Hemispheric Mechanisms Controlling Voluntary and Spontaneous Facial Expressions

1990 ◽  
Vol 2 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Michael S. Gazzaniga ◽  
Charlotte S. Smylie

The capacity of each disconnected cerebral hemisphere to control a variety of facial postures was examined in three split-brain patients. The dynamics of facial posturing were analyzed in 30-msec optical disc frames that were generated off videotape recordings of each patient's response to lateralized stimuli. The results revealed that commands presented to the left hemisphere effecting postures of the lower facial muscles showed a marked asymmetry, with the right side of the face sometimes responding up to 180 msec before the left side of the face. Commands presented to the right hemisphere elicited a response only if the posture involved moving the upper facial muscles. Spontaneous postures filmed during free conversation were symmetrical. The results suggest that while either hemisphere can generate spontaneous facial expressions only the left hemisphere is efficient at generating voluntaly expressions. This contrasts sharply with the fact that both hemispheres can carry out a wide variety of other voluntary movements with the hand and foot.

2018 ◽  
Vol 30 (3) ◽  
pp. 393-410 ◽  
Author(s):  
Genevieve Quek ◽  
Dan Nemrodov ◽  
Bruno Rossion ◽  
Joan Liu-Shuang

In daily life, efficient perceptual categorization of faces occurs in dynamic and highly complex visual environments. Yet the role of selective attention in guiding face categorization has predominantly been studied under sparse and static viewing conditions, with little focus on disentangling the impact of attentional enhancement and suppression. Here we show that attentional enhancement and suppression exert a differential impact on face categorization supported by the left and right hemispheres. We recorded 128-channel EEG while participants viewed a 6-Hz stream of object images (buildings, animals, objects, etc.) with a face image embedded as every fifth image (i.e., OOOOFOOOOFOOOOF…). We isolated face-selective activity by measuring the response at the face presentation frequency (i.e., 6 Hz/5 = 1.2 Hz) under three conditions: Attend Faces, in which participants monitored the sequence for instances of female faces; Attend Objects, in which they responded to instances of guitars; and Baseline, in which they performed an orthogonal task on the central fixation cross. During the orthogonal task, face-specific activity was predominantly centered over the right occipitotemporal region. Actively attending to faces enhanced face-selective activity much more evidently in the left hemisphere than in the right, whereas attending to objects suppressed the face-selective response in both hemispheres to a comparable extent. In addition, the time courses of attentional enhancement and suppression did not overlap. These results suggest the left and right hemispheres support face-selective processing in distinct ways—where the right hemisphere is mandatorily engaged by faces and the left hemisphere is more flexibly recruited to serve current tasks demands.


Author(s):  
Maida Koso-Drljević ◽  
Meri Miličević

The aim of the study was to test two assumptions about the lateralization of the processing of emotional facial expressions: the assumption of right hemisphere dominance and the valence assumption and to egsamine the influence of gender of the presented stimulus (chimera) and depression as an emotional state of participants. The sample consisted of 83 female students, with an average age of 20 years. Participants solved the Task of Recognizing Emotional Facial Expressions on a computer and then completed the DASS-21, Depression subscale. The results of the study partially confirmed the assumption of valence for the dependent variable - the accuracy of the response. Participants were recognizing more accurately the emotion of sadness than happiness when it is presented on the left side of the face, which is consistent with the valence hypothesis, according to which the right hemisphere is responsible for recognizing negative emotions. However, when it comes to the right side of the face, participants were equally accurately recognizing the emotion of sadness and happiness, which is not consistent with the valence hypothesis. The main effect of the gender of the chimera was statistically significant for the accuracy of the response, the recognition accuracy was higher for the male chimeras compared to the female. A statistically significant negative correlation was obtained between the variable sides of the face (left and right) with the achieved result on the depression subscale for the dependent variable - reaction time. The higher the score on the depressive subscale, the slower (longer) is reaction time to the presented chimera, both on the left and on the right.


2004 ◽  
Vol 15 (1-2) ◽  
pp. 23-34 ◽  
Author(s):  
Manas K. Mandal ◽  
Nalini Ambady

Recent research indicates that (a) the perception and expression of facial emotion are lateralized to a great extent in the right hemisphere, and, (b) whereas facial expressions of emotion embody universal signals, culture-specific learning moderates the expression and interpretation of these emotions. In the present article, we review the literature on laterality and universality, and propose that, although some components of facial expressions of emotion are governed biologically, others are culturally influenced. We suggest that the left side of the face is more expressive of emotions, is more uninhibited, and displays culture-specific emotional norms. The right side of face, on the other hand, is less susceptible to cultural display norms and exhibits more universal emotional signals.


1991 ◽  
Vol 4 (2) ◽  
pp. 81-87 ◽  
Author(s):  
Andrew W. Young ◽  
Brenda M. Flude ◽  
Andrew W. Ellis

We report a delusional misidentification incident lasting some hours in which a man who had suffered a right hemisphere stroke, HW, mistook a student for his daughter. Investigation of HW's face processing abilities showed unimpaired ability to recognize familiar faces and match facial expressions, but severe impairments of unfamiliar face matching both on the Benton test and a task requiring the matching of disguised and undisguised faces. The incident shows some similarity to the Frégoli delusion, which has also been noted following brain injury affecting the right cerebral hemisphere.


1970 ◽  
Vol 30 (3) ◽  
pp. 763-766 ◽  
Author(s):  
Walter F. McKeever ◽  
Maurice D. Huling

Under conditions of monocular unihemispheric projection of word stimuli to the brain, 10 normal Ss uniformly showed superior word recognition ability of the left, as opposed to the right, cerebral hemisphere. Left-hemisphere recognitions were significantly more frequent than right-hemisphere recognitions for both eyes, but the extent of left-hemisphere superiority was significantly greater for the left eye. The results support the hypothesis that words projected to the right hemisphere traverse a less efficient route to the language centers of the left hemisphere.


2021 ◽  
pp. 83-87
Author(s):  
D.S. Khapchenkova ◽  
◽  
S.О. Dubyna ◽  
K.Yu. Yena ◽  
◽  
...  

Bell's palsy is an acute peripheral paralysis of the facial nerve of unknown etiology. The facial nerve is the seventh cranial nerve. One part of the facial nerve is the motor fibers that innervate the facial muscles. The facial nerve emerges from the brain between the posterior edge of the pons and the medulla oblongata with two roots. The main motor nucleus is responsible for the voluntary control of facial muscles. There are central and peripheral paresis of the facial nerve. Central paresis occurs during а stroke. Peripheral paresis (unilateral muscle weakness of the entire half of the face) develops when the facial nerve is affected from the motor nucleus to the exit from the stylomastoid foramen. Among the various localizations of damage to the peripheral part of the facial nerve, the most common is Bell's palsy as a result of edema and compression of the nerve in the bone canal. Clinical symptoms of facial nerve neuropathy are characterized by acute paralysis or paresis of facial muscles: smoothed skin fold on the affected side of the face; swelling of the cheeks; an inability to close the eyelid, Bell's symptom; facial muscle weakness. The degree of damage is determined by the House Brackmann scale. Treatment with glucocorticosteroids, antiviral drugs, physiotherapy procedures. Purpose — to present a clinical case of a patient with Bell's palsy as an example of delayed diagnosis, treatment and, as a result, long-term restoration of the facial muscles functions. Clinical case. The boy after suffering from the flu, began to complain of acute ear pain, vomiting, lack of movement in the right half of the face, dizziness, insomnia. Asymmetry of the face, lack of movement of the right side of the face, inability to completely close the right eye, a symptom of sailing on the right, muscle weakness were revealed during examination. The general condition of the patient improved, facial expressions were restored, sleep was normalized after hormonal, metabolic therapy, physiotherapy procedures. Conclusions. The article describes a case of inflammation of the facial nerve or Bell's palsy in a teenager who developed on the background of the flu. Timely diagnosis and treatment of the above pathology is the key to a satisfactory prognosis for the restoration of facial expressions, prevention of negative consequences of the the disease. The research was carried out in accordance with the principles of the Helsinki Declaration. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: facial nerve, Bell's palsy, flu, inflammation.


1992 ◽  
Vol 4 (4) ◽  
pp. 311-322 ◽  
Author(s):  
Barry Horwitz ◽  
Cheryl L. Grady ◽  
James V. Haxby ◽  
Mark B. Schapiro ◽  
Stanley I. Rapoport ◽  
...  

Primate extrastriate visual cortex is organized into an occipitotemporal pathway for object vision and an occipitoparietal pathway for spatial vision. Correlations between normalized regional cerebral blood flow values (regional divided by global flows), obtained using H215O and positron emission tomography, were used to examine functional associations among posterior brain regions for these two pathways in 17 young men during performance of a face matching task and a dot-location matching task. During face matching, there was a significant correlation in the right hemisphere between an extrastriate occipital region that was equally activated during both the face matching and dot-location matching tasks and a region in inferior occipitotemporal cortex that was activated more during the face matching task. The corresponding correlation in the left hemisphere was not significantly different from zero. Significant intrahemispheric correlations among posterior regions were observed more often for the right than for the left hemisphere. During dot-location matching, many significant correlations were found among posterior regions in both hemispheres, but significant correlations between specific regions in occipital and parietal cortex shown to be reliably activated during this spatial vision test were found only in the right cerebral hemisphere. These results suggest that (1) correlational analysis of normalized rCBF can detect functional interactions between components of proposed brain circuits, and (2) face and dot-location matching depend primarily on functional interactions between posterior cortical areas in the right cerebral hemisphere. At the same time, left hemisphere cerebral processing may contribute more to dot-location matching than to face matching.


2013 ◽  
Vol 27 (3) ◽  
pp. 142-148 ◽  
Author(s):  
Konstantinos Trochidis ◽  
Emmanuel Bigand

The combined interactions of mode and tempo on emotional responses to music were investigated using both self-reports and electroencephalogram (EEG) activity. A musical excerpt was performed in three different modes and tempi. Participants rated the emotional content of the resulting nine stimuli and their EEG activity was recorded. Musical modes influence the valence of emotion with major mode being evaluated happier and more serene, than minor and locrian modes. In EEG frontal activity, major mode was associated with an increased alpha activation in the left hemisphere compared to minor and locrian modes, which, in turn, induced increased activation in the right hemisphere. The tempo modulates the arousal value of emotion with faster tempi associated with stronger feeling of happiness and anger and this effect is associated in EEG with an increase of frontal activation in the left hemisphere. By contrast, slow tempo induced decreased frontal activation in the left hemisphere. Some interactive effects were found between mode and tempo: An increase of tempo modulated the emotion differently depending on the mode of the piece.


Author(s):  
Elizabeth Schechter

This chapter defends the 2-agents claim, according to which the two hemispheres of a split-brain subject are associated with distinct intentional agents. The empirical basis of this claim is that, while both hemispheres are the source or site of intentions, the capacity to integrate them in practical reasoning no longer operates interhemispherically after split-brain surgery. As a result, the right hemisphere-associated agent, R, and the left hemisphere-associated agent, L, enjoy intentional autonomy from each other. Although the positive case for the 2-agents claim is grounded mainly in experimental findings, the claim is not contradicted by what we know of split-brain subjects’ ordinary behavior, that is, the way they act outside of experimental conditions.


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