scholarly journals The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face

Cortex ◽  
2016 ◽  
Vol 81 ◽  
pp. 168-175 ◽  
Author(s):  
Sarah B. Wallwork ◽  
Kerwin Talbot ◽  
Danny Camfferman ◽  
G.L. Moseley ◽  
G.D. Iannetti
Keyword(s):  
Blink Reflex ◽  
Stimulus Position ◽  
The Face

scholarly journals The effect of face inversion for neurons inside and outside fMRI-defined face-selective cortical regions

2015 ◽  
Vol 113 (5) ◽  
pp. 1644-1655 ◽  
Author(s):  
Jessica Taubert ◽  
Goedele Van Belle ◽  
Wim Vanduffel ◽  
Bruno Rossion ◽  
Rufin Vogels
Keyword(s):  
Face Processing ◽  
Neuronal Response ◽  
Image Manipulation ◽  
Stimulus Position ◽  
Primate Brain ◽  
Cell Recording ◽  
The Face ◽  
High Concentrations ◽  
Cortical Regions ◽  
Inverted Face

It is widely believed that face processing in the primate brain occurs in a network of category-selective cortical regions. Combined functional MRI (fMRI)-single-cell recording studies in macaques have identified high concentrations of neurons that respond more to faces than objects within face-selective patches. However, cells with a preference for faces over objects are also found scattered throughout inferior temporal (IT) cortex, raising the question whether face-selective cells inside and outside of the face patches differ functionally. Here, we compare the properties of face-selective cells inside and outside of face-selective patches in the IT cortex by means of an image manipulation that reliably disrupts behavior toward face processing: inversion. We recorded IT neurons from two fMRI-defined face-patches (ML and AL) and a region outside of the face patches (herein labeled OUT) during upright and inverted face stimulation. Overall, turning faces upside down reduced the firing rate of face-selective cells. However, there were differences among the recording regions. First, the reduced neuronal response for inverted faces was independent of stimulus position, relative to fixation, in the face-selective patches (ML and AL) only. Additionally, the effect of inversion for face-selective cells in ML, but not those in AL or OUT, was impervious to whether the neurons were initially searched for using upright or inverted stimuli. Collectively, these results show that face-selective cells differ in their functional characteristics depending on their anatomicofunctional location, suggesting that upright faces are preferably coded by face-selective cells inside but not outside of the fMRI-defined face-selective regions of the posterior IT cortex.

Defensive peripersonal space: the blink reflex evoked by hand stimulation is increased when the hand is near the face

2012 ◽  
Vol 107 (3) ◽  
pp. 880-889 ◽  
Author(s):  
C. F. Sambo ◽  
M. Liang ◽  
G. Cruccu ◽  
G. D. Iannetti
Keyword(s):  
Electrical Stimulation ◽  
Brain Stem ◽  
Median Nerve ◽  
Safety Margin ◽  
Peripersonal Space ◽  
Blink Reflex ◽  
Hand Position ◽  
Electromyographic Activity ◽  
The Face ◽  
Stimulation Of

Electrical stimulation of the median nerve at the wrist may elicit a blink reflex [hand blink reflex (HBR)] mediated by a neural circuit at brain stem level. As, in a Sherringtonian sense, the blink reflex is a defensive response, in a series of experiments we tested, in healthy volunteers, whether and how the HBR is modulated by the proximity of the stimulated hand to the face. Electromyographic activity was recorded from the orbicularis oculi, bilaterally. We observed that the HBR is enhanced when the stimulated hand is inside the peripersonal space of the face, compared with when it is outside, irrespective of whether the proximity of the hand to the face is manipulated by changing the position of the arm ( experiment 1) or by rotating the head while keeping the arm position constant ( experiment 3). Experiment 2 showed that such HBR enhancement has similar magnitude when the participants have their eyes closed. Experiments 4 and 5 showed, respectively, that the blink reflex elicited by the electrical stimulation of the supraorbital nerve, as well as the N20 wave of the somatosensory evoked potentials elicited by the median nerve stimulation, are entirely unaffected by hand position. Taken together, our results provide compelling evidence that the brain stem circuits mediating the HBR in humans undergo tonic and selective top-down modulation from higher order cortical areas responsible for encoding the location of somatosensory stimuli in external space coordinates. These findings support the existence of a “defensive” peripersonal space, representing a safety margin advantageous for survival.

scholarly journals A geometric model of defensive peripersonal space

2016 ◽  
Vol 115 (1) ◽  
pp. 218-225 ◽  
Author(s):  
R. J. Bufacchi ◽  
M. Liang ◽  
L. D. Griffin ◽  
G. D. Iannetti
Keyword(s):  
Goodness Of Fit ◽  
Geometric Model ◽  
Peripersonal Space ◽  
Blink Reflex ◽  
The Body ◽  
Hand Position ◽  
Body Area ◽  
Empirical Observation ◽  
Spatial Features ◽  
The Face

Potentially harmful stimuli occurring within the defensive peripersonal space (DPPS), a protective area surrounding the body, elicit stronger defensive reactions. The spatial features of the DPPS are poorly defined and limited to descriptive estimates of its extent along a single dimension. Here we postulated a family of geometric models of the DPPS, to address two important questions with respect to its spatial features: What is its fine-grained topography? How does the nervous system represent the body area to be defended? As a measure of the DPPS, we used the strength of the defensive blink reflex elicited by electrical stimulation of the hand (hand-blink reflex, HBR), which is reliably modulated by the position of the stimulated hand in egocentric coordinates. We tested the goodness of fit of the postulated models to HBR data from six experiments in which we systematically explored the HBR modulation by hand position in both head-centered and body-centered coordinates. The best-fitting model indicated that 1) the nervous system's representation of the body area defended by the HBR can be approximated by a half-ellipsoid centered on the face and 2) the DPPS extending from this area has the shape of a bubble elongated along the vertical axis. Finally, the empirical observation that the HBR is modulated by hand position in head-centered coordinates indicates that the DPPS is anchored to the face. The modeling approach described in this article can be generalized to describe the spatial modulation of any defensive response.

scholarly journals Prepulse inhibition vs cognitive modulation of the hand-blink reflex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Viviana Versace ◽  
Stefania Campostrini ◽  
Luca Sebastianelli ◽  
Leopold Saltuari ◽  
Josep Valls-Solé ◽  
...  
Keyword(s):  
Prepulse Inhibition ◽  
Visual Processing ◽  
Blink Reflex ◽  
Experimental Conditions ◽  
Median Nerve Stimulation ◽  
Contralateral Hand ◽  
The Face ◽  
Cognitive Modulation ◽  
Self Protection ◽  
Self Stimulation

AbstractThe excitability of brainstem circuitries mediating defensive blinking in response to abrupt sensory inputs is continuously modulated by cortical areas, e.g., the hand-blink reflex (HBR), elicited by intense electrical median nerve stimulation, is enhanced when the stimulated hand is close to the face, with the behavioural purpose to optimize self-protection from increased threat. Here we investigated whether such cortically mediated HBR facilitation can be influenced by prepulse inhibition (PPI), which is known to occur entirely at the subcortical level. Twenty healthy volunteers underwent HBR recordings in five experimental conditions. In conditions 1 and 2, the stimulated hand was held either near (1) or far (2) from the face, respectively. In conditions 3 and 4, stimulation of the hand near the face was preceded by a peri-liminal prepulse to the index finger of the contralateral hand held either near (3) or far from the face (4). In condition 5, participants self-triggered the stimulus eliciting the HBR. We observed a reproducible HBR in 14 out of 20 participants and measured onset latency and area of the HBR in orbicularis oculi muscles bilaterally. HBR area decreased and latency increased in condition 2 relative to condition 1; HBR area decreased and latency increased markedly in condition 3, and somewhat less in condition 4, relative to conditions 1 and 2; self-stimulation (condition 5) also suppressed HBRs, but less than prepulses. These findings indicate that PPI of the HBR is more robust than the cognitive modulation exerted by top-down cortical projections. Possibly, an attentional shift to a prepulse may serve to reduce blinking in response to perturbation when it is convenient, in a given situation, not to interrupt ongoing visual processing.

scholarly journals Transcutaneous trigeminal nerve stimulation modulates the hand blink reflex

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Beniamina Mercante ◽  
Nicola Loi ◽  
Francesca Ginatempo ◽  
Monica Biggio ◽  
Andrea Manca ◽  
...  
Keyword(s):  
Median Nerve ◽  
Trigeminal Nerve ◽  
Nerve Stimulation ◽  
Blink Reflex ◽  
Infraorbital Nerve ◽  
Hand Position ◽  
Median Nerve Stimulation ◽  
Trigeminal Nerve Stimulation ◽  
Before And After ◽  
The Face

AbstractThe hand-blink reflex (HBR) is a subcortical response, elicited by the electrical stimulation of the median nerve, whose magnitude is specifically modulated according to the spatial properties of the defensive peripersonal space (DPPS) of the face. For these reasons, the HBR is commonly used as a model to assess the DPPS of the face. Little is known on the effects induced by the activation of cutaneous afferents from the face on the DPPS of the face. Therefore, we tested the effect of non-painful transcutaneous trigeminal nerve stimulation (TNS) on the amplitude of the HBR. Fifteen healthy participants underwent HBR recording before and after 20 min of sham- and real-TNS delivered bilaterally to the infraorbital nerve in two separate sessions. The HBR was recorded bilaterally from the orbicularis oculi muscles, following non-painful median nerve stimulation at the wrist. The HBR amplitude was assessed in the “hand‐far” and “hand‐near” conditions, relative to the hand position in respect to the face. The amplitudes of the hand-far and hand-near HBR were measured bilaterally before and after sham- and real-TNS. Real-TNS significantly reduced the magnitude of the HBR, while sham-TNS had no significant effect. The inhibitory effect of TNS was of similar extent on both the hand-far and hand-near components of the HBR, which suggests an action exerted mainly at brainstem level.

scholarly journals Clinical case of Parry–Romberg syndrome

2019 ◽  
Vol 9 (1) ◽  
pp. 75-82
Author(s):  
V. B. Voitenkov ◽  
V. N. Komantsev ◽  
E. V. Ekusheva ◽  
N. V. Skripchenko ◽  
N. V. Marchenko
Keyword(s):  
Asymmetric Reduction ◽  
Subcutaneous Fat ◽  
Unknown Origin ◽  
Well Being ◽  
Blink Reflex ◽  
Submandibular Salivary Gland ◽  
Diagnostic Challenge ◽  
Hemifacial Atrophy ◽  
The Face ◽  
Parry Romberg Syndrome

PParry–Romberg syndrome, also known as progressive hemifacial atrophy, is a rare clinical entity of unknown origin with atrophy of skin and subcutaneous fat changes. A classic case of Parry–Romberg syndrome in a woman age 43 is presented. Initial facial changes appeared at the age of 20 years amid complete well-being and in the next 21 years a subcutaneous fat atrophy of the left half face developed, resulting in characteristic deformity changes. No other complaints and manifestations of the disease (epileptic seizures, headache, involvement of the other half of the face and/or extremities) were present at the timeof survey. The analysis of blink reflex, galvanic skin reflex, needle electromyography of the m. orbicularis oris from two sides, computed tomography of the skull bones revealed no pathological changes. The face infrared thermography confirmed asymmetric reduction of temperature on the ipsilateral side. Magnetic resonance scan showed hypotrophy of the left masticatory muscle, the left submandibular salivary gland, thinning of subcutaneous fat layer, changes in the white matter of the brain. Despite the typical clinical features the Parry - Romberg syndrome is a diagnostic challenge known and it is necessary to inform doctors about the latest achievements in the study of etiology, management and prognosis of the disorder.

scholarly journals Modulation of exteroceptive electromyographic responses in defensive peripersonal space

2019 ◽  
Vol 121 (4) ◽  
pp. 1111-1124 ◽  
Author(s):  
Viviana Versace ◽  
Stefania Campostrini ◽  
Luca Sebastianelli ◽  
Leopold Saltuari ◽  
Markus Kofler
Keyword(s):  
Silent Period ◽  
Peripersonal Space ◽  
Blink Reflex ◽  
The Body ◽  
Electromyographic Activity ◽  
Sensory Afferents ◽  
Eyes Closed ◽  
Cutaneous Silent Period ◽  
The Face ◽  
Long Loop Reflex

The cutaneous silent period (CSP) to noxious finger stimulation constitutes a robust spinal inhibitory reflex that protects the hand from injury. In certain conditions, spinal inhibition is interrupted by a brief burst-like electromyographic activity, dividing the CSP into two inhibitory phases (I1 and I2). This excitatory component is termed long-loop reflex (LLR) and is presumed to be transcortical in origin. Efficient defense from environmental threats requires sensorimotor integration between multimodal sensory afferents and planning of defensive movements. In the defensive peripersonal space (DPPS) immediately surrounding the body, we interact with objects and persons with increased alertness. We investigated whether CSP differs when the stimulated hand is in the DPPS of the face compared with a distant position. Furthermore, we investigated the possible role of vision in CSP modulation. Fifteen healthy volunteers underwent CSP testing with the handheld either within 5 cm from the nose (near) or away from the body (far). Recordings were obtained from first dorsal interosseous muscle following index (D2) or little finger (D5) stimulation with varying intensities. A subgroup of subjects underwent CSP recordings in near and far conditions, both with eyes open and with eyes closed. No inhibitory CSP parameter differed between stimulation in near and far conditions. LLRs occurring following D2 stimulation were significantly larger in near than far conditions at all stimulus intensities, irrespective of subjects seeing their hand. Similar to the hand-blink reflex, spinally organized protective reflexes may be modulated by corticospinal facilitatory input when the hand enters the DPPS of the face. NEW & NOTEWORTHY The present findings demonstrate for the first time that a spinally organized protective reflex, the cutaneous silent period (CSP), may be modulated by top-down corticospinal facilitatory input when the stimulated hand enters the defensive peripersonal space (DPPS) of the face. In particular, the cortically mediated excitatory long-loop reflex, which may interrupt the CSP, is facilitated when the stimulated hand is in the DPPS, irrespective of visual control over the hand. No spinal inhibitory CSP parameter differs significantly in or outside the DPPS.

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