A number of neuroimaging findings have been interpreted as evidence that the left inferior frontal gyrus (IFG) subserves retrieval semantic knowledge. We provide a fundamentally different interpretation, it is not knowledge per se associated with IFG activity but rather selection information among competing alternatives from memory. Selection demands were varied across three tasks in single group subjects. Functional magnetic resonance imaging signal overlapping regions was dependent on all...

Neuroimaging studies have revealed an association between word generation and activity in the left inferior frontal gyrus (IFG) that is attentuated with item repetition. The experiment reported here examined effects of repeated generation, under conditions which completion was either decreased or increased, on measured during whole-brain echoplanar functional magnetic resonance imaging. Activity IFG repetition reduced competition but increased competition; this pattern contrasted to observed...

What are the neural bases of semantic memory? Traditional beliefs that temporal lobes subserve retrieval knowledge, arising from lesion studies, have been recently called into question by functional neuroimaging studies finding correlations between and activity in left prefrontal cortex. Has taught us something new about cognition older methods could not reveal or has it merely identified brain is correlated with but causally related to process retrieval? We examined ability patients focal...

To produce a word, the intended word must be selected from competing set of other words. In domains where competition affects selection process, left inferior frontal gyrus (LIFG) responds to among incompatible representations. The aim this study was test whether LIFG is necessary for resolution in production. Using methodological approach applying same rigorous analytic methods neuropsychological data as done with neuroimaging data, we compared brain activation patterns normal speakers...

Recent neuroscience evidence suggests that some higher-order tasks might benefit from a reduction in sensory filtering associated with low levels of cognitive control. Guided by neuroimaging findings, we hypothesized cathodal (inhibitory) transcranial direct current stimulation (tDCS) will facilitate performance flexible use generation task. Participants saw pictures artifacts and generated aloud either the object’s common or an uncommon for it, while receiving tDCS (1.5 mA) over left right...

To make sense of the world around us, our brain must remember overlapping features millions objects. Crucially, it also represent each object's unique feature-convergence. Some theories propose that an integration area (or "convergence zone") binds together separate features. We report investigation knowledge objects' and identity, link between them. used functional magnetic resonance imaging to record neural activity, as humans attempted detect a cued fruit or vegetable in visual noise. we...

One of the most remarkable features human brain is its ability to adapt rapidly and efficiently external task demands. Novel non-routine tasks, for example, are implemented faster than structural connections can be formed. The neural underpinnings these dynamics far from understood. Here we develop apply novel methods in network science quantify how patterns functional connectivity between regions reconfigure as subjects perform 64 different tasks. By applying dynamic community detection...

Abstract Lesion and neuroimaging studies suggest the amygdala is important in perception production of negative emotion; however, effects emotion regulation on amygdalar response to stimuli remain unknown. Using event-related fMRI, we tested hypothesis that voluntary modulation associated with changes neural activity within amygdala. Negative neutral pictures were presented instructions either “maintain” emotional or “passively view” picture without regulating emotion. Each presentation was...

The prefrontal cortex is crucial for the ability to regulate thought and control behavior. development of human cerebral characterized by an extended period maturation during which young children exhibit marked deficits in cognitive control. We contend that prolonged immaturity is, on balance, advantageous positive consequences this developmental trajectory outweigh negative. Particularly, we argue impedes convention learning, delayed a necessary adaptation learning social linguistic...

Abstract Retrieval of conceptual information from action pictures causes greater activation than object bilaterally in human motion areas (MT/MST) and nearby temporal regions. By contrast, retrieval words left middle superior gyri, anterior dorsal to the MT/MST. We performed two fMRI experiments replicate extend these findings regarding words. In first experiment, subjects judgments under conditions that stressed visual semantic information. Under conditions, again activated posterior...

Is our knowledge about the appearance of objects more closely related to verbal thought or perception? In a behavioural study using property verification task, Kosslyn (1976) reported that there are both amodal and perceptual representations concepts, but may be easily accessed. However, Solomon (1997) argued due nature Kosslyn's stimuli, subjects able bypass semantics entirely perform this task differences in strength association between words true trials (e.g., cat-whiskers) those false...

For over a century, link between left prefrontal cortex and language processing has been accepted, yet the precise characterization of this remains elusive. Recent advances in both study sentence neuroscientific frontal lobe function suggest an intriguing possibility: The demands to resolve competition incompatible characterizations linguistic stimulus may recruit top-down cognitive control processes mediated by cortex. We use functional magnetic resonance imaging test hypothesis that...

Abstract Patients with focal lesions to the left inferior frontal gyrus (LIFG; BA 44/45) exhibit difficulty language production and comprehension tasks, although nature of their impairments has been somewhat difficult characterize. No reported cases suggest that these patients are Broca's aphasics in classic agrammatic sense. Recent case studies, however, do reveal a consistent pattern deficit regarding general cognitive processes: They reliably impaired on tasks which conflicting...

Abstract A long‐standing pursuit in cognitive neuropsychology has been to understand the role of Broca’s area language processing. Although a prevailing view equate this region with grammatical abilities both production and comprehension, host recent evidence from brain imaging patient research revealed rather general for patch cortex complex cognition, even when performance is untapped—namely, that it regulates mental activity there need resolve among competing representations. In light,...