Sequence Of Stimuli Research Articles

Influence of Thermal and Gustatory Stimulus in the Initiation of the Pharyngeal Swallow and Bolus Location Instroke

Introduction/ObjectiveThe aim of this study is to analyze the influence of sour taste and cold temperature in the initiation of the pharyngeal swallow (IPS) and bolus location at pharyngeal swallow onset in individuals after stroke. MethodsCross-sectional prospective study. The study included 52 individuals with unilateral ischemic stroke. Each individual was assessed by videofluoroscopic swallowing study with 5ml of paste bolus offering four different stimuli (natural, cold, sour, and sour-cold). The individuals were divided into two groups according to the offer sequence. Group 1 (G1) – received a randomized sequence of stimuli (24 individuals), and Group 2 (G2) –the stimuli were offered in the following order: natural, cold, sour, and sour-cold(28 individuals). The IPS time and bolus location at pharyngeal swallow onset were analyzed. The bolus location at pharyngeal swallow onset was defined using six different levels. ResultsIndividuals in G1 did not show a significant difference in IPS time between stimuli. However, individuals in G2 presented a significantly shorter IPS time with the sour and sour-cold stimuli than with natural or cold stimuli. The bolus location at pharyngeal swallow onset did not show significant difference between stimuli in both groups. On the other hand, in the G2 it was observed higher frequency of swallowing with sour-cold stimulus at level 1 (the bolus head was located in any region between the fauces pillar and the point where the tongue crosses the inferior border of the mandible). ConclusionThe sour and sour-cold stimuli influenced the IPS time when they were offered in a sequential order. Moreover, both the IPS time and bolus location at pharyngeal swallow onset were not influenced by the sour and sour cold-bolus when offered in a random sequence.

Impaired Perception and Neural Processing of Rules in Developmental Dyslexia

Rules and regularities of language are typically processed in an implicit and effortless way in the human brain. Individuals with developmental dyslexia have problems in implicit learning of regularities in sequential stimuli, but the neural basis of this deficit has not been studied. This study investigated extraction and utilization of a complex auditory rule at neural and perceptual levels in 18 adults with dyslexia and 20 typical readers. Mismatch negativity (MMN) and P3a responses to rule violations in speech stimuli, reflecting change detection and attention switch, respectively, were recorded with electroencephalogram. Both groups reported no or little explicit awareness of the rule, suggesting implicit processing. People with dyslexia showed deficient extraction of the rule evidenced by diminished MMNs estimated to originate particularly from the left perisylvian region. The group difference persisted in the attentive condition after the participants were told about the rule, and behavioral detection of the rule violations was poor in people with dyslexia, possibly suggesting difficulties also in utilizing explicit information of the rule. Based on these results, the speech processing difficulties in dyslexia extend beyond phoneme discrimination and basic auditory feature extraction. Challenges in implicit extraction and effortless adoption of complex auditory rules may be central to language learning difficulties in dyslexia.

A theory of memory for binary sequences: Evidence for a mental compression algorithm in humans.

Working memory capacity can be improved by recoding the memorized information in a condensed form. Here, we tested the theory that human adults encode binary sequences of stimuli in memory using an abstract internal language and a recursive compression algorithm. The theory predicts that the psychological complexity of a given sequence should be proportional to the length of its shortest description in the proposed language, which can capture any nested pattern of repetitions and alternations using a limited number of instructions. Five experiments examine the capacity of the theory to predict human adults’ memory for a variety of auditory and visual sequences. We probed memory using a sequence violation paradigm in which participants attempted to detect occasional violations in an otherwise fixed sequence. Both subjective complexity ratings and objective violation detection performance were well predicted by our theoretical measure of complexity, which simply reflects a weighted sum of the number of elementary instructions and digits in the shortest formula that captures the sequence in our language. While a simpler transition probability model, when tested as a single predictor in the statistical analyses, accounted for significant variance in the data, the goodness-of-fit with the data significantly improved when the language-based complexity measure was included in the statistical model, while the variance explained by the transition probability model largely decreased. Model comparison also showed that shortest description length in a recursive language provides a better fit than six alternative previously proposed models of sequence encoding. The data support the hypothesis that, beyond the extraction of statistical knowledge, human sequence coding relies on an internal compression using language-like nested structures.

Why Does Dual-Tasking Hamper Implicit Sequence Learning?

Research on the limitations of dual-tasking might profit from using setups with a predictable sequence of stimuli and responses and assessing the acquisition of this sequence. Detrimental effects of dual-tasking on implicit sequence learning in the serial reaction time task (SRTT; Nissen & Bullemer, 1987) – when paired with an uncorrelated task – have been attributed to participants’ lack of separating the streams of events in either task. Assuming that co-occurring events are automatically integrated, we reasoned that participants could need to first learn which events co-occur, before they can acquire sequence knowledge. In the training phase, we paired an 8-element visual-manual SRTT with an auditory-vocal task. Afterwards, we tested under single-tasking conditions whether SRTT sequence knowledge had been acquired. By applying different variants of probabilistic SRTT-tone pairings across three experiments, we tested what type of predictive relationship was needed to preserve sequence learning. In Experiment 1, where half of the SRTT-elements were paired to 100% with one specific tone and the other half randomly, only the fixedly paired elements were learned. Yet, no sequence learning was found when each of the eight SRTT-elements was paired with tone identity in a 75%–25% ratio (Experiment 2). Sequence learning was, however, intact when the 75%–25% ratio was applied to the four SRTT target locations instead (Experiment 3). The results suggest that participants (when lacking a separation of the task representations while dual-tasking) can learn a sequence inherent in one of two tasks to the extent that across-task contingencies can be learned first.

Emotional visual mismatch negativity: a joint investigation of social and non-social dimensions in adults with autism

Unusual behaviors and brain activity to socio-emotional stimuli have been reported in Autism Spectrum Disorder (ASD). Atypical reactivity to change and intolerance of uncertainty are also present, but little is known on their possible impact on facial expression processing in autism. The visual mismatch negativity (vMMN) is an electrophysiological response automatically elicited by changing events such as deviant emotional faces presented among regular neutral faces. While vMMN has been found altered in ASD in response to low-level changes in simple stimuli, no study has investigated this response to visual social stimuli. Here two deviant expressions were presented, neutral and angry, embedded in a sequence of repetitive neutral stimuli. vMMN peak analyses were performed for latency and amplitude in early and late time windows. The ASD group presented smaller amplitude of the late vMMN to both neutral and emotional deviants compared to the typically developed adults (TD) group, and only the TD group presented a sustained activity related to emotional change (i.e., angry deviant). Source reconstruction of the vMMNs further revealed that any change processing elicited a reduced activity in ASD group compared to TD in the saliency network, while the specific processing emotional change elicited activity in the temporal region and in the insula. This study confirms atypical change processing in ASD and points to a specific difficulty in the processing of emotional changes, potentially playing a crucial role in social interaction deficits. Nevertheless, these results require to be further replicated with a greater sample size and generalized to other emotional expressions.

Mathematical Modeling of Working Memory in the Presence of Random Disturbance using Neural Field Equations

In this paper, we describe a neural field model which explains how a population of cortical neurons may encode in its firing pattern simultaneously the nature and time of sequential stimulus events. Moreover, we investigate how noise-induced perturbations may affect the coding process. This is obtained by means of a two-dimensional neural field equation, where one dimension represents the nature of the event (for example, the color of a light signal) and the other represents the moment when the signal has occurred. The additive noise is represented by a Q-Wiener process. Some numerical experiments reported are carried out using a computational algorithm for two-dimensional stochastic neural field equations.

Optimization of Visual Stimulus Sequence in a Brain-Computer Interface Based on Code Modulated Visual Evoked Potentials.

Brain-computer interfaces based on code-modulated visual evoked potentials provide high information transfer rates, which make them promising alternative communication tools. Circular shifts of a binary sequence are used as the flickering pattern of several visual stimuli, where the minimum correlation between them is critical for recognizing the target by analyzing the EEG signal. Implemented sequences have been borrowed from communication theory without considering visual system physiology and related ergonomics. Here, an approach is proposed to design optimum stimulus sequences considering physiological factors, and their superior performance was demonstrated for a 6-target c-VEP BCI system. This was achieved by defining a time-factor index on the frequency response of the sequence, while the autocorrelation index ensured a low correlation between circular shifts. A modified version of the non-dominated sorting genetic algorithm II (NSGAII) multi-objective optimization technique was implemented to find, for the first time, 63-bit sequences with simultaneously optimized autocorrelation and time-factor indexes. The selected optimum sequences for general (TFO) and 6-target (6TO) BCI systems, were then compared with m-sequence by conducting experiments on 16 participants. Friedman tests showed a significant difference in perceived eye irritation between TFO and m-sequence (p = 0.024). Generalized estimating equations (GEE) statistical test showed significantly higher accuracy for 6TO compared to m-sequence (p = 0.006). Evaluation of EEG responses showed enhanced SNR for the new sequences compared to m-sequence, confirming the proposed approach for optimizing the stimulus sequence. Incorporating physiological factors to select sequence(s) used for c-VEP BCI systems improves their performance and applicability.

Heart rate variability changes during task shifting testing in pre‐symptomatic Alzheimer’s disease

AbstractBackgroundEarly detection of Alzheimer’s disease (AD) is vital to begin and monitor treatments. However, as AD pathology begins long before the onset of symptoms, early detection is difficult. Previous studies have suggested differences in the cardiac and autonomic nervous systems (ANS) in AD patients, providing a possible non‐invasive marker of disease onset. The goal of this study is to compare heart rate variability (HRV) measures, representative of cardiac and ANS function, at rest as well as during cognitive testing to assess the use of HRV as a possible marker of pre‐symptomatic AD.MethodAll participants are cognitively healthy (CH) separated into two subgroups based on ratios of amyloid/tau proteins in cerebrospinal fluid (CSF): normal (CH‐NAT, n=22) and pathological (CH‐PAT, n=36), which represents pre‐symptomatic AD. Heart rate variability (HRV) was assessed during 5‐minute intervals at rest and during Task Shifting testing. Participants were required to name the color or word of a colored word for each stimulus by pressing a button, with two sequential stimuli per trial. The trial could be switching (color‐word or word‐color) or repeat (color‐color or word‐word). ECG traces from subgroups of CH‐NATs (n=8) and CH‐PATs (n=13) were initially screened to remove ectopic beats, followed by identification of normal RR‐intervals (NN). HRV was analyzed as standard deviation of NN (SDNN), root mean squared of successive differences (RMSSD) in the time domain as well as high (HF) and low frequency (LF) in the frequency domain to assess changes to autonomic, and particularly parasympathetic, input to the heart.ResultComparing HRV changes assessed during rest and the task shifting testing in each individual, differences became apparent between CH‐NAT and CH‐PAT groups. In the CH‐NAT group, little to no change in SDNN and RMSSD occurred during cognitive testing from rest. The CH‐PAT group however showed a 20 percent drop in both SDNN and RMSSD during testing, indicating an imbalance of the ANS.ConclusionThis study provides a new approach and technique using HRV to non‐invasively differentiate between normal and pre‐symptomatic AD in cognitively healthy people.

Modulation of neural oscillations during working memory update, maintenance, and readout: An hdEEG study.

Working memory (WM) performance is very often measured using the n‐back task, in which the participant is presented with a sequence of stimuli, and required to indicate whether the current stimulus matches the one presented n steps earlier. In this study, we used high‐density electroencephalography (hdEEG) coupled to source localization to obtain information on spatial distribution and temporal dynamics of neural oscillations associated with WM update, maintenance and readout. Specifically, we a priori selected regions from a large fronto‐parietal network, including also the insula and the cerebellum, and we analyzed modulation of neural oscillations by event‐related desynchronization and synchronization (ERD/ERS). During update and readout, we found larger θ ERS and smaller β ERS respect to maintenance in all the selected areas. γLOW and γHIGH bands oscillations decreased in the frontal and insular cortices of the left hemisphere. In the maintenance phase we observed decreased θ oscillations and increased β oscillations (ERS) in most of the selected posterior areas and focally increased oscillations in γLOW and γHIGH bands in the frontal and insular cortices of the left hemisphere. Finally, during WM readout, we also found a focal modulation of the γLOW band in the left fusiform cortex and cerebellum, depending on the response trial type (true positive vs. true negative). Overall, our study demonstrated specific spectral signatures associated with updating of memory information, WM maintenance, and readout, with relatively high spatial resolution.

Effect of sinusoidally amplitude modulated broadband noise stimuli on stream segregation in individuals with sensorineural hearing loss

Background and Aim: Auditory stream segre­gation is a phenomenon that splits sounds into different streams. The temporal cues that contri­bute for stream segregation have been previ­ously studied in normal hearing people. In peo­ple with sensorineural hearing loss (SNHL), the cues for temporal envelope coding is not usually affected, while the temporal fine structure cues are affected. These two temporal cues depend on the amplitude modulation frequency. The present study aimed to evaluate the effect of sin­usoidal amplitude modulated (SAM) broadband noises on stream segregation in individuals with SNHL. Methods: Thirty normal hearing subjects and 30 subjects with mild to moderate bilateral SNHL participated in the study. Two experi­ments were performed; in the first experiment, the AB sequence of broadband SAM stimuli was presented, while in the second experiment, only B sequence was presented. A low (16 Hz) and a high (256 kHz) standard modulation fre­quency were used in these experiments. The subjects were asked to find the irregularities in the rhythmic sequence. Results: Both the study groups could identify the irregularities similarly in both the experi­ments. The minimum cumulative delay was sli­ghtly higher in the SNHL group. Conclusion: It is suggested that the temporal cues provided by the broadband SAM noises for low and high standard modulation frequencies were not used for stream segregation by either normal hearing subjects or those with SNHL. Keywords: Stream segregation; sinusoidal amplitude modulation; sensorineural hearing loss

Time course of the unmasked attentional blink.

The Attentional Blink (AB) usually refers to the impaired report of a second target (T2) if it appears within 200-500ms after a first target within a rapid sequence of distractors. The present study focused on a less studied AB variant known as the unmasked AB, where T2 is the last item of the sequence and T2 report is unaffected. This aspect of the unmasked AB holds promise for an experimental paradigm in which measures of on-going event-related processing are unconfounded by differences in late-stage processing. To fully characterize the unmasked AB paradigm, we used a randomization statistics approach to comprehensively examine the electroencephalographic signature of the unmasked AB. We examined the unmasked AB with auditory and visual T2s-participants attended to either the auditory or visual information within a sequence of paired auditory-visual stimuli, and reported targets within the attended modality stream while ignoring the other. As predicted, T2 report was unaffected by the unmasked AB. The visual AB was associated with delayed but intact N2 and P3 components, and a suppressed N1. We suggest that this N1 is linked to auditory processing of the distractor stream, and reflects the cognitive system prioritizing the processing of visual targets over auditory distractors in response to AB-related processing load. The auditory AB only indicated a delayed but intact P3. Collectively, these findings support the view that the AB limits the entry of information into consciousness via a late-stage modal bottleneck, and suggest an ongoing compensatory response at early latencies.

Emotional facial expressions affect visual rule learning in 7- to 8-month-old infants

Rule learning (RL) is an implicit learning mechanism that allows infants to detect and generalize rule-like repetition-based patterns (such as ABB and ABA) from a sequence of elements. Increasing evidence shows that RL operates both in the auditory and the visual domain and is modulated by the perceptual expertise with the to-be-learned stimuli. Yet, whether infants’ ability to detect a high-order rule from a sequence of stimuli is affected by affective information remains a largely unexplored issue. Using a visual habituation paradigm, we investigated whether the presence of emotional expressions with a positive and a negative value (i.e., happiness and anger) modulates 7- to 8-month-old infants’ ability to learn a rule-like pattern from a sequence of faces of different identities. Results demonstrate that emotional facial expressions (either positive and negative) modulate infants’ visual RL mechanism, even though positive and negative facial expressions affect infants’ RL in a different manner: while anger disrupts infants’ ability to learn the rule-like pattern from a face sequence, in the presence of a happy face infants show a familiarity preference, thus maintaining their learning ability. These findings show that emotional expressions exert an influence on infants’ RL abilities, contributing to the investigation on how emotion and cognition interact in face processing during infancy.

Tones disrupt visual fixations and responding on a visual-spatial task.

The current study used an eye tracker to examine how auditory input affects the latency of visual saccades, fixations, and response times while using variations of a Serial Response Time (SRT) task. In Experiment 1, participants viewed a repeating sequence of visual stimuli that appeared in different locations on a computer monitor and they had to quickly determine if each visual stimulus was red/blue. The visual sequence was either presented in silence or paired with tones. Compared with the silent condition, the tones slowed down red/blue discriminations and delayed the latency of first fixations to the visual stimuli. To ensure the interference was not occurring during the decision or response phase and to better understand the nature of auditory interference, we removed the red/blue discrimination task in Experiment 2, manipulated cognitive load, and developed a gaze-contingent procedure where the timing of each visual stimulus was dependent on a saccade crossing a gaze-contingent boundary surrounding the target. Participants were slower at initiating their saccades or fixations and made more fixations under high load. As in Experiment 1, auditory interference was found with participants being more likely to fixate on the visual stimuli and were faster at fixating on the visual stimuli in the unimodal condition. These findings suggest that auditory interference effects occur early in the course of processing and provide insights into potential mechanisms underlying modality dominance effects. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

On optimal fMRI designs for correlated errors

Functional magnetic resonance imaging (fMRI) techniques involve studying the brain activity of an experimental subject in response to a mental stimulus, such as a picture or a video shown to the subject. The design problem in fMRI studies is to come up with the best sequence of stimuli to be shown to subjects which enables the precise estimation of the brain activity. In previous analytical studies concerning fMRI designs, it has been assumed that the errors are independent over time. The current state-of-the-art method to find optimal designs for the situations when the errors are correlated is to use the genetic algorithm. In this paper, we analytically obtain the optimal designs in a subclass for the situations when the errors over time are assumed to have an auto-regressive (AR) structure. Since such optimal designs might not exist, in practice, we advocate the use of what we call g-lag orthogonal designs. We show that these g-lag orthogonal designs perform reasonably well under a wide range of conditions under the models with correlated errors.

Learning visual contour tracing in a deep recurrent network based on a cortical columnar architecture

Problem. Visual segmentation mechanisms comprise rapid base grouping of simple features by pre-configured circuits and slower but more flexible incremental grouping by dynamically enhancing feature representations (Roelfsema, Ann. Rev. Neurosci., 2006). How can neural circuits for low- and intermediate-level vision learn such mechanisms? Deep learning provides a framework to develop neuroscience-related models, in which inductive biases constrain model computations (Richards et al., Nat. Neurosci., 2019). Here, we investigate the task of contour tracing to incrementally group visual items for decision-making in a reinforcement learning scenario (Roelfsema, Lamme & Spekreijse, Nature, 1998) with architectural constraints inspired by cortical columns. Method. We propose a multi-layer, recurrent, convolutional network where each layer is composed of retinotopically organized cortical columns. Such columns are modeled as pairs of interacting excitatory-inhibitory (E-I) neurons in discrete feature channels. E-I pair activations are computed from input filtering, lateral integration, activity normalization over neuronal pools, and top-down modulating feedback. Reinforcement signals are provided during training, from which the network can learn rewarding actions over sequential stimulus presentations, similar to the corresponding psychophysical experiments in monkeys, where the task is to fixate and hold gaze at a fixation cue and finally making a saccade to target items indicated by tagging via learned neural tracing. Results and Conclusion. The network successfully solves incremental grouping tasks after learning to act in accordance with the different phases of contour target presentation. Activity spreads along the target line to enhance its neural representation relative to a distractor. Inspection of the model reveals that maintaining fixations is mediated by E-I interactions, while the tracing operation that constitutes incremental grouping is mainly implemented by feedforward and recurrent excitatory interactions.

The Mutational and Transcriptional Landscapes of Hepatocarcinogenesis in a Rat Model.

SummaryHepatocellular carcinoma (HCC) initiation is characterized by stepwise accumulation of molecular alterations, during which the early events are largely unknown. Here, we presented a comprehensive genomic and transcriptomic landscape at stages of hepatitis, cirrhosis, and HCC by using a diethylnitrosamine-induced rat HCC model. We observed the early occurrence of gene instability and aberrant cancer associated signaling pathways in liver hepatitis. We further characterized the progressive molecular changes during hepatocarcinogenesis, wherein the intense rivalry between tumor-suppressive and oncogenic strengths occurred in cirrhosis stage. Despite the significant pathological difference, mutation signatures and expression landscape are highly similar between hepatitis and cirrhosis stages. Furthermore, we identified PI3K-Akt signaling pathway as a key pathway in the process of hepatocarcinogenesis through integrative analysis, and PIK3CD is a potential biomarker indicating HCC recurrence. The dynamic immune response during hepatocarcinogenesis, such as continuous decline of monocytes, suggests an immunological intervention strategy beyond chemoprevention for liver cancer.

Rehearsal of tactile working memory: Premotor cortex recruits two dissociable neuronal content representations.

Recent working memory (WM) research has focused on identifying brain regions that retain different types of mental content. Only few neuroimaging studies have explored the mechanism of attention‐based refreshing, which is a type of rehearsal and is thought to implement the dynamic components of WM allowing for update of WM contents. Here, we took advantage of the distinct coding properties of the superior parietal lobe (SPL), which retains spatial layout information, and the right inferior frontal gyrus (IFG), which retains frequency information of vibrotactile stimuli during tactile WM. In an fMRI delayed match‐to‐sample task, participants had to internally rehearse sequences of spatial layouts or vibratory frequencies. Our results replicate the dissociation of SPL and IFG for the retention of layout and frequency information in terms of activation differences between conditions. Additionally, we found strong premotor cortex (PMC) activation during rehearsal of either stimulus type. To explore interactions between these regions we used dynamic causal modeling and found that activation within the network was best explained by a model that allows the PMC to drive activity in the SPL and IFG during rehearsal. This effect was content‐specific, meaning that the PMC showed stronger influence on the SPL during pattern rehearsal and stronger influence on the IFG during frequency rehearsal. In line with previously established PMC contributions to sequence processing, our results suggest that it acts as a content‐independent area that flexibly recruits content‐specific regions to bring a WM item into the focus of attention during the rehearsal of tactile stimulus sequences.

A Benchmark Dataset for RSVP-Based Brain-Computer Interfaces.

This paper reports on a benchmark dataset acquired with a brain–computer interface (BCI) system based on the rapid serial visual presentation (RSVP) paradigm. The dataset consists of 64-channel electroencephalogram (EEG) data from 64 healthy subjects (sub1,…, sub64) while they performed a target image detection task. For each subject, the data contained two groups (“A” and “B”). Each group contained two blocks, and each block included 40 trials that corresponded to 40 stimulus sequences. Each sequence contained 100 images presented at 10 Hz (10 images per second). The stimulus images were street-view images of two categories: target images with human and non-target images without human. Target images were presented randomly in the stimulus sequence with a probability of 1∼4%. During the stimulus presentation, subjects were asked to search for the target images and ignore the non-target images in a subjective manner. To keep all original information, the dataset was the raw continuous data without any processing. On one hand, the dataset can be used as a benchmark dataset to compare the algorithms for target identification in RSVP-based BCIs. On the other hand, the dataset can be used to design new system diagrams and evaluate their BCI performance without collecting any new data through offline simulation. Furthermore, the dataset also provides high-quality data for characterizing and modeling event-related potentials (ERPs) and steady-state visual evoked potentials (SSVEPs) in RSVP-based BCIs. The dataset is freely available from http://bci.med.tsinghua.edu.cn/download.html.

Contributions of Different Spatial Modulations of Brightness Gradients to the Control of Visual Attention

The targets of visual selective attention are the most informative parts of images. All new data in recent years have pointed to the importance of second-order features – spatial inhomogeneities in brightness gradients – in solving a variety of visual tasks. We addressed the problem of determining how priorities of second-order features are distributed from the point of view of attracting attention. All information from initial images of objects other than modulations of specific modalities was removed. As a result, each object was represented in three versions: images consisting of modulations of contrast, orientation, and spatial frequency. In experiment 1, images formed from modulations of different dimensionalities but with the same spatial frequency competed for attention. In experiment 2, modulations of the same dimensionality but different frequencies were used. The direction of the subject’s attention was evaluated by recording eye movements. The first saccade after stimulus onset was assessed. The observations showed that in the object orientation discrimination task using pairs of sequential stimuli, images formed from modulations of contrast and orientation of lower spatial frequency had a significant advantage in competing for attention. This result is explained by the notion that in competing for attention, areas of images with greater amplitude of brightness gradient modulation had the advantage in competing for attention.

Perceptual Oscillations in Gender Classification of Faces, Contingent on Stimulus History.

SummaryPerception is a proactive ‘‘predictive’’ process, in which the brain takes advantage of past experience to make informed guesses about the world to test against sensory data. Here we demonstrate that in the judgment of the gender of faces, beta rhythms play an important role in communicating perceptual experience. Observers classified in forced choice as male or female, a sequence of face stimuli, which were physically constructed to be male or female or androgynous (equal morph). Classification of the androgynous stimuli oscillated rhythmically between male and female, following a complex waveform comprising 13.5 and 17 Hz. Parsing the trials based on the preceding stimulus showed that responses to androgynous stimuli preceded by male stimuli oscillated reliably at 17 Hz, whereas those preceded by female stimuli oscillated at 13.5 Hz. These results suggest that perceptual priors for face perception from recent perceptual memory are communicated through frequency-coded beta rhythms.