Frontiers of Neurology and Neuroscience最新文献

In 1943, Tsuneo Imura, a neuropsychiatrist at Tokyo University, proposed a new aphasic syndrome and designated it as Gogi (word meaning) aphasia. According to Imura, it is characterized by (1) difficulty in comprehending spoken words despite good perception of sound, (2) disorders of expression due to loss of vocabulary and verbal paraphasia, (3) preserved ability of repetition, and (4) selective difficulty in reading and writing kanji (Japanese logographic character) with preserved ability of reading and writing kana (Japanese syllabic character). To be more specific, the difficulty in comprehending spoken words in Gogi aphasia is limited to substantive words as the name of the syndrome indicates, while comprehension of syntax remains unimpaired. Preserved repetition ability cannot be simply regarded as an automatic response, that is, echolalia, because the patient's attitude in repeating was quizzical, picking up the particular word he did not comprehend. Imura vaguely attributed the responsible lesion to the second and third temporal gyri on the left side. Although the general pattern of the syndrome can be placed in the category of transcortical sensory aphasia, its uniqueness as the syndrome still stands out. Another uniqueness of the syndrome is its characteristic pattern of dissociated kanji-kana difficulty in reading and writing. This linguistic symptomatology observed in Gogi aphasia was first introduced to the western academic world on a German neuropsychiatric journal by Panse and Shimoyama in 1955. Ever since, the existence of Gogi aphasia as an independent syndrome among disorders of spoken language has gradually gained international recognition. But whether the pattern of the kanji-kana dissociation described by Imura is an integral part of the syndrome remains unsettled. A recently proposed concept of semantic dementia suggests symptomatic continuation of word meaning loss with non-linguistic semantic memory loss.

The representation of cognitive function in the cerebral cortex has a long and cherished history, but much evidence also supports a critical role of subcortical structures in the operations of cognition. The idea of subcortical dementia, first proposed in 1932 and substantially expanded in the 1970s, is the most prominent formulation intended to capture the phenomenology of cognitive impairment attributable to subcortical involvement. Despite criticism highlighting its imprecision, subcortical dementia has endured as a useful general concept assisting the classification of dementia syndromes based on the primary site(s) of neuropathology. As neuroscientific knowledge expanded with the advent of modern structural and functional neuroimaging, a more detailed understanding of the contributions of specific subcortical regions emerged, such that the cognitive affiliations of the basal ganglia, thalamus, cerebellum, brainstem, and white matter are all better defined. Important advances have been made by the study of both neurodegenerative diseases and focal lesions. Today, the complex admixture of cortical and subcortical foundations of cognition is increasingly well appreciated, and has been conceptually organized within the broadly inclusive notion of distributed neural networks. These networks are thought to integrate cortical and subcortical gray and white matter structures throughout the brain into functional neuronal ensembles subserving various domains of cognition. In this light, specific disorders of subcortical regions produce cognitive sequelae that can be usefully analyzed within the context of networks that involve key cortical regions as well. The study of subcortical contributions to cognition has been highly informative in expanding neurobehavioral thinking to include regions beyond the cerebral cortex, adding nuance and sophistication to the conceptualization of brain-behavior relationships.

Hallucinations, delusions, and confabulations are common symptoms between neurology and psychiatry. The neurological diseases manifesting with such symptoms (dementia, epilepsy, Korsakoff's disease, brain tumors, Parkinson's disease, migraine, right hemisphere stroke and others) would be the key to understand their biological mechanisms, while the cognitive sciences, neuropharmacology and functional neuroimaging would be the tools of such researches. It is possible to understand the perceptive rules of the mind and the mechanisms of the human consciousness based on these symptoms. However, hallucinations and delusions manifest with extraordinary vehemence with psychiatric disorders such as psychosis and schizophrenia, with which there is no evidence of brain lesions. Furthermore, they are subjective symptoms, and they do not have biological markers. Hence, they are prone to high inter-individual variability and depend on other variables (such as education, history of trauma), and are therefore difficult to reduce to unequivocal constructs. Causative mechanisms are probably multiple. For understanding these symptoms, a common framework between neurology and psychiatry is still missing. The psychopathology of French alienists over the 19th century, of S. Freud, and of Henry Ey over the 20th century gave way, in the second half of the 20th century, to the adoption of the DSM and neurosciences, to pursue a pure neurological perspective. However, although psychodynamic models seem nowadays (in a technological era) less influential, detailed clinical evaluations focusing on emotional-cognitive paradigms are probably the only way to lead to new neurobiological researches.

Elements of "frontal" syndromes and executive dysfunction have been pondered by humans since ancient times, perhaps because executive dysfunction often threatens the very characteristics that make us human. This chapter provides a historical account of scientific advancements related to frontal lobe functioning and how the term has transformed over time. From ancient Greek philosophy to early neuroscientific animal studies to the default mode network, knowledge about the neural underpinnings of executive functioning has blossomed, almost so broadly that the behemoth term comprising broad neuropsychological functions may struggle to be provide specificity on its own without further clarification.

Of the main principles of human neuropsychology, the best known may be cerebral specialization: the left and right hemispheres play different roles in language and other higher-order functions. This chapter discusses when and how and by whom the differences were found. It begins with an account of Gall's cortical localization theory, which set the stage. It then describes the discoveries themselves, reviews how the differences were explained, and concludes with a summary of further developments.

Tracing the history of neglect is intriguing, as diverse terminologies have been used to characterize a multi-factorial disorder with rather startling manifestations. In part, heterogeneous terms may have hinted at distinct subtypes. Thus, different variants of hemi-inattention and neglect relate conceptually, but may be functionally dissociable. Patients with neglect, acting as if the world-space they perceive is full, do not phenomenally experience the omissions or absences so patently obvious to an observer. From the late 19th century, hemi-inattention was described according to its prominent manifestations, visual, bodily or spatial. Since then, diverse terms including imperception, inattention, unilateral visual inattention, unilateral spatial agnosia, and neglect, among others, reflected proposed underlying mechanisms. Major theories presented to account for this curious, even astonishing, neurological disorder, included disruption of body-scheme, perceptual rivalry and extinction, forgetting or amnesia for half the body, and highly nuanced models of distribution of directed spatial attention, and of disrupted perceptual processes. Unlike neurological counterparts, already designated as hemi-syndromes by the first part of the 20th century, not until about 1970 did neglect become so broadly recognized as a syndrome. Earlier, commonalities were identified, features conceptually clustered, and then subtypes were distinguished. Neglect was designated as an overarching term for a class of disorder with distinct subtypes, including visual, motor, extrapersonal, bodily or personal, other somatosensory, and representational. Specificity for modality, chronology, material, and symptom severity was noted. Remarkable clinical, neuropsychological, and behavioral manifestations of hemi-inattention and neglect may involve varying proposed mechanisms of higher cognitive functions, all within a spectrum of clinical disorder. Concepts of connectivity and interaction, neural networks, and functional integration enhance understanding of dysfunction, recovery, and compensation in neglect and inattention. Focus on distinct manifestations clustered under the umbrella of neglect offers a vantage point for examining historical trends in approach to the phenomenon.

We live in a world surrounded by sound. Throughout life, we are exposed to music: from lullabies and songs taught at school to instrumental music both heard and played for pleasure. Every nation, along with its own language, has unique forms of music and dance. "Music knows no boundaries," as the saying goes. Just as language impairment is known as "aphasia," impairment of the perception of music is called "amusia." In this article, we will first classify the types of amusia. This will be followed by an introduction to the classical research of Salomon Eberhard Henschen (1847-1930), and to a discussion of higher auditory functions in which we highlight cases of amusia encountered in a person and through the literature.

The kanji and kana (or kanji vs. kana) problem in the Japanese language denotes the dissociation between kanji (morphograms) and kana (phonograms) in reading/comprehension and writing. Since paragraphia of kana in a patient with amyotrophic lateral sclerosis was first reported in 1893, kanji-kana dissociation has been the central topic in Japanese aphasiology. Recent advancements in lesion-to-symptom analyses and functional imaging studies have identified some areas whose damage causes dissociative disturbances of reading or writing between kanji and kana. That is, (1) angular alexia with agraphia causes kanji agraphia; alexia of kana with an angular gyrus lesion is the result of a damage to the middle occipital gyrus; (2) alexia with agraphia for kanji is caused by a posterior inferior temporal cortex (mid-fusiform/inferior temporal gyri; visual word form area) lesion, whereas pure agraphia for kanji is caused by a posterior middle temporal gyrus lesion; and (3) pure alexia, particularly for kanji, results from a mid-fusiform gyrus lesion (Brodmann's Area [BA] 37), whereas pure alexia for kana results from a posterior fusiform/inferior occipital gyri lesion (BA 18/19).

Neuropsychological rehabilitation is one of the subspecialties of neuropsychology, along with neuropsychological assessment, cognitive process descriptions, and anatomo-functional correlation, but it is still frequently underrecognized, even from a historical point of view. In this chronological review, we propose following some of the historical descriptions of cognitive recovery, and the suggested procedures and therapies to improve this recovery from mythological periods and the antiquity to recent contemporary periods and the birth of formal neuropsychological rehabilitation in neurological and psychiatric conditions.