Response to visual threat following damage to the pulvinar

Biomedical Reviews, 2008

The amygdala (Am) is a relatively voluminous gray substance, located in the depth of the ventromedial temporal lobe. The Am has diverse afferent and efferent connections throughout the neuraxis, and is involved in the modulation of neuroendocrine functions, visceral effector mechanisms, and in complex patterns of behavior: learning and memory, aggression and defense, pain modulation, reproduction, food intake, etc. A recently revealed important function of the Am is that it acts as the brain ' lighthouse' which constantly monitors the environment for stimuli which signal a threat to the organism. The data from patients with extensive lesions of the striate cortex indicate that unseen fearful and fear-conditioned faces elicit increased Am responses. Thus, also extrageniculostriate pathways are involved. A multisynaptic pathway from the retina to the Am via the superior colliculus and several thalamic nuclei was recently suggested. We here present data based on retrograde neuronal labeling that the parabigeminal nucleus emits a substantial bilateral projection to the Am. This small cholinergic nucleus (Ch8 group) in the midbrain tegmentum is a subcortical relay visual center that is reciprocally connected with the superior colliculus. We suggest the existence of a second extrageniculostriate multisynaptic connection to Am: retina -superior colliculus -parabigeminal nucleus -Am. This pathway might be very effective since all tracts listed above are bilateral. The function of the Am by the rapid response to the sources of threat before conscious detection is significantly altered by various neuropsychiatric diseases.

Neuron, 2004

and Franç ois Mauguiè re 1,3 1 Hô pital Neurologique 69003 Lyon structures remain poorly described. However, this infor-France mation is crucial to understand the precise role of these 2 INSERM Unité 280 brain structures in emotion processing. Scalp event-151 cours Albert Thomas related potential (ERP) studies present some discrep-69424 Lyon cedex 04 ancy in terms of latencies and source locations of dif-France ferential responses to facial expressions. Some have 3 Federative Neuroscience Institute of Lyon reported late latency differential activities after 300 ms Université Claude Bernard Lyon 1 in fronto-central (Carretie and Iglesias, 1995; Munte et 69003 Lyon al., 1998) or temporal (Krolak-Salmon et al., 2001) areas. France Others have found earlier specific responses in frontal (Eimer and Holmes, 2002) or temporal (Batty and Taylor, 2003) areas. Magnetoencephalographic and single-neu-Summary ron studies in human have shown a temporal spreading of activities related to emotional versus neutral faces The amygdala involvement in fear processing has been from 100 ms to more than 500 ms poststimulus, particureported in behavioral, electrophysiological, and funclarly in the amygdala and the OFC (Kawasaki et al., 2001; tional imaging studies. However, the literature does Streit et al. , 1999, 2001). Since all emotions do not imply not provide precise data on the temporal course of the same behavioral consequences, one may ask facial emotional processing. Intracranial event-related whether a temporal hierarchy exists in processing the potentials to facial expressions were recorded in epidifferent facial expressions. Does the processing time leptic patients implanted with depth electrodes during course differ across emotions? a presurgical evaluation. Specific potentials to fear

NeuroImage, 2003

This study examined neural responses in nine right-handed healthy individuals while they viewed mild and intense expressions of four emotions (fear, disgust, happiness, and sadness) contrasted with neutral faces in four event-related functional magnetic resonance imaging experiments. Orthogonal polynomial trend analysis revealed a significant linear increase in the fusiform extrastriate cortical response to increasing intensities of all four emotional expressions, which was significantly greater to increasing intensities of fear and disgust than happiness and sadness, and a significant linear decrease in response to sadness in another extrastriate region. The amygdala was activated by high-intensity fearful expressions, consistent with findings from previous studies, and by low-but not high-intensity sad expressions. Significant linear increases in response to increasing intensities of fear, disgust, and happiness occurred within the hippocampus, anterior insula, and putamen, respectively. Conversely, significant linear decreases in hippocampal and putamen responses occurred to increasing intensities of sadness. We provide the first demonstration of differential increases in extrastriate and limbic responses to signals of increasing danger than to those of other emotions, and significant decreases in these responses to signals of increasing sadness in others. We suggest that this differential pattern of response to different categories of emotional signals allows the preferential direction of visual attention to signals of imminent danger than to other, less-salient emotional stimuli.

Human Brain …, 2006

Physiology & Behavior, 2007

Consistent with the hypothesis that the amygdala is central to fear activation, brain imaging studies show that fear stimuli activate the amygdala, even when conscious recognition is prevented by backward masking. The bulk of the data suggest that the amygdala can be activated from potentially accessible but unattended fear stimuli. Activation of the amygdala facilitates low level visual processing. Several lines of evidence suggest that activation of the amygdala is mediated by a subcortical pathway. Thus, according to data from patients with lesions in the primary visual cortex, the amygdala can be activated in the absence of cortical processing. There is considerable support for the hypothesis that visual stimuli can access the amygdala via a pathway that includes the superior colliculus and the pulvinar nucleus of the thalamus. These data are consistent with an evolutionary argument, focusing of the role of snakes as a predator on primates.

Social Cognitive and Affective Neuroscience, 2014

Little is known about the network of brain regions activated prior to explicit awareness of emotionally salient social stimuli. We investigated this in a functional magnetic resonance imaging study using a technique that combined elements of binocular rivalry and motion flash suppression in order to prevent awareness of fearful faces and houses. We found increased left amygdala and fusiform gyrus activation for fearful faces compared to houses, despite suppression from awareness. Psychophysiological interaction analyses showed that amygdala activation was associated with task-specific (fearful faces greater than houses) modulation of an attention network, including bilateral pulvinar, bilateral insula, left frontal eye fields, left intraparietal sulcus and early visual cortex. Furthermore, we report an unexpected main effect of increased left parietal cortex activation associated with suppressed fearful faces compared to suppressed houses. This parietal finding is the first report of increased dorsal stream activation for a social object despite suppression, which suggests that information can reach parietal cortex for a class of emotionally salient social objects, even in the absence of awareness.

Social cognitive and affective neuroscience, 2013

The amygdala is known to play an important role in the response to facial expressions that convey fear. However, it remains unclear whether the amygdalas response to fear reflects its role in the interpretation of danger and threat, or whether it is to some extent activated by all facial expressions of emotion. Previous attempts to address this issue using neuroimaging have been confounded by differences in the use of control stimuli across studies. Here, we address this issue using a block design functional magnetic resonance imaging paradigm, in which we compared the response to face images posing expressions of fear, anger, happiness, disgust and sadness with a range of control conditions. The responses in the amygdala to different facial expressions were compared with the responses to a non-face condition (buildings), to mildly happy faces and to neutral faces. Results showed that only fear and anger elicited significantly greater responses compared with the control conditions involving faces. Overall, these findings are consistent with the role of the amygdala in processing threat, rather than in the processing of all facial expressions of emotion, and demonstrate the critical importance of the choice of comparison condition to the pattern of results.

Cognitive, Affective, & Behavioral Neuroscience, 2009

Social Cognitive and Affective Neuroscience, 2012

Recent event-related brain potential studies revealed the selective processing of emotional and threatening pictures. Integrating the picture viewing and threat-of-shock paradigm, the present study examined the processing of emotional pictures while they were explicitly instructed to cue threat of real world danger (i.e. electric shocks). Toward this end, 60 pleasant, neutral and unpleasant IAPS-pictures were presented (1 s) as a continuous random stream while high-density EEG and self-reported threat were assessed. In three experimental runs, each picture category was used once as a threat-cue, whereas in the other conditions the same category served as safety-cue. An additional passive viewing run served as a no-threat condition, thus, establishing a threat-safety continuum (threat-cue-safety-cue-no-threat) for each picture category. Threat-of-shock modulated P1, P2 and parieto-occipital LPP amplitudes. While the P1 component differentiated among threat-and no-threat conditions, the P2 and LPP effects were specific to pictures signaling threat-of-shock. Thus, stimulus processing progressively gained more accurate information about environmental threat conditions. Interestingly, the finding of increased EPN and centro-parietal LPP amplitudes to emotional pictures was independent from threat-of-shock manipulation. Accordingly, the results indicate distinct effects associated with the intrinsic significance of emotional pictures and explicitly instructed threat contingencies.

NeuroImage, 2006

Attention may reflexively shift towards the location of perceived threats, but it is still unclear how these spatial biases recruit the distributed fronto-parietal cortical networks involved in other aspects of selective attention. We used event-related fMRI to determine how brain responses to a neutral visual target are influenced by the emotional expression of faces appearing at the same location during a covert orienting task. On each trial, two faces were briefly presented, one in each upper visual field (one neutral and one emotional, fearful or happy), followed by a unilateral target (a small horizontal or vertical bar) replacing one of the faces. Participants had to discriminate the target orientation, shown on the same (valid) or opposite (invalid) side as the emotional face. Trials with faces but no subsequent target (cue-only trials) were included to disentangle activation due to emotional cues from their effects on target detection. We found increased responses in bilateral temporo-parietal areas and right occipito-parietal cortex for fearful faces relative to happy faces, unrelated to the subsequent target and cueing validity. More critically, we found a selective modulation of intraparietal and orbitofrontal cortex for targets following an invalid fearful face, as well as an increased visual response in right lateral occipital cortex for targets following a valid fearful face. No such effects were observed with happy faces. These results demonstrate that fearful faces can act as exogenous cues by increasing sensory processing in extrastriate cortex for a subsequent target presented at the same location, but also produce a cost in disengaging towards another location by altering the response of IPS to invalidly cued targets. Neural mechanisms responsible for orienting attention towards emotional vs. non-emotional stimuli are thus partly shared in parietal and visual areas, but also partly distinct.