Recognition Memory as a Method of Assessing Intelligence of an Infant with Quadriplegia

The authors demonstrate a test of visual cognitive abilities (Fagan Test of Infant Intelligence) in the assessment and management of a ventilator-dependent infant with quadriplegia. Assessment of visual recognition memory indicated that the infant's cognitive development progressed normally, despite severe physical limitations and a prolonged stay in hospital. The results suggested that the infant would benefit from age-appropriate auditory, visual and social stimulation and a specialized program of rehabilitation. The test may be particularly useful in assessing the intellectual abilities of infants whose motor dysfunction precludes effective response to traditional tests of sensorimotor intelligence.     

Functional Transitions Between Epileptiform-Like Activity and Associative Memory in Hippocampal Region CA3

Clinical and experimental observations indicate that the hippocampus is critical in the formation of declarative memories. Interestingly, electrophysiological studies have demonstrated that the region also has a particularly low seizure threshold, where globally synchronous synaptic activity can occur. By using a detailed biophysical model of area CA3, it is shown how septal cholinergic modulation, through three distinct mechanisms, can interact with intrinsic and synaptic conductances to influence population behavior. A dissection of each mechanism demonstrates a variety of population firing activity ranging from fully synchronized behavior to a mixture of repetitive bursting and oscillations in reduced subsets of neurons, ideal for forming accurate associations during a learning and recall task.     

The Role of Attention in the Context of Associative Memory

We model the mechanism of the retrieval of associations from the associative memory during visual scene analysis. During the analysis of the visual scene, the retrieval phase of the associative memory is divided into two stages: the attention stage and the binding stage. In the attention stage, an attention window selects patterns representing objects for further access. In the binding stage, the selected patterns form an address vector. The behavior of the model is demonstrated by theoretical analysis and empirical experiment.     

Neurophysiological Investigations of a Recognition Memory System for Imprinting in the Domestic Chick

The responsiveness of neurons in a region of the chick brain involved in the learning process of imprinting, the right intermediate and medial hyperstriatum ventrale (right IMHV), has been investigated in unanaesthetized, trained and untrained chicks. The results demonstrate that neuronal responsiveness in this region reflects a variety of behavioural consequences of imprinting and is markedly altered as a result of the learning process. Groups of chicks (nine in each group) were either dark-reared or trained (imprinted) by exposure to a rotating red box or a rotating blue cylinder. Recordings of single or small groups of neurons were subsequently made from 156 sites in the right IMHV while the 2-day-old chicks were free to move in a running wheel. There was a highly significant increase in the proportion of sites responsive to the stimulus used to train the birds compared to the proportion responsive to that stimulus in dark-reared birds (30 and 9% respectively). These changes were found when either the red box or the blue cylinder was used to train the bird, the changes being similar for both stimuli. There was also a significant increase in the mean magnitude of the change in neuronal activity on stimulus presentation for the training stimulus compared to the same stimulus when not used in the bird's training. No significant effects of the training experience of the chicks were found upon either the magnitude of evoked activity or the proportion of sites responsive to a rotating stuffed jungle fowl or the sound of the maternal call. The presence of the training stimulus was selectively signalled by the response at certain sites. At other sites there was response generalization across stimulus shape or colour. A comparison with results for the left IMHV demonstrates both similarities and differences in neuronal responsiveness between the two regions. In both regions imprinting selectively enhances neuronal responsiveness to the training stimulus. However, for trained birds the mean proportion of sites responding to whichever of the red box or the blue cylinder was not used in the bird's training was significantly lower in the right than the left IMHV. These results are discussed in relationship to previously reported asymmetries in the response of the right and left IMHV regions to imprinting. A model is introduced to explain the physiological findings. The effects of training on right IMHV neuronal function are consistent with a long-term role for this region in the recognition memory of imprinting.     

An Account of Interference in Associative Memory: Learning the Fan Effect

Associative learning is an essential feature of human cognition, accounting for the influence of priming and interference effects on memory recall. Here, we extend our account of associative learning that learns asymmetric item-to-item associations over time via experience (Thomson, Pyke, Trafton, & Hiatt, 2015) by including link maturation to balance associations between longer-term stability while still accounting for short-term variability. This account, combined with an existing account of activation strengthening and decay, predicts both human response times and error rates for the fan effect (Anderson, 1974; Anderson & Reder, 1999) for both target and foil stimuli.     

Malingering Scales for the Continuous Recognition Memory Test and the Continuous Visual Memory Test

Continuous Visual Memory Test (CVMT) and Continuous Recognition Memory Test (CRM) scores of 24 litigants with definite malingered neurocognitive dysfunction (definite MND) were contrasted with those of 27 patients with moderate (n = 12) and severe (n = 15) traumatic brain injury (TBI). Analysis with chi-square identified 20 CVMT and 33 CRM items that discriminated the definite MND from TBI cases. Receiver operating characteristic (ROC) area under curve (AUC) was 0.918 for the CVMT scale, and 0.962 for the CRM scale, p = 0.184. Cutting scores were derived yielding sensitivity and specificity of 0.83 and 0.889 for the 20-item CVMT scale, and 0.875 and 0.93 for the 33-item CRM scale. On cross-validation contrasting performance of 17 litigants with evidence of probable MND and non-litigating psychiatric (n = 14) and neurologic (n = 13) patients, ROC AUC was 0.779 for the CVMT scale, and 0.847 for the CRM scale, p = 0.447. Sensitivity and specificity were 0.35 and 0.93 for the CVMT, and 0.529 and 0.96 for the CRM, using the cutting scores from the derivation sample. ROC AUC differences contrasting values for the definite MND/TBI comparison to the probable MND/neurologic and psychiatric comparison approached significance for the CRM SVT scale (p = 0.059), and for the CVMT SVT scale (p = 0.082). These data suggest that the malingering scales for the CVMT and CRM are more sensitive to definite rather than probable MND, and these scales are better at ruling in than ruling out malingered visual memory deficits.     

Malingering Scales for the Continuous Recognition Memory Test and the Continuous Visual Memory Test

Continuous Visual Memory Test (CVMT) and Continuous Recognition Memory Test (CRM) scores of 24 litigants with definite malingered neurocognitive dysfunction (definite MND) were contrasted with those of 27 patients with moderate (n = 12) and severe (n = 15) traumatic brain injury (TBI). Analysis with chi-square identified 20 CVMT and 33 CRM items that discriminated the definite MND from TBI cases. Receiver operating characteristic (ROC) area under curve (AUC) was 0.918 for the CVMT scale, and 0.962 for the CRM scale, p = 0.184. Cutting scores were derived yielding sensitivity and specificity of 0.83 and 0.889 for the 20-item CVMT scale, and 0.875 and 0.93 for the 33-item CRM scale. On cross-validation contrasting performance of 17 litigants with evidence of probable MND and non-litigating psychiatric (n = 14) and neurologic (n = 13) patients, ROC AUC was 0.779 for the CVMT scale, and 0.847 for the CRM scale, p = 0.447. Sensitivity and specificity were 0.35 and 0.93 for the CVMT, and 0.529 and 0.96 for the CRM, using the cutting scores from the derivation sample. ROC AUC differences contrasting values for the definite MND/TBI comparison to the probable MND/neurologic and psychiatric comparison approached significance for the CRM SVT scale (p = 0.059), and for the CVMT SVT scale (p = 0.082). These data suggest that the malingering scales for the CVMT and CRM are more sensitive to definite rather than probable MND, and these scales are better at ruling in than ruling out malingered visual memory deficits.     

Construct validity of the Continuous Recognition Memory test

A principal factor analysis was performed on variables derived from a neuropsychological battery administered to 100 healthy young adults in order to investigate the construct validity of the Continuous Recognition Memory test (CRM). It was hypothesized that CRM "hits" and "false alarms" would load on different factors. The factors that emerged in the analysis were labeled "Verbal Ability", "Divided Attention", "Attention to Visual Detail", "Visuomotor Integration and Planning", and "Learning and Memory". As expected, CRM hits had a significant loading on the Learning and Memory factor. However, CRM false alarms did not have a significant loading on the Divided Attention factor as expected and, instead, loaded significantly on the Attention to Visual Detail factor. A second analysis was performed using variables from the delayed condition of the memory measures. In this analysis, the CRM delayed recognition variable had significant loadings on both a "Nonverbal Memory" factor and a "Verbal Memory" factor. These analyses support the construct validity of CRM hits as a measure of learning and memory and suggest that false alarms provide a measure of attention to visual detail.     

Construct Validity of the Continuous Recognition Memory Test

A principal factor analysis was performed on variables derived from a neuropsychological battery administered to 100 healthy young adults in order to investigate the construct validity of the Continuous Recognition Memory test (CRM). It was hypothesized that CRM “hits” and “false alarms” would load on different factors. The factors that emerged in the analysis were labeled “Verbal Ability”, “Divided Attention”, “Attention to Visual Detail”, “Visuomotor Integration and Planning”, and “Learning and Memory”. As expected, CRM hits had a significant loading on the Learning and Memory factor. However, CRM false alarms did not have a significant loading on the Divided Attention factor as expected and, instead, loaded significantly on the Attention to Visual Detail factor. A second analysis was performed using variables from the delayed condition of the memory measures. In this analysis, the CRM delayed recognition variable had significant loadings on both a “Nonverbal Memory” factor and a “Verbal Memory” factor. These analyses support the construct validity of CRM hits as a measure of learning and memory and suggest that false alarms provide a measure of attention to visual detail.     

Validation of the Face Name Associative Memory Exam in cognitively normal older individuals

The recently developed Face Name Associative Memory Exam (FNAME), a challenging paired associative learning task, shows promise in detecting the subtle cognitive changes characteristic of preclinical Alzheimer's disease. In this study, we evaluated the validity and reliability of the FNAME in 210 cognitively normal older individuals (58-90 years of age). Construct validity of the measure was assessed by principal components analysis, which revealed two independent factors. Correlations between the FNAME subtests and another episodic memory test were significant. The results indicated strong test-retest reliability in a subsample (n = 41). Normative data stratified by age were also generated.     

CERAD Praxis Memory and Recognition in Relation to Other Measures of Memory

Free Recall and Recognition memory of the CERAD (The Consortium to Establish a Registry for Alzheimer's Disease) Constructional Praxis task is investigated as adjunctive nonverbal memory measures to the CERAD Neuropsychological battery. Participants were administered an expanded CERAD neuropsychological battery which included Free Recall of the Constructional Praxis task. Significant correlations were observed between the Constructional Praxis Free Recall and both memory and visuospatial measures, however, correlations with memory measures were significantly higher. Constructional Praxis Free Recall was a significant predictor of diagnosis resulting in high sensitivity and specificity for patients diagnosed with Alzheimer's disease (n = 88) versus Normal Controls (n = 83) with an overall hit rate of 88%. Results suggest that the Constructional Praxis Free Recall procedure is a useful addition to the CERAD neuropsychological battery. Normative data for clinical use is presented for Constructional Praxis Free Recall, as well as a Constructional Praxis Recognition memory procedure which was administered to a subsample of the normal group.     

Learning-dependent Changes in the Responses to Visual Stimuli of Neurons in a Recognition Memory System

When young chicks are trained by exposing them to a conspicuous object they learn its characteristics. The learning process is known as imprinting. In the present study neuronal activity in a region crucial for imprinting was shown to be affected by training and by the object on which the chicks had been trained. The region is the intermediate and medial part of the left hyperstriatum ventrale (left IMHV). No such effects were found in a visual projection area, the left hyperstriatum accessorium. Domestic chicks were imprinted on either a rotating red box (n=7 chicks) or a rotating blue box (n=8). When the chicks were approximately 48 h old they were anaesthetized and multiple-unit activity was recorded in simultaneous, single penetrations through each of the two regions. Records were also made from eight dark-reared chicks. Whilst recording, the red or blue box, placed in front of the contralateral eye, was switched on to give a total of 20 rotations, the interval between each rotation being 10 s. The alternative stimulus was then presented 20 times. Unit activity in the 3 s before and after stimulus onset was compared and the data for each of the 20 presentations were combined. In the left IMHV 18 out of a total of 115 recording sites (16%) responded significantly to the stimuli; in the left hyperstriatum accessorium 39 out of 126 recording sites (26%) did so. Measures of unit activity at each recording site were combined for a given penetration to provide a 'mean penetration response'. The response to the red box differed from the response to the blue box in the left IMHV of dark-reared chicks. After training with the blue box the response to both boxes was similar to the response to the blue box in dark-reared birds. After training with the red box the response to both boxes was similar to the response to the red box in dark-reared birds. No significant effects were found in the left hyperstriatum accessorium. The two training boxes were virtually identical apart from the differences in colour and brightness. Training appeared to stabilize the response of the visually naive left IMHV to the training stimulus whilst changing its response to the alternative, but similar stimulus. That is, one consequence of training is that the two stimuli are placed in the same category, and this neural change may provide a basis for stimulus generalization. The underlying neural system is modelled and a mechanism that allows such stimuli to be discriminated is proposed.     

Neurophysiological and Clinical Aspects of Glucocorticoids and Memory: A Review

Neuropsychologists are increasingly involved in the assessment and treatment of individuals with glucocorticoid (GC) dysfunction. This review examines the clinical and neurophysiological changes associated with alterations in GC levels, with specific emphasis on changes in hippocampal plasticity and memory impairments. Hypothalamic-pituitary-adrenal (HPA) axis regulation of GC production and GC effects at hippocampal receptors are examined. GC-related changes in memory and hippocampal plasticity are considered in a wide array of populations, including animals, healthy adults, patients receiving exogenous GC treatments, and patients with neuropsychiatric disorders resulting in GC dysregulation. Hypotheses regarding GC-related memory changes are considered, with emphasis on hippocampal neurotoxicity and changes in excitatory amino acids, glucose metabolism and neurotrophic factors. These hypotheses are examined, with special attention given to inconsistencies and contradictions within this body of research. Finally, implications for neuropsychological evaluation and future research are presented.     

Some Aspects of Order and Symbolism in Schizophrenia

Developing out Rümke's term of “Praecox-Gefühl”, it is described that the schizophrenic disorder in his way of being is the fundamental underlying reason for dissociation of his thoughts and feelings. This consequently leads to a distortion in his system of sign recognition and the meaning attached to the different semantic and syntactic levels. By means of the “Wahnarbeit” and other mechanisms the schizophrenic tries to build another order in which he can feel more at ease with his overwhelming experiences. The conceptualization of his thoughts is performed by using a “principle of symmetry”—attaching the meaning of one perceived object (I) of reality to another conceptualized object (II). Very often we are unable to understand the individualistic nature of schizophrenic symbolization because of this mechanism.     

Epilepsy in the Elderly: Some Clinical and Pharmacotherapeutic Aspects

Summary: The majority of epileptic seizures and epilepsies are no longer manifested in childhood and adolescence; instead their incidence is higher at the age of 65 years or older than during the first two decades of life. After cerebrovascular disorders and dementias, epileptic seizures and epilepsies now constitute the third most frequent neurologic problem encountered in the elderly. Important clinical features of epilepsy in the elderly related to the diagnosis include the most common seizure types and causes. Special features of drug treatment for epilepsy in the elderly result not only from the physiologic changes in the elderly but also from the particular pharmacology of the respective drugs. Because elderly patients very often require other long-term medication in addition to antiepileptic therapy, drug interactions between different antiepileptic drugs and between antiepileptics and other drugs can be of major significance. Other special features of pharmacotherapy for epilepsy in the elderly include the presence of liver and kidney diseases.     

Somatostatin Neurons of the Bed Nucleus of Stria Terminalis Enhance Associative Fear Memory Consolidation in Mice

Excessive fear learning and generalized, extinction-resistant fear memories are core symptoms of anxiety and trauma-related disorders. Despite significant evidence from clinical studies reporting hyperactivity of the bed nucleus of stria terminalis (BNST) under these conditions, the role of BNST in fear learning and expression is still not clarified. Here, we tested how BNST modulates fear learning in male mice using a chemogenetic approach. Activation of GABAergic neurons of BNST during fear conditioning or memory consolidation resulted in enhanced cue-related fear recall. Importantly, BNST activation had no acute impact on fear expression during conditioning or recalls, but it enhanced cue-related fear recall subsequently, potentially via altered activity of downstream regions. Enhanced fear memory consolidation could be replicated by selectively activating somatostatin (SOM), but not corticotropin-releasing factor (CRF), neurons of the BNST, which was accompanied by increased fear generalization. Our findings suggest the significant modulation of fear memory strength by specific circuits of the BNST.SIGNIFICANCE STATEMENT The bed nucleus of stria terminalis (BNST) mediates different defensive behaviors, and its connections implicate its integrative modulatory role in fear memory formation; however, the involvement of BNST in fear learning has yet to be elucidated in detail. Our data highlight that BNST stimulation enhances fear memory formation without direct effects on fear expression. Our study identified somatostatin (SOM) cells within the extended amygdala as specific neurons promoting fear memory formation. These data underline the importance of anxiety circuits in maladaptive fear memory formation, indicating elevated BNST activity as a potential vulnerability factor to anxiety and trauma-related disorders.     

Associative image analysis: a method for automated quantification of 3D multi-parameter images of brain tissue

Brain structural complexity has confounded prior efforts to extract quantitative image-based measurements. We present a systematic 'divide and conquer' methodology for analyzing three-dimensional (3D) multi-parameter images of brain tissue to delineate and classify key structures, and compute quantitative associations among them. To demonstrate the method, thick ( approximately 100 microm) slices of rat brain tissue were labeled using three to five fluorescent signals, and imaged using spectral confocal microscopy and unmixing algorithms. Automated 3D segmentation and tracing algorithms were used to delineate cell nuclei, vasculature, and cell processes. From these segmentations, a set of 23 intrinsic and 8 associative image-based measurements was computed for each cell. These features were used to classify astrocytes, microglia, neurons, and endothelial cells. Associations among cells and between cells and vasculature were computed and represented as graphical networks to enable further analysis. The automated results were validated using a graphical interface that permits investigator inspection and corrective editing of each cell in 3D. Nuclear counting accuracy was >89%, and cell classification accuracy ranged from 81 to 92% depending on cell type. We present a software system named FARSIGHT implementing our methodology. Its output is a detailed XML file containing measurements that may be used for diverse quantitative hypothesis-driven and exploratory studies of the central nervous system.     

Patterns of performance on the Fuld Object Memory Evaluation in elderly inpatients with depression or dementia

The Fuld Object Memory Evaluation (Fuld, 1981) was administered to 80 elderly adults (aged 60 to 90 years) who were hospitalized for evaluation and treatment of primary degenerative dementia (PDD), other organic disorders (e.g., Parkinson's disease or multi-infarct dementia), or major depression. Although mean performance in each of the diagnostic groups was below normative levels reported by Fuld (1981), PDD patients performed significantly more poorly than those with depression or other organic disorders. Analysis of subscore patterns failed to support the hypothesis of a selective memory deficit in depression, and substantial overlap in scores was observed between the depressed group and patients with organic disorders other than PDD. Object Memory Evaluation performance was influenced by global mental status and secondary psychiatric diagnoses, but not by education, age, or physical health.