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. 2026 Oct 11;30(9):e70411. doi: 10.1002/ejp.70411

How the Brain Interprets Pain in Autistic People: Does Sex Matter?

Yelena Granovsky 1,2,✉, Irit Weissman‐Fogel 3, Tseela Hoffman 3, Merry Kalingel Levi 4, Eynat Gal 4, Elliot Sprecher 1, Merav Shor 1, Tami Bar‐Shalita 5,6
PMCID: PMC13655186  PMID: 42860550

ABSTRACT

Background

While psychophysical studies suggest heightened pain sensitivity in individuals with autism spectrum disorder (ASD), the relationship between subjective pain experience and cortical neurophysiological responses and whether this relationship is sex‐dependent, remains poorly understood.

Methods

This cross‐sectional two‐group comparison study included 50 adults with Level 1 ASD and 52 age‐, sex‐ and IQ‐matched typically developing controls (TDC). Pain ratings and cortical contact heat‐evoked potentials (CHEPs) were recorded in response to 52°C phasic heat stimuli. ANOVA and regression models assessed the effects of group, sex and pain ratings on CHEP amplitudes.

Results

Compared to TDC, autistic participants reported higher pain scores (p = 0.004) and had lower N2 amplitudes (p = 0.02). A significant Group × Sex interaction (p < 0.001) was associated with the lowest N2 amplitudes in autistic females (p < 0.05). Regardless of group, in females, higher N2 amplitudes were associated with higher pain scores (p = 0.042; model p = 0.032), whereas this association was not significant in males (p > 0.05). Within‐group correlation analyses in females showed a significant pain–N2 amplitude relationship in TDC (r = 0.734; p = 0.004) but not in autistic participants (r = 0.371; p = 0.192). Across groups and sexes, higher N2 amplitude values were associated with greater attention‐to‐detail autistic traits (p = 0.009).

Conclusions

Our findings suggest a dissociation between subjective pain experience and cortical responses to nociceptive stimulation in autism, particularly among females, consistent with different salience‐related or attentional pain processing. These results underscore the importance of considering sex and autism when interpreting pain‐evoked cortical responses and challenge the assumption that pain‐evoked potentials provide universally objective measures of pain.

Significance

This study identifies sex‐related differences in the relationship between subjective pain ratings and cortical responses to nociceptive stimulation in autistic and typically developing individuals. Autistic females showed particularly attenuated N2 amplitudes and a weaker correspondence between pain ratings and cortical responses, suggesting different salience‐related or attentional processing of nociceptive stimuli. These findings highlight the importance of considering sex and autistic traits when interpreting pain‐evoked cortical responses in autism.

1. Introduction

Autism represents a group of neurodevelopmental conditions associated with changes in cognitive, emotional, social and behavioural changes (Association 2013). Differences in activity of central neural circuits in individuals with autism spectrum disorder (ASD), including autistic people with low support needs, are reflected in differences in brain metabolism (Tebartz van Elst et al. 2014; Wood et al. 2021) and structural and functional cortical organisation (Conti et al. 2017; Rane et al. 2015). These differences might translate into an imbalance of the excitation‐inhibition equilibrium of cortical networks which, in turn, is related to autistic symptoms.

The reports on pain sensitivity in autism are contradictory; while some studies did not reveal differences between ASD and typically‐developed controls (TDC) participants (Failla et al. 2018; Vaughan et al. 2020), others report enhanced pain sensitivity to experimental stimuli (Asmika et al. 2018; Dubois et al. 2020; Failla et al. 2020; Vaughan et al. 2020). Our recent findings confirmed the latter, pointing towards a pro‐nociceptive psychophysical profile in ASD Level 1 (Hoffman et al. 2023). However, whether the psychophysical profile correlates with neurophysiological pain‐evoked responses in ASD has not been systematically studied.

The cortical pain‐evoked potentials (pain EPs) are considered objective measures of perceived experimental pain, providing information on endogenous processing of nociceptive signals in response to noxious stimuli, manifested in the amplitude and latency of the N2P2 components. There is a positive relationship between perceived pain and the amplitudes of pain EPs in healthy individuals, with females showing higher amplitudes (Chao et al. 2007; Granovsky et al. 2016; Granovsky et al. 2008; Roberts et al. 2008; Valeriani et al. 2012). Moreover, decreased pain scores in response to psychological or pharmacological analgesic manipulations are linked to decreased pain EPs amplitudes (Lier et al. 2020; Moont et al. 2011; Paloyelis et al. 2016; Truini et al. 2010). The described relationship between pain perception and pain EP amplitude in healthy individuals may position this measure as a sensitive and reliable physiological parameter for evaluating individual sensory profiles in various clinical situations.

The relationship between pain behavioural and neurophysiological responses in individuals with neurodevelopmental conditions is of high research and clinical interest. However, to the best of our knowledge, this has not been systematically studied in autistic people. Currently, there are only two published reports that address pain EPs in ASD (Chien et al. 2020; Chien et al. 2017), noting relationships between autistic behavioural characteristics and pain EPs (Chien et al. 2017). However, these studies did not aim to explore the association between pain‐evoked psychophysical and neurophysiological responses, nor did they examine the role of sex.

In this project, we aimed to evaluate the relationship between psychophysical and cortical neurophysiological correlates of pain‐evoked responses in adults with ASD Level 1. We hypothesised that due to the structural differences and underlying functional and neurochemical changes in the brains of autistic individuals, the relationships between subjective and objective pain characteristics will differ from those presented in TDC. We also hypothesised that these differences may be sex‐related.

2. Methods

The institutional review board of the Rambam Health Care Campus (# 0496‐17), Tel Aviv University (# 0001123‐1) and University of Haifa (# 064/18) approved the study protocol in accordance with the Helsinki Declaration. Each patient signed a written informed consent form prior to commencing the experiment in the presence of a physician.

2.1. Participants

Participants diagnosed with ASD Level 1 (low support needs) aged 18–55 years, verified according to the Autism Diagnostic Observation Schedule—Second Edition (ADOS‐2) interview performed by ADOS‐2 certified assessors, as well as age‐ and sex‐matched typically developing control (TDC) subjects, were recruited by a convenience snowball sampling from several autistic centers in the country and the general population, respectively, between May 2018 and November 2021. Inclusion criteria for both groups required no language barriers. Exclusion criteria for both groups included reporting on chronic pain diagnoses, pregnancy, scores lower than 80 on the verbal, performance and full‐scale IQ as measured by the Wechsler Abbreviated Scale of Intelligence—Second Edition (WASI‐II). In addition, the exclusion criteria for the TDC group included any neurological or psychiatric disorders. All participants were asked to avoid the use of analgesics, medication for attention‐deficit hyperactivity disorder and any sedative drugs 24 h prior to the experimental testing.

2.2. Study Design

This is a cross‐sectional two‐group comparison study, described in detail in our recently published papers (please see Hoffman et al. 2023; Kalingel Levi et al. 2025). In the present paper, we explore the relationships between psychophysical and neurophysiological correlates of contact heat pain EPs in autistic and neurotypical males and females and their correlations with the Autism Spectrum Quotient (AQ) sub‐scales of Attention Switching Difficulty and Attention to Details (Baron‐Cohen et al. 2001).

2.3. Contact Heat‐Evoked Potentials (CHEPs) Stimulation Parameters

CHEPs were recorded in response to the phasic heat stimuli at 52°C. Twenty phasic stimuli per block, given at the inter‐stimulus interval of 10 s, onset‐to‐onset, were applied to the upper volar aspect of the forearm on the right side and were slightly repositioned after each stimulus to avoid spatial summation. The heat stimuli were delivered by a 27‐mm diameter thermode that covered an area of 572.5 mm2 (PATHWAY, Sensory Analyser System; Medoc, Israel). The baseline temperature was set at 32°C, the temperature increase and decrease rates were 70°C/s and 40°C/s, respectively. After each stimulus, the participants were asked to verbally rate their pain on a 0–100 numeric pain scale (NPS).

2.4. CHEPS Recording

The recording was performed with a 64 ActiCHamp Brain Vision system (Brain Products GmbH, Munich, Germany). The sampling rate was set to 500 Hz with a 0.15–100 Hz bandpass filter and a notch filter of 50 Hz to reduce electrical noise interference. Each electrode's impedance was lowered to 20 kΩ or less. The reference electrode was placed on the bridge of the participant's nose. The ground electrode was placed on the forehead.

2.5. CHEPS Analyses

The Cz (vertex) recordings, where the pain‐evoked potentials were reported to consistently demonstrate the largest amplitudes (Bromm and Lorenz 1998), were processed and analysed. Each recording epoch of 1500 ms included a period of 500 ms for baseline correction of single trials. Stimulus onset was marked by a TTL pulse from the CHEPs to the EEG system at the onset of the temperature increase. Subject data were included in further statistical analyses if there were at least 10 well‐identified evoked potential waveforms, free from blinking and eye movement, or muscle artefacts, within the 250‐ to 800‐ms time window after stimulus onset. We determined the amplitude and latency of the N2 and P2 peaks and the N2P2 amplitude, on the averaged waveform from all artefact‐free traces. To minimise measuring errors, we excluded recordings with N2P2 amplitude less than 5 μV from the analysis, which would have been of similar amplitude as the background electroencephalographic activity (Granovsky et al. 2016) and therefore considered as undetectable.

2.6. Statistical Analysis

JMP (SAS Institute, Cary, NC) was used for statistical analyses. Demographic parameters, pain scores and CHEPs characteristics were compared using t‐tests or non‐parametric comparisons, as appropriate. To improve data normality and comply with ANOVA's residual error assumptions, the CHEPs parameters underwent log transformation; for the same reason, the pain score values underwent the arcsine square root transformation. Note that on back‐transformation to original units, for graphical presentation, the amplitude values in the ANOVA models are presented as geometric means with asymmetric 95% upper and lower confidence limits (95% CL). ANOVA models explored the influence of group (ASD or TCD), pain‐evoked reports, sex and their interactions, on N2, P2 and N2P2 CHEPs amplitudes.

The parameter of sex was included in the ANOVA models given its widely‐reported effect on pain EPs amplitudes (Granovsky et al. 2016; Roberts et al. 2008) and on the amplitudes of event‐related potentials (ERPs), in general (Conroy and Polich 2007; Hoffman and Polich 1999). Since the factor of sex was included in the CHEPs analysis, it was also included in the ANOVA model that tested the Group, Sex and their interaction on the pain scores. Further, following Chien et al.'s (2017) approach who tested the relationships between the AQ questionnaire‐based autistic traits (Baron‐Cohen et al. 2001) for attention and the CHEPS components amplitude of significant group difference, 3 additional ANOVA models tested the effect of attention characteristics via the AQ, a 50‐item self‐report measuring five domains linked to ASD, sub‐scores (the Attention to Detail and the Attention Switching Difficulty) on the relevant amplitude and their interaction with the factors of Group and Sex. Mood's non‐parametric median test was applied for the group comparison of CHEPs characteristics and the pain scores. Statistical significance was set at p < 0.05.

3. Results

3.1. Demographic and Descriptive Characteristics of the Study Population

One hundred eighty‐three participants (N = 95 were diagnosed with ASD Level 1) signed the consent form. ASD diagnosis had not been confirmed according to the ADOS‐2 in 16 participants; in addition, 2 autistic individuals had discontinued their participation and 3 were excluded based on the WASI‐II score < 80, resulting in 74 autistic individuals entered into the study. Further, the pain EPs recordings were missing or discontinued in 10 autistic persons for technical reasons (N = 1) or refusal to undergo or complete the testing due to sensory reactivity (N = 9). Thus, the autistic group for this study consisted of 64 participants. The TDC group included 87 participants (among 88 consented persons, one discontinued). Further, 25 TDC were identified with sensory modulation dysfunction (SMD)—a difficulty in regulating responses to sensory stimuli manifested as over‐ or under‐responsiveness and documented with altered brain activity (Granovsky et al. 2019) and therefore excluded. Thus, in total, this study comprised 64 participants diagnosed with ASD Level 1 and 62 TDC participants whose pain EPs recordings were completed.

A detectable free of artefacts N2P2 waveform in response to contact heat stimulation at 52°C was demonstrated in 50 autistic participants (15 females) and 52 TDC (13 females). Among the study participants, 20 reported routine use of one or more psychiatric medications (ASD = 18). Eleven individuals used antidepressants, 15 used antipsychotic medications and 6 used both.

The TDC sub‐group was slightly older than that of the autistic sub‐group (28 years, range 18–47 vs. 24 years, range 19–50, p = 0.049). No IQ (WASI) group differences were detected (111.6 ± 11.2, ASD vs. 112.7 ± 9.4, TDC, p = 0.518).

The descriptive data for CHEPs and pain responses are presented in Table 1.

TABLE 1.

The descriptive characteristics of contact heat‐evoked potentials (CHEPS) amplitudes and latencies and pain scores in the ASD and TDC participants.

Variable ASD TDC
Pain scores, NPS 35.9 (0–98.5) 19.6 (1–73.3)
N2 amplitude, μV −12.0 (0.2−38.4) −11.4 (3.5–30.2)
N2 latency, ms 449 (352–580) 447 (406–508)
P2 amplitude, μV 19.5 (1.2–50.9) 17 (4–42.7)
P2 latency, ms 589 (492–682) 582 (514–644)
N2P2 amplitude, μV 30.1 (16.7–63.4) 28.4 (12.6–58.8)
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Note: All the data presented in median and minimal‐maximal range.

Abbreviations: ASD, Autism Spectrum Disorder; TDC, typical developing control.

3.2. The Effect of Group and Sex Factors on the Pain Scores

In line with our previously published data (Hoffman et al. 2023), a significant Group effect (p = 0.004, model p = 0.021) was found, confirming higher pain perception in autistic individuals. No effect of Sex or the Group × Sex interaction has been detected.

3.3. The Relationships Between Pain‐Evoked Reports and CHEPs Amplitudes in ASD and TDC

3.3.1. N2 Amplitude

Due to the need for log transformation (for N2 amplitude, this consisted of multiplication by −1 and taking the log10 of the result) and to avoid a more complex transformation involving an additive constant, the few positive values of the N2 amplitude (1 autistic male, 1 autistic female and 2 neurotypical males) were excluded from the ANOVA. The model (p = 0.017) revealed a significant effect of the Group (p = 0.02, lower amplitude in ASD group), the Pain scores (p = 0.026—overall, higher pain scores were associated with higher amplitudes), Group × Sex (p < 0.001) and the Pain scores × Sex (p = 0.028) interactions. A triple Group × Sex × Pain score interaction was not significant (p = 0.533). A Tukey post hoc analysis performed for the Group × Sex interaction revealed that autistic females had the lowest amplitudes as compared with the autistic males (p = 0.003), neurotypical females (p = 0.006), or neurotypical males (p = 0.035). The neurotypical females, as expected, had higher amplitudes than the neurotypical males; however, these differences did not reach statistical significance. The ANOVA results are presented in Figure 1A.

FIGURE 1.

FIGURE 1

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Sex differences in N2, P2 and N2P2 CHEPs amplitudes in ASD and TDC groups. ASD females—red filled diamonds. ASD males—blue filled diamonds. TDC females—red blank diamonds. TDC males—blue blank diamonds. Symbols are geometric means; error bars represent the 95% confidence limits; *p < 0.05. **p < 0.01.

3.3.2. P2 Amplitude

The ANOVA model (p = 0.046) indicated a significant Sex effect on the P2 amplitude (p = 0.006; higher amplitude in females), regardless of the group. The ANOVA results are presented in Figure 1B.

3.3.3. N2P2 Amplitude

The ANOVA model (p = 0.043) revealed a significant effect of Pain scores (p = 0.045—higher pain is associated with higher amplitude), Sex (p = 0.034; higher amplitude in females) and Group × Sex (p = 0.049) interactions were found. A post hoc analysis indicated higher N2P2 amplitude in neurotypical females as compared with the neurotypical males (p = 0.040, Figure 1C).

The grand‐average waveform for autistic and neurotypical males and females is presented in Figure 2.

FIGURE 2.

FIGURE 2

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Grand‐average waveforms for autistic and neurotypical males (blue lines) and females (red lines). Solid lines represent autistic participants and dashed lines represent neurotypical participants.

3.4. The Relationship Between the N2 Amplitudes and the Pain Scores in Males and Females

The observed interaction between Pain scores and Sex for the N2 amplitude may suggest that the relationship between pain and amplitudes is sex‐specific. Since the triple Group × Sex × Pain score interaction was not informative, in order to test this hypothesis, regression models were analysed examining the effects of Group, Pain scores and their interaction separately for males and females. The results indicated that in females, regardless of study group, higher N2 amplitude values were associated with higher pain scores (p = 0.042; model p = 0.032). In neurotypical females, higher amplitudes were demonstrated (p = 0.008) (Figure 3A). When examining within‐group pain‐amplitude correlations, higher pain scores significantly correlated with N2 amplitude in neurotypical (r = 0.734; p = 0.004) but not in autistic (r = 0.371; p = 0.192) females.

FIGURE 3.

FIGURE 3

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The relationship between the N2 amplitudes and the pain‐evoked scores in autistic and neurotypical females (A) and males (B). Regardless of the group (ASD, filled diamonds) or TDC (blank diamonds), higher N2 amplitudes were associated with higher pain scores in females (red diamonds), but not in males (blue diamonds). The data are presented in the original, untransformed values.

In contrast to females, the regression model was not significant in males, indicating a lack of pain‐N2 amplitude association (model p = 0.652; Figure 3B).

3.5. The Effect of Autistic Traits on the N2 Amplitude

Since significant group differences were found only in the N2 amplitude, further analyses were applied on this EPs component employing the factors of the Attention‐relevant AQ sub‐scales, Group Sex and their interactions. A significant ANOVA model (corrected p = 0.034) was detected for the AQ—Attention to Details sub‐scale. In addition to the reported Group and Sex effects on the N2 amplitude (p = 0.002 and p = 0.048, respectively), the AQ—Attention to Details scores was associates with the N2 amplitude value (p = 0.009) – higher amplitude was associated with higher Attention to Details. Further, significant Group × Sex interaction (p = 0.002) confirmed the lower N2 amplitude in autistic females as compared with the ASD autistic (p = 0.004), TDC females (p = 0.003), or TDC males (p = 0.006). No significant interactions were observed between AQ Attention‐to‐Detail scores and Sex (p = 0.194) or Group (p = 0.982).

No significant model was observed for the Attention Switching Difficulty sub‐scale (corrected p = 0.197). As expected, both the attentional characteristics scores were significantly higher in the ASD group: (the Attention to Details: 5 (0–10) vs. 1 (0–5), corrected p < 0.001; Attention Switching Difficulty: 4 (1–10) vs. 3 (0–6), corrected p < 0.001).

3.6. Sensitivity Analysis: The Role of Psychiatric Medication in the Sex‐Specific Findings for N2 Amplitude

Twenty participants were receiving psychiatric medication, including 18 autistic individuals (7 females) and 2 neurotypical male participants (one receiving ADHD medication and one receiving an antidepressant).

The medication status did not differ significantly between autistic males and females (Fisher's exact test, two‐tailed p = 0.497), although a numerically higher proportion of females (53.8%) than males (38.5%) were receiving psychiatric medication.

After excluding medicated participants, the overall ANOVA model for N2 amplitude was borderline significant (p = 0.052), consistent with the reduction in sample size. Importantly, the Group × Sex interaction remained statistically significant (p = 0.002, ηp 2 = 0.129), with an effect size comparable to that observed in the full sample (ηp 2 = 0.117); both correspond to medium‐to‐large effect sizes. Thus, exclusion of medicated participants did not materially alter the magnitude or direction of the observed sex‐specific effect. To facilitate interpretation of the significant Group × Sex interaction, Tukey‐adjusted pairwise comparisons showed that autistic females exhibited lower N2 amplitudes than autistic males (p = 0.011), neurotypical females (p = 0.009) and neurotypical males (p = 0.032).

4. Discussion

This is the first study to address the association between pain‐related psychophysical and cortical neurophysiological responses in individuals diagnosed with ASD Level 1. Our findings revealed several key insights: (1) Discrepancy between psychophysical and cortical responses: although the ASD group reported higher pain ratings than the TDC group, their CHEP amplitudes were either comparable to those of the neurotypicals (for the P2 and N2P2 components) or even lower (for the N2 component). (2) Sex‐related differences in cortical responses: unlike the TDC group, where females typically exhibit higher pain‐evoked amplitudes, autistic females showed attenuated cortical responses compared to autistic males and both TDC sub‐groups. (3) Sex‐dependent association between psychophysical and neurophysiological responses: a significant correlation between pain ratings and N2 amplitude was observed only in females, with a stronger association in TDC than in ASD. These findings highlight distinct, sex‐related patterns of pain‐evoked cortical responses in autistic individuals compared to TDC, suggesting potential differences in the underlying neural mechanisms of pain processing.

Current knowledge regarding pain‐evoked cortical activity in autistic individuals remains limited. This may be due to heightened sensory reactivity (Isenstein et al. 2026), limiting overall data quality (Abdolzadegan et al. 2020; Eldridge et al. 2014). To date, only two studies—both from the same research group—have examined pain EPs in autism (Chien et al. 2020; Chien et al. 2017). Using a similar CHEPs methodology, the authors reported attenuated P2 amplitudes in the autistic group, whereas we observed attenuation in the N2 component. Methodological differences such as sample sizes and the proportion of females may account for these discrepancies. It is also plausible that the presence of intellectual disability in Chien et al.'s sample represents a major factor underlying the divergent findings. Although no research has directly compared caudal anterior cingulate cortex (cACC, a main contributor to the P2 component (Garcia‐Larrea et al. 2003)) functioning between autistic individuals with and without intellectual disability, the reduced cACC connectivity reported in autism (Zhou et al. 2016) may disproportionately affect autistic individuals with cognitive disabilities and, in turn, contribute to the attenuated P2 amplitudes.

The N2 and P2 pain EPs amplitudes are believed to reflect neuronal activity in functionally distinct cortical regions. Intra‐cortical recordings and dipole modelling of laser‐evoked potentials have demonstrated that the cortical generators of the N2 component primarily reflect activity in the bilateral primary and secondary somatosensory cortices (SI, SII) and to a lesser extent, in the insular and mid‐anterior cingulate cortices (Bromm and Lorenz 1998; Frot et al. 2008; Garcí‐Larrea et al. 1997). The SII and posterior insula are known to encode the perception of both noxious and non‐noxious stimuli (Frot et al. 2007; Garcia‐Larrea et al. 2003; Lenz et al. 1998), suggesting that the N2 amplitude may reflect the functionality of the sensory‐discriminative ‘lateral’ pain subsystem. In contrast, the P2 component is primarily generated in caudal ACC, reflecting the activity of the affective‐motivational ‘medial’ pain subsystem (Derbyshire 2000; Peyron et al. 2000; Tölle et al. 1999).

Although these traditional generator models have linked N2 and P2 to partially distinct dimensions of nociceptive processing, their functional interpretation should be considered in light of evidence that the N2P2 complex is not exclusively pain‐specific but rather reflects a multimodal cortical response involved in detecting behaviorally relevant or salient sensory events and initiating attentional orienting (Iannetti et al. 2008; Legrain et al. 2011; Ronga et al. 2013). Indeed, pain perception and salience processing are inherently interconnected, as nociceptive stimuli are among the most behaviorally relevant sensory events encountered by the nervous system (Legrain et al. 2011). Within this framework, the reduced N2 amplitudes observed in the ASD group, particularly among autistic females, are more likely to reflect altered salience‐related cortical processing of nociceptive stimuli than a selective impairment of sensory‐discriminative pain processing. This interpretation is consistent with evidence for atypical attentional processing and sensory responsivity in autism (Green et al. 2015; Keehn et al. 2013), as well as broader models of salience processing implicating the salience network in the detection of behaviorally relevant stimuli and allocation of neural resources (Uddin 2015). Moreover, salience network disruptions are documented also in other psychiatric conditions. Reduced amplitudes of salience‐related brain responses have been described in schizophrenia and bipolar disorder (Minichino et al. 2016), as well as in individuals with non‐suicidal self‐injury (Leone et al. 2021). From this perspective, reduced N2 amplitudes may represent a transdiagnostic neurophysiological marker of altered salience processing, rather than an autism‐specific indicator of pain dysfunction. Such an interpretation may also help explain the present findings, in which autistic individuals reported greater pain intensity than TDC despite exhibiting reduced N2 amplitudes.

Our central finding is an association between attenuated CHEPs amplitudes observed in autistic individuals and female sex. This opposes findings of higher amplitudes in neurotypical females (Chao et al. 2007; Granovsky et al. 2016; Granovsky et al. 2008; Roberts et al. 2008; Valeriani et al. 2012). Such a pattern of sex‐related differences in neuronal oscillations and ERP amplitudes (Melynyte et al. 2018) may be explained by enhanced interhemispheric structural and functional connectivity (Ingalhalikar et al. 2014), as well as greater grey matter volume (Ritchie et al. 2018) in neurotypical females. Thus, the attenuated N2 response in autistic females may reflect altered salience detection or attentional orienting to nociceptive stimuli, potentially contributing to the weaker correspondence between cortical responses and subjective pain.

Research on autism has historically focused on males, leaving processing mechanisms in autistic females underexplored and often assuming shared neurobiology across sexes—a bias largely driven by the higher prevalence of autism in males (Maenner et al. 2020). The underestimation of sex as a factor in ASD research may be linked to the Extreme Male Brain theory (Baron‐Cohen 2002) that assumes that autistic individuals—regardless of sex—share a cognitively ‘hyper‐masculinised’ profile. However, growing evidence suggests that overlooking sex differences may lead to an oversimplified understanding of the biological basis of autism (Ridley 2019). Indeed, the results of several recent studies report on sex‐related differences in the associations between phenotypic autistic traits and physiological responses (Brito et al. 2019; Neuhaus et al. 2021). Furthermore, our data reveal clear sex differences in cortical responses within the autistic group, challenging the assumption of a unitary ‘extreme male’ profile and considering sex as a meaningful factor in autism research.

Another dimension of the sex‐related pattern in pain‐evoked cortical activity revealed in our study is the association observed between N2 amplitude and perceived pain in females, but not in males. Regardless of diagnostic status (ASD or TDC), higher pain ratings in females related to higher N2 amplitude values. To the best of our knowledge, this is the second published study to examine the relationship between neurophysiological and psychophysical characteristics of pain EPs in relation to sex. The previous study, conducted by our group (Kisler et al. 2016), similarly found a significant correlation exclusively in females, though in that case, it was a negative association between P2 amplitude and perceived pain. While methodological differences between the studies may account for some variation in the reports, our findings suggest that pain EPs amplitudes may be more reflective of pain‐related salience responses in females than in males, challenging the notion of their universal applicability across sexes. Moreover, altered salience‐related or attentional processing may contribute to the weaker association between N2 amplitude and pain ratings observed in autistic females. However, according to our findings, the relationship between N2 amplitude and the autistic trait of attention to detail appears to be independent of sex, highlighting a distinction between sex‐related and trait‐related modulation of cortical pain processing.

Considering our findings in light of the study's limitations, we acknowledge that ASD Level 1 individuals, predominantly males, may limit the generalizability of our findings. Additionally, while this study reveals sex differences in brain activity, sex distribution was not even within each group, which may have impacted the study's findings. Further, forms of body‐focused repetitive behaviours and use of psychiatric medications have been associated with different brain activity (Lelic et al. 2017; Thakkar et al. 2008), yet these were not considered in this study. We have also to admit that the excluded ASD subgroup with missing or discontinued EPs recording (N = 9, three females, ADOS assessment: median [25th, 75th] = 10 [8, 14]; 67% having SMD) is likely not random but instead reflects individuals with a more extreme autistic phenotype. Finally, attentional engagement during nociceptive stimulation was not measured. Given current evidence that the N2P2 complex is influenced by attentional orienting and stimulus salience, future studies should incorporate objective measures or experimental manipulations of attention to clarify the contribution of these processes to pain‐evoked cortical responses in autism.

In summary, our findings suggest that the relationship between pain‐related subjective experience and cortical responses to nociceptive stimuli may differ according to sex and ASD diagnosis. The attenuated N2 amplitudes observed particularly in autistic females, together with the weaker correspondence between N2 amplitude and pain ratings in this group, are consistent with different salience‐related or attentional processing of nociceptive stimuli. These findings highlight the importance of considering sex in the neurobiology of autism.

Author Contributions

This study was designed by Irit Weissman‐Fogel, Tami Bar‐Shalita, Eynat Gal and Yelena Granovsky. The experiments were performed by Tseela Hoffman, Merry Kalingel Levi and Merav Shor. The data were analysed by Yelena Granovsky and Elliot Sprecher and the results were critically examined by all authors. Yelena Granovsky had a primary role in preparing the manuscript, which was edited by Irit Weissman‐Fogel and Tami Bar‐Shalita. All authors have approved the final version of the manuscript and agree to be accountable for all aspects of the work.

Funding

This study was funded by the Israel Science Foundation grant # 1005/17.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Data S1: STROBE checklist.

EJP-30-0-s001.docx (31.7KB, docx)

Acknowledgements

Artificial intelligence was utilised for English‐language editing.

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