Rapid forgetting of faces in congenital prosopagnosia.

Congenital prosopagnosia (CP) is a life-long impairment in face recognition that occurs in the absence of any known brain damage. It is still unclear whether this disorder is related to a visual deficit, or to an impairment in encoding, maintaining or retrieving a face from memory. We tested CPs and matched neurotypical controls using a delayed estimation task in which a target face was shown either upright or inverted. Participants were asked to select the target face out of a cyclic space of morphed faces that could either resemble the target face, or not. The inclusion of upright and inverted faces enabled to examine the extent of the face inversion effect, a well-known face specific effect often associated with holistic processing. To enable disentangling visual from mnemonic processing, reports were required either following 1 and 6 sec retention interval, or simultaneously while the target face was still visible. Controls showed slower forgetting of upright compared to inverted faces. In contrast, CPs exhibited rapid forgetting of upright faces that was comparable to their performance and to performance of controls on inverted faces. Such forgetting was evident in random errors in which the selected faces did not resemble the face in memory, implying a time related decrease in the probability to access the correct face in memory. Importantly, CPs exhibited no inversion effect across all retention intervals, including the simultaneous one, suggesting that their abnormal rapid forgetting could be explained by an impairment in holistic visual processing of upright faces.

Incidence and impact of stroke following surgery for low-grade gliomas.

OBJECTIVE: Ischemic complications are a common cause of neurological deficits following low-grade glioma (LGG) surgeries. In this study, the authors evaluated the incidence, risk factors, and long-term implications of intraoperative ischemic events. METHODS: The authors retrospectively evaluated patients who had undergone resection of an LGG between 2013 and 2017. Analysis included pre- and postoperative demographic, clinical, radiological, and anesthetic data, as well as intraoperative neurophysiology data, overall survival, and functional and neurocognitive outcomes. RESULTS: Among the 82 patients included in the study, postoperative diffusion-weighted imaging showed evidence of acute ischemic strokes in 19 patients (23%), 13 of whom (68%) developed new neurological deficits. Infarcts were more common in recurrent and insular surgeries (p < 0.05). Survival was similar between the patients with and without infarcts. Immediately after surgery, 27% of the patients without infarcts and 58% of those with infarcts experienced motor deficits (p = 0.024), decreasing to 16% (p = 0.082) and 37% (p = 0.024), respectively, at 1 year. Neurocognitive functions before and 3 months after surgery were generally stable for the two groups, with the exception of a decline in verbal rhyming ability among patients with infarcts. Confusion during awake craniotomy was a strong predictor of the occurrence of an ischemic stroke. Mean arterial pressure at the beginning of surgery was significantly lower in the infarct group. CONCLUSIONS: Recurrent surgeries and insular tumor locations are risk factors for intraoperative strokes. Although they do not affect survival, these strokes negatively affect patient activity and performance status, mainly during the first 3 postoperative months, with gradual functional improvement over 1 year. Several intraoperative parameters may suggest the impending development of an infarct.

The Rapid Forgetting of Faces.

How are faces forgotten? Studies examining forgetting in visual working memory (VWM) typically use simple visual features; however, in ecological scenarios, VWM typically contains complex objects. Given their significance in everyday functioning and their visual complexity, here we investigated how upright and inverted faces are forgotten within a few seconds, focusing on the raw errors that accompany such forgetting and examining their characteristics. In three experiments we found that longer retention intervals increased the size of errors. This effect was mainly accounted for by a larger proportion of random errors - suggesting that forgetting of faces reflects decreased accessibility of the memory representations over time. On the other hand, longer retention intervals did not modulate the precision of recall - suggesting that forgetting does not affect the precision of accessible memory representation. Thus, when upright and inverted faces are forgotten there is a complete failure to access them or a complete collapse of their memory representation. In contrast to the effect of retention interval (i.e., forgetting), face inversion led to larger errors that were mainly associated with decreased precision of recall. This effect was not modulated by the duration of the retention interval, and was observed even when memory was not required in the task. Therefore, upright faces are remembered more precisely compared to inverted ones due to perceptual, rather than mnemonic processes.