Fumie Saito

Gaze but not arrows: A dissociative impairment after right superior temporal gyrus damage

Superior temporal sulcus (STS) activation has consistently been demonstrated in the normal brain when viewing eyes, and thus this area is implicated as a gaze processing region in humans. In a recent report, we have presented a case, M.J., with a well-circumscribed lesion to the right superior temporal gyrus (STG), who demonstrated impaired discrimination of gaze direction. In the aim to make distinct whether this impairment is unique to gaze, we have applied a spatial cueing paradigm established by Kingstone and colleagues. In our experiment, pictorial gaze and symmetrical arrows were centrally presented as non-predictive, spatial cues in detecting peripheral targets. Fifteen normal subjects and M.J. participated in the experiment. In concordance with previous reports, controls demonstrated a significant facilitation of reaction times in detecting targets cued by congruent gaze/arrows, compared with incongruent cues. In striking contrast, M.J. showed no such congruency advantage for gaze, in the face of a normal congruency advantage for arrows. We have demonstrated that a circumscribed lesion to the right STG impairs the ability to utilize biological directional information such as gaze, but leaves the non-biological counterpart (arrows) intact. This dissociation implies that indeed, the STS specializes in processing gaze.

A deficit in discriminating gaze direction in a case with right superior temporal gyrus lesion

The superior temporal sulcus (STS) region is well recognized as being heavily involved in detecting and discriminating gaze. Lesions confined to this area are quite rare in humans, and so the research has mainly depended on animal studies and functional neuroimaging in normal human subjects. We report one such rare case, a 54-year-old Japanese female with a possible congenital s anomaly who, after a cerebral hemorrhage, demonstrated a lesion almost completely confined to the entire right superior temporal gyrus (STG). In the subacute phase, the patient showed evidence of left hemispatial neglect, from which she gradually recovered. In the chronic phase, she showed a puzzling difficulty in obtaining eye-contact. We have conducted, in conjunction with conventional neuropsychological evaluations, experimental assessment of her ability in gaze cognition. Her performance on neuropsychological testing demonstrated no compromise in intellect, memory, or language skills, and a close-to-full recovery from neglect. On gaze cognition experiments, she was repeatedly shown to perceive left gaze as straight, and to a lesser degree, straight gaze as right. We suggest that the function of the STG in detecting gaze, together with the directional information it receives from earlier visual areas, may be associated, when damaged, with this deficit in detecting contra-directional gaze. We have demonstrated for the first time that a single circumscribed lesion to the STG results in both gaze processing deficit and concurrent aberrant gaze behavior of the victim herself, implicating a mechanism within the STG as an interface between gaze of others and gaze of self.

Progressive prosopagnosia at a very early stage of frontotemporal lobar degeneration

Background:  The present paper describes a patient with a right temporal lobe variant (RTLV) of frontotemporal lobar degeneration (FTLD).

Early initiation of L-dopa therapy enables stable development of executive function in tetrahydrobiopterin (BH4) deficiency

Executive function (EF) has been presumed to be mediated by the dopaminergic system in the prefrontal cortex. However, little is known about the early development of this function and the roles dopamine plays in it. Tetrahydrobiopterin (BH4) deficiencies are genetic disorders affecting catecholamine and serotonin biosynthesis which, if untreated, result in motor and cognitive symptoms including impairment of EF. A comprehensive neuropsychological test battery was administered to six participants with BH4 deficiency (four males, two females, mean Full‐scale intelligence quotient [FIQ] 63.8 [SD 14.7]); all were on replacement therapy with L‐dopa and BH4, but time of initiation of treatment varied. Age range (median) was 28 days to 41 years (2y 6mo) at initiation of treatment and 10 to 47 years (19y) at follow‐up. On non‐EF tests, performance agreed with those of IQ‐matched controls (four males, two females; mean age 16y 6mo [SD 6mo]; mean FIQ 62.3 [SD 13.4]). On EF tests those who initiated treatment after 2 years 6 months of age performed poorly. In patients with BH4 deficiency, replacement therapy should be started in the first weeks or months of life. Patients diagnosed before the age of 2 years 6 months obtain normal EF, which suggests dopamine may play a critical role in ensuring stable development of EF in early life.

Emergence of realism: Enhanced visual artistry and high accuracy of visual numerosity representation after left prefrontal damage

Over the last two decades, evidence of enhancement of drawing and painting skills due to focal prefrontal damage has accumulated. It is of special interest that most artworks created by such patients were highly realistic ones, but the mechanism underlying this phenomenon remains to be understood. Our hypothesis is that enhanced tendency of realism was associated with accuracy of visual numerosity representation, which has been shown to be mediated predominantly by right parietal functions. Here, we report a case of left prefrontal stroke, where the patient showed enhancement of artistic skills of realistic painting after the onset of brain damage. We investigated cognitive, functional and esthetic characteristics of the patient׳s visual artistry and visual numerosity representation. Neuropsychological tests revealed impaired executive function after the stroke. Despite that, the patient׳s visual artistry related to realism was rather promoted across the onset of brain damage as demonstrated by blind evaluation of the paintings by professional art reviewers. On visual numerical cognition tasks, the patient showed higher performance in comparison with age-matched healthy controls. These results paralleled increased perfusion in the right parietal cortex including the precuneus and intraparietal sulcus. Our data provide new insight into mechanisms underlying change in artistic style due to focal prefrontal lesion.

Sustained Attention Function Evaluation During Cooking Based on Egocentric Vision

The attention function has been classified into (i) sustained attention, (ii) selective attention, (iii) controlled attention, (iv) distributed attention, and (v) capacity for attention. Ordinarily, in order to evaluate the function of attention, the digital cancellation test (D-CAT) or trail making test (TMT) are employed. However, these evaluations are in the form of paper tests, and cannot effectively evaluate small changes in activities daily of living in real time. Accordingly, we focus on human behavior during the act of cooking, in which multitasking is common and many types of ordinary movements are performed. We previously proposed a method of evaluating distributive attention during cooking and showed its effectiveness. In this study, a method for evaluating sustained attention is proposed. Specifically, we acquire an egocentric video by an egocentric vision and estimate line-of-sight based on the visual attention model that is integrated from the three kind of models (category-specific attention, top-down attention, and bottom-up attention). After that, we define line-to-sight information from high saliency area on the visual attention model.

Attention Behavior Evaluation during Daily Living Based on Egocentric Vision

In this paper, we propose a system for understanding attention behavior in daily living using an egocentric vision. As the visual attention models, several studies have been made on bottom-up attention and topdown attention. However, in the human brain, there are functions for specifically responding to faces and body parts. Therefore, we define a “category-specific attention model” for the specific response function and integrate the three model types of top-down attention, bottom-up attention, and category-specific attention to generate an attention map. And we extracted area of the higher saliency on the attention map. In the extracted area, we were verified whether divided attention is working or not from two approaches. The first approach detected the object by object recognition on what is seen. The second approach focused on the movement of the hand holding the food. The movement of the hand is generated using the movement orientation histogram calculated from the optical flow. In concrete terms, we evaluated the divided attention by the following 4 tasks; (i) a serial task of cutting only. (ii) as a parallel task, a task of cutting and task of checking whether the deep pan is boiling over or not. (iii) a serial task and cognitive load task. (iv) a parallel task and cognitive load task. On this occasion, there was a significant difference in both the movement orientation histogram of the hand and number of the deep pan confirmations based on the existence of a cognitive load issue, and it was confirmed that this could be used to distinguish between states when cognitive function is decreasing and the normal state. 