Maria Korsnes - Academia.edu (original) (raw)

Papers by Maria Korsnes

Perceptual and motor skills, 1995

Pictorial stimuli were presented in serial lists and tested for recognition. 11 men and 9 women p... more Pictorial stimuli were presented in serial lists and tested for recognition. 11 men and 9 women participated at retention intervals of 5, 15, and 25 sec. The length of retention interval interacted with primacy and recency effects as observed in earlier studies of abstract stimuli, indicating similar basic memory functions for different types of visual stimuli. A shift from recency to primacy dominance remained despite the likelihood of verbal rehearsal. At short retention intervals a recency effect predominated and with longer delays a primacy effect predominated recognition.

Touching for shape recognition has been shown to activate occipital areas in addition to somatose... more Touching for shape recognition has been shown to activate occipital areas in addition to somatosensory areas. In this study we asked if this combination of somatosensory and other sensory processing areas also exist in other kinds of touch recognition. In particular, does touch for texture roughness matching activate other sensory processing areas apart from somatosensory areas? We addressed this question with functional magnetic resonance imaging (fMRI) using wooden abstract stimulus objects whose shape or texture were to be identified. The participants judged if pairs of objects had the same shape or the same texture. We found that the activated brain areas for texture and shape matching have similar underlying structures, a combination of the primary motor area and somatosensory areas. Areas associated with object-shape processing were activated between stimuli during shape matching and not texture roughness matching, while auditory areas were activated during encoding of texture and not for shape stimuli. Matching of textures also involves left BA47, an area associated with retrieval of relational information. We suggest that texture roughness is recognized in a framework of ordering. Left-lateralized activations favoring texture might reflect semantic processing associated with grading roughness quantitatively, as opposed to the more qualitative distinctions between shapes.

American journal of Alzheimer's disease and other dementias, Jan 17, 2015

Earlier detection of dementia requires increased knowledge of how to help people in the early sta... more Earlier detection of dementia requires increased knowledge of how to help people in the early stages of dementia. However, few studies have focused on how psychotherapy should be adapted to improve the outcome of therapy for people with Alzheimer's disease. The aims of the present study were to identify and to explore possible obstacles encountered during the use of manual-based psychotherapy for people with early-stage Alzheimer's disease. The study found that individual adaptations to the treatment manual were necessary, particularly the modification of memory aids in order to adapt them to patients' functional level and previous experience with modern technology. In addition, caregivers were essential for both treatment and homework completion, while reduced awareness constituted an obstacle for adherence to the manual.

Nordisk tidsskrift for helseforskning, 2015

Patients with mental disorders are often less active than the general population and inactivity o... more Patients with mental disorders are often less active than the general population and inactivity over time reduces mental and physical health. We know from previous studies that physical activity contributes to improved mental and physical health, but it is not clear whether any type of physical activity will give the same effect. The objective of this pilot study was to investigate whether the nature of the physical activity the patients participated in during their stay in a psychiatric ward would make a difference in outcome related to improved mental and physical health. Fifty patients (39 women) participated, mean age 80 years (SD 6.0), length of stat from 3 to 28 weeks (mean 8.8, SD 4.4). Patients were offered different types of physical activity and physical therapy in addition to cognitive psychotherapy and supporting conversations. They were subsequently divided into three groups (self-training, joint exercise, regular walking). We examined the difference in treatment effect with regard to general mental health, depression, balance, physical strength and walking skills. Average values showed significant improvements on all tests except for the timed walking tests. Depression scores according to the MADRS was at least one category lower on discharge than on arrival for 31 of the 36 participants. We find that older patients with moderate to severe depression benefit greatly from the treatment they receive during their stay at the age psychiatric ward. The improvements are significant both for mental and physical health. Furthermore, the findings indicate that walking appears to be a type of activity that has especially good effect on mental health.

Journal of Integrative Neuroscience, 2014

Evidence from recent studies challenge traditional memory system accounts of separate mechanisms ... more Evidence from recent studies challenge traditional memory system accounts of separate mechanisms for implicit and explicit memory. The motive behind the present study was to further investigate whether common activations can be detected during explicit and implicit memory performance when using the same procedure for both tasks. Functional magnetic resonance imaging (fMRI) showed separate neural activation to perceptual repetition priming and perceptual recognition of real and nonsense objects, both in terms of the brain regions involved and in the direction of repeated-novel activations. Repetition priming showed deactivation for repeated stimuli in regions not overlapping regions activated in conscious recognition, activation patterns in the two tasks involved largely separate networks. Common activations were observed in three areas, considered as being involved in processes such as stimulus analyses, task monitoring and attention, i.e., processes external to memory. We interpret this as indicating an almost complete dissociation between the networks involved in priming and recognition memory.

Journal of Behavioral and Brain Science, 2014

Normal aging and depression both slow information processing speed which leads to poorer attentio... more Normal aging and depression both slow information processing speed which leads to poorer attentional control, shallower inhibition monitoring, poorer encoding, poorer updating of short term memory, and subsequent poorer learning, set-shifting, error monitoring, inhibition control, and cognitive planning. A combination of aging and depression amplifies these cognitive effects. Deterioration in frontal brain functioning in normal aging is irreversible, but altering of frontal brain function due to depression may be reversible. Since the symptoms are indistinguishable, it is difficult to separate effects of depression and aging with use of neuropsychological tests, even when premorbid history is known. Statistical group effects show more severe cognitive effects in late life depression than in normal aging or depression in younger persons, but no particular cognitive markers of depression in older subjects have been identified. Attention and inhibition are closely related, but their relationship needs to be studied further. It is not clear, whether a problem with inhibition of irrelevant stimuli occurs because of attentional deficits due to late life depression, or if it is a primary consequence of the depression. Further studies on the relationship between inhibition, attention and processing speed involving homogeneous depressed and nondepressed groups of different age may help disentangle this relationship.

Scandinavian Journal of Psychology, 2006

Fast perceptual priming in the left and right hemispheres. Scandinavian Journal of Psychology , 4... more Fast perceptual priming in the left and right hemispheres. Scandinavian Journal of Psychology , 47 , 85 -91.

Scandinavian Journal of Psychology, 1996

effects in visual shortterm memory for words and abstract spatial patterns. scandinavian Journal ... more effects in visual shortterm memory for words and abstract spatial patterns. scandinavian Journal of Psychology, 37, 62-13. Two experiments tested the effects of list postion, and retention-interval in recognition for two distinct stimulus categories in young adults. Stimulus categories were spatial abstract patterns and words presented on a computer screen. At short delay intervals recency effects predominates and at longer delay intervals a primacy effect predominates in both experiments, indicating similar basic memory processes producing the serial position functions for the two different categories of visual stimuli, but as length of retention-interval increases, memory for first list items improves for words and remains constant for abstract patterns. Recency functions are similar for both stimulus categories tested.

Scandinavian Journal of Psychology, 2007

We investigated hemispheric differences and inter-hemispheric transfer of facilitation in automat... more We investigated hemispheric differences and inter-hemispheric transfer of facilitation in automatic semantic priming, using prime-target pairs composed of words of the same category but not associated (e.g. skirt-glove), and a blank-target baseline condition. Reaction time and accuracy were measured at short (300 ms) intervals between prime and target onsets, using a go/no-go task to discriminate between word or non-word targets. Reaction times were facilitated more for target words presented in the right visual field (RVF) compared to the left visual field (LVF), and targets presented in RVF were primed in both visual fields, whereas targets presented in LVF were primed by primes in the LVF only. These results suggest that both hemispheres are capable of automatic priming at very short stimulus onset asymmetries (SOA), but crosshemisphere priming occurs only in the left hemisphere.

Perceptual and Motor Skills, 1993

List memory of 6 young and 6 older human adults was tested with lists of four visual items (black... more List memory of 6 young and 6 older human adults was tested with lists of four visual items (black and white patterns and colored abstract paintings). We investigated the effects of varying the length of the recognition interval on the serial-position function for picture recognition in the two age groups. Increases in the retention interval showed a consistent modification of the shape of the serial-position function from a monotonically increasing function at the shortest interval to a monotonically decreasing function at the longest interval. The time course of these changes was faster for older adults than for young adults. Age differences in the length of the interval required for a shift in the serial-position functions from recency to primacy effects were strikingly similar to those previously found between young people and nonhuman species.

Neuropsychologia, 2008

Drawings depicting familiar objects and unreal structures were presented twice, and participants ... more Drawings depicting familiar objects and unreal structures were presented twice, and participants (N=16) determined whether line drawings were real (familiar) or unreal (unfamiliar). The second presentation (repetition) of a drawing was typically responded to faster and more accurately than the first presentation and was accompanied by reduced activation in occipitotemporal (fusiform) and lateral precuneus regions, and increased activation in medial precuneus regions. The behavioral effects and reduced activations (e.g., lateral precuneus) on the second presentation were less pronounced for unreal objects than for real objects. Activation changes in the medial precuneus - increased activation on repetition and reduced activation for novel unreal objects - was further supported by the increased activation in this area during rest and reduced activation when workload was increased (i.e., processing novel unreal objects). The results from the present study in conjunction with those from several previous studies converge on the conclusion that the occipitotemporal and lateral regions of the precuneus are primarily involved in object priming, whereas the medial portion of precuneus primarily activates and deactivates as a function of workload.

Journal of Affective Disorders, 2012

Background: The aims of the study were to examine the validity of the MADRS and to compare it wit... more Background: The aims of the study were to examine the validity of the MADRS and to compare it with the validity of the Cornell Scale for Depression in Dementia (CSDD). Methods: We included 140 patients without dementia, with mean age 81.5 (sd 7.7) years. Trained psychiatric nurses interviewed all of them using the MADRS. In addition, for 70 patients caregivers were interviewed using the CSDD. A psychiatrist who had no access to the MADRS or the CSDD results made a diagnosis of depression according to the DSM-IV criteria for major depression, and the ICD-10 criteria was also applied for the 70 patients assessed with the CSDD. Results: Twenty-two out of the 140 had depression according to the DSM IV criteria, whereas 25 out of 70 had depression according to the ICD-10 criteria. The area under the curve (auc) in a receiver operating characteristic analysis was 0.86 (95% CI 0.79-0.93) for the MADRS using the DSM-IV criteria. The best cut-off point was 16/17 with sensitivity of 0.80 and specificity of 0.82. The AUC for the CSDD was 0.83 (95% CI 0.71-0.95). The recommended cut-off score on the CSDD of 7/8 was valid but not the best in this study. Limitations: The patients were diagnosed with a diagnosis of depression by only one psychiatrist, and the procedures in the two centres were not exactly the same. Conclusions: The MADRS has good discriminating power to detect depression in elderly persons and should be preferred to the CSDD for use with persons without dementia.

Epilepsia, 2010

The aim of the study was to investigate behavioral and brain activation in nonpsychotic hallucina... more The aim of the study was to investigate behavioral and brain activation in nonpsychotic hallucinating individuals. Auditory hallucinations are reported by patients with epilepsy, although less frequent than visual hallucinations are. If behavioral and neuronal activation patterns in hallucinating patients with epilepsy are found to be similar to what has been found in hallucinating patients with schizophrenia, this would support a unique neuronal representation for auditory hallucinations cutting across diagnostic groups. We report behavioral and functional magnetic resonance imaging (fMRI) data from six epilepsy patients experiencing auditory hallucinations compared with six healthy control subjects. The participants had to report which of two simultaneously presented simple speech sounds they perceived on each trial, using a dichotic stimulus presentation mode. The results showed that the patients failed to show an expected right ear advantage on the task, and they also showed significantly reduced activation in temporal, frontal, and cingulate cortex areas. The results are discussed in relation to a view that neuropsychological and functional neuroimaging indices of auditory hallucinations may be orthogonal to diagnostic category and not unique to patients with schizophrenia.

Cortex, 2013

Men are often believed to have a functionally more asymmetrical brain organization than women, bu... more Men are often believed to have a functionally more asymmetrical brain organization than women, but the empirical evidence for sex differences in lateralization is unclear to date. Over the years we have collected data from a vast number of participants using the same consonant-vowel dichotic listening task, a reliable marker for language lateralization. One dataset comprised behavioral data from 1782 participants (885 females, 125 non-right-handers), who were divided in four age groups (children &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10 yrs, adolescents = 10-15 yrs, younger adults = 16-49 yrs, and older adults &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;50 yrs). In addition, we had behavioral and functional imaging (fMRI) data from another 104 younger adults (49 females, aged 18-45 yrs), who completed the same dichotic listening task in a 3T scanner. This database allowed us to comprehensively test whether there is a sex difference in functional language lateralization. Across all participants and in both datasets a right ear advantage (REA) emerged, reflecting left-hemispheric language lateralization. Accordingly, the fMRI data revealed a leftward asymmetry in superior temporal lobe language processing areas. In the N = 1782 dataset no main effect of sex but a significant sex by age interaction emerged: the REA increased with age in both sexes but as a result of an earlier onset in females the REA was stronger in female than male adolescents. In turn, male younger adults showed greater asymmetry than female younger adults (accounting for &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1% of variance). There were no sex differences in children and older adults. The males in the fMRI dataset (N = 104) also had a greater REA than females (accounting for 4% of variance), but no sex difference emerged in the neuroimaging data. Handedness did not affect these findings. Taken together, our findings suggest that sex differences in language lateralization as assessed with dichotic listening exist, but they are (a) not necessarily reflected in fMRI data, (b) age-dependent and (c) relatively small.

Brain Structure and Function, 2009

We report fMRI activation data for a female patient with epilepsy, who was tested before and 2 ye... more We report fMRI activation data for a female patient with epilepsy, who was tested before and 2 years after resection surgery, to assess changes in fMRI activation. Areas within her right ATL/MTL were removed during surgery, including the right hippocampus. A visuospatial task was used in which novel and familiar pictures of objects, animals, scenes and buildings were randomly presented. Half of the pictures were novel to the patient, while half of the pictures were familiar pictures from the same stimulus categories. Despite unchanged visuo-spatial IQ-scores and equal performance on the fMRI task pre-and post-surgery, there was evidence of changes in functional organization of the brain as seen in the pre-versus postsurgery fMRI data. It is suggested that maintenance of memory performance from pre-to post-surgery might be due to functional reorganization in the brain, as evidenced in the fMRI data.

Brain Structure and Function, 2010

Previous literature suggest that processing of visually presented shapes and textures starts in t... more Previous literature suggest that processing of visually presented shapes and textures starts in the early visual areas, but subsequently follow different pathways. The purpose of this experiment was to further investigate differential activation for shapes and textures in order elucidate the pathways involved in visual shape and texture matching. In the present study, brain areas involved in discrimination of shapes and textures are mapped, using the same set of stimuli for shape and texture decisions. Texture matching activates more prefrontal regions than shape matching, particularly regions in the left middle frontal gyrus and bilateral inferior frontal gyrus. Shape specific activation includes an occipital/temporal region which is associated with multimodal object matching. The pattern of results suggests that recognition of textures may be based upon different ordering conditions in memory, which involve a prefrontal network and require a great deal more workload than the holistic representation of shape.

Behavioural Neurology, 1996

Two experiments examined short-term memory for order information in six patients diagnosed with P... more Two experiments examined short-term memory for order information in six patients diagnosed with Parkinson's disease (PD) and six control subjects while event related potentials (ERPs) were recorded. The subjects were tested for recognition of abstract spatial designs and words after a 5 s retention interval. The PD patients failed to respond in 29% of all trials, but the overall accuracy was similar to that in the control group when these trials were excluded. The corresponding ERP results show serial position variations both after presentation of the probe items, and after presentation of the memory set items. The amplitudes were generally lower at all positions for the PD patients at the parietal midline electrode, and the amplitudes were similar for both groups at the frontal electrode. Also, the ERP latencies were significantly slower for the PD patients than for the control group at all conditions. Indirectly the data are consistent with an interpretation of cognitive deficit in PD stressing attention resources.

Acta Psychologica, 1996

Memory for serial position in four-item lists of words or abstract designs was tested at retentio... more Memory for serial position in four-item lists of words or abstract designs was tested at retention intervals of 5-25 seconds in two subject groups, aged 25-35 and 60-75 years; accuracy and choice reaction times (RT) were recorded. Increasing the retention interval transformed the serial position curve from recency to primacy but produced no overall reduction in memory performance in terms of accuracy. RTs varied as a function of both serial position and retention interval. Under all conditions the memory of older subjects was less accurate and they exhibited longer RTs compared to young subjects, but the age differences did not interact with list position or retention interval for either response indicator. The results suggest that age differences in memory can be explained by a single factor of mental speed limiting encoding efficiency and affecting decision times.

Journal of Affective Disorders, 2013

Background: We examined women with recurrent brief depression (RBD) with and without episodes of ... more Background: We examined women with recurrent brief depression (RBD) with and without episodes of hypomania with an n-back working memory paradigm to assess how working memory load affects the neurological network corresponding to working memory for these groups. Method: Participants (n ¼ 33) were medication-free and mostly euthymic while performing a 1-back and a 2-back task in the fMRI scanner. Differential activation results between the tasks were assessed globally and within seven predefined regions of interest associated with working memory activation. The patient groups were compared with healthy women and matched for age, handedness, and length of education. Results: Poor task modulation was observed in both RBD groups in the prefrontal cortex (BA9) in the 1-back task and activation during the 2-back task, particularly in a subgroup with a history of brief hypomanic episodes (RBD-H) compared with the subgroup without such episodes (RBD-O). Task modulation in the right parahippocampal gyrus (BA27) distinguished the RBD-O group, and task modulation in the right insula clearly distinguished the RBD-H group. Limitations: Small sample size and recruitment of most patients through media that may induce a selection bias towards better-functioning subjects. Conclusion: The observed lack of deactivation within the right insula has also been reported in patients with bipolar I disorders. Activation differences in BA9 and the parahippocampal region between RBD patients with and without a history of hypomania suggest different functional hypersensitivity of early limbic regions and ability to sustain attention and working memory, respectively, possibly identifying functional differences between the two subgroups.