scholarly journals Distribution of colour-selective activity in the monkey inferior temporal cortex revealed by functional magnetic resonance imaging

2009 ◽  
Vol 30 (10) ◽  
pp. 1960-1970 ◽  
Author(s):  
Takuya Harada ◽  
Naokazu Goda ◽  
Tadashi Ogawa ◽  
Minami Ito ◽  
Hiroshi Toyoda ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Temporal Cortex ◽  
Inferior Temporal Cortex ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Selective Activity

scholarly journals Cannabis affects people differently: inter-subject variation in the psychotogenic effects of Δ9-tetrahydrocannabinol: a functional magnetic resonance imaging study with healthy volunteers

2012 ◽  
Vol 43 (6) ◽  
pp. 1255-1267 ◽  
Author(s):  
Z. Atakan ◽  
S. Bhattacharyya ◽  
P. Allen ◽  
R. Martín-Santos ◽  
J. A. Crippa ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Healthy Volunteers ◽  
Temporal Cortex ◽  
Psychotic Symptoms ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Middle Temporal ◽  
The Right

BackgroundCannabis can induce transient psychotic symptoms, but not all users experience these adverse effects. We compared the neural response to Δ9-tetrahydrocannabinol (THC) in healthy volunteers in whom the drug did or did not induce acute psychotic symptoms.MethodIn a double-blind, placebo-controlled, pseudorandomized design, 21 healthy men with minimal experience of cannabis were given either 10 mg THC or placebo, orally. Behavioural and functional magnetic resonance imaging measures were then recorded whilst they performed a go/no-go task.ResultsThe sample was subdivided on the basis of the Positive and Negative Syndrome Scale positive score following administration of THC into transiently psychotic (TP; n = 11) and non-psychotic (NP; n = 10) groups. During the THC condition, TP subjects made more frequent inhibition errors than the NP group and showed differential activation relative to the NP group in the left parahippocampal gyrus, the left and right middle temporal gyri and in the right cerebellum. In these regions, THC had opposite effects on activation relative to placebo in the two groups. The TP group also showed less activation than the NP group in the right middle temporal gyrus and cerebellum, independent of the effects of THC.ConclusionsIn this first demonstration of inter-subject variability in sensitivity to the psychotogenic effects of THC, we found that the presence of acute psychotic symptoms was associated with a differential effect of THC on activation in the ventral and medial temporal cortex and cerebellum, suggesting that these regions mediate the effects of the drug on psychotic symptoms.

scholarly journals Neuronal correlates of functional magnetic resonance imaging in human temporal cortex

Brain ◽  
2009 ◽  
Vol 133 (1) ◽  
pp. 46-59 ◽  
Author(s):  
George A. Ojemann ◽  
David P. Corina ◽  
Neva Corrigan ◽  
Julie Schoenfield-McNeill ◽  
Andrew Poliakov ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Temporal Cortex ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

scholarly journals Functional magnetic resonance imaging changes in amnestic and nonamnestic mild cognitive impairment during encoding and recognition tasks

2009 ◽  
Vol 15 (3) ◽  
pp. 372-382 ◽  
Author(s):  
MARY M. MACHULDA ◽  
MATTHEW L. SENJEM ◽  
STEPHEN D. WEIGAND ◽  
GLENN E. SMITH ◽  
ROBERT J. IVNIK ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Temporal Cortex ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Complex Scene ◽  
Amnestic Mci

AbstractFunctional magnetic resonance imaging (fMRI) shows changes in multiple regions in amnestic mild cognitive impairment (aMCI). The concept of MCI recently evolved to include nonamnestic syndromes, so little is known about fMRI changes in these individuals. This study investigated activation during visual complex scene encoding and recognition in 29 cognitively normal (CN) elderly, 19 individuals with aMCI, and 12 individuals with nonamnestic MCI (naMCI). During encoding, CN activated an extensive network that included bilateral occipital–parietal–temporal cortex; precuneus; posterior cingulate; thalamus; insula; and medial, anterior, and lateral frontal regions. Amnestic MCI activated an anatomic subset of these regions. Non-amnestic MCI activated an even smaller anatomic subset. During recognition, CN activated the same regions observed during encoding except the precuneus. Both MCI groups again activated a subset of the regions activated by CN. During encoding, CN had greater activation than aMCI and naMCI in bilateral temporoparietal and frontal regions. During recognition, CN had greater activation than aMCI in predominantly temporoparietal regions bilaterally, while CN had greater activation than naMCI in larger areas involving bilateral temporoparietal and frontal regions. The diminished parietal and frontal activation in naMCI may reflect compromised ability to perform nonmemory (i.e., attention/executive, visuospatial function) components of the task. (JINS, 2009, 15, 372–382.)

scholarly journals More is less: increased processing of unwanted memories facilitates forgetting

2018 ◽  
Author(s):  
Tracy H. Wang ◽  
Katerina Placek ◽  
Jarrod A. Lewis-Peacock
Keyword(s):  
Magnetic Resonance Imaging ◽  
Prefrontal Cortex ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Temporal Cortex ◽  
Fmri Data ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Alternative Account ◽  
Ventral Temporal Cortex

ABSTRACTThe intention to forget can produce long-lasting effects. This ability has been linked to suppression of both rehearsal and retrieval of unwanted memories – processes that are mediated by prefrontal cortex and hippocampus. Here, we describe an alternative account of deliberate forgetting in which the intention to forget is associated with increased engagement with the unwanted information. We used pattern classifiers to decode functional magnetic resonance imaging (fMRI) data from a task in which participants viewed a series of pictures and were instructed to remember or forget each one. Pictures followed by a forget instruction elicited higher levels of processing in ventral temporal cortex compared to those followed by a remember instruction. This boost in processing led to more forgetting, particularly for items that showed moderate (vs. weak or strong) activation. This result is consistent with the non-monotonic plasticity hypothesis, which predicts weakening and forgetting of memories that are moderately activated.

scholarly journals Thinking fast or slow? Functional magnetic resonance imaging reveals stronger connectivity when experienced neurologists diagnose ambiguous cases

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Berry van den Berg ◽  
Anique B H de Bruin ◽  
Jan-Bernard C Marsman ◽  
Monicque M Lorist ◽  
Henk G Schmidt ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Cognitive Processing ◽  
Temporal Cortex ◽  
Clinical Information ◽  
Dual Process ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Fast Recognition

Abstract For ∼40 years, thinking about reasoning has been dominated by dual-process theories. This model, consisting of two distinct types of human reasoning, one fast and effortless and the other slow and deliberate, has also been applied to medical diagnosis. Medical experts are trained to diagnose patients based on their symptoms. When symptoms are prototypical for a certain diagnosis, practitioners may rely on fast, recognition-based reasoning. However, if they are confronted with ambiguous clinical information slower, analytical reasoning is required. To examine the neural underpinnings of these two hypothesized forms of reasoning, 16 highly experienced clinical neurologists were asked to diagnose two types of medical cases, straightforward and ambiguous cases, while functional magnetic resonance imaging was being recorded. Compared with reading control sentences, diagnosing cases resulted in increased activation in brain areas typically found to be active during reasoning such as the caudate nucleus and frontal and parietal cortical regions. In addition, we found vast increased activity in the cerebellum. Regarding the activation differences between the two types of reasoning, no pronounced differences were observed in terms of regional activation. Notable differences were observed, though, in functional connectivity: cases containing ambiguous information showed stronger connectivity between specific regions in the frontal, parietal and temporal cortex in addition to the cerebellum. Based on these results, we propose that the higher demands in terms of controlled cognitive processing during analytical medical reasoning may be subserved by stronger communication between key regions for detecting and resolving uncertainty.

scholarly journals Object Representations in the Temporal Cortex of Monkeys and Humans as Revealed by Functional Magnetic Resonance Imaging

2009 ◽  
Vol 101 (2) ◽  
pp. 688-700 ◽  
Author(s):  
Andrew H. Bell ◽  
Fadila Hadj-Bouziane ◽  
Jennifer B. Frihauf ◽  
Roger B. H. Tootell ◽  
Leslie G. Ungerleider
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Temporal Cortex ◽  
Body Part ◽  
Body Parts ◽  
Object Representations ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Semantic Categories

Increasing evidence suggests that the neural processes associated with identifying everyday stimuli include the classification of those stimuli into a limited number of semantic categories. How the neural representations of these stimuli are organized in the temporal lobe remains under debate. Here we used functional magnetic resonance imaging (fMRI) to identify correlates for three current hypotheses concerning object representations in the inferior temporal (IT) cortex of monkeys and humans: representations based on animacy, semantic categories, or visual features. Subjects were presented with blocked images of faces, body parts (animate stimuli), objects, and places (inanimate stimuli), and multiple overlapping contrasts were used to identify the voxels most selective for each category. Stimulus representations appeared to segregate according to semantic relationships. Discrete regions selective for animate and inanimate stimuli were found in both species. These regions could be further subdivided into regions selective for individual categories. Notably, face-selective regions were contiguous with body-part-selective regions, and object-selective regions were contiguous with place-selective regions. When category-selective regions in monkeys were tested with blocks of single exemplars, individual voxels showed preferences for visually dissimilar exemplars from the same category and voxels with similar preferences tended to cluster together. Our results provide some novel observations with respect to how stimulus representations are organized in IT cortex. In addition, they further support the idea that representations of complex stimuli in IT cortex are organized into multiple hierarchical tiers, encompassing both semantic and physical properties.

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