Intracranial EEG correlates of implicit relational inference within the hippocampus

Drawing inferences from past experiences enables adaptive behavior in future situations. Inference has been shown to depend on hippocampal processes. Usually, inference is considered a deliberate and effortful mental act which happens during retrieval, and requires the focus of our awareness. Recent fMRI studies hint at the possibility that some forms of hippocampus-dependent inference can also occur during encoding and possibly also outside of awareness. Here, we sought to further explore the feasibility of hippocampal implicit inference, and specifically address the temporal evolution of implicit inference using intracranial EEG. Presurgical epilepsy patients with hippocampal depth electrodes viewed a sequence of word pairs, and judged the semantic fit between two words in each pair. Some of the word pairs entailed a common word (e.g.,‘winter - red’, ‘red - cat’) such that an indirect relation was established in following word pairs (e.g, ‘winter - cat’). The behavioral results suggested that drawing inference implicitly from past experience is feasible because indirect relations seemed to foster ‘fit’ judgments while the absence of indirect relations fostered 'do not fit' judgments, even though the participants were unaware of the indirect relations. A event-related potential (ERP) difference emerging 400 ms post-stimulus was evident in the hippocampus during encoding, suggesting that indirect relations were already established automatically during encoding of the overlapping word pairs. Further ERP differences emerged later post-stimulus (1500 ms), were modulated by the participants' responses and were evident during encoding and test. Furthermore, response-locked ERP effects were evident at test. These ERP effects could hence be a correlate of the interaction of implicit memory with decision-making. Together, the data map out a time-course in which the hippocampus automatically integrates memories from discrete but related episodes to implicitly influence future decision making.

[Irreversible bilateral amaurosis in a 36-year-old immigrant]

We report on a 36-year-old man with a history of mild head trauma. The initial clinical findings and the CT-scan of the brain revealed no pathological result, although the patient suffered from weakness of the right arm and bilateral blindness. Those findings were interpreted as psychogenic disorder. Nine days later he developed an instable gait, a child like attitude, amnesia and enuresis. The CT-scan revealed a subacute bilateral occipital stroke in the region of the arteriae cerebri posteriors. No cause for the stroke was found. In spite of the rareness of cortical blindness in young people as a cause of stroke, a detailed medical history and clinical examination should always be performed, and by unclearness additional investigations should be considered.

In What Sense Are Emotions Evaluations?

Abstract: In this chapter, we first introduce the idea that emotions are evaluations. Next, we explore two approaches attempting to account for this idea in terms of attitudes that are alleged to become emotional when taking evaluative contents. According to the first approach, emotions are evaluative judgments. According to the second, emotions are perceptual experiences of evaluative properties. We explain why this theory remains unsatisfactory insofar as it shares with the evaluative judgement theory the idea that emotions are evaluations in virtue of their contents. We then outline an alternative – the attitudinal theory of emotions. It parts with current theorizing about the emotions in elucidating the fact that emotions are evaluations not in terms of what they represent, but in terms of the attitude subjects take towards what they represent. We explore what sorts of attitudes emotions are and claim that they are felt bodily attitudes.