Pernicious Anemia Unveiled: Unusual Hemolytic Complications and Clinical Implications.

Pernicious anemia (PA) is an autoimmune condition resulting in impaired vitamin B12 absorption that commonly presents with gastritis and neurological symptoms. In rare cases, associated vitamin B12 deficiency can contribute to significant red blood cell lysis, and patients can present with PA-induced pseudo-thrombotic microangiopathy (TMA) hemolytic anemia. This case describes a 59-year-old male presenting with a two-week history of gastrointestinal pain with bleeding who had anemia and hemodynamic instability on initial evaluation. After the endoscopy/colonoscopy did not reveal any active sources of bleeding and packed red blood cells failed to stabilize the patient, it was found that he had low serum B12 with anti-intrinsic factor and anti-parietal cell antibodies. A coordinated clinical approach, including parenteral cyanocobalamin and daily oral folic acid supplementation, stabilized the patient, highlighting the importance of distinguishing PA-induced pseudo-TMA from true TMA hemolytic anemia.

Perception and memory reinstatement engage overlapping face selective regions within human ventral temporal cortex.

Humans have the remarkable ability to vividly retrieve sensory details of past events. According to the theory of sensory reinstatement, during remembering, brain regions specialized for processing specific sensory stimuli are reactivated to support content specific retrieval. Recently, several studies have emphasized transformations in the spatial organization of these reinstated activity patterns. Specifically, studies of scene stimuli suggest a clear anterior shift in the location of retrieval activations compared with activity observed during perception. However, it is not clear that such transformations occur universally, with inconsistent evidence for other important stimulus categories, particularly faces. One challenge in addressing this question is the careful delineation of face-selective cortices, which are inter-digitated with other selective regions, in configurations that spatially differ across individuals. Therefore, we conducted a multi-session neuroimaging study to first carefully map individual participants (9 males and 7 females) face-selective regions within ventral temporal cortex (VTC), followed by a second session to examine the activity patterns within these regions during face memory encoding and retrieval. While face-selective regions were expectedly engaged during face perception at encoding, memory retrieval engagement exhibited a more selective and constricted reinstatement pattern within these regions, but did not show any consistent direction of spatial transformation (e.g., anteriorization). We also report on unique human intracranial recordings from VTC under the same experimental conditions. These findings highlight the importance of considering the complex configuration of category selective cortex in elucidating principles shaping the neural transformations that occur from perception to memory.Significance statement Sensory reinstatement suggests that brain regions involved in the initial sensory processing of a stimulus are reactivated to support successful memory retrieval. However, recent findings have suggested reinstated cortical activations occur anterior to perceptually driven activities, particularly for scene stimuli. It remains unclear if this anteriorization occurs for other stimuli, such as faces. To address this question, we conducted a multi-session fMRI study to identify face selective regions in ventral temporal cortex, and examined activities within these regions during face-memory reinstatement. Results showed retrieval activity closely aligns with the perceptual neural substrate, confirming individual-specific face-selective regions without consistent spatial shifts. This underscores the importance of considering individual functional organizations when investigating the neural substrates of perception-memory transformations.

Individual-specific memory reinstatement patterns within human face-selective cortex.

Humans have the remarkable ability to vividly retrieve sensory details of past events. According to the theory of sensory reinstatement, during remembering, brain regions involved in the sensory processing of prior events are reactivated to support this perception of the past. Recently, several studies have emphasized potential transformations in the spatial organization of reinstated activity patterns. In particular, studies of scene stimuli suggest a clear anterior shift in the location of retrieval activations compared with those during perception. However, it is not clear that such transformations occur universally, with evidence lacking for other important stimulus categories, particularly faces. Critical to addressing these questions, and to studies of reinstatement more broadly, is the growing importance of considering meaningful variations in the organization of sensory systems across individuals. Therefore, we conducted a multi-session neuroimaging study to first carefully map individual participants face-selective regions within ventral temporal cortex (VTC), followed by a second session to examine the correspondence of activity patterns during face memory encoding and retrieval. Our results showed distinct configurations of face-selective regions within the VTC across individuals. While a significant degree of overlap was observed between face perception and memory encoding, memory retrieval engagement exhibited a more selective and constricted reinstatement pattern within these regions. Importantly, these activity patterns were consistently tied to individual-specific neural substrates, but did not show any consistent direction of spatial transformation (e.g., anteriorization). To provide further insight to these findings, we also report on unique human intracranial recordings from VTC under the same experimental conditions. Our findings highlight the importance of considering individual variations in functional neuroanatomy in the context of assessing the nature of cortical reinstatement. Consideration of such factors will be important for establishing general principles shaping the neural transformations that occur from perception to memory.