The K-9 Unit

Abstract

This paper describes the process of evaluating and designing interventions for sensory processing preferences using the Adult Sensory Profile. The measure is theoretically based on Dunn's Model of Sensory Processing (1997) which describes the intersection of neurological threshold and behavioral responses resulting in the following four quadrants: sensory sensitivity, sensation avoiding, low registration and sensation seeking. The compatibility of this model and recovery is discussed along with specific strategies for matching environments and sensory processing preferences.     

Category priming with aliens: Analysing the influence of targets' prototypicality on the centre surround inhibition mechanism

Marginally perceptible prototypes as primes lead to slowed reactions to related category exemplars as compared to unrelated ones. This at first glance counterintuitive finding has been interpreted as evidence for a particular mechanism of lateral inhibition, namely the centre surround inhibition mechanism. We investigated the semantic surround of category labels by experimentally manipulating the prototypicality of stimuli. Participants first learned two new categories of fantasy creatures in a 5-day-long learning phase before they worked through a semantic priming task with the category prototypes as primes and category exemplars as targets. For high-prototypical targets we observed benefit effects from related primes, whereas for low-prototypical targets we observed cost effects. The results define when the centre surround inhibition mechanism is applied, and furthermore might explain why previous studies with word stimuli (i.e., material that prevents experimental manipulation of prototypicality) observed mixed results concerning the prototypicality of targets.     

The multiple roles of Broca's discovery in the development of the modern neurosciences

Using the classical clinico-anatomical correlation method of the French clinical school, Paul Broca confirmed the localization of "language" in the frontal lobe. He actually discovered the lateralization of language in the left hemisphere. These contributions eventually led to the demise of the older concept of the "sensorium commune," because Broca's ideas implied the presence of motor functions in the hemispheres. Although Broca worked within the theoretical motif of the "faculty" psychology, the reflex-oriented "associationist" psychology soon became the predominant theoretical framework of localization, because it accommodated the motor aspect of hemispheric function. Since Broca's time, the study of the biology of language has proceeded along two parallel but sometimes separate lines in the experimental and clinical traditions.     

Lateralization of temporal lobe dysfunction and verbal encoding

The contribution of encoding deficits to verbal-learning difficulties known to be associated with temporal lobe dysfunction was investigated. Auditory and visual false-recognition tasks, which assess verbal encoding strategies, were given to patients with left-temporal-lobe (LTL) and right-temporal-lobe (RTL) surgical excisions and to a group of normal controls (NC). On both auditory and visual tasks, LTL patients made significantly more false-recognition errors than the other subjects on related, but not unrelated, words in the test list. The findings indicate that LTL patients are able to initially encode verbal material and that a breakdown in information processing occurs at a later stage. On the auditory tasks, the performance of RTL patients did not differ from that of NC subjects. However, on the visual tasks, RTL patients, as compared to both LTL and NC subjects, made fewer false-recognition errors. The performance of RTL patients, in contrast to LTL patients, could be interpreted as a reduced encoding of the visual attribute of verbal material. Another possible explanation considered was difficulty in familiarity discrimination.     

Developmental changes in infants' sensitivity to octave-band noises

Localization responses to octave-band noises with center frequencies at 200, 400, 1000, 2000, 4000, and 10,000 Hz were obtained from infants 6, 12, and 18 months of age. During an experimental trial, an octave-band noise was presented on one of two speakers located 45° to each side of the infant. A head turn to the noise (correct response) was rewarded by activating an animated toy on top of the speaker. The intensity of the noise was varied over trials (method of constant stimuli) to determine thresholds at each center frequency. Thresholds for the lower frequencies were approximately 5–8 db higher in the 6-month-old infants compared to the older infants. However, there were no consistent differences among groups at the higher frequencies. Infant thresholds were found to be 20–30 db higher than adult thresholds at the lower frequencies. At the higher frequencies thresholds for infants were approaching those of adults.     

Why Mikey's right and my key's wrong: The significance of stress and word boundaries in a child's output system

The systematic errors children make in the course of phonological development, like adult production errors and adult phonological processes, can provide evidence of language production mechanisms. A detailed investigation of the environments in which velar stops are fronted by a phonologically delayed child reveals that fronting is dependent on both word stress and word boundaries; that it shows lexical exceptions; and that it occurs in output only. This distribution suggests that the child has output lexical representations which are independent of input lexical representations, and that the fronting error occurs in these output representations. It also suggests that prosodic features are crucial to the identification of articulatory features within these representations. Such an analysis has implications for theories of lexical access, and for the development of lexical access in children.     

Speech dominance and handedness in the normal human

Spectral analysis was used to measure the coherence or similarity of form between occipital and temporal evoked potentials. In both right- and left-handers, coherence was greater in the left hemisphere for click stimuli and in the right hemisphere for flash stimuli. Similar asymmetries occurred in left but not right speech dominant patients whose speech lateralization has been determined by the intracarotid amytal test. Right-handers and males, however, showed significantly larger amplitudes of auditory responses in the right hemisphere. Left-handers and females reversed this pattern. It was concluded that within a basically left speech dominant organization, males and right-handers would emphasize the verbal, temporal structure of auditory information and the nonverbal, spatial structure of visual information. Females and left-handers would tend to reverse this emphasis.