation using the following steps: (1) Acquire a 500 ms data window. (2) EEG source projection (subject specific head model). (3) Linear detrending. (4) Phase estimation (continuous Morlet Wavelet transform). (5) Project phase estimate to the end of window. (6) Generate trigger if criteria for stimulation are met. Since a TMS pulse will subsequently contaminate the EEG signal with a large artifact, TMS is only performed for half of the estimated triggers, leaving the remaining for determining the performance. For phase estimation the Morlet wavelet was chosen due to its ability to handle non-stationary data. We targeted four phases (0°, 90°, 180° and 270°) in 15 subjects in a frequency band of 4 Hz centered on the subject μ -frequency. For each subject, we performed 60 stimulations for each phase. Results We were able to estimate the pericentral μ -phase with short latency. The analysis loop was updated with an average rate of more than 1500 Hz (Intel i7-4770 CPU). Therefore, the processing latency was negligible compared to the ∼ 3 ms latency of EEG data from the amplifier. To determine the performance, we analyzed the non-stimulated triggers using a centered 500 ms time window. The intended phase was hit with a mean absolute error of 48.6° across all subjects. We mainly attribute this variability to the fact that pericentral μ -power had often diminished at the intended stimulation time complicating estimation of the phase. Conclusion We present a framework capable of targeting the individual phase of the pericentral μ -rhythm with an acceptable accuracy using standard computer hardware. In practice, quite long windows are needed to stabilize frequency and amplitude estimation, and while an instantaneous phase estimate is produced by projecting to the end of the window, it is difficult to ensure that the oscillation is not diminished at the stimulation time. The presented framework readily generalizes to estimation of other states estimated from EEG data and other stimulation settings. Acknowledgements: Funded by the Novo Nordisk Foundation Interdisciplinary Synergy Program 2014 “BASICS”; NNF14OC0011413.

Racial bias in empathy: Do we process dark- and fair-colored hands in pain differently? An EEG study

The aim of this study was to identify racial bias influences on empathic processing from early stimulus encoding, over categorization until late motor processing stages by comparing brain responses (electroencephalogram) to pictures of fair- and dark-colored hands in painful or neutral daily-life situations. Participants performed a pain judgment task and a skin color judgment task. Event-related brain potentials (ERPs) substantiated former findings of automatic empathic influences on stimulus encoding, reflected by the early posterior negativity (EPN), and late controlled influences on the stimulus categorization, as reflected by the late posterior positivity (P3b). Concerning the racial bias in empathy (RBE) effect, more positive amplitudes in the 280–340 ms time window over frontocentral electrodes in the painful than the neutral condition for fair- but not dark-colored hands speak for an early influence of racial bias. This was further supported by correlations with empathic concern scores for fair- but not dark-colored stimuli. Additionally, P3b amplitude differences between fair- and dark-colored hands to painful stimuli increased with the implicit racial attitude of participants, suggesting that the categorization stage is not completely immune to racial bias. Regarding the motor processing stages, power change values in the upper beta-band (19–30 Hz) revealed for painful compared to neutral stimuli larger facilitation of sensorimotor activity before the response and larger inhibition after the response, independent of skin color. In conclusion, present findings speak for an influence of the RBE on early perceptual encoding but also on the late categorization stage that depends on the participant's implicit attitude towards racial outgroups.

Probing the Timing Recruitment of Broca’s Area in Speech Production for Mandarin Chinese: A TMS Study

Although Broca’s area is widely recognized to play an important role in speech production, neuroscientists still debate on its timing recruitment across different languages. In order to investigate the precise time course of phonological encoding for Mandarin Chinese, we applied real triple-pulse transcranial magnetic stimulation (tpTMS) and sham tpTMS within Broca’s area at five different time windows respectively (150 ms, 225 ms, 300 ms, 400 ms and 500 ms) in picture naming task in Mandarin Chinese. To exclude unspecific TMS effects and to make sure that the effects observed in the study were really due to stimulation at Broca’s area, we also conducted a control experiment by a different group of subjects. Significant increases in reaction times (RTs) were observed when real TMS stimulation at Broca’s area was applied at 225 ms, 300 ms and 400 ms time windows with a peak at 225 ms, compared with sham TMS stimulation at other time windows. Our findings support the hypothesis that the phonological encoding in speech production for Chinese language may approximately start from 200 ms and end around 400 ms post target onset, a little earlier than that from 355 ms to 455 ms for Indo-European languages.

The two processes underlying the testing effect– Evidence from Event-Related Potentials (ERPs)

Theoretical explanations of the testing effect (why people learn better from a test than a re-study) have largely focused on either the benefit of attempting to retrieve the answer or on the benefit of re-encoding the queried information after a successful retrieval. While a less parsimonious account, prior neuroimaging evidence has led us to postulate that both of these processes contribute to the benefit of testing over re-study. To provide further empirical support for our position, we recorded ERPs while subjects attempted to recall the second word of a pair when cued with the first. These ERPs were analyzed based on the current response accuracy and as a function of accuracy on the subsequent test, yielding three groups: the first and second tests were correct, the first was correct and the second was not, both were incorrect. Mean amplitude waveforms during the first test showed different patterns depending on the outcome patterns: Between 400 and 700 ms the amplitudes were most positive when both tests were correct and least positive when both were incorrect; mean amplitudes between 700 and 1000 ms only differed as a function of subsequent memory. They were more positive when the second test was correct. Importantly, the later component only predicted subsequent memory when the answers were not overlearned, i.e. only correctly recalled once previously. We interpret the 400–700 ms time window as a component reflecting a retrieval attempt process, which differs as a function of both current and subsequent accuracy, and the later time window as a component reflecting a re-encoding process, which only involves learning from tests, both of which are involved in the testing effect.

Pre-articulatory electrical activity associated with correct naming in individuals with aphasia

Picture naming is a language task that involves multiple neural networks and is used to probe aphasia-induced language deficits. The pattern of neural activation seen in healthy individuals during picture naming is disrupted in individuals with aphasia, but the time-course of the disruption remains unclear. Specifically, it remains unclear which anatomical and temporal aspects of neural processing are necessary for correct naming. Here, we tested two individuals with stroke induced aphasia, and compared the differences in the event-related potentials (ERPs) and current sources when they made correct vs. erroneous responses during picture naming. The pre-articulatory ERP activity was significantly different between the two responses. Current source analysis revealed that the ability to recruit left temporal and frontal areas within a 300–550 ms time window after stimulus onset contributed to correct responses. These results suggest that targeted neuromodulation in these areas could lead to better treatment outcomes in patients with aphasia.

An ERP Investigation of Object-Scene Incongruity

Abstract. The present study investigated the temporal dynamics of the object-scene congruity during a categorization task of objects embedded in a scene. Participants (n = 28) categorized objects in scenes as natural or man-made while event-related brain potentials (ERPs) were recorded. The object-scene associations were either congruous (e.g., a tent in a field) or incongruous (e.g., a fridge in a desert). The results confirmed that contextual congruity affects item processing in the 300–500 ms time window with larger N300/N400 complex in the incongruous than in the congruous condition. However, unlike previous work which found an effect of congruity starting at ~ 250 ms poststimulus on fronto-central regions, the earliest sign of a reliable context congruity effect arose at ~ 170 ms at left centro-parietal regions in the present study. The present results are in line with those of previous studies showing that object and context are processed in parallel with continuous interactions from 150 to 500 ms, possibly through feed-forward co-activation of populations of neurons selective to the processing of the object and its context. The present finding provides novel evidence suggesting that online context violations might affect earlier visual processes and routines of matching between possible scene-congruent activated schemas and the upcoming information about the item to process.

Sensory and semantic activations evoked by action attributes of manipulable objects: Evidence from ERPs

“Two route” theories of object-related action processing posit different temporal activation profiles of grasp-to-move actions (rapidly evoked based on object structure) versus skilled use actions (more slowly activated based on semantic knowledge). We capitalized on the exquisite temporal resolution and multidimensionality of Event-Related Potentials (ERPs) to directly test this hypothesis. Participants viewed manipulable objects (e.g., calculator) preceded by objects sharing either “grasp”, “use”, or no action attributes (e.g., bar of soap, keyboard, earring, respectively), as well as by action-unrelated but taxonomically-related objects (e.g., abacus); participants judged whether the two objects were related. The results showed more positive responses to “grasp-to-move” primed objects than “skilled use” primed objects or unprimed objects starting in the P1 (0–150 ms) time window and continuing onto the subsequent N1 and P2 components (150–300 ms), suggesting that only “grasp-to-move”, but not “skilled use”, actions may facilitate visual attention to object attributes. Furthermore, reliably reduced N400s (300–500 ms), an index of semantic processing, were observed to taxonomically primed and “skilled use” primed objects relative to unprimed objects, suggesting that “skilled use” action attributes are a component of distributed, multimodal semantic representations of objects. Together, our findings provide evidence supporting two-route theories by demonstrating that “grasp-to-move” and “skilled use” actions impact different aspects of object processing and highlight the relationship of “skilled use” information to other aspects of semantic memory.

Dissociable Electroencephalograph Correlates of Visual Awareness and Feature-Based Attention.

Background: The relationship between awareness and attention is complex and controversial. A growing body of literature has shown that the neural bases of consciousness and endogenous attention (voluntary attention) are independent. The important role of exogenous attention (reflexive attention) on conscious experience has been noted in several studies. However, exogenous attention can also modulate subliminal processing, suggesting independence between the two processes. The question of whether visual awareness and exogenous attention rely on independent mechanisms under certain circumstances remains unanswered.Methods: In the current study, electroencephalograph recordings were conducted using 64 channels from 16 subjects while subjects attempted to detect faint speed changes of colored rotating dots. Awareness and attention were manipulated throughout trials in order to test whether exogenous attention and visual awareness rely on independent mechanisms.Results: Neural activity related to consciousness was recorded in the following cue-locked time-windows (event related potential, cluster- based permutation test): 0–50, 150–200, and 750–800 ms. With a more liberal threshold, the inferior occipital lobe was found to be the source of awareness-related activity in the 0–50 ms range. In the later 150–200 ms range, activity in the fusiform and post-central gyrus was related to awareness. Awareness-related activation in the later 750–800 ms range was more widely distributed. This awareness-related activation pattern was quite different from that of attention. Attention-related neural activity was emphasized in the 750–800 ms time window and the main source of attention-related activity was localized to the right angular gyrus. These results suggest that exogenous attention and visual consciousness correspond to different and relatively independent neural mechanisms and are distinct processes under certain conditions.

O175 High-density ERPS for working memory for faces, words, and figures in young and elder healthy volunteers

Objectives We aimed at studying brain electrical activity underlying the changes in working memory encoding for different kinds of visual stimuli, related to healthy aging. Methods The participants were young healthy adults (10 female and 12 male), aged 20–30 years and elder healthy adults (12 female and 12 male), aged 50–70 years. All participants performed three delayed match-to-sample visual tasks. The stimuli were monochrome photographs of unfamiliar faces, patterns composed of 8 cubes, and 5-letter Russian abstract nouns. Participants had to memorize the first stimulus in a pair and compare it to the second stimulus presented with 2000 ms delay. 128-channel EEG was recorded with 500 Hz digitization rate. We analyzed the visual response elicited by the first stimulus in a pair and the following slow potential (CNV). Results The task-specific age-related differences ( p 0.05 ) were found in N170 component. Its amplitude was reduced for geometric patterns, and enhanced for faces and words in Elder compared to Young group. The differences were task-specific in their topography in 450–900 ms time window (LPP) and in early CNV. The non-specific age-related amplitude reduction ( p 0.05 ) in elders was in P100 and P300 components, and the non-specific amplitude increase was in N280 and CNV in the central region. Discussion Brain activity during visual item encoding and maintenance showed task-specific and non-specific differences between elder and young healthy participants, depending on the latency of the recorded components of evoked activity. Conclusions The non-specific increased electrical brain activity recorded from the scalp surface in Elder group can be a manifestation of general compensatory processes taking place in the certain brain structures in healthy aging. Significance The results may have a prognostic value for healthy aging vs. age-related memory problems.

Corrigendum.

Corrigendum.

Estimation of Synaptic Conductances in Presence of Nonlinear Effects Caused by Subthreshold Ionic Currents.

Subthreshold fluctuations in neuronal membrane potential traces contain nonlinear components, and employing nonlinear models might improve the statistical inference. We propose a new strategy to estimate synaptic conductances, which has been tested using in silico data and applied to in vivo recordings. The model is constructed to capture the nonlinearities caused by subthreshold activated currents, and the estimation procedure can discern between excitatory and inhibitory conductances using only one membrane potential trace. More precisely, we perform second order approximations of biophysical models to capture the subthreshold nonlinearities, resulting in quadratic integrate-and-fire models, and apply approximate maximum likelihood estimation where we only suppose that conductances are stationary in a 50–100 ms time window. The results show an improvement compared to existent procedures for the models tested here.