Frontotemporal Dementia: What Can the Behavioral Variant Teach Us about Human Brain Organization?
Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, USA. The Neuroscientist
(Impact Factor: 6.84).
06/2011; 18(4):373-85. DOI: 10.1177/1073858411410354
The behavioral variant of frontotemporal dementia (bvFTD) slowly undermines emotion, social behavior, personal conduct, and decision making. These deficits occur in concert with focal neurodegeneration that can be quantified with modern structural and functional imaging and neuropathological methods. As a result, studies of bvFTD have helped to clarify brain structures, networks, and neurons that prove critical for normal social-emotional functioning. In this article, the authors review the evolving bvFTD literature and propose a simple, testable network-based working model for understanding bvFTD.
Available from: Agustin Ibanez
- "Interestingly, the specific network of the ACC and orbital frontoinsular regions seems to be involved in processing the emotional salience of stimuli (Seeley et al., 2007). This evidence likely suggests that one aspect of the decreased ability to attend to salient, socially significant cues may depend on the connectivity in a right frontoinsular intrinsic network that is selectively targeted by this disease (Seeley, Crawford, Zhou, Miller, & Greicius, 2009; Shany-Ur et al., 2012).Together, all these findings suggest that the specific pattern of social cognition impairment in the bvFTD can be understood as general deficits in the integration of the social context triggered by an abnormal frontoinsular-temporal network (Ibanez & Manes, 2012; Seeley et al., 2012). "
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ABSTRACT: Empathy is a highly flexible and adaptive process that allows for the interplay of prosocial behavior in many different social contexts. Empathy appears to be a very situated cognitive process, embedded with specific contextual cues that trigger different automatic and controlled responses. In this review, we summarize relevant evidence regarding social context modulation of empathy for pain. Several contextual factors, such as stimulus reality and personal experience, affectively link with other factors, emotional cues, threat information, group membership, and attitudes toward others to influence the affective, sensorimotor, and cognitive processing of empathy. Thus, we propose that the frontoinsular-temporal network, the so-called social context network model (SCNM), is recruited during the contextual processing of empathy. This network would (1) update the contextual cues and use them to construct fast predictions (frontal regions), (2) coordinate the internal (body) and external milieus (insula), and (3) consolidate the context-target associative learning of empathic processes (temporal sites). Furthermore, we propose these context-dependent effects of empathy in the framework of the frontoinsular-temporal network and examine the behavioral and neural evidence of three neuropsychiatric conditions (Asperger syndrome, schizophrenia, and the behavioral variant of frontotemporal dementia), which simultaneously present with empathy and contextual integration impairments. We suggest potential advantages of a situated approach to empathy in the assessment of these neuropsychiatric disorders, as well as their relationship with the SCNM.
Available from: Rajith N de Silva
- "Abnormal reactivity to and comprehension of a range of emotional stimuli are a hallmark of FTLD and in particular the canonical syndromic subtypes of behavioural variant frontotemporal dementia and semantic dementia (SemD). These deficits of emotion processing have been linked to regional atrophy and altered connectivity in frontolimbic circuitry, including orbitofrontal cortex, ventral striatum, insula, and amygdala   . The SemD syndrome is of particular interest because it is underpinned by selective erosion of semantic memory: the human memory system that governs conceptual and encyclopaedic knowledge about words and objects based on an individual's accumulated experience of the world. "
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ABSTRACT: Phobias are among the few intensely fearful experiences we regularly have in our everyday lives, yet the brain basis of phobic responses remains incompletely understood. Here we describe the case of a 71 year old patient with a typical clinico-anatomical syndrome of semantic dementia led by selective (predominantly right-sided) temporal lobe atrophy, who showed striking amelioration of previously disabling claustrophobia following onset of her cognitive syndrome. We interpret our patient's newfound fearlessness as an interaction of damaged limbic and autonomic responsivity with loss of the cognitive meaning of previously threatening situations. This case has implications for our understanding of brain network disintegration in semantic dementia, and the neuro-cognitive basis of phobias more generally.
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ABSTRACT: Neurodegenerative diseases often cause focal damage to brain structures mediating social cognition and personality, resulting in altered interpersonal communication and behavior. We review recent research describing this phenomenon in various aspects of social cognition.
Corresponding to their pervasive socioemotional deficits, patients with frontotemporal dementia perform poorly on laboratory-based tasks including recognizing emotions, attending to salient information that guides social behavior, representing social knowledge, comprehending others' mental states, and maintaining insight to their own difficulties. Together with poor executive and regulation mechanisms, these social cognition deficits ultimately impact behavior. Patients with logopenic and nonfluent primary progressive aphasia have some deficits recognizing emotional prosody, whereas those with the semantic variant show more widespread deficits in social comprehension. Although Alzheimer's disease patients perform poorly on some social cognition tasks, this typically reflects general cognitive impairment, and their real-life social functioning is less affected than in diseases targeting frontotemporal structures. Studies in motor diseases such as Parkinson's suggest some degradation of emotion recognition and social comprehension, which should be investigated further.
We summarize recent findings concerning perception and evaluation of socioemotional information, social knowledge storage and access, advanced information processing mechanisms, and behavioral response selection and regulation across various neurodegenerative diseases.
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