Phonological short-term store impairment after cerebellar lesion: A single case study

The cerebellum is a recent addition to the growing list of cerebral areas involved in the multifaceted structural system that sustains verbal working memory (vWM), but its contribution is still a matter of debate. Here, we present a patient with a selective deficit of vWM resulting from a bilateral cerebellar ischemic lesion. After this acute event, the patient had impaired immediate and delayed word-serial recall and auditory-verbal delayed recognition. The digit span, however, was completely preserved. To investigate the cerebellar contribution to vWM, four experiments addressing the function of different vWM phonological loop components were performed 18 months after the lesion, and results were compared with normative data or, when needed, with a small group of matched controls. In Experiment 1, digit span was assessed with different presentation and response modalities using lists of digits of varying lengths. In Experiment 2, the articulatory rehearsal system was analyzed by measurement of word length and articulatory suppression effects. Experiment 3 was devoted to analyzing the phonological short-term store (ph-STS) by the recency effect, the phonological similarity effect, short-term forgetting, and unattended speech. Data suggested a possible key role of the semantic component of the processed material, which was tested in Experiment 4, in which word and nonword-serial recall with or without interpolating activity were analyzed. The patient showed noticeably reduced scores in the tasks that primarily or exclusively engaged activity of the ph-STS, namely those of Experiment 3, and good performance in the tests that investigated the recirculation of verbal information. This pattern of results implicates the ph-STS as the cognitive locus of the patient's deficit. This report demonstrates a cerebellar role in encoding and/or strengthening the phonological traces in vWM. (c) 2008 Elsevier Ltd. All rights reserved.The cerebellum is a recent addition to the growing list of cerebral areas involved in the multifaceted structural system that sustains verbal working memory (vWM), but its contribution is still a matter of debate. Here, we present a patient with a selective deficit of vWM resulting from a bilateral cerebellar ischemic lesion. After this acute event, the patient had impaired immediate and delayed word-serial recall and auditory-verbal delayed recognition. The digit span, however, was completely preserved. To investigate the cerebellar contribution to vWM, four experiments addressing the function of different vWM phonological loop components were performed 18 months after the lesion, and results were compared with normative data or, when needed, with a small group of matched controls. In Experiment 1, digit span was assessed with different presentation and response modalities using lists of digits of varying lengths. In Experiment 2, the articulatory rehearsal system was analyzed by mea

The neuropsychological profile of cerebellar damage: The sequencing hypothesis

[No abstract available

Inability to process negative emotions in cerebellar damage. A functional transcranial doppler sonographic study

Objectives. Recent studies have implicated the cerebellum as part of a circuitry that is necessary to modulate higher-order and behaviorally relevant information in emotional domains. However, little is known about the relationship between the cerebellum and emotional processing. This study examined cerebellar function specifically in the processing of negative emotions. Methods. Transcranial Doppler ultrasonography was performed to detect selective changes in middle cerebral artery flow velocity during emotional stimulation in patients affected by focal or degenerative cerebellar lesions and in matched healthy subjects. Changes in flow velocity during non-emotional (motor and cognitive tasks) and emotional (relaxing and negative stimuli) conditions were recorded. Results. In the present study we found that during negative emotional task, the hemodynamic pattern of the cerebellar patiens was significantly different to that of controls. Indeed, whereas relaxing stimuli did not elicit

Cerebellum and Detection of Sequences, from Perception to Cognition

The idea that cerebellar processing is required in a variety of cognitive functions is well accepted in the neuroscience community. Nevertheless, the definition of its role in the different cognitive domains remains rather elusive. Current data on perceptual and cognitive processing are reviewed with special emphasis on cerebellar sequencing properties. Evidences, obtained by neurophysiological and neuropsychological lesion studies, converge in highlighting comparison of temporal and spatial information for sequence detection as the key stone of cerebellar functioning across modalities. The hypothesis that sequence detection might represent the main contribution of cerebellar physiology to brain functioning is presented and the possible clinical significance in cerebellar-related diseases discussed.The idea that cerebellar processing is required in a variety of cognitive functions is well accepted in the neuroscience community. Nevertheless, the definition of its role in the different cognitive domains remains rather elusive. Current data on perceptual and cognitive processing are reviewed with special emphasis on cerebellar sequencing properties. Evidences, obtained by neurophysiological and neuropsychological lesion studies, converge in highlighting comparison of temporal and spatial information for sequence detection as the key stone of cerebellar functioning across modalities. The hypothesis that sequence detection might represent the main contribution of cerebellar physiology to brain functioning is presented and the possible clinical significance in cerebellar-related diseases discussed

Oculomotor deficits affect neuropsychological performance in oculomotor apraxia type 2

Introduction: Ataxia with oculomotor aprmda type 2 is a rare and early-disabling neurode-generative disease, part of a subgroup of autosomal recessive cerebellar ataxia, in which oculomotor symptoms (e.g., increased saccade latency and hypometria) and executive function deficits have been described. The aim of this study was to evaluate the impact of oculomotor symptoms on cognitive performance and, in particular, over reading in 2 Italian siblings affected by ataxia with oculomotor apraxia type 2. Methods: The neuropsychological profiles and the oculomotor patterns during nonverbal and verbal tasks were recorded and analyzed. Results: Saccadic intrusions and/or nystagmus were observed in all eye movement tasks. The neuropsychological profiles were substantially preserved, with only subtle deficits that affected visuomotor integration and attention. Reading ability decreased and became impaired. The reading scan was disturbed by saccadic intrusions and/or nystagmus. However, an ad hoc reading task demonstrated that deficits appeared only when the items that were displayed enhanced oculomotor requests. The preservation of lexical-semantic processes confirmed that the reading disability was caused by oculomotor deficits, not cognitive problems. Conclusion: Present findings indicate that in patients who are affected by ataxia with oculomotor apraxia type 2, performance on neuropsychological tests, especially those that require rapid performance and eye or hand eye control, must be analyzed with respect to oculomotor components. (C) 2012 Elsevier Ltd. All rights reserved.Introduction: Ataxia with oculomotor apraxia type 2 is a rare and early-disabling neurodegenerative disease, part of a subgroup of autosomal recessive cerebellar ataxia, in which oculomotor symptoms (e.g., increased saccade latency and hypometria) and executive function deficits have been described. The aim of this study was to evaluate the impact of oculomotor symptoms on cognitive performance and, in particular, over reading in 2 Italian siblings affected by ataxia with oculomotor apraxia type 2. Methods: The neuropsychological profiles and the oculomotor patterns during nonverbal and verbal tasks were recorded and analyzed. Results: Saccadic intrusions and/or nystagmus were observed in all eye movement tasks. The neuropsychological profiles were substantially preserved, with only subtle deficits that affected visuomotor integration and attention. Reading ability decreased and became impaired. The reading scan was disturbed by saccadic intrusions and/or nystagmus. However, an ad ho

Cerebellar Damage Impairs Executive Control and Monitoring of Movement Generation

Executive control of motor responses is a psychological construct of the executive system. Several studies have demonstrated the involvement of the cerebral cortex, basal ganglia, and thalamus in the inhibition of actions and monitoring of performance. The involvement of the cerebellum in cognitive function and its functional interaction with basal ganglia have recently been reported. Based on these findings, we examined the hypothesis of cerebellar involvement in executive control by administering a countermanding task in patients with focal cerebellar damage. The countermanding task requires one to make a movement in response to a 'go' signal and to halt it when a 'stop' signal is presented. The duration of the go process (reaction time; RT), the duration of the stop process (stop signal reaction time; SSRT), and their relationship, expressed by a psychometric function, are recorded as measures of executive control. All patients had longer go process duration in general and in particular, as a proactive control, as demonstrated by the increase in RT after erroneously performed stop trials. Further, they were defective in the slope of the psychometric function indicating a difficulty on triggering the stop process, although the SSRT did not differ from controls. Notably, their performance was worse when lesions affected deep cerebellar nuclei. Our results support the hypothesis that the cerebellum regulates the executive control of voluntary actions. We speculate that its activity is attributed to specific cerebellar influence over the cortico-striatal loop

Cerebellar damage impairs executive control and monitoring of movement generation.

Executive control of motor responses is a psychological construct of the executive system. Several studies have demonstrated the involvement of the cerebral cortex, basal ganglia, and thalamus in the inhibition of actions and monitoring of performance. The involvement of the cerebellum in cognitive function and its functional interaction with basal ganglia have recently been reported. Based on these findings, we examined the hypothesis of cerebellar involvement in executive control by administering a countermanding task in patients with focal cerebellar damage. The countermanding task requires one to make a movement in response to a 'go' signal and to halt it when a 'stop' signal is presented. The duration of the go process (reaction time; RT), the duration of the stop process (stop signal reaction time; SSRT), and their relationship, expressed by a psychometric function, are recorded as measures of executive control. All patients had longer go process duration in general and in particular, as a proactive control, as demonstrated by the increase in RT after erroneously performed stop trials. Further, they were defective in the slope of the psychometric function indicating a difficulty on triggering the stop process, although the SSRT did not differ from controls. Notably, their performance was worse when lesions affected deep cerebellar nuclei. Our results support the hypothesis that the cerebellum regulates the executive control of voluntary actions. We speculate that its activity is attributed to specific cerebellar influence over the cortico-striatal loop

Atrophic degeneration of cerebellum impairs both the reactive and the proactive control of movement in the stop signal paradigm

The cognitive control of movement suppression, including performance monitoring, is one of the core properties of the executive system. A complex cortical and subcortical network involving cerebral cortex, thalamus, subthalamus, and basal ganglia, has been regarded as the neural substrate of inhibition of programmed movements. By using the countermanding task, a suitable tool to explore behavioral components of movement suppression, the contribution of the cerebellum in the proactive control and monitoring of voluntary action has been recently described in patients affected by focal lesions involving in particular the cerebellar dentate nucleus. Here we evaluated the performance on the countermanding task in a group of patients with cerebellar degeneration, in which the cerebellar cortex was diffusely affected, and showed that they display additionally a longer latency in countermanding engaged movements. Overall, the present data confirm the role of the cerebellum in executive control of action inhibition by extending the contribution to reactive motor suppression

Go process analysis for groups of FCb patients and controls.

<p>The left portion of each panel shows data from FCb groups and controls; the right portion of each panel (highlighted by the grey area) shows FCb− and FCb+ patient data. (A) Reaction time in the go trials of the GOT (white bars) and the CMT (black bars) task for FCb patients and controls (A1) and after sorting for DCN involvement in the cerebellar lesion (A2). The lower part of panel A1 and A2 shows the average difference in RT (CMT – GOT) for each of the groups indicated. (B) RT standard deviations (RT_SD) for the same groups as in A. The lower part of panel B1 and B2 shows the average difference in RT_SD (CMT – GOT) for each of the groups indicated. (C) Difference in RT of go trials following stop canceled trials (postC) and go trials following stop not canceled (error) trials (postE) from go trials preceded and followed by a go trial (go-go-go sequence) for the same groups in A and B. Significant differences (p<0.05) between groups and tasks are indicated (*). Thick lines indicate significant comparisons when considering FCb−, FCb+, and controls.</p

Normalized inhibition function.

<p>Each plot shows the group's probability to fail in canceling the stop trials (pE) as a function of ZRFT (black dots). The goodness of fit, slopes of the regression lines (black solid lines), and significant differences (*; p<0.05) between groups are indicated.</p