Central Cognitive Processes Research Articles

Effects of Vigabatrin on Cognitive Function and Mood When Used as Add‐on Therapy in Patients with Intractable Epilepsy

Cognitive function and mood of patients with epilepsy who received 2 g/day vigabatrin (GVG) in addition to their usual antiepileptic drugs (AEDs) was assessed on two occasions: before start of treatment (baseline) and 4 weeks after start of treatment. A battery of selected psychological tasks measuring attention, mental speed, motor speed, central cognitive processing, and perceptuomotor performance was used, along with standardized, objective mood assessments. A comparison group (n = 15) of patients receiving stable medication was also tested to evaluate practice effects of the psychometric tests. Administration of 2 g/day GVG significantly decreased response time on a test of central cognitive processing ability (arithmetic). No adverse effect was noted on any other test of cognitive function or mood.

Wh-gap Binding and Ellipsis — a Grammar for an Input System

This paper argues that pragmatic processes and syntactic constraints interact, that we can nevertheless retain the assumption that the natural language faculty is fully encapsulated, and that the problems posed by the phenomenon of gapping (bare argument ellipsis) can be resolved by analysing gapping as an instance of such interaction. A new model of language is sketched out, a model which is a formal reconstruction of assumptions about the language faculty and its relation to central cognitive processes made by Fodor. and Sperber and Wilson. A fragment is defined to cover pronominal anaphoric dependency and quantifier binding, and a new analysis of bare argument ellipsis (gapping) is presented.

Modularity of Mind Revisited

This paper discusses Shanon's suggestion in his article 'Remarks on the Modularity of Mind' ([1988], pp. 331-52) that the Fodorean notion of modularity (Fodor [1983]) as 'structural and fixed' should be replaced by 'one which is dynamic, (and) context-dependent' (Shanon [1988], p. 331). I propose to comment briefly upon the major points of Shanon's attack on Fodor in Section 2 of this paper (which will concern the structure of the modules) and Section 3 (which will deal with methodological arguments). In Section 4 I argue that, whilst Shanon claims victory on both counts, such a victory is at best Pyrrhic: Shanon's revision of the modularity thesis deprives it of its capacity to account for the discrepancy between our knowledge of input systems and our comparative ignorance of cognitive organization within the brain. Nor does it succeed in putting anything constructive in place of this capacity. In Section 5 I shall make the further claim that this attempt to revise Fodorean modularity lends unintentional support to Fodor's despondency about our chances of providing a scientific account of the central cognitive processes. So, Shanon's whole attempt to provide a scientific account of cognition by revising the definition of modularity fails, because it cannot withstand the methodological criticisms he levels at Fodor.

Effects of nicotine gum on psychomotor performance in smokers and non-smokers

Two experiments were conducted to investigate the effects of nicotine on human performance. In the first study six smokers, who had been allowed to smoke normally prior to testing, completed a battery of psychometric tests (choice reaction time, memory scanning, tracking and flicker fusion threshold) at set points over 4 h after chewing 0, 2, or 4 mg nicotine polacrilex gum. A second study followed a similar design, but used five non-smoker volunteers who were required to chew only the 0 or 2 mg nicotine gum. Blood nicotine levels following the gum were measured in all subjects. The results indicate that additional nicotine improved both the speed and accuracy of motor activity among the smokers, but did not enhance central cognitive processes. No drug effects were found in the non-smoker study.

Mechanisms of Whole-Body Vibration Effects on Human Performance

Oscillatory ship motion and vibration effects on crews in modern naval air and sea systems can be the limiting factor in mission performance. The mechanisms of these effects, however, have not yet been clearly delineated; nor have a practical taxonomy and standard methodology for distinguishing and evaluating the deleterious action of whole-body vibratory motion on human performance been established. Some effects of vibration on performance appear to be directly attributable to immediate mechanical disruption of input and /or output (i.e., interference at the points of contact—displays or controls—between operator and task). Far more meager is clear evidence for time-dependent disruptive or degrading effects of vibration on central cognitive processes: these of course may also be affected indirectly by changes in the physiological state (including motion sickness and fatigue) induced by the motion or vibration. The distinction between direct and indirect mechanisms of performance decrement in the motion environment has important implications for both protective measures and the focus of future research. This report considers published work on the performance effects of vibration in relation to the etiology of performance change and those implications. A critical review of the methodology of performance studies in motion and vibration environments is under way at the Naval Biodynamics Laboratory; and a series of experiments (some previously published) on whole-body vibration effects on performance is also in progress. While the duality of the mechanisms of action of oscillatory motion on performance remains an open question, the evidence so far adduced for other than direct mechanical effects is sparse, at least in the frequency range of major body resonance phenomena. Further experimentation, including long-duration studies, is needed to resolve this question. Implications both for future research directions and for current national and international standardization efforts in this area are discussed.

Nonverbal behavior and thought processing.

Generally, clinicians assessing mental status interpret patients' nonverbal behavior in terms of its discharge, expressive, interactional, or neurological properties. The present study addresses the conceptualization of hand movement behavior as related to central cognitive processes, and attempts to identify encoding-related motor behavior by comparing the hand movements of subordinate bilingual subjects in situations of dominant- and nondominant-language and low- and high-imagery verbalization. Compared to the parallel dominant-language situation, subjects verbalizing in their nondominant language produced more speech-primacy and groping hand movements. Also, in comparison with the verbalization about a high-imagery topic, when the subjects encoded a low-imagery topic they displayed more pointing movements. Unless they are aware of these movements, clinicians evaluating bilingual patients may interpret an increase in encoding-related motor activity as reflecting psychopathology. Apart from this psychodiagnostic significance, hypothetical implications of these findings for the study of aphasia and information processing mechanisms are discussed.

Autonomic classical conditioning as a function of awareness of stimulus contingencies

Two groups of 32 college students were presented compound CSs (lights and tones presented simultaneously) during a classical conditioning paradigm. By means of a masking task and verbal instructions, a partially informed group was made aware of only the visual CS's contingency with the UCS, while a fully informed group was made aware of both the visual and auditory contingencies. Autonomic indices of conditioning (electrodermal responses, heart rate, and digital pulse volume) were later measured to the individual component CSs and to various compound CSs. It was found that: (1) the partially informed group exhibited conditioning exclusively to the visual CS+ and to compounds which included the visual CS+, while (2) the fully informed group exhibited conditioning to both visual and auditory CS+s. The results confirm the importance of awareness in human autonomic discrimination classical conditioning. It is suggested that human autonomic conditioning may be usefully conceptualized as an information processing task with the autonomic indices of conditioning reflecting central cognitive processes.

Hand Movements and Nondominant Fluency in Bilinguals

16 subordinate bilingual subjects produced 5-min. monologues in their nondominant languages, i.e., English or Spanish. Hand-movement activity manifested during the videotape monologues was scored and related to measures of fluency in the nondominant language. The hand-movement behavior categorized as Groping Movement was significantly related to all of the nondominant-language fluency measures. These correlations support the assumption that Groping Movement may have a function in the process of verbal encoding. The results are discussed in terms of the possibility of monitoring central cognitive processes through the study of "visible" motor behavior.

Retinal locus and acuity in visual information processing

Much recent visual information processing research has employed linear or rectangular letter displays subtending up to 8 deg of visual angle in width. Subsequent theory based on these data has assumed the simultaneous availability to some central processor of all n targets. Data on retinal acuity suggest that this assumption is gratuitous. Six subjects served in a tachistoscopic speeded letter recognition task wherein display luminance, retinal target locus, number of alternative target positions, and stimulus degradation by superimposition of a dot grid were manipulated orthogonally. Identification reaction times increased on the order of 100 msec as targets were located 3 deg from the fovea center, and results under convergent operations in the design suggested that these reaction time increases were a manifestation of peripheral stimulus degradation factors (such as acuity, masking, and luminance) rather than more central cognitive processes.