Attentional control in the aging brain: insights from an fMRI study of the stroop task

Several recent studies of aging and cognition have attributed decreases in the efficiency of working memory processes to possible declines in attentional control, the mechanism(s) by which the brain attempts to limit its processing to that of task-relevant information. Here we used fMRI measures of neural activity during performance of the color-word Stroop task to compare the neural substrates of attentional control in younger (ages: 21-27 years old) and older participants (ages: 60-75 years old) during conditions of both increased competition (incongruent and congruent neutral) and increased conflict (incongruent and congruent neutral). We found evidence of age-related decreases in the responsiveness of structures thought to support attentional control (e.g., dorsolateral prefrontal and parietal cortices), suggesting possible impairments in the implementation of attentional control in older participants. Consistent with this notion, older participants exhibited more extensive activation of ventral visual processing regions (i.e., temporal cortex) and anterior inferior prefrontal cortices, reflecting a decreased ability to inhibit the processing of task-irrelevant information. Also, the anterior cingulate cortex, a region involved in evaluatory processes at the level of response (e.g., detecting potential for error), showed age-related increases in its sensitivity to the presence of competing color information. These findings are discussed in terms of newly emerging models of attentional control in the human brain.     

Lesions of the ventral hippocampus, but not the dorsal hippocampus, impair conditioned fear expression and inhibitory avoidance on the elevated T-maze

The hippocampus has been suggested to be involved in spatial (or configural) memory and also in the inhibition of certain response or goal alternatives. An increasing number of anatomical, physiological, and behavioral studies indicate that the hippocampus is functionally heterogeneous along the dorsal-ventral axis. Identification of distinct behavioral roles for the dorsal (DH) and ventral (VH) hippocampus may resolve differences between the various theoretical accounts of hippocampal function. The present study examined the effects of electrolytic lesions restricted to the DH or VH on fear-conditioned freezing, passive avoidance on the elevated T-maze (ETM) test of anxiety, and general activity in male Sprague-Dawley (Charles-River derived) albino rats. We found that rats with lesions of the VH, but not DH showed reduced freezing to both context and tone conditioned stimuli (CS). Rats with VH lesions also showed a reduced latency to emerge from the enclosed arm on trials 2 and 3 of the ETM (indicating reduced anxious behavior), while having no effect on the latency to escape from the open arms on trial 4. There were no differences in activity between the groups. These results indicate that the VH and DH are differentially involved in passive avoidance on the ETM and conditioned freezing to context and tone CS. We suggest that the VH may be specifically involved in modulating goal-oriented, defensive behavior expression through hypothalamic and amygdaloid connections.     

The great transition: A process view of history and its implications

The collapse of confidence since the nineteenth century, and the turbulence which has followed, are incorporated in an historical model describing the development of western civilization. It suggests that they are threshold symptoms of a forthcoming transition of profound importance and without earlier parallel. Three different, and not mutually exclusive perceptions of the transition are provided. There is no suggestion that we can anticipate what will happen, but recent rapid advances in communications and information technologies are likely to play a critical formative part in a development which will involve both a growth in collective self‐consciousness and the conceptual expansion of our minds.     

Cognitive performance is improved while walking: Differences in cognitive–sensorimotor couplings between children and young adults

We investigated how 9-year-olds and young adults performed a working memory task under different difficulty conditions while walking on a treadmill. Stride-length and stride-time variability tended to decrease with cognitive load in young adults, whereas children showed an increase in walking variability when cognitive load was very high. Participants in both age groups improved their cognitive performance when walking at their preferred speed as opposed to sitting or walking at a fixed, non-preferred speed. We conclude that the interaction of walking and cognitive performance is influenced by sharing resources between two tasks, and that performance improvements in cognition may be caused by an exercise-induced activation of resources.     

Can hearing puter activate pupil? Phonological competition and the processing of reduced spoken words in spontaneous conversations

In listeners' daily communicative exchanges, they most often hear casual speech, in which words are often produced with fewer segments, rather than the careful speech used in most psycholinguistic experiments. Three experiments examined phonological competition during the recognition of reduced forms such as [pjut?r] for computer using a target-absent variant of the visual world paradigm. Listeners' eye movements were tracked upon hearing canonical and reduced forms as they looked at displays of four printed words. One of the words was phonologically similar to the canonical pronunciation of the target word, one word was similar to the reduced pronunciation, and two words served as unrelated distractors. When spoken targets were presented in isolation (Experiment 1) and in sentential contexts (Experiment 2), competition was modulated as a function of the target word form. When reduced targets were presented in sentential contexts, listeners were probabilistically more likely to first fixate reduced-form competitors before shifting their eye gaze to canonical-form competitors. Experiment 3, in which the original /p/ from [pjut?r] was replaced with a “real” onset /p/, showed an effect of cross-splicing in the late time window. We conjecture that these results fit best with the notion that speech reductions initially activate competitors that are similar to the phonological surface form of the reduction, but that listeners nevertheless can exploit fine phonetic detail to reconstruct strongly reduced forms to their canonical counterparts.     

Matters Olympic and Paralympic

Over the past several years, I have been arguing that nature sports such as surfing, backcountry skiing, and mountaineering are best described as sports in which athletes interact dynamically with natural features rather than compete with other humans. This article is part of a larger attempt to trace the implications of that view. Specifically, I consider the relationship between nature sports and competition. To this purpose, I address three separate, but related topics: First, I reply to Leslie Howe’s article, ‘On Competing Against Oneself, Or, I Need to Get a Different Voice in My Head’, in which she argues that there is a version of self-competition that is central to nature sports. Second, I argue that adapting nature sports to fit into formal competitive frameworks is problematic because, when we do so, the focus shifts from athletes interacting with natural features to athletes using natural features to outdo other athletes. And third, I argue that nature sports may seem competitive because the interaction between humans and natural features produces a type of intensity that is very similar to the intensity produced in competition. I argue further that because nature sports can produce this intensity in an environment that is not based on competition, they present an important alternative to traditional sports.     

Nietzsche,competition and athletic ability

The purpose of this paper is to examine the relationship between Friedrich Nietzsche's notion of the agon (Greek for contest) and the construction of athletic ability. In ‘Homer's contest’, Nietzsche claims that the ancient Greek agon was a contest that included only the most qualified competitors battling each other for honour and victory. Nietzsche seeks to restore the agon in contemporary society. Nietzsche believes that contests have lost this agonistic meaning since they are no more than contrived competitions between underqualified opponents. I am extending the discussion to the domain of sport. If we stage an agon reminiscent of Greek antiquity, we could have a genuine competition between the most qualified athletes.     

Trash talking,respect for opponents and good competition

Trash talking, which is the North American term for verbal barbs directed at opponents during a sporting event in order to gain a competitive edge, is widely accepted by athletes and the athletic community as a legitimate part of sport. It is, however, morally indefensible. A simple Kantian injunction against treating opponents merely as objects to be overcome is sufficient to condemn this verbal abuse. Attempts to justify trash talking as a strategic ploy that implies no disrespect are disingenuous in view of the fact that its effectiveness depends on opponents' being offended by it. Nor can we defend trash talking as enhancing the goal of athletic competition, since the ability to verbally abuse opponents and remain impervious to their abuse are extraneous to the athletic excellence that contests are designed to measure. Attempts to deflect criticisms by partially immunizing sport from moral scrutiny are implausible. With few exceptions, we judge actions in sport by the same moral standards that we use in any other context. Moreover, the view that neither trash talking nor other actions in sport are fit subjects for strict moral scrutiny is inconsistent with the often-heard claim that sport promotes moral development.     

Revisiting Competitive Categories: A Reply to Royce

In this article, I respond to the criticisms that Richard Royce has made of my theory of competition in Sport, Ethics and Philosophy. While I find some of his attacks misplaced, a number of his criticisms address key difficulties to which I offer clarification and defense.