Postoperative memory impairment is a major concern in patients undergoing hippocampectomy for mesial temporal lobe epilepsy (MTLE). The Wada test, which involves administering anesthesia via the internal carotid artery (ICA), has traditionally been used for functional risk assessment. However, it poses clinical issues, such as inducing language impairment and disturbances of consciousness. The authors have developed an advanced testing method called “Selective Anesthesia for Functional Evaluation (SAFE),” which uses microcatheters to selectively anesthetize specific regions. PCA-SAFE targets the posterior cerebral artery (PCA) to enable evaluation of memory function specifically within the hippocampal region while avoiding impact on language areas. This paper presents cases of discordance between language and memory lateralization identified through this method and demonstrates its utility in predicting postoperative memory outcomes. Additionally, we discuss the importance of personalized functional evaluation in epilepsy surgery and offer future perspectives.

Abstract attitude advocated by Goldstein “also known as categorical attitude” is a concept to denote the ability to use conceptual categories in order to classify things according to their attributes and to think symbolically rather than concretely. This paper discusses the author's motivation for focusing on abstract attitude, the impairment of abstract attitude in frontotemporal dementia and semantic dementia, the relationship between abstract attitude and semantic memory, interpersonal communication, and situational judgment, and the symptomatic similarities between semantic dementia and autism spectrum disorder. Abstract attitude represents one of the mental activities broadly involved in human cognition and behavior. Through this paper, the author hopes to increase the number of researchers interested in abstract attitude, advance research on the neural basis, and ultimately contribute to the development of treatments and rehabilitation methods for impairments in abstract attitude.

Recent brain MRI research represents a “network approach” that seeks to elucidate the brain as a network and mental disorders as changes within/between network(s), and has the potential to sublate the classical opposition in neuropsychology between localizationism and holism. Based on clinical experience in caring for patients with delusional disorder, the author entered the field of delusion research and has examined, through brain MRI studies, a three-factor model that maps definitions of delusion onto neuroscientific mechanisms. At present, this framework is being extended to psychotic symptoms as a whole and applied to treatment, with the aim of developing “clinically usable biomarkers” of delusions and psychosis.

The time perspective, the cognition of “the flow of time,” refers to its progression from the past to the present and into the future. This paper presents neuroscientific research findings on the cognition of “the flow of time” in healthy individuals, while also introducing studies involving numerous cases of acquired brain injury and dementia. Furthermore, it examines the characteristics reported in the cognition of “the flow of time” in autism spectrum disorder.

The Japanese writing system uniquely combines two distinct scripts, kana and kanji. In this review, we revisit the dual-route model proposed by Iwata and Sakurai as a theoretical framework and provide a multidimensional overview of the neural mechanisms underlying Japanese reading and writing by integrating evidence from intracranial electrophysiology, cerebral perfusion imaging, and lesion-based case studies. Analyses using electrocorticography revealed that kanji reading is associated with early activation of bilateral ventral pathways, whereas kana reading shows delayed engagement of a left-lateralized dorsal network. Data-driven analyses of cerebral perfusion patterns in patients with primary progressive aphasia demonstrated a selective association between frontal lobe hypoperfusion and impaired kana writing. In addition, a detailed analysis of a single case with infarction of the internal capsule indicated that kana writing depends not only on frontal cortical regions but also on cortico-subcortical networks linking the thalamus and frontal cortex. Together, these findings provide insights into the structural and functional diversity underlying Japanese reading and writing.

There is accumulating evidence that late-life mood disorders differ from early-onset cases in their clinical features and disease course, and their association with neurodegenerative diseases. In this article, we review previous studies and introduce our recent research on tau pathology in late-life mood disorders based on in vivo imaging and brain bank autopsy data. Florzolotau (18F) enables visualization of diverse tau pathologies not only in Alzheimer's disease but also in non-Alzheimer's tauopathies, and our findings demonstrate that both Alzheimer's and non-Alzheimer's tau pathologies are involved in late-life mood disorders.

This paper reviews the historical development of research on the semantic system in neuropsychology, using category-specific semantic impairments as a starting point. It surveys major theoretical frameworks, including the sensory/functional theory, domain-specific hypotheses, the conceptual structure account, the Hub-and-Spoke hypothesis, and the Controlled Semantic Cognition (CSC) model. It also discusses the background and significance of the field's shift in primary clinical focus toward semantic dementia. Finally, it argues for the importance of a bidirectional framework in which theory is refined through theory-informed clinical practice, strengthening the reciprocal relationship between theoretical models and clinical applications.

Neuropsychological symptoms are increasingly conceptualized not only in terms of classical focal lesion-symptom relationships, but also as network disorders that arise from disruptions across multiple cortical regions and their white-matter connections. This network-based perspective can enhance clinical interpretation and diagnostic reasoning by linking observable behaviors to distributed neural systems. In a patient with subarachnoid hemorrhage causing a circumscribed lesion of the corpus callosum (body to anterior splenium), we used diffusion tensor imaging (DTI) to examine the relationship between callosal subregional damage and callosal disconnection syndromes. Longitudinal assessment showed improvement in left-hand praxis (apraxia) during imitation, whereas deficits for verbal-command-guided actions partially persisted; these symptom trajectories co-varied with tractography-derived callosal connectivity measures, consistent with dynamic changes in interhemispheric communication. We also investigated non-fluent/agrammatic primary progressive aphasia (nfvPPA). Patients with buccofacial apraxia (BFA) demonstrated more severe agrammatism than those without BFA, and voxel-based morphometry (VBM) further showed that BFA severity correlated with atrophy in the left inferior-to-middle frontal gyri. These findings suggest that BFA in nfvPPA may share an anatomical substrate closer to agrammatism than to apraxia of speech and could serve as a clinically useful marker of grammatical impairment and frontal network degeneration. Overall, integrating neuropsychological assessment with quantitative neuroimaging enables visualization of symptom-related neural substrates, refines phenotypic characterization, and provides a robust framework for bridging clinical observations to mechanistic models of brain-behavior relationships.

We report a man in his 50s who showed nonaphasic misnaming due to a right cerebellar hemorrhage. His speech was incoherent, characterized by neologisms, unrelated paraphasias, and monemic paraphasias. In-depth testing revealed that semantic, phonological, and grammatical domains were all well-preserved. While the paraphasias in spontaneous speech gradually improved and disappeared by four months, he consistently referred to a wheelchair as a “multipurpose baby carriage” or a “rickshaw” until discharge. His remarkable memory disturbance and disorientation also disappeared four months later, but anosognosia was observed throughout the course. On a CT scan 1.5 months post-onset, a low-density area was observed in the right cerebellum, and IMP-SPECT at three months revealed decreased blood flow in the right cerebellum, left ventrolateral frontal lobe, left basal ganglia and thalamus.

The decline in left frontal lobe function observed on SPECT was presumed to contribute to the manifestation of his symptoms.

Dressing disability is a condition that arises from higher brain dysfunction. Although the parietal lobe has been implicated as the responsible lesion area, there have been no reported cases of dressing disability following cerebellum damage.

We report a case in which a patient experienced a recurrent hemorrhagic infarction in the left cerebellum following an initial hemorrhagic infarction in the left temporo-parietal region. After the recurrence, the patient exhibited a specific dressing apraxia characterized by difficulty with posterior manipulation during the donning of a front-opening shirt. The patient is a right-handed woman in 81 age.

Following the recurrence, the patient exhibited impairments in mental rotation and a decline in intellectual functioning. Further in-depth assessment of dressing-related abilities revealed: (1) intact recognition of clothing items and body parts, (2) preserved understanding of the spatial correspondence between clothing and body, and (3) no deficits in the manipulation of garments. Notably, the observed errors were confined to posterior dressing actions, which are difficult to visually monitor.

Based on these findings, it is considered that the dressing disability observed in this case resulted from impaired non-visual spatial cognitive processing due to left cerebellum damage, which interfered with the manipulation of shirts involving dynamic morphological changes over time.

We performed long-term rehabilitation on two semantic dementia (SD) patients with different degrees of severity. We found that vocabulary reacquisition training was effective for patients with severe SD who have advanced language impairment, provided they had awareness of their illness and were able to reinforce their learning at home. Furthermore, vocabulary training for SD patients who were aware of their condition contributed to psychological stability by helping maintain their vocabulary recall abilities. However, training alone proved insufficient for generalizing vocabulary use to everyday conversation. Furthermore, in the SD patient with more severe language impairment and difficulty with vocabulary training, we found that incorporating activities that leveraged preserved abilities into daily life, in combination with care services, helped prevent behavioral disturbances commonly observed in the progressive stage. These approaches may reduce the burden of nursing care and help patients maintain a satisfactory home life. In the rehabilitation of patients with SD, it is important to anticipate the progression of the disease from the outset of intervention and to tailor interventions according to the stage of the disease.