The contribution of the inferior parietal cortex to spoken language production

This functional MRI study investigated the involvement of the left inferior parietal cortex (IPC) in spoken language production (Speech). Its role has been apparent in some studies but not others, and is not convincingly supported by clinical studies as they rarely include cases with lesions confined to the parietal lobe. We compared Speech with non-communicative repetitive tongue movements (Tongue). The data were analyzed with both univariate contrasts between conditions and probabilistic independent component analysis (ICA). The former indicated decreased activity of left IPC during Speech relative to Tongue. However, the ICA revealed a Speech component in which there was correlated activity between left IPC, frontal and temporal cortices known to be involved in language. Therefore, although net synaptic activity throughout the left IPC may not increase above baseline conditions during Speech, one or more local systems within this region are involved, evidenced by the correlated activity with other language regions.     

Space and the parietal cortex

Current views of the parietal cortex have difficulty accommodating the human inferior parietal lobe (IPL) within a simple dorsal versus ventral stream dichotomy. In humans, lesions of the right IPL often lead to syndromes such as hemispatial neglect that are seemingly in accord with the proposal that this region has a crucial role in spatial processing. However, recent imaging and lesion studies have revealed that inferior parietal regions have non-spatial functions, such as in sustaining attention, detecting salient events embedded in a sequence of events and controlling attention over time. Here, we review these findings and show that spatial processes and the visual guidance of action are only part of the repertoire of parietal functions. Although sub-regions in the human superior parietal lobe and intraparietal sulcus contribute to vision-for-action and spatial functions, more inferior parietal regions have distinctly non-spatial attributes that are neither conventionally 'dorsal' nor conventionally 'ventral' in nature.     

Action, mindreading and embodied social cognition

One of the central insights of the embodied cognition (EC) movement is that cognition is closely tied to action. In this paper, I formulate an EC-inspired hypothesis concerning social cognition. In this domain, most think that our capacity to understand and interact with one another is best explained by appeal to some form of mindreading. I argue that prominent accounts of mindreading likely contain a significant lacuna. Evidence indicates that what I call an agent??s actional processes and states??her goals, needs, intentions, desires, and so on??likely play important roles in and for mindreading processes. If so, a full understanding of mindreading processes and their role in cognition more broadly will require an understanding of how actional mental processes interact with, influence, or take part in mindreading processes.     

Stimulus expectancy modulates inferior frontal gyrus and premotor cortex activity in auditory perception

In studies on auditory speech perception, participants are often asked to perform active tasks, e.g. decide whether the perceived sound is a speech sound or not. However, information about the stimulus, inherent in such tasks, may induce expectations that cause altered activations not only in the auditory cortex, but also in frontal areas such as inferior frontal gyrus (IFG) and motor cortices, even in the absence of an explicit task. To investigate this, we applied spectral mixes of a flute sound and either vowels or specific music instrument sounds (e.g. trumpet) in an fMRI study, in combination with three different instructions. The instructions either revealed no information about stimulus features, or explicit information about either the music instrument or the vowel features. The results demonstrated that, besides an involvement of posterior temporal areas, stimulus expectancy modulated in particular a network comprising IFG and premotor cortices during this passive listening task.     

On the distinction between perception and cognition

To uphold the distinction between perception and cognition for certain classes of tasks or phenomena, it is proposed that three criteria must be met: (1) when perceptual and cognitive functions serve different biological purposes, (2) when stimulus information in dynamic events is necessary, but not sufficient for veridical perception, and (3) when the task emphasizes explicit retrieval, as opposed to implicit use of information. Conversely, when the three criteria have not been met, conditions for theoretical unification exist.     

Bodily expressions,feelings, and the direct perception account of social cognition

Phenomenology and the Cognitive Sciences - In this paper, I will argue in favor of a direct perception account of social cognition (DP), focusing on the idea that we can directly grasp at least...     

Inhibition and the right inferior frontal cortex

It is controversial whether different cognitive functions can be mapped to discrete regions of the prefrontal cortex (PFC). The localisationist tradition has associated one cognitive function - inhibition - by turns with dorsolateral prefrontal cortex (DLPFC), inferior frontal cortex (IFC), or orbital frontal cortex (OFC). Inhibition is postulated to be a mechanism by which PFC exerts its effects on subcortical and posterior-cortical regions to implement executive control. We review evidence concerning inhibition of responses and task-sets. Whereas neuroimaging implicates diverse PFC foci, advances in human lesion-mapping support the functional localization of such inhibition to right IFC alone. Future research should investigate the generality of this proposed inhibitory function to other task domains, and its interaction within a wider network.     

Distinct contributions of the caudate nucleus, rostral prefrontal cortex, and parietal cortex to the execution of instructed tasks

When we behave according to rules and instructions, our brains interpret abstract representations of what to do and transform them into actual behavior. In order to investigate the neural mechanisms behind this process, we devised an fMRI experiment that explicitly isolated rule interpretation from rule encoding and execution. Our results showed that a specific network of regions (including the left rostral prefrontal cortex, the caudate nucleus, and the bilateral posterior parietal cortices) is responsible for translating rules into executable form. An analysis of activation patterns across conditions revealed that the posterior parietal cortices represent a mental template for the task to perform, that the inferior parietal gyrus and the caudate nucleus are responsible for instantiating the template in the proper context, and that the left rostral prefrontal cortex integrates information across complex relationships.     

Differentiation and unification in perception and cognition

It has been suggested that the development of distinctions between perception and cognition depends upon the perspective and the level of analysis chosen. Similarly, the unification of perception and cognition may be achieved from other perspectives and when other levels of analyses are applied. The fruitfulness, and disadvantages, of diverse suggestions for differentation/unification of perception and cognition are discussed briefly.     

An on-line laboratory in cognition and perception

The design of a computer-based laboratory system requires the coordination of pedagogical and technical goals. The development of our on-line laboratory in cognition and perception is described. The laboratory consists of 11 on-line experiments in which the student participates as both experimenter and subject. The software was designed for maximum transportability: Programs were written in a low-level BASIC, with thorough documentation; flexibility is provided both within and across experiments to suit local constraints; and the experiments are supported by a student manual, instructor’s manual, and implementation notes. Criteria for selecting experiments, implementation of the experiments, and preliminary evaluation of the laboratory are discussed.     

Integrating rewards and cognition in the frontal cortex

Research indicates that the dorsolateral prefrontal cortex (DLPFC) contributes to working memory and executive control, whereas the ventral frontal cortex (VFC) contributes to affective and motivational processing. Few studies have examined both the functional specificity and the integration of these regions. We did so using fMRI and a verbal working memory task in which visual cues indicated whether recall performance on an upcoming trial would be linked to a monetary reward. On the basis of prior findings obtained in delayed response tasks performed by nonhuman primates, we hypothesized that (1) VFC would show an increase only in response to a cue indicating potential for a monetary reward; (2) DLPFC would show sustained activity across a delay interval for all trials, though activity in rewarded trials would be enhanced; and (3) regions engaged in speech-based rehearsal would be relatively insensitive to monetary incentive. Our hypotheses about DLPFC and rehearsal-related regions were confirmed. In VFC regions, we failed to observe statistically significant effects of reward when the cue or delay epochs of the task were examined in isolation. However, an unexpected and significant deactivation was observed in VFC during the delay epoch; furthermore, a post hoc voxelwise analysis indicated a complex interaction between (1) the cue and delay epochs of the task and (2) the reward value of the trials. The pattern of activation and deactivation across trial types suggests that VFC is sensitive to reward cues, and that portions of DLPFC and VFC may work in opposition during the delay epoch of a working memory task in order to facilitate task performance.     

Action,affordances, and anorexia: body representation and basic cognition

We evaluate a growing trend towards anti-representationalism in cognitive science in the context of recent research into the development and maintenance of anorexia nervosa in cognitive neuropsychiatry. We argue two things: first, that this research relies on an explanatorily robust concept of representation—the concept of a long-term body schema; second, that this body representation underlies our most basic environmental interactions and affordance perception—the psychological phenomena supposed to be most hospitable to a non-representationalist treatment.     

Left inferior frontal cortex can compensate the inhibitory functions of right inferior frontal cortex and pre-supplementary motor area

Right-IFG and pre-SMA are associated with inhibitory responses. We used functional Magnetic Resonance Imaging to explore whether the contralateral homotopic regions can functionally replace them. An adolescent, with an extensive traumatic lesion of the right cerebral hemisphere having occurred 5 years earlier, performed a motor response inhibition task (Go/Nogo), which was properly accomplished and associated to activations in the left-IFC, precuneus and occipital cortex. Such functional remodelling is in line with the theory of ‘near equipotentiality’ of the cerebral hemispheres.     

Interaction between affect and cognition in word perception

Investigated the hypothesis that the accuracy with which a briefly shown word is perceived depends on both the affective tone of the word and the activation of the corresponding memory code. To increase activation, expectation and word frequency were manipulated. Ss were exposed to a 25-ms flash of a target word. They then chose, from a word pair, the target word. In half the trials, this word pair was given before the flash to create an expectation. Consistent with the hypothesis, when the words were infrequent, accuracy in perception was lower for affective than for neutral words regardless of expectation. When the words were frequent, there was no effect of affective tone in the absence of expectation; in the presence of expectation, accuracy was higher for affective than for neutral words. The valence of the affective words had no effect. Results are interpreted in terms of attentional mechanisms implicated in conscious perception.