Sensory Decision Research Articles

Comparable responses to a wide range of olfactory stimulation in women and men

The evidence for differences between women and men in terms of olfactory abilities is contradictory. We analyzed women and men’s performance and reactions to a wider range of odour exposure outcomes than usually studied, to assess possible differences and similarities between sexes. Measures of sensitivity and sensory decision rule were established in 37 women and 39 men. Perceptual, cognitive, symptom-related and autonomic nervous system (skin conductance level and heart-rate variability) reactions were also assessed during extended ambient odour exposure, as well as participants’ self-rated chemical intolerance. Bayesian analyses consistently revealed greater support for sex-related similarities than differences, suggesting that women and men perform and react comparably not only in terms of basic olfactory measures, but also to environmental odour exposure mimicking everyday situations.

Temporal order judgment of multisensory stimuli in rat and human.

We do not fully understand the resolution at which temporal information is processed by different species. Here we employed a temporal order judgment (TOJ) task in rats and humans to test the temporal precision with which these species can detect the order of presentation of simple stimuli across two modalities of vision and audition. Both species reported the order of audiovisual stimuli when they were presented from a central location at a range of stimulus onset asynchronies (SOA)s. While both species could reliably distinguish the temporal order of stimuli based on their sensory content (i.e., the modality label), rats outperformed humans at short SOAs (less than 100 ms) whereas humans outperformed rats at long SOAs (greater than 100 ms). Moreover, rats produced faster responses compared to humans. The reaction time data further revealed key differences in decision process across the two species: at longer SOAs, reaction times increased in rats but decreased in humans. Finally, drift-diffusion modeling allowed us to isolate the contribution of various parameters including evidence accumulation rates, lapse and bias to the sensory decision. Consistent with the psychophysical findings, the model revealed higher temporal sensitivity and a higher lapse rate in rats compared to humans. These findings suggest that these species applied different strategies for making perceptual decisions in the context of a multimodal TOJ task.

Transformation of acoustic information to sensory decision variables in the parietal cortex

The process by which sensory evidence contributes to perceptual choices requires an understanding of its transformation into decision variables. Here, we address this issue by evaluating the neural representation of acoustic information in the auditory cortex-recipient parietal cortex, while gerbils either performed a two-alternative forced-choice auditory discrimination task or while they passively listened to identical acoustic stimuli. During task engagement, stimulus identity decoding performance from simultaneously recorded parietal neurons significantly correlated with psychometric sensitivity. In contrast, decoding performance during passive listening was significantly reduced. Principal component and geometric analyses revealed the emergence of low-dimensional encoding of linearly separable manifolds with respect to stimulus identity and decision, but only during task engagement. These findings confirm that the parietal cortex mediates a transition of acoustic representations into decision-related variables. Finally, using a clustering analysis, we identified three functionally distinct subpopulations of neurons that each encoded task-relevant information during separate temporal segments of a trial. Taken together, our findings demonstrate how parietal cortex neurons integrate and transform encoded auditory information to guide sound-driven perceptual decisions.

Chemical Intolerance Is Associated With Altered Response Bias, not Greater Sensory Sensitivity.

Chemical intolerance is a surprisingly prevalent condition or affliction characterized by adverse reactions to low levels of chemical, often odorous stimulation. Sufferers often assume that their plight is due to an uncommon sensory acuteness, yet studies repeatedly fail to reveal altered detection thresholds. Here, we investigated whether self-reported chemical intolerance is associated with altered sensory sensitivity or response bias. The sensory acuity (sensitivity; A) and sensory decision rule (criterion; B) to n-butanol was assessed using the method of constant stimuli in 82 participants with different degrees of chemical intolerance (low to high). Higher self-reported chemical intolerance was associated with a lower criterion, but not with sensitivity.

Cortical State Fluctuations during Sensory Decision Making

SummaryIn many behavioral tasks, cortex enters a desynchronized state where low-frequency fluctuations in population activity are suppressed. The precise behavioral correlates of desynchronization and its global organization are unclear. One hypothesis holds that desynchronization enhances stimulus coding in the relevant sensory cortex. Another hypothesis holds that desynchronization reflects global arousal, such as task engagement. Here, we trained mice on tasks where task engagement could be distinguished from sensory accuracy. Using widefield calcium imaging, we found that performance-related desynchronization was global and correlated better with engagement than with accuracy. Consistent with this link between desynchronization and engagement, rewards had a long-lasting desynchronizing effect. To determine whether engagement-related state changes depended on the relevant sensory modality, we trained mice on visual and auditory tasks and found that in both cases desynchronization was global, including regions such as somatomotor cortex. We conclude that variations in low-frequency fluctuations are predominately global and related to task engagement.

Segregation, connectivity, and gradients of deactivation in neural correlates of evidence in social decision making

Functional imaging studies of sensory decision making have detected a signal associated with evidence for decisions that is consistent with data from single-cell recordings in laboratory animals. However, the generality of this finding and its implications on our understanding of the organization of the fMRI signal are not clear. In the present functional imaging study, we investigated decisions in an elementary social cognition domain to identify the neural correlates of evidence, their segregation, connectivity, and their relationship to task deactivations. Besides providing data in support of an evidence-related signal in a social cognition task, we were interested in embedding these neural correlates in models of supramodal associative cortex placed at the top of a hierarchy of processing areas. Participants were asked to decide which of two depicted individuals was saddest based on information rich in sensory features (facial expressions) or through contextual cues suggesting the mental state of others (stylized drawings of mourning individuals). The signal associated with evidence for the decision was located in two distinct networks differentially recruited depending on the information type. Using the largest peaks of the signal associated with evidence as seeds in a database of connectivity data, these two networks were retrieved. Furthermore, the hubs of these networks were located near or along a ribbon of cortex located between task activations and deactivations between areas affected by perceptual priming and the deactivated areas of the default network system. In associative cortex, these findings suggest gradients of progressive relative deactivation as a possible neural correlate of the cortical organization envisaged by structural models of cortical organization and by predictive coding theories of cortical function.

A neurotransmitter produced by gut bacteria modulates host sensory behaviour.

Animals coexist in commensal, pathogenic or mutualistic relationships with complex communities of diverse organisms including microbes1. Some bacteria produce bioactive neurotransmitters which have been proposed to modulate host nervous system activity and behaviors2,3. However, the mechanistic basis of this microbiota-brain signaling and its physiological relevance is largely unknown. Here we show that in C. elegans, the neuromodulator tyramine produced by gut-colonizing commensal Providencia bacteria bypasses the requirement for host tyramine biosynthesis to manipulate a host sensory decision. Bacterially-produced tyramine is likely converted to octopamine by the host tyramine β-hydroxylase enzyme. Octopamine in turn targets the OCTR-1 octopamine receptor on the ASH nociceptive neurons to modulate an aversive olfactory response. We identify genes required for tyramine biosynthesis in Providencia, and show that these genes are necessary for modulation of host behavior. We further find that C. elegans colonized by Providencia preferentially select these bacteria in food choice assays, and that this selection bias requires bacterially produced tyramine and host octopamine signaling. Our results demonstrate that a neurotransmitter produced by gut microbiota mimics the functions of the cognate host molecule to override host control of a sensory decision, thereby promoting fitness of both host and microbe.

Network modeling and Internet of things for smart and connected health systems—a case study for smart heart health monitoring and management

Heart disease is a leading cause of death in the US. Recent advances in the Internet of Things (IoT) provide a great opportunity to realize smart and connected health systems through IoT monitoring and sensor-based data analytics of cardiac disorders. However, big data arising from the large-scale IoT system pose a significant challenge for efficient and effective sensory information processing and decision making. Very little has been done to glean pertinent information about the disease-altered cardiac activity in the context of large-scale IoT network. In this study, we propose a parallel computing framework for multi-level network modeling and monitoring of cardiac dynamics to realize the potential of IoT-enabled smart health management. Specifically, dissimilarities among cardiac signals are firstly characterized among heartbeats for an individual patient, as well as among representative heartbeats for different patients. Then, a stochastic learning approach is developed to optimize the embedding of cardiac signals into a beat-to-beat network model, as well as a patient-to-patient network model. Further, we develop a parallel computing algorithm to improve the computational efficiency. Finally, a statistical process monitoring scheme is designed to harness network features for real-time monitoring and anomaly detection of cardiac activities. Experimental results show the proposed methodology has strong potential to realize a smart and interconnected system for cardiac health management in the context of large-scale IoT network.

Targeted Cortical Manipulation of Auditory Perception

SummaryDriving perception by direct activation of neural ensembles in cortex is a necessary step for achieving a causal understanding of the neural code for auditory perception and developing central sensory rehabilitation methods. Here, using optogenetic manipulations during an auditory discrimination task in mice, we show that auditory cortex can be short-circuited by coarser pathways for simple sound identification. Yet when the sensory decision becomes more complex, involving temporal integration of information, auditory cortex activity is required for sound discrimination and targeted activation of specific cortical ensembles changes perceptual decisions, as predicted by our readout of the cortical code. Hence, auditory cortex representations contribute to sound discriminations by refining decisions from parallel routes.

To court or not to court - a multimodal sensory decision in Drosophila males.

When Drosophila males encounter another fly, they have to make a rapid assessment to ensure the appropriate response: should they court, fight or pursue a different action entirely? Previous work has focused on the significance of sensory cues detected by the male during these encounters; however, recent evidence highlights the importance of the male's own internal state in shaping his responses. Additionally, once triggered, courtship is not a rigid sequence of motor actions, but rather a finely tuned behavioural display that must continually update in response to sensory feedback. Here, we review recent findings highlighting how sensory information and internal states are integrated ensuring appropriate action selection, and how they sustain and fine-tune motor output. We further discuss recent advances in our understanding of species differences in sensory processing that may contribute to reproductive isolation.

Targeted Cortical Manipulation of Auditory Perception

Driving perception by direct activation of neural ensembles in cortex is a necessary step for achieving a causal understanding of the perceptual code and developing central sensory rehabilitation methods. Here, using optogenetic manipulations during an auditory discrimination task in mice, we show that auditory cortex can be short-circuited by coarser pathways for simple sound identification. Yet, when the sensory decision becomes more complex, involving temporal integration of information, auditory cortex activity is required for sound discrimination and targeted activation of specific cortical ensembles changes perceptual decisions as predicted by our readout of the cortical code. Hence, auditory cortex representations contribute to sound discriminations by refining decisions from parallel routes.

Context-dependent tactile texture-sensitivity in monkey M1 and S1 cortex.

Caudal primary motor cortex (M1, area 4) is sensitive to cutaneous inputs, but the extent to which the physical details of complex stimuli are encoded is not known. We investigated the sensitivity of M1 neurons (4 Macaca mulatta monkeys) to textured stimuli (smooth/rough or rough/rougher) during the performance of a texture discrimination task and, for some cells, during a no-task condition (same surfaces; no response). The recordings were made from the hemisphere contralateral to the stimulated digits; the motor response (sensory decision) was made with the nonstimulated arm. Most M1 cells were modulated during surface scanning in the task (88%), but few of these were texture-related (24%). In contrast, 44% of M1 neurons were texture related in the no-task condition. Recordings from the neighboring primary somatosensory cortex (S1), the potential source of texture-related signals to M1, showed that S1 neurons were significantly more likely to be texture related during the task (57 vs 24%) than M1. No difference was observed in the no-task condition (52 vs. 44%). In these recordings, the details about surface texture were relevant for S1 but not for M1. We suggest that tactile inputs to M1 were selectively suppressed when the animals were engaged in the task. S1 was spared these controls, as the same inputs were task-relevant. Taken together, we suggest that the suppressive effects are most likely exerted directly at the level of M1, possibly through the activation of a top-down gating mechanism specific to motor set/intention. NEW & NOTEWORTHY Sensory feedback is important for motor control, but we have little knowledge of the contribution of sensory inputs to M1 discharge during behavior. We showed that M1 neurons signal changes in tactile texture, but mainly outside the context of a texture discrimination task. Tactile inputs to M1 were selectively suppressed during the task because this input was not relevant for the recorded hemisphere, which played no role in generating the discrimination response.

Preference modulates smelling behaviour in olfactory decision tasks

ABSTRACTWhen people are shown a pair of images and asked to identify which one is more attractive, their gaze shifts to the image they will eventually choose, prior to making the decision. Many researchers have examined the relationship between this gaze bias and decision processes, but not the relationships between other sensory modalities and decision processes. This study examined behaviour in relation to olfactory decision tasks. In accordance with the concept of gaze bias, the likelihood of participants smelling the item they eventually chose immediately before the decision was greater when they were instructed to identify an item that was more, versus less, favoured. The likelihood of smelling the item that was eventually chosen last was also greater than chance when participants were instructed to identify the more masculine item. These results suggest that a bias to sample a chosen item last is a common phenomenon regardless of sensory modality.

Cortical correlates of perceptual decision making during tactile spatial pattern discrimination.

Perceptual decision making involves a distributed cortical network including areas related to sensory feature extraction, decision formation, and finally signalling the decision through a motor response. Although these processing steps are supposed to occur in sequence, the seemingly instant mapping of a perceptual decision onto a motor response renders these processes almost indistinguishable. To dissociate cortical areas related to sensory decision making from areas that prepare the subsequent motor response, we performed functional magnetic resonance imaging during a tactile spatial pattern discrimination task with interleaved immediate and delayed response conditions. Decision difficulty was manipulated parametrically by adding spatial noise to the tactile patterns, resulting in a rise in decision time with increasing noise. We assumed that areas involved in making the decision should show a variation in their activation with decision time and irrespective of whether (immediate response condition) or not (delayed response condition) a motor response could be prepared in advance. To exhibit these putative decision areas, we used response time, as was obtained in the immediate response condition, as parametric predictor for the difficulty-dependent variations of blood oxygenation level-dependent (BOLD)-activity in both response conditions. BOLD activations in right (contralateral) postcentral sulcus, right intraparietal sulcus (IPS) and bilateral anterior insula (aINS) reflected this parametric modulation in both response conditions, suggesting a role of these areas in tactile decisions independent of decision-specific motor preparation. Furthermore, a multivariate pattern analysis performed on the BOLD responses in the delayed response condition for a single difficulty level independently validated IPS and aINS as decision-related areas.

Sensory impairment after stroke: Exploring therapists' clinical decision making

Stroke survivors experience sensory impairments that significantly limit upper-limb functional use. Lack of clear research-based guidelines about their management exacerbates the uncertainty in occupational therapists' decision making to support these clients. This study explores occupational therapists' clinical decision making regarding upper-limb, post-stroke sensory impairments that can ultimately inform approaches to support therapists working with such clients. Twelve therapists participated in a qualitative descriptive study. Transcripts of semi-structured interviews were analyzed using content analysis. Three overarching categories were identified: deciding on the focus of interventions (describing intervention choices), it all depends (outlining factors considered when choosing interventions), and managing uncertainty in decision making (describing uncertainty and actions taken to resolve it). Providing training about post-stroke sensory impairment and decision making may improve therapists' decision making and ultimately improve client outcomes. Further research is needed to understand the impact of uncertainty on occupational therapy decision making and resulting care practices.

Collective enumeration.

Many joint decisions in everyday life (e.g., Which bar is less crowded?) depend on approximate enumeration, but very little is known about the psychological characteristics of counting together. Here we systematically investigated collective approximate enumeration. Pairs of participants made individual and collective enumeration judgments in a 2-alternative forced-choice task and when in disagreement, they negotiated joint decisions via verbal communication and received feedback about accuracy at the end of each trial. The results showed that two people could collectively count better than either one alone, but not as well as expected by previous models of collective sensory decision making in more basic perceptual domains (e.g., luminance contrast). Moreover, such collective enumeration benefited from prior, noninteractive practice showing that social learning of how to combine shared information about enumeration required substantial individual experience. Finally, the collective context had a positive but transient impact on an individual's enumeration sensitivity. This transient social influence may be explained as a motivational factor arising from the fact that members of a collective must take responsibility for their individual decisions and face the consequences of their judgments.

Decision Making during the Psychological Refractory Period

In spite of its massively parallel architecture [1], the human brain is fundamentally limited if required to perform two tasks at the same time [2, 3]. This limitation can be studied with the psychological refractory period (PRP) paradigm, where two stimuli that require speeded responses occur in close succession [4]. Interference generally takes the form of a delay in the time to respond to the second stimulus [5]. Previous studies suggested that sensory decisions require the accumulation of sensory evidence [6, 7] and that the PRP reflects the inability to form more than one decision at a time [4, 8]. In the present study, we used a psychophysical reverse-correlation technique [9, 10] to measure the time-course of evidence accumulation during the PRP. We found that the accumulation of evidence could occur during the PRP albeit with a reduced efficiency, which implies that multiple decision processes can occur in parallel in the human brain. In addition to the reduced efficiency of evidence accumulation, our results uncover an additional delay in the routing of the decision to motor structures during the PRP, which implies that the process of sensory decision making is separable from the preparation of a motor response [11-13].

A Hybrid Sensory Evaluation and Decision Support System for Vegetable Breeding Selections

A Hybrid Sensory Evaluation and Decision Support System for Vegetable Breeding Selections

Accumulating decisional evidence without awareness

Event Abstract Back to Event Accumulating decisional evidence without awareness Joel Pearson1* and Alexandra Vlassova1 1 The University of New South Wales, Psychology, Australia The mystery of the possible functions of conscious awareness has captivated the minds of scientists and philosophers for generations. Recently, there has been a surge of interest in exploring the role of awareness in the context of decision‐making. A particularly controversial and heavily debated claim is that information can be processed and evaluated unconsciously. Here, we address this issue through a novel paradigm that allows us to control and manipulate both awareness and the decision variables. Random‐ dot‐motion stimuli, which require the gradual accumulation of evidence for a decision to be reached, were suppressed from conscious awareness by a dichoptic dynamic noise pattern. We found that information in the suppressed signal modulated decision accuracy, which suggests that evidence was accumulated outside of awareness. This unconscious boost to accuracy was not accompanied by a similar boost to confidence. These results indicate that information that is accumulated in the absence of conscious awareness can improve accuracy on a sensory decision‐making task. Our findings present compelling evidence that perceptual and metacognitive awareness are not necessary for evidence to be accumulated and an accurate decision to be made. Keywords: Decision Making, Awareness, consciousness mechanisms, sensory decision making, Consciousness Conference: ACNS-2012 Australasian Cognitive Neuroscience Conference, Brisbane, Australia, 29 Nov - 2 Dec, 2012. Presentation Type: Symposium Presentation Topic: Other Citation: Pearson J and Vlassova A (2012). Accumulating decisional evidence without awareness. Conference Abstract: ACNS-2012 Australasian Cognitive Neuroscience Conference. doi: 10.3389/conf.fnhum.2012.208.00005 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 24 Oct 2012; Published Online: 26 Oct 2012. * Correspondence: Dr. Joel Pearson, The University of New South Wales, Psychology, Sydney, Australia, jpearson@unsw.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Joel Pearson Alexandra Vlassova Google Joel Pearson Alexandra Vlassova Google Scholar Joel Pearson Alexandra Vlassova PubMed Joel Pearson Alexandra Vlassova Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Developmental differences in sensory decision making involved in deciding to try a novel fruit

This research compared sensory processing and personality traits involved in deciding to try a novel fruit (guava) in adults and children. The research employed an age, sex, and food neophobia matched between-participant design to examine sensory decision making in choosing to eat a novel fruit. Forty-four adults (Study 1) and 68 children (Study 2) took part. In each study, participants were separated into two groups to investigate whether prior assessment of a familiar and liked fruit (apple) that shares similar visual characteristics to the target novel fruit (guava) increased the likelihood that an individual would decide to try it. All participants completed appetitive and familiarity ratings by sensory stages: vision, smell, and touch, prior to trying (tasting) the fruit. Participants (or their parents) also completed the general and food neophobia scales and adults also completed the sensation-seeking scale. Twenty-eight adults (64%) tried the guava and 16 did not (36%). In the second study, 22 children decided not to try the novel fruit (32%). Significant predictors of whether the adult tried the target fruit were Thrill and Adventure Seeking, Experience Seeking, General Neophobia, and 'appealing to touch'. In children, Food Neophobia, concurrent presentation of a familiar fruit alongside the target and visual assessment of the target predicted decision to try the novel fruit. This study suggests that touch is pertinent to adults' decision to try a novel fruit, whereas visual cues appear to be more important for children.