Sustained peripheral somatosensory stimulations, such as high-frequency repetitive somatosensory stimulation (HF-RSS) and vibrated stimulation, are effective in altering the balance between excitation and inhibition in the somatosensory cortex (S1) and motor cortex (M1). A recent study reported that whole-hand water flow (WF) stimulation induced neural disinhibition in the M1. Based on previous results, we hypothesized that whole-hand WF stimulation would lead to neural disinhibition in the S1 because there is a strong neural connection between M1 (...) and S1 and aimed to examine whether whole-hand WF stimulation would change the neural balance between excitation and inhibition in the S1. Nineteen healthy volunteers were studied by measuring excitation and inhibition in the S1 before and after each of the four 15-min interventions. The excitation and inhibition in the S1 were assessed using somatosensory evoked potentials (SEPs) and paired-pulse inhibition (PPI) induced by single- and paired-pulse stimulations, respectively. The four interventions were as follows: control, whole-hand water immersion, whole-hand WF, and HF-RSS. The results showed no significant changes in SEPs and PPI following any intervention. However, changes in PPI with an interstimulus interval (ISI) of 30 ms were significantly correlated with the baseline value before whole-hand WF. Thus, the present findings indicated that the whole-hand WF stimulation had a greater decreased neural inhibition in participants with higher neural inhibition in the S1 at baseline. Considering previous results on M1, the present results possibly show that S1 has lower plasticity than M1 and that the duration (15 min) of each intervention may not have been enough to alter the balance of excitation and inhibition in the S1. (shrink)

This study describes the results of experiments motivated by an attempt to understand spectral processing in the cerebral cortex (DeValois and DeValois, 1988; Pribram, 1971, 1991). This level of inquiry concerns processing within a restricted cortical area rather than that by which spatially separate circuits become synchronized during certain behavioral and experiential processes. We recorded neural responses for 55 locations in the somatosensory (barrel) cortex of the rat to various combinations of spatial frequency (texture) and temporal frequency (...) stimulation of their vibrissae. The recordings obtained from single and multi-unit bursts of spikes were mapped as surface distributions of local dendritic potentials. The distributions showed a variety of patterns that are asymmetric with respect to the spatial and temporal parameters of stimulation, and were, therefore, not simply reflecting whisker flick rate. Next, a simulation of our results showed that these surface distributions of local dendritic potentials can be described by Gabor-like functions much as in the visual system. The results provide support for a model of distributed cortical processing that imposes a physiologically derived frame (the limited extent of a dendritic patch) and an anatomically derived (axonal) sampling of the distributed process. This combination provides a complex Gabor wavelet that encodes phase, which is necessary to processing such details as edges and texture in a scene. The synchronization across cortical areas that make the Gabor wavelet processes within restricted cortical areas available to one another (the binding problem) proceed at a ''higher order'' level of integration. Both levels of distributed processing accomplish computation in the conjoint spacetime and spectral domain. (shrink)

In people with chronic low back pain, maladaptive structural and functional changes on a cortical level have been identified. On a functional level, somatosensory cortical excitability has been shown to be reduced in chronic pain conditions, resulting in cortical disinhibition. The occurrence of structural and/or functional maladaptive cortical changes in people with CLBP could play a role in maintaining the pain. There is currently no measurement protocol for cortical excitability that employs stimulation directly to the lower back. We developed (...) a protocol for the measurement of single pulse somatosensory evoked potential waveforms and paired-pulse behavior generated from sensory nerves of the lower back and quantified its test–retest reliability in a sample of 30 healthy individuals to gain insights into the normal variability of cortical responses, which could then be compared to results from people with CLBP. We investigated cortical excitability by measuring SEPs and PPB. PPB was defined as the ratio of the amplitude of the second cortical response divided by the first cortical response. A2s was determined by subtracting the response to single-pulse stimuli from the paired pulse stimuli response to account for linear superposition effects. The test–retest reliability of the protocol was very poor with no evidence of systematic bias but a high amount of random variability between sessions. There was no significant difference in the right side PPB for session 1 and session 2 ; mean session difference [ = −0.44 ; t = −1.17, p = 0.26]. The ICC3.1 for the outlier-removed right side PPB were 0.19 and 0.43 for left side PPB. This finding potentially has wider implications for PPB protocols. If these findings were replicated in other groups and other nerves, it would question the validity of this measure more generally. However, these findings are restricted to healthy people and sensory nerves of the lower back and may not be generalizable. (shrink)

BackgroundDuring the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation.ObjectiveThis study extends our previous findings by further characterizing how the brain differentially processes physical ‘touch’ stimulation and ‘imagined’ stimulation.DesignEleven healthy women participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions – imagined (...) dildo self-stimulation and imagined speculum stimulation – were included to characterize the effects of erotic versus non-erotic imagery.ResultsImagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipp... (shrink)

The functions of the somatosensory system are multiple. We use tactile input to localize and experience the various qualities of touch, and proprioceptive information to determine the position of different parts of the body with respect to each other, which provides fundamental information for action. Further, tactile exploration of the characteristics of external objects can result in conscious perceptual experience and stimulus or object recognition. Neuroanatomical studies suggest parallel processing as well as serial processing within the cerebral somatosensory (...) system that reflect these separate functions, with one processing stream terminating in the posterior parietal cortex (PPC), and the other terminating in the insula. We suggest that, analogously to the organisation of the visual system, somatosensory processing for the guidance of action can be dissociated from the processing that leads to perception and memory. In addition, we find a second division between tactile information processing about external targets in service of object recognition and tactile information processing related to the body itself. We suggest the posterior parietal cortex subserves both perception and action, whereas the insula principally subserves perceptual recognition and learning. (shrink)

We review evidence for multifaceted functional specialization of somatosensory information processing, both within and outside classical somatosensory cortex. We argue that the nature of such specialization has not yet been clarified adequately to regard the proposed action/perception dichotomy as being established. However, we believe this is a good working hypothesis that can motivate further work.

The model presented in the target article includes feature processing and higher representations. I argue, based on neuropsychological evidence, that spatial representations are also involved in perceptual awareness of somatosensory events. Second, there is an asymmetry, with a right-hemisphere–based bilateral representation of the body. Third, the specific aspect of bodily awareness concerning motor function monitoring involves a network that includes the premotor cortex.

Mismatch brain responses to unpredicted rare stimuli are suggested to be a neural indicator of prediction error, but this has rarely been studied in the somatosensory modality. Here, we investigated how the brain responds to unpredictable and predictable rare events. Magnetoencephalography responses were measured in adults frequently presented with somatosensory stimuli that were occasionally replaced by two consecutively presented rare stimuli [unpredictable rare stimulus and predictable rare stimulus ; p = 0.1 for each]. The FRE and PR were (...) electrical stimulations administered to either the little finger or the forefinger in a counterbalanced manner between the two conditions. The UR was a simultaneous electrical stimulation to both the forefinger and the little finger. The grand-averaged responses were characterized by two main components: one at 30–100 ms and the other at 130–230 ms latency. Source-level analysis was conducted for the primary somatosensory cortex and the secondary somatosensory cortex. The M55 responses were larger for the UR and PR than for the FRE in both the SI and the SII areas and were larger for the UR than for the PR. For M150, both investigated areas showed increased activity for the UR and the PR compared to the FRE. Interestingly, although the UR was larger in stimulus energy and had a larger prediction error potential than the PR, the M150 responses to these two rare stimuli did not differ in source strength in either the SI or the SII area. The results suggest that M55, but not M150, can possibly be associated with prediction error signals. These findings highlight the need for disentangling prediction error and rareness-related effects in future studies investigating prediction error signals. (shrink)

The issue of whether information is processed in parallel or in series in the somatosensory system is complicated by a number of factors. Included among these is the failure on the part of the scientific community to reach a consensus as to what actually constitutes the primary somatosensory cortex (SI) in higher primates. A second, related issue is the marked difference in the organization of the cortical areas subserving somatosensation across species.

The parietal cortex is divided into two major functional regions: the anterior parietal cortex that includes primary somatosensory cortex, and the posterior parietal cortex (PPC) that includes the rest of the parietal lobe. The PPC contains multiple representations of space. In Dijkerman & de Haan's (D&dH's) model, higher spatial representations are separate from PPC functions. This model should be developed further so that the functions of the somatosensory system are integrated with specific functions within (...) the PPC and higher spatial representations. Through this further specification of the model, one can make better predictions regarding functional interactions between somatosensory and visual systems. (shrink)

Focus of attention is one of the most influential factors facilitating motor performance. Previous evidence supports that the external focus strategy, which directs attention to movement outcomes, is associated with better motor performance than the internal focus strategy, which directs attention to body movements. However, recent studies have reported that the EF strategy is not effective for some individuals. Furthermore, neuroimaging studies have demonstrated that the frontal and parietal areas characterize individual optimal attentional strategies for motor tasks. However, whether the (...) sensory cortices are also functionally related to individual optimal attentional strategy remains unclear. Therefore, the present study examined whether an individual’s sensory processing ability would reflect the optimal attentional strategy. To address this point, we explored the relationship between responses in the early sensory cortex and individuals’ optimal attentional strategy by recording steady-state somatosensory evoked potentials and steady-state visual evoked potentials. Twenty-six healthy young participants first performed a motor learning task with reaching movements under IF and EF conditions. Of the total sample, 12 individuals showed higher after-effects under the IF condition than the EF condition, whereas the remaining individuals showed the opposite trend. Subsequently, we measured SSSEP from bilateral primary somatosensory cortices while presenting vibrotactile stimuli and measured SSVEP from bilateral primary visual cortices while presenting checkerboard visual stimuli. The degree of increasing SSSEP response when the individuals in the IF-dominant group directed attention to vibrotactile stimuli was significantly more potent than those in the EF-dominant individuals. By contrast, the individuals in the EF-dominant group showed a significantly larger SSVEP increase while they directed attention to visual stimuli compared with the IF-dominant individuals. Furthermore, a significant correlation was observed such that individuals with more robust IF dominance showed more pronounced SSSEP attention modulation. These results suggest that the early sensory areas have crucial brain dynamics to characterize an individual’s optimal attentional strategy during motor tasks. The response characteristics may reflect the individual sensory processing ability, such as control of priority to the sensory inputs. Considering individual cognitive traits based on the suitable attentional strategy could enhance adaptability in motor tasks. (shrink)

Background: We like to think about sexual activity as something fixed, basic and primal. However, this does not seem to fully capture reality. Even when we relish sex, we may be capable of mentalizing, talking, voluntarily postponing orgasm, and much more. This might indicate that the central control mechanisms of sexual activity are quite flexible and susceptible to learning mechanisms, and that cortical brain areas play a critical part. Objective: This study aimed to identify those cortical areas and mechanisms most (...) consistently implicated in sexual activity. Design: A comprehensive review of the human functional neuroimaging literature on sexual activity, i.e. genital stimulation and orgasm, is made. Results: Genital stimulation recruits the classical somatosensory matrix, but also areas far beyond that. The posterior insula may be particularly important for processing input from the engorged penis and coordinating penile responses. Extrastriate visual cortex tracks sexual arousal and responds to genital stimulation even when subjects have their eyes closed. The ventromedial prefrontal cortex is also tightly coupled to sexual arousal, but low activity in this area predicts high sexual arousal. Conclusion: This review has indicated cortical sites where activity is moderated by tactile genital inflow and high sexual arousal. Behavioral implications are discussed and where possible the relevance for learning mechanisms is indicated. Overall, it is clear that the cerebral cortex has something to say about sexual activity. Keywords: functional neuroimaging; insula; ventromedial prefrontal cortex; extrastriate visual cortex; penis; clitoris; orgasm (Published: 15 March 2012) Citation: Socioaffective Neuroscience & Psychology 2012, 2 : 17337 - DOI: 10.3402/snp.v2i0.17337. (shrink)

Background. Although genital sensations are an essential aspect of sexual behavior, the cortical somatosensory representation of genitalia in women and men remain poorly known and contradictory results have been reported. Objective. To conduct a systematic review of studies based on electrophysiological and functional neuroimaging studies, with the aim to identify insights brought by modern methods since the early descriptions of the sensory homunculus in the primary somatosensory cortex . Results. The review supports the interpretation that there are (...) two distinct representations of genital sensations in SI, one on the medial surface and the other on the lateral surface. In addition, the review suggests that the secondary somatosensory cortex and the posterior insula support a representation of the affective aspects of genital sensation. Conclusion. In view of the erogenous character of sensations originating in the genitalia, future studies on this topic should systematically assess qualitatively as well as quantitatively the sexually stimulating and/or sexually pleasurable characteristics of sensations felt by subjects in response to experimental stimuli. (shrink)

Libet discovered that a substantial duration (> 0.5-1.0 s) of direct electrical stimulation of the surface of the somatosensory cortex at threshold currents is required before human subjects can report that a conscious somatosensory experience had occurred. Using a reaction time method we confirm that a similarly long stimulation duration at threshold currents is required for activation of elementary visual experiences (phosphenes) in human subjects following stimulation of the surface of the striate cortex. However, the reaction (...) times for the subject to respond to the cessation of the visual experience after the end of electrical stimulation could be as brief as 225-242 ms. We also carried out extensive studies in cats under a variety of anesthetic conditions using the same electrodes and parameters of stimulation employed in the human studies to study the patterns of neuronal activity beneath the stimulating surface electrode. Whereas sufficiently strong currents can activate neurons within milliseconds, stimulating currents close to threshold activate sustained neural activity only after at least 350-500 ms. When currents are close to threshold, some neurons are inhibited for several hundreds of millisecond before the balance between inhibition and excitation shifts towards excitation. These results suggest that the prolonged latencies, i.e., latencies beyond 200-250 ms, for the emergence of conscious experience following direct cortical stimulation result from a delay in the sustained activation of underlying cortical neurons at threshold currents rather than being due to any unusually long duration in central processing time. Intracellular records from cortical neurological cells during repetitive electrical stimulation of the surface of the feline striate cortex demonstrate that such stimulation induces a profound depolarizing shift in membrane potential that may persist after each stimulus train. Such a depolarization is evidence that extracellular K+ concentrations have increased during electrical stimulation. Such an increase in extracellular K+ progressively increases cortical excitability until the threshold for sustained activation of cortical neurons is reached and then exceeded. Consequently, the long latency for threshold activation of cortical neurons depends upon a dynamically increasing cortical facilatory process that begins hundreds of milliseconds before there is sustained activation of such neurons. In some cases, this facilatory process must overcome an initial stimulus-induced inhibition before neuronal firing commences. (shrink)

Recent application of theories of embodied or grounded cognition to the recognition and interpretation of facial expression of emotion has led to an explosion of research in psychology and the neurosciences. However, despite the accelerating number of reported findings, it remains unclear how the many component processes of emotion and their neural mechanisms actually support embodied simulation. Equally unclear is what triggers the use of embodied simulation versus perceptual or conceptual strategies in determining meaning. The present article integrates behavioral research (...) from social psychology with recent research in neurosciences in order to provide coherence to the extant and future research on this topic. The roles of several of the brain's reward systems, and the amygdala, somatosensory cortices, and motor centers are examined. These are then linked to behavioral and brain research on facial mimicry and eye gaze. Articulation of the mediators and moderators of facial mimicry and gaze are particularly useful in guiding interpretation of relevant findings from neurosciences. Finally, a model of the processing of the smile, the most complex of the facial expressions, is presented as a means to illustrate how to advance the application of theories of embodied cognition in the study of facial expression of emotion. (shrink)

Based on theoretical considerations of Aurell (1979) and Block (1995), we argue that object recognition awareness is distinct from purely sensory awareness and that the former is mediated by neuronal activities in areas that are separate and distinct from cortical sensory areas. We propose that two of the principal functions of neuronal activities in sensory cortex, which are to provide sensory awareness and to effect the computations that are necessary for object recognition, are dissociated. We provide examples of how (...) this dissociation might be achieved and argue that the components of the neuronal activities which carry the computations do not directly enter the awareness of the subject. The results of these computations are sparse representations (i.e., vector or distributed codes) which are activated by the presentation of particular sensory objects and are essentially engrams for the recognition of objects. These final representations occur in the highest order areas of sensory cortex; in the visual analyzer, the areas include the anterior part of the inferior temporal cortex and the perirhinal cortex. We propose, based on lesion and connectional data, that the two areas in which activities provide recognition awareness are the temporopolar cortex and the medial orbitofrontal cortex. Activities in the temporopolar cortex provide the recognition awareness of objects learned in the remote past (consolidated object recognition), and those in the medial orbitofrontal cortex provide the recognition awareness of objects learned in the recent past. The activation of the sparse representation for a particular sensory object in turn activates neurons in one or both of these regions of cortex, and it is the activities of these neurons that provide the awareness of recognition of the object in question. The neural circuitry involved in the activation of these representations is discussed. (shrink)

The aim of this paper is to develop and defend an Attentional View of bodily awareness, on which attention is necessary for bodily awareness. The original formulation of the Attentional View is due to Marcel Kinsbourne. First, I will show that the Attentional View of bodily awareness as formulated by Kinsbourne is superior to other accounts in the literature for characterizing the relationship between attention and bodily awareness. Kinsbourne’s account is the only account in the literature so far which can (...) accommodate key neurological diseases such as personal neglect. Second, when I consider Kinsbourne’s view in more detail, I will argue that Kinsbourne’s Attentional View faces problems because it is too reductive. Kinsbourne deviates from the standard taxonomy on which there is a body schema and a body image. Instead he reduces the body image to the neural representation of the body in the somatosensory cortex, the body schema and attentional shifts. I will present two challenges to Kinsbourne’s view which demonstrate that Kinsbourne’s reduction of the body image is unsuccessful. Finally, I will present a revised version of the Attentional View that is both empirically adequate and philosophically satisfactory. (shrink)

To further develop three-dimensional (3D) applications, it is important to elucidate the negative effects of 3D applications on the human body and mind. Thus, this study investigated differences in the effects of visual fatigue on cognition and brain activity using visual and auditory tasks induced by watching a 1-h movie in two dimensions (2D) and 3D. Eighteen young men participated in this study. Two conditions were randomly performed for each participant on different days, namely, watching the 1-h movie on television (...) in 2D (control condition) and 3D (3D condition). Before and after watching the 1-h movie on television, critical flicker fusion frequency (CFF: an index of visual fatigue), and response accuracy and reaction time for the cognitive tasks were determined. Brain activity during the cognitive tasks was evaluated using a multi-channel near-infrared spectroscopy system. In contrast to the control condition, the decreased CFF, and the lengthened reaction time and the decreased activity around the right primary somatosensory cortex during Go/NoGo blocks in the visual task at post-viewing in the 3D condition were significant, with significant repeated measures correlations among them. Meanwhile, in the auditory task, the changes in cognitive performance and brain activity during the Go/NoGo blocks were not significant in the 3D condition. These results suggest that the failure or delay in the transmission of visual information to the primary somatosensory cortex due to visual fatigue induced by watching a 3D movie reduced the brain activity around the primary somatosensory cortex, resulting in poor cognitive performance for the visual task. This suggests that performing tasks that require visual information, such as running in the dark or driving a car, immediately after using a 3D application, may create unexpected risks in our lives. Thus, the findings of this study will help outlining precautions for the use of 3D applications. (shrink)

Several arguments suggest that motor planning may share embodied neural mechanisms with mental rotation (MR). However, it is not well established whether this overlap occurs regardless of the type of stimulus that is manipulated, in particular manipulable or non-manipulable objects and body parts. We here used high-density electroencephalography (EEG) to examine the cognitive similarity between MR of objects that do not afford specific hand actions (chairs) and bodily stimuli (hands). Participants had identical response options for both types of stimuli, and (...) they gave responses orally in order to prevent possible interference with motor imagery. MR of hands and chairs generated very similar behavioral responses, time-courses and neural sources of evoked-response potentials (ERPs). ERP segmentation analysis revealed distinct time windows during which differential effects of stimulus type and angular disparity were observed. An early period (90–160 ms) differentiated only between stimulus types, and was associated with occipito-temporal activity. A later period (290–330 ms) revealed strong effects of angular disparity, associated with electrical sources in the right angular gyrus and primary motor/somatosensory cortex. These data suggest that spatial transformation processes and motor planning are recruited simultaneously, supporting the involvement of motor emulation processes in MR. (shrink)

The concept of empathy describes our capacity to understand the emotions and intentions of others and to relate to our conspecifics. Numerous studies investigated empathy as a state as well as a stable personality trait. For example, recent studies in neuroscience suggest, among other brain areas such as the insula or the ACC, a role of the somatosensory cortices for empathy. Since the classic understanding of the primary somatosensory cortex is to represent touch on the body surface, (...) we here aimed to test whether tactile performance is linked to the personality trait empathy. To test this, we examined the tactile acuity of 95 healthy participants by using a two-point discrimination threshold task at the index fingers. Trait empathy was assessed by employing the interpersonal reactivity index, which measures self-reported empathy with four scales. Results of regression analyses suggested the subscale empathic concern to be positively associated with performance in the tactile acuity task. We discuss this finding in the light of recent studies on empathy and consider possible implications of tactile training to enhance empathy. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:The Aspiration to the Condition of TouchChristopher Perricone"The Dance," written by William Carlos Williams in 1944 is one of my favorite poems: I return to it regularly. Williams gives us a feel for that life of the kermess (a carnival) in his poem through Breughel's picture, as it were three times removed from the event itself. Of course, unlike Plato, I would argue that the vitality of the kermess (...) is not lost in the poem; it is actually enhanced by a subtle sleight of hand. The poem isn't primarily about Breughel's picture. It is about dance, about the dancers who go round, their squeal, the crude music, its rollicking measures, the dancers kicking and rolling and swinging, their hips, bellies, and butts. Reading and re-reading this poem, I "see" those ordinary folk of Breughel's great picture. I "hear" their music. I "move" to their dance. The poem seems a condensation, a summary of the fine arts. Perhaps the poem is about poetry's power to reinvigorate imaginatively what we hear and see. Perhaps I think of festivities at which I have danced, how such festivities are essential to the human experience. Perhaps, William Carlos Williams in 1944, World War II coming to a close, was anticipating similar good times. As always, it's best to let the poem speak for itself:In Breughel's great picture, The Kermess,the dancers go round, they go round and around, the squeal and the blare and the tweedle of bagpipes, a bugle and fiddles tipping their bellies (round as the thick-sided glasses whose wash they impound) their hips and their bellies off balance to turn them. Kicking and rolling about the [End Page 229] Fair Grounds, swinging their butts, those shanks must be sound to bear up under such rollicking measures, prance as they dance In Breughel's great picture, The Kermess.The visual, musical, and literary arts do much to educate our senses, especially our senses of sight and hearing. The well-formed visual and auditory sensations we gain from the arts are, as it were, the melody of those experiences. They are the images we store away, the tunes we whistle. However, here, I want to draw attention to an overlooked, although not entirely disregarded, sense, i.e., touch. I want to argue that touch is the bass line to the melody of sight and hearing in the arts, i.e., that touch keeps the work of art coherent and grounded.This is an old idea. Bernhard Berenson had the idea when he was examining the painters of the Italian renaissance. Berenson argued that great painting stimulates touch, which inspires, our "tactile imagination," which produces our "tactile values." Here lay, according to Berenson the genius of Giotto. Tactile imagination and values enchance the "material significance" of a work; they act as a "test of reality." Berenson was on to something not only about painting but about the arts in general. However, in the late nineteenth and early twentieth centuries he lacked the scientific evidence about touch and its role in human relationships to develop his idea of tactile values to any great extent.1Although Berenson had keen intuitions, he didn't know about the biological/psychological nuts and bolts of touch. Thus, he never knew about the detailed nature and extent of our physical contact with other physical things in the world. He didn't know about Merkel's discs, Ruffini and Pacinian corpuscles. He didn't know about hierarchical and parallel levels of brain processing. Berenson didn't know that more brain space in the somatosensory cortex is given to the hand than to any other part of the body, that your fingers especially have a high density of touch receptors compared to other body areas. Today, all this information is standard textbook fare.2 Many neuroscientific details need to be worked. However, a general picture based on hard evidence has begun to emerge.This information adds significant substance to Berenson's ideas. Berenson's "third dimension" is essentially a sense of temperature, pressure, vibration, and texture. And chances are the tactile imagination is inspired most by what is touched by... (shrink)

Riassunto: Il dibattito in filosofia della mente è caratterizzato dal crescente interesse per nuove forme di eliminativismo, note con il nome di teorie enattiviste radicali della mente. Secondo la concezione enattivista radicale, il contenuto intenzionale di uno stato mentale è empiricamente sottodeterminato, pertanto non può essere utilizzato quale elemento di una spiegazione naturalistica del comportamento. Tuttavia, sebbene il riferimento ai contenuti intenzionali non sia conciliabile con il naturalismo ontologico, esso è invece compatibile con una forma di naturalismo metodologico. Seguendo l’analisi (...) semantica proposta da Carnap per i termini teorici, è possibile concepire uno stato mentale come un veicolo simbolico il cui significato è stabilito per mezzo di osservazioni e scelte convenzionali. Attraverso un caso di studio riguardante le funzioni cognitive della corteccia somatosensoriale, l’articolo fornisce le indicazioni programmatiche per un’interpretazione delle spiegazioni intenzionali del comportamento in accordo con la metodologia delle scienze naturali. Parole chiave: Contenuto mentale; Enattivismo radicale; Intenzionalità; Naturalismo; Teleosemantica; Teoria della spiegazione T he Methodological Status of Intentional Contents: The philosophy of mind debate is characterized by increasing consensus regarding a new type of eliminativism, also known as the radical enactivist theory of mind. According to the radical enactivist view, the intentional content of a mental state is empirically undetermined, therefore it cannot figure as part of a naturalistic explanation of behavior. However, although the notion of intentional content is not compatible with any form of ontological naturalism, it is compatible with a form of methodological naturalism. Following Carnap’s semantic analysis of theoretical concepts, it is possible to conceive of intentional mental states as a symbolic vehicles whose meaning can be conventionally established on the basis of empirical observation. In order to support this claim, I refer to a case study on the cognitive functions of somatosensory cortex. This article provides arguments for building an intentional explanation of behavior based on methodological approaches in the natural sciences. Keywords: Mental Content; Radical Enactivism; Intentionality; Naturalism; Teleosemantics; Theory of Explanation. (shrink)

This paper discusses recent neuroscientific research that indicates a solution for what we label the ''causal problem'' of pain qualia, the problem of how the brain generates pain qualia. In particular, the data suggest that pain qualia naturally supervene on activity in a specific brain region: the anterior cingulate cortex (ACC). The first section of this paper discusses several philosophical concerns regarding the nature of pain qualia. The second section overviews the current state of knowledge regarding the neuroanatomy and (...) physiology of pain processing. The third section highlights the recent research by Rainville et al. [(1997) Pain affect encoded in human anterior cingulate but not somatosensory cortex, Science, 277, 968-971], which suggests that pain affect is encoded in the ACC. The final section of the paper spells out exactly how these data affect the causal problem of pain qualia. (shrink)

Modified action, either artificially induced or occurring naturally during life-span, alters organization and processing of primary somatosensory cortex, thereby serving as a predictor of age-related changes. These findings, together with the interconnectedness between motor-sensory systems and temporally-distributed processing across hierarchical levels, throws into question a sharp division between early perception and cognition, and suggest that composite codes of perception and action might not be limited to higher areas.

The processes whereby our brains continue to learn about a changing world in a stable fashion throughout life are proposed to lead to conscious experiences. These processes include the learning of top-down expectations, the matching of these expectations against bottom-up data, the focusing of attention upon the expected clusters of information, and the development of resonant states between bottom-up and top-down processes as they reach an attentive consensus between what is expected and what is there in the outside world. It (...) is suggested that all conscious states in the brain are resonant states and that these resonant states trigger learning of sensory and cognitive representations. The models which summarize these concepts are therefore called Adaptive Resonance Theory, or ART, models. Psychophysical and neurobiological data in support of ART are presented from early vision, visual object recognition, auditory streaming, variable-rate speech perception, somatosensory perception, and cognitive-emotional interactions, among others. It is noted that ART mechanisms seem to be operative at all levels of the visual system, and it is proposed how these mechanisms are realized by known laminar circuits of visual cortex. It is predicted that the same circuit realization of ART mechanisms will be found in the laminar circuits of all sensory and cognitive neocortex. Concepts and data are summarized concerning how some visual percepts may be visibly, or modally, perceived, whereas amodal percepts may be consciously recognized even though they are perceptually invisible. It is also suggested that sensory and cognitive processing in the What processing stream of the brain obey top-down matching and learning laws that are often complementary to those used for spatial and motor processing in the brain's Where processing stream. This enables our sensory and cognitive representations to maintain their stability as we learn more about the world, while allowing spatial and motor representations to forget learned maps and gains that are no longer appropriate as our bodies develop and grow from infanthood to adulthood. Procedural memories are proposed to be unconscious because the inhibitory matching process that supports these spatial and motor processes cannot lead to resonance. (shrink)

ObjectiveIn this study we used functional magnetic resonance imaging to investigate whether motor imagery of handwriting and circle drawing activates a similar handwriting network as writing and drawing itself.MethodsEighteen healthy right-handed participants wrote the German word “Wellen” and drew continuously circles in a sitting and lying position to capture kinematic handwriting parameters such as velocity, pressure and regularity of hand movements. Afterward, they performed the same tasks during fMRI in a MI and an executed condition.ResultsThe kinematic analysis revealed a general (...) correlation of handwriting parameters during sitting and lying except of pen pressure during drawing. Writing compared to imagined writing was accompanied by an increased activity of the ipsilateral cerebellum and the contralateral sensorimotor cortex. Executed compared to imagined drawing revealed elevated activity of a fronto–parieto-temporal network. By contrasting writing and drawing directly, executed writing induced an enhanced activation of the left somatosensory and premotor area. The comparison of the MI of these tasks revealed a higher involvement of occipital activation during imagined writing.ConclusionThe kinematic results pointed to a high comparability of writing in a vertical and horizontal position. Overall, we observed highly overlapping cortical activity except of a higher involvement of motor control areas during motor execution. The sparse difference between writing and drawing can be explained by highly automatized writing in healthy individuals. (shrink)

Sensation elicited by a skin stimulus was subjectively reported to feel stronger when followed by a stimulus to somatosensory cerebral cortex , even when C was delayed by up to 400 ms or more. This expands the potentiality for retroactive effects beyond that previously known as backward masking. It also demonstrates that the content of a sensory experience can be altered by another cerebral input introduced after the sensory signal arrives at the cortex. The long effective S-C (...) intervals support the thesis that a duration of cortical activity of up to 0.5 s is required before awareness of a sensory stimulus is developed. (shrink)

Human adaptive behavior in sensorimotor control is aimed to increase the confidence in feedforward mechanisms when sensory afferents are uncertain. It is thought that these feedforward mechanisms rely on predictions from internal models. We investigate whether the brain uses an internal model of physical laws to help estimate body equilibrium when tactile inputs from the foot sole are depressed by carrying extra weight. As direct experimental evidence for such a model is limited, we used Judoka athletes thought to have built (...) up internal models of external loads as compared with Non-Athlete participants and Dancers. Using electroencephalography, we first tested the hypothesis that the influence of tactile inputs was amplified by descending cortical efferent signals. We compared the amplitude of P1N1 somatosensory cortical potential evoked by electrical stimulation of the foot sole in participants standing still with their eyes closed. We showed smaller P1N1 amplitudes in the Load compared to No Load conditions in both Non-Athletes and Dancers. This decrease neural response to tactile stimulation was associated with greater postural oscillations. By contrast in the Judoka’s group, the neural early response to tactile stimulation was unregulated in the Load condition. This suggests that the brain can selectively increase the functional gain of sensory inputs, during challenging equilibrium tasks when tactile inputs were mechanically depressed by wearing a weighted vest. In Judokas, the activation of regions such as the right posterior inferior parietal cortex as early as the P1N1 is likely the source of the neural responses being maintained similar in both Load and No Load conditions. An overweight internal model stored in the right PPC known to be involved in maintaining a coherent representation of one’s body in space can optimize predictive mechanisms in situations with high balance constraints. This hypothesis has been confirmed by showing that postural reaction evoked by a translation of the support surface on which participants were standing wearing extra-weight was improved in Judokas. (shrink)

Knee proprioception deficits and neuroplasticity have been indicated following injury to the anterior cruciate ligament. Evidence is, however, scarce regarding brain response to knee proprioception tasks and the impact of ACL injury. This study aimed to identify brain regions associated with the proprioceptive sense of joint position at the knee and whether the related brain response of individuals with ACL reconstruction differed from that of asymptomatic controls. Twenty-one persons with unilateral ACL reconstruction of either the right or left knee, as (...) well as 19 controls matched for sex, age, height, weight and current activity level, performed a knee joint position sense test during simultaneous functional magnetic resonance imaging. Integrated motion capture provided real-time knee kinematics to activate test instructions, as well as accurate knee angles for JPS outcomes. Recruited brain regions during knee angle reproduction included somatosensory cortices, prefrontal cortex and insula. Neither brain response nor JPS errors differed between groups, but across groups significant correlations revealed that greater errors were associated with greater ipsilateral response in the anterior cingulate, supramarginal gyrus and insula. This is the first study to capture brain response using fMRI in relation to quantifiable knee JPS. Activated brain regions have previously been associated with sensorimotor processes, body schema and interoception. Our innovative paradigm can help to guide future research investigating brain response to lower limb proprioception. (shrink)

Background: The regulation of muscle force is a vital aspect of sensorimotor control, requiring intricate neural processes. While neural activity associated with upper extremity force control has been documented, extrapolation to lower extremity force control is limited. Knowledge of how the brain regulates force control for knee extension and flexion may provide insights as to how pathology or intervention impacts central control of movement.Objectives: To develop and implement a neuroimaging-compatible force control paradigm for knee extension and flexion.Methods: A magnetic resonance (...) imaging safe load cell was used in a customized apparatus to quantify force during neuroimaging. Visual biofeedback and a target sinusoidal wave that fluctuated between 0 and 5 N was provided via an MRI-safe virtual reality display. Fifteen right leg dominant female participants completed a knee extension and flexion force matching paradigm during neuroimaging. The force-matching error was calculated based on the difference between the visual target and actual performance. Brain activation patterns were calculated and associated with force-matching error and the difference between quadriceps and hamstring force-matching tasks were evaluated with a mixed-effects model.Results: Knee extension and flexion force-matching tasks increased BOLD signal among cerebellar, sensorimotor, and visual-processing regions. Increased knee extension force-matching error was associated with greater right frontal cortex and left parietal cortex activity and reduced left lingual gyrus activity. Increased knee flexion force-matching error was associated with reduced left frontal and right parietal region activity. Knee flexion force control increased bilateral premotor, secondary somatosensory, and right anterior temporal activity relative to knee extension. The force-matching error was not statistically different between tasks.Conclusion: Lower extremity force control results in unique activation strategies depending on if engaging knee extension or flexion, with knee flexion requiring increased neural activity for the same level of force and no difference in relative error. These fMRI compatible force control paradigms allow precise behavioral quantification of motor performance concurrent with brain activity for lower extremity sensorimotor function and may serve as a method for future research to investigate how pathologies affect lower extremity neuromuscular function. (shrink)