Past research suggests that the similarity between the objects associated with actions impacts visual action identification and action production. Indeed, people often confuse actions that are visually similar, as well as actions that are associated with visually similar objects. However, because the action errors often involve actions that are visually similar and are associated with visually similar objects, it is difficult to disambiguate between the influences of object similarity and action similarity. In our experiments, healthy participants were asked to learn to associate nonword names and actions with novel objects. Participants were first shown each object and its action and were then asked to visually identify each object. In Experiment 1, participants were then asked to produce the action associated with each object, and in Experiment 2, they were asked to visually identify the action associated with each object. Actions were confused more often when they were associated with similar objects than when they were associated with dissimilar objects. Furthermore, following an object naming error, participants were more likely to produce the action associated with the erroneous name than any other erroneous action. The results suggest that the visual characteristics of the objects influenced action production and action identification. (JINS, 2007, 13, 1021–1034.)

This is the fifth symposium to appear in the Journal of the International Neuropsychological Society (JINS). This symposium was developed in tandem with a Memory Disorders Research Society conference symposium on semantic memory in probable Alzheimer's disease (AD); the conference was held in Boston in October, 1998. Three of the conference presenters agreed to submit papers based on their talks to this JINS symposium. A concerted effort was made to solicit additional papers from researchers who have consistently weighed in on either the storage-loss or retrieval-difficulty side of the debate regarding semantic memory in AD, and from researchers who have obtained some evidence consistent with one view as well as some evidence consistent with the other view. In the end, not only was the theoretical continuum fairly well represented, but the methodological continuum, with regard to the types of tasks used and the degree to which the tasks required implicit versus explicit utilization of semantic knowledge, was also well covered.

Trajectories of saccadic eye movements can be modulated by the presence of a competing visual distractor. It is proposed that the superior colliculus (SC) controls the initial deviation through competitive lateral interactions. Given the ramifications of connections between basal ganglia (BG) thalamo-cortical circuitry and the SC, it was anticipated that this modulation would be differentially effected in those with Huntington's disease, which in its early stages is primarily a disorder of the BG. Horizontal deviation was determined for exogenously driven and endogenously driven vertical saccades in the presence of peripheral distractors. For neurologically healthy participants, the initial trajectories of both saccade types curved away from distractor locations, as predicted. However, for HD participants exogenous saccades consistently deviated leftwards, irrespective of distractor location. Endogenous saccades also revealed anomalous horizontal deviation, with significant leftward deviation evident for saccades directed upward and significant rightward deviation for saccades directed downward. Further, both groups generated a comparable proportion of erroneous responses to distractor stimuli, but only neurologically healthy participants demonstrated a response time advantage for compatible target/distractor presentation. These results suggest anomalous regulation of distractor-related activity in HD. (JINS, 2006, 12, 455–464.)

Objectives: In unpredictable situations, individuals often show tradeoffs between response initiation and inhibition speeds. We tested the hypothesis that Parkinson’s disease (PD) motor subtypes differentially impact tradeoffs between these two action-oriented processes. We predicted that, compared to tremor dominant (TD) patients, predominant postural instability and gait dysfunction (PIGD) patients would show exacerbated tradeoffs between response initiation and inhibition in situations requiring the sudden potential need to interrupt an action. Methods: Fifty-one PD patients (subdivided into PIGD [n=27] and TD [n=24]) and 21 healthy controls (HCs) completed a choice reaction task to establish baseline response initiation speed between groups. Subsequently, participants completed a stop-signal task which introduced an occasional, unpredictable stop stimulus. We measured changes in initiation speed in preparation of an unpredictable stop (i.e., proactive slowing) and inhibition latency (i.e., stop-signal reaction time). Results: Compared to HCs, PD patients showed slower response initiation speeds in the choice reaction task. All groups showed proactive slowing in the stop-signal task but the magnitude was considerably larger in PIGD patients, almost twice as large as TD patients. PD patients, irrespective of motor subtype, showed longer inhibition latencies than HCs. Conclusions: PIGD and TD subtypes both showed exacerbated response inhibition deficits. However, PIGD patients showed much more pronounced proactive slowing in situations with an expected yet unpredictable need to stop action abruptly. This suggests that PIGD is accompanied by exaggerated tradeoffs between response initiation and inhibition processes to meet situational action demands. We discuss putative neural mechanisms and clinical implications of these findings. (JINS, 2017, 23, 665–674)

This study assessed whether verbal memory performance indexed by the California Verbal Learning Test (CVLT) can organize and reduce the heterogeneity of schizophrenia. The temporal stability, cognitive and clinical validity of: (a) a putatively cortical-subcortical-normative typology derived from dementia patients' scores on the CVLT and (b) a memory performance dichotomy based on a psychometric criterion and 1 CVLT summary score were evaluated. These memory subtypes were examined in 102 schizophrenia patients, 55 of whom were assessed again 3 years later. The results indicate that both methods yield potentially valuable illness distinctions on a cross-sectional basis, but fail to show truly trait-like properties. Furthermore, the evidence favors the validity of a parsimonious dichotomy over a more complex dementia-based typology. (JINS, 2006, 12, 782–791.)

This paper highlights major developments over the past two to three decades in the neuropsychology of movement and its disorders. We focus on studies in healthy individuals and patients, which have identified cognitive contributions to movement control and animal work that has delineated the neural circuitry that makes these interactions possible. We cover advances in three major areas: (1) the neuroanatomical aspects of the “motor” system with an emphasis on multiple parallel circuits that include cortical, corticostriate, and corticocerebellar connections; (2) behavioral paradigms that have enabled an appreciation of the cognitive influences on the preparation and execution of movement; and (3) hemispheric differences (exemplified by limb praxis, motor sequencing, and motor learning). Finally, we discuss the clinical implications of this work, and make suggestions for future research in this area. (JINS, 2017, 23, 768–777)

In comparison to the basal ganglia, prefrontal cortex, and medial temporal lobes, the cerebellum has been absent from recent research on the neural substrates of categorization and identification, two prominent tasks in the learning and memory literature. To investigate the contribution of the cerebellum to these tasks, we tested patients with cerebellar pathology (seven with bilateral degeneration, six with unilateral lesions, and two with midline damage) on rule-based and information-integration categorization tasks and an identification task. In rule-based tasks, it is assumed that participants learn the categories through an explicit reasoning process. In information-integration tasks, optimal performance requires the integration of information from multiple stimulus dimensions, and participants are typically unaware of the decision strategy. The identification task, in contrast, required participants to learn arbitrary, color-word associations. The cerebellar patients performed similar to matched controls on all three tasks and performance did not vary with the extent of cerebellar pathology. Although the interpretation of these null results requires caution, these data contribute to the current debate on cerebellar contributions to cognition by providing boundary conditions on understanding the neural substrates of categorization and identification, and help define the functional domain of the cerebellum in learning and memory. (JINS, 2008, 14, 760–770.)

Patients with mild to moderate Alzheimer's disease and normal controls were tested on a retrograde amnesia test with semantic content (Neologism and Vocabulary Test, or NVT), consisting of neologisms to be defined. Patients showed a decrement as compared to normal controls, pointing to retrograde amnesia within semantic memory. No evidence for a gradient within this amnesia was found, although one was present on an autobiographic test of retrograde amnesia that had a wider time scale. Several explanations for these results are presented, including one that suggests that extended retrograde amnesia and semantic memory deficits are in fact one and the same deficit. (JINS, 2005, 11, 40–48.)

Objectives: Impairments of Theory of Mind (ToM) have been repeatedly demonstrated in patients with schizophrenia (SCZ). However, only a handful of studies have explored deficits in affective and cognitive subcomponents of ToM. Thus, this study aims to examine affective and cognitive ToM abilities in SCZ by using a novel, verbal paradigm. Methods: Twenty-four SCZ and 22 healthy comparison subjects (HC) completed a battery of tasks, which consisted of: (i) Brief Cognitive Assessment Tool for Schizophrenia (B-CATS), (ii) three well-established tasks measuring social cognitive abilities, and (iii) original tasks which assess ability to infer cognitive and affective mental states based on everyday verbal social interactions. Results: In line with previous findings, SCZ were outperformed by HC in all tasks. However, the interaction effect of the group and the task showed that cognitive (as opposed to affective) ToM was more profoundly impaired in patients with SCZ. Conclusions: It is proposed that in SCZ group cognitive ToM is more impaired as it involves more effortful reflective processes, while affective ToM, which is more automatic and based on reflexive processes, may differentiate patients from healthy comparison subjects to a lesser extent. (JINS, 2018, 24, 305–309)

Objectives: The third edition of the California Verbal Learning Test (CVLT-3) includes a new index termed List A versus Novel/Unrelated recognition discriminability (RD) on the Yes/No Recognition trial. Whereas the Total RD index incorporates false positive (FP) errors associated with all distractors (including List B and semantically related items), the new List A versus Novel/Unrelated RD index incorporates only FP errors associated with novel, semantically unrelated distractors. Thus, in minimizing levels of source and semantic interference, the List A versus Novel/Unrelated RD index may yield purer assessments of yes/no recognition memory independent of vulnerability to source memory difficulties or semantic confusion, both of which are often seen in individuals with primarily frontal-system dysfunction (e.g., early Huntington’s disease [HD]). Methods: We compared the performance of individuals with Alzheimer’s disease (AD) and HD in mild and moderate stages of dementia on CVLT-3 indices of Total RD and List A versus Novel/Unrelated RD. Results: Although AD and HD subgroups exhibited deficits on both RD indices relative to healthy comparison groups, those with HD generally outperformed those with AD, and group differences were more robust on List A versus Novel/Unrelated RD than on Total RD. Conclusions: Our findings highlight the clinical utility of the new CVLT-3 List A versus Novel/Unrelated RD index, which (a) maximally assesses yes/no recognition memory independent of source and semantic interference; and (b) provides a greater differentiation between individuals whose memory disorder is primarily at the encoding/storage level (e.g., as in AD) versus at the retrieval level (e.g., as in early HD). (JINS, 2018, 24, 833–841)

Objectives: The current study aimed to examine if televised media about mild traumatic brain injury (mTBI) framed in a sensationalized manner had a negative impact on cognitive functioning and persistent mTBI symptoms. Methods: One hundred two participants (MAge=37.16; SD=22.61) with a history of post-acute mTBI, recruited through a community research registry and an undergraduate recruitment system, were included in this study. Participants were assessed with a measure of health literacy, the Short Test of Functional Health Literacy in Adults (S-TOFHLA), and randomized to watch either a sensationalized or non-sensationalized news clip focused on mTBI. They were then assessed with the Paced Auditory Serial Addition Test (PASAT), Rivermead Post Concussion Symptoms Questionnaire (RPQ), Patient Reported Outcome Measures Information System (PROMIS) Depression scale, and the Posttraumatic Stress Disorder Checklist for the Diagnostic and Statistical Manual of Mental Disorders 5th edition (PCL-5). Results: Bayesian analyses indicated that sensationalized media—alone (βPASAT=−0.08; βRPQ=−0.08) or in the context of covariates (βPASAT=−0.11; βRPQ=−0.14)—was not a strong predictor of PASAT score or post-concussion syndrome symptom severity. Conclusions: Although media sensationalization of mTBI symptoms is not desirable, this study suggests that one brief exposure to sensationalized information may not have a meaningful immediate impact on the cognitive functioning or symptom reporting of individuals with a history of mTBI. Future research should examine long-term and downstream effects of sensationalized media reporting in samples with greater diversity of TBI history. (JINS, 2019, 25, 90–100)