The Cortical Neuroanatomy Related to Specific Neuropsychological Deficits in Alzheimer's Continuum

BACKGROUND AND PURPOSE: In Alzheimer's continuum (a comprehensive of preclinical Alzheimer's disease [AD], mild cognitive impairment [MCI] due to AD, and AD dementia), cognitive dysfunctions are often related to cortical atrophy in specific brain regions. The purpose of this study was to investigate the association between anatomical pattern of cortical atrophy and specific neuropsychological deficits. METHODS: A total of 249 participants with Alzheimer's continuum (125 AD dementia, 103 MCI due to AD, and 21 preclinical AD) who were confirmed to be positive for amyloid deposits were collected from the memory disorder clinic in the department of neurology at Samsung Medical Center in Korea between September 2013 and March 2018. To analyze neuropsychological test-specific neural correlates representing the relationship between cortical atrophy measured by cortical thickness and performance in specific neuropsychological tests, a linear regression analysis was performed. Two neural correlates acquired by 2 different standardized scores in neuropsychological tests were also compared. RESULTS: Cortical atrophy in several specific brain regions was associated with most neuropsychological deficits, including digit span backward, naming, drawing-copying, verbal and visual recall, semantic fluency, phonemic fluency, and response inhibition. There were a few differences between 2 neural correlates obtained by different z-scores. CONCLUSIONS: The poor performance of most neuropsychological tests is closely related to cortical thinning in specific brain areas in Alzheimer's continuum. Therefore, the brain atrophy pattern in patients with Alzheimer's continuum can be predict by an accurate analysis of neuropsychological tests in clinical practice.

Empathy for Distress in Humans and Rodents / 神经科学通报·英文版

Empathy is traditionally thought to be a unique ability of humans to feel, understand, and share the emotional state of others. However, the notion has been greatly challenged by the emerging discoveries of empathy for pain or distress in rodents. Because empathy is believed to be fundamental to the formation of prosocial, altruistic, and even moral behaviors in social animals and humans, studies associated with decoding the neural circuits and unraveling the underlying molecular and neural mechanisms of empathy for pain or distress in rodents would be very important and encouraging. In this review, the author set out to outline and update the concept of empathy from the evolutionary point of view, and introduce up-to-date advances in the study of empathy and its neural correlates in both humans and rodents. Finally, the author highlights the perspectives and challenges for the further use of rodent models in the study of empathy for pain or distress.

Messages from the Brain Connectivity Regarding Neural Correlates of Consciousness

Consciousness has become a legitimate theme of neuroscientific discourse over the last two decades. Neuroscientific investigation seeking neural correlates of consciousness (NCC) has ranged from the neuronal level to the system level. Regarding system level studies, there is a large body of evidence supporting the idea that functional connectivity studies can help in examining NCC. Functional connectivity studies have suggested the involvement of the thalamo-cortical, frontoparietal, and other cortico-cortical connectivity under anesthetic-induced unconsciousness and in disorders of consciousness. Likewise, effective connectivity has been used to investigate the causal interactions among elements of functional connectivity in various consciousness states, and provided a deeper understanding of NCC. Moreover, as an extended version of connectivity studies, complex network methods have also been used for studies on NCC. In this review, we focused on the aspect of the brain system level of NCC including functional and effective connectivity networks from methodological perspectives. In addition, as for states of consciousness, anesthetic-induced unconsciousness and disorders of consciousness are the main subjects. This review discusses what we have learned from recent studies about the exploration of human brain connectivity on consciousness and its neural correlates.

Neuroanatomical Basis of Apraxia

Apraxia is a cognitive disorder in which the patient is not able to carry out learned, skilled movement despite preserved motor and sensory system, coordination, comprehension, and cooperation. Several types of apraxia have been postulated according to the involved body part (buccofacial apraxia, limb apraxia) or to the pathophysiology (ideational apraxia, ideomotor apraxia etc.) The main brain lesions for apraxia include left parietal, frontal cortex, their underlying white matter, corpus callosum and some subcortical structures. In this review, the anatomical substrates for apraxia based on underlying physiological mechanism will be discussed.