Longitudinal neuropsychological report of aphasia following left-subcortical hemorrhage

The neuropsychological assessments of a patient with language disturbance following left thalamic-putaminal hemorrhage over a $\text{2}\text{1}\text{2}\text{-}\text{year}$ period are presented together with premorbid measures of performance. Findings indicate that behavioral deficits which are both linguistic and nonlinguistic in nature differ from cortical aphasic syndromes in symptomatology and recovery course. The deficit pattern is also unlike that in other reported cases of left-subcortical lesions. Persistent dysarthria with fluent speech, limitation of verbal span and repetition, agraphia and anomia, and disturbances in self-regulation of behavior were noted, in addition to recovery of an initially severe auditory comprehension deficit. A distinguishing feature of this case was the relative preservation of reading comprehension in all four assessments.     

Transfer of conditioned appetitive stimuli to conditioned aversive excitatory and inhibitory stimuli

The transfer of Pavlovian appetitive stimuli to Pavlovian aversive stimuli was examined in three experiments. In Experiment 1, rats received appetitive (Ap) conditioning designed to establish a flashing-light stimulus as either a CS+, CSo, or CS? for food, or to maintain it as a novel stimulus for US-alone subjects. Then, the stimulus was employed as a signal for weak shock in conditioned-emotional-response (CER) training. Both acquisition and extinction results showed that the ApCS+ facilitated and the ApCS? retarded aversive excitatory conditioning relative to the ApCSo and US-alone controls. Experiment 2 replicated the findings of Experiment 1 with both a moderate and a severe shock in CER training. In Experiment 3, different groups received the same appetitive conditioning as before, but to a flashing-light stimulus which was then employed as a signal for no shock in CER training. The ApCS? facilitated and the ApCS+ retarded aversive inhibitory conditioning relative to ApCSo and US-alone controls. Collectively, these findings establish that, in Pavlovian conditioning, transfer of an appetitive CS to an aversive excitor or inhibitor is facilitated by maintaining the initial conditioning contingency.     

Differences in spatial knowledge acquired from maps and navigation

Models of the spatial knowledge people acquire from maps and navigation and the procedures required for spatial judgments using this knowledge are proposed. From a map, people acquire survey knowledge encoding global spatial relations. This knowledge resides in memory in images that can be scanned and measured like a physical map. From navigation, people acquire procedural knowledge of the routes connecting diverse locations. People combine mental simulation of travel through the environment and informal algebra to compute spatial judgments. An experiment in which subjects learned an environment from navigation or from a map evaluates predictions of these models. With moderate exposure, map learning is superior for judgments of relative location and straight-line distances among objects. Learning from navigation is superior for orienting oneself with respect to unseen objects and estimating route distances. With extensive exposure, the performance superiority of maps over navigation vanishes. These and other results are consonant with the proposed mechanisms.     

Hemispheric asymmetries in the perception of musical intervals as a function of musical experience and family handedness background

This study examines the effect of musical experience and family handedness background on the categorization of musical intervals (two-note chords). Right-handed subjects, who were divided into four groups on the basis of musical training and presence (or absence) of left-handed family members, categorized musical intervals which were monaurally presented to left or right ear. The results, based on consistency and discreteness of categorization, showed: (1) Musicians' performance is superior to nonmusicians'; (2) musicians and nonmusicians differ significantly on their ear of preference; (3) family handedness background significantly affects ear of preference among musicians but not among nonmusicians.     

Cerebral excitation profiles in language processing: The photic probe paradigm

A photic probe paradigm was developed in order to assess the cerebral excitation patterns corresponding to acoustic and linguistic operations independently of specific signal parameters. Average Evoked Potentials (AEPs) to a photic stimulus were recorded at the anterior temporal and posterior regions of both hemispheres of subjects engaged in acoustic, phonetic, and semantic processing of verbal material. Patterns of attenuation and enhancement of the probe AEP amplitudes were observed over the left and right hemispheres, respectively, with the magnitude of change varying reliably as a function of processing task. The implications of these findings for models of cerebral specialization for language are discussed.     

Impaired ranking of semantic attributes in dementia

The present work explored the loss of semantic attributes that is said to occur in dementia. In the first two experiments, subjects had to select attributes that went with concepts like airplane and church. The finding that demented subjects maintained high levels of accuracy when selecting attributes suggested that the semantic content of their concepts was relatively well preserved. The organization of the content was explored in a third experiment by having subjects order attributes according to their relative importance in defining concepts. While demented subjects performed better than chance, they did not rank attributes as well as healthy aged subjects, suggesting a disruption in organization whereby the importance of central attributes is reduced. The hypothesized disruption in organization is viewed in relation to the learning and memory deficit that is the hallmark of the dementias.     

Developmental changes in face processing: results from multidimensional scaling

Multidimensional scaling procedures were used to investigate developmental changes in the ability to process previously unfamiliar faces. Eighty male subjects, aged 7, 9, 12, or adult, rated the similarity of pairs of faces. The faces were presented to subjects in either the upright or the inverted orientation. Multidimensional scaling analyses suggest that subjects of all ages use similar information in judging the similarity of faces. However, for upright faces, individual subjects under age 10 seem to use fewer features at a time. The results argue against a qualitative shift in face processing at age 10, and suggest that the improvement in face recognition ability noted at this age is due at least in part to an increased ability to consider more features simultaneously.     

Onsets and rimes as units of spoken syllables: evidence from children

The effects of syllable structure on the development of phonemic analysis and reading skills were examined in four experiments. The experiments were motivated by theories that syllables consist of an onset (initial consonant or cluster) and a rime (vowel and any following consonants). Experiment 1 provided behavioral support for the syllable structure model by showing that 8-year-olds more easily learned word games that treated onsets and rimes as units than games that did not. Further support for the cohesiveness of the onset came from Experiments 2 and 3, which found that 4- and 5-year-olds less easily recognized a spoken or printed consonant target when it was the first phoneme of a cluster than when it was a singleton. Experiment 4 extended these results to printed words by showing that consonant-consonant-vowel nonsense syllables were more difficult for beginning readers to decode than consonant-vowel-consonant syllables.