OBJECTIVETo explore the neuropsychological characteristics of children with attention deficit hyperactivity disorder (ADHD).

METHODSNeuropsychological tests, including visual working memory, Stroop test, digits inverse reciting, vocabulary fluency, Wisconsin card sort test (WCST), and Temporal discounting were used to evaluate the capacity of response inhibition, phonological working memory, visual working memory executive function and delayed satisfying capacity of subjects.

RESULTS1. The ADHD children spent longer time [ADHD-I (84(20), ADHD-C: 98 (31), normal: 70 (28)] to accomplish color naming and made more errors [ADHD-I: 3 (3), ADHD-C: 6 (19), normal: 2 (5)] than the normal control when the color was inconsistent with the word meaning in Stroop test (P < 0.01). 2. The scores of digits reciting [ADHD-I: 3 (3), ADHD-C: 3 (4), normal 4 (4)] inverse was lower in ADHD than in normal control (P < 0.01). 3. The representation of ADHD was poorer than normal control in visual working memory [ADHD-I: 21 (3), ADHD-C: 20 (5), Normal: 20 (3)], and in delayed visual memory [ADHD-I: 19 (5), ADHD-C: 19 (5), Normal: 20 (5)] (P < 0.01). 4. The scores of vocabulary fluency [ADHD-I: 1 (1), ADHD-C: 2 (1), normal: 0 (0)] was lower in ADHD than in normal control (P < 0.01). 5. In WCST, the ADHD children made more errors [ADHD-I :15 (17), ADHD-C: 15 (15), normal: 13 (13)] and less classification [ADHD-I: 5 (4), ADHD-C: 5 (4), normal: 5 (3)] than normal control (P < 0.01). 6. In Temporal discounting, the ADHD children showed significantly more impairments than normal control did (P < 0.01). 7. There was significant difference between the two subtype groups on some tests (P < 0.01).

CONCLUSIONSObvious cognitive impairments were found in children with ADHD, involving poor response inhibition, impaired working memory, dysfunction of planning and set-shifting, and there was no significant difference between the two subtype groups.

Attention Deficit Disorder with Hyperactivity ; classification ; immunology ; physiopathology ; psychology ; Child ; Cognition Disorders ; physiopathology ; psychology ; Humans ; Memory ; Memory Disorders ; immunology ; psychology ; Memory, Short-Term ; physiology ; Neuropsychological Tests

OBJECTIVETo investigate the neuropsychological characteristics of selective attention such as attention control, working memory and attention persistence of frontal lobe in children with nonverbal learning disabilities (NLD).

METHODSWith Auditory Detection Test (ADT), Wisconsin Card Sorting Test (WCST) and C-WISC, 14 children with NLD and 23 controls were tested and the results of sub-tests of C-WISC were analyzed with factor analysis. ADT was mainly applied to test the ability of auditory discernment and the function of dominance lateralization in the cerebra; WCST was employed to test the function of working memory which was based on the frontal lobe, and, C-WISC, to test the intelligent structure and characteristics.

RESULTSCompared with control group, the correct response rate of ADT in NLD group was much lower (P < 0.01), and the number of incorrect response was much larger (P < 0.01). Children with NLD had deficits of auditory selective attention. Moreover, the number of categories achieved (CA) and perseverative error (PE) of WCST were much lower (P < 0.05), which indicated that children with NLD had the disorders of selective attention and performance function. Factor analysis showed that perceptual organization (PO) related to visual space and freedom from distractibility (FD) related to attention persistence in NLD group were obviously lower than those in control group (P < 0.01, P < 0.05). These findings further supported the above-mentioned results.

CONCLUSIONSChildren with NLD had attention control disorder and working memory disorder mainly in frontal lobe; we suppose that the disorder in right frontal lobe was distinctive.

Attention ; Child ; Frontal Lobe ; physiopathology ; Humans ; Language Development Disorders ; physiopathology ; Learning Disorders ; diagnosis ; physiopathology ; Memory, Short-Term ; Neuropsychological Tests

The largely consistent columnar circuitry observed throughout the cortex may serve to continuously predict bottom-up activation based on invariant memories. This "memory-prediction" function is essential to efficient and accurate perception. Many of the defined cognitive deficits associated with schizophrenia suggest a breakdown of memory-prediction function. As deficits in memory-prediction function are proposed to lie more proximal to the biological causes of schizophrenia than deficits in standard cognitive constructs, tests that more directly probe memory-prediction function may be especially sensitive predictors of conversion in individuals at high-risk for schizophrenia. In this article, we review the conceptual basis for this hypothesis, and outline how it may be tested with specific cognitive paradigms. The accurate identification of cognitive processes that precede the onset of psychosis will not only be useful for clinicians to predict which young people are at greatest risk for schizophrenia, but will also help determine the neurobiology of psychosis onset, thus leading to new and effective treatments for preventing schizophrenia and other psychoses.
Cognition Disorders ; Humans ; Memory ; Neuropsychological Tests ; Predictive Value of Tests ; Risk Assessment ; Schizophrenia ; etiology ; physiopathology ; Schizophrenic Psychology

OBJECTIVETo assess functional relationship by calculating inter- and intra-hemispheric electroencephalography (EEG) coherence at rest and during a working memory task of patients with mild cognitive impairment (MCI).

METHODSThe sample consisted of 69 subjects: 35 patients (n=17 males, n=18 females; 52-71 years old) and 34 normal controls (n=17 males, n=17 females; 51~63 years old). Mini-mental state examination (MMSE) of two groups revealed that the scores of MCI patients did not differ significantly from those of normal controls (P>0.05). In EEG recording, subjects were performed at rest and during working memory task. EEG signals from F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 electrode pairs are resulted from the inter-hemispheric action, and EEG signals from F3-C3, F4-C4, C3-P3, C4-P4, P3-O1, P4-O2, T5-C3, T6-C4, T5-P3 and T6-P4 electrode pairs are resulted from the intra-hemispheric action for delta (1.0-3.5 Hz), theta (4.0-7.5 Hz), alpha-1 (8.0-10.0 Hz), alpha-2 (10.5-13.0 Hz), beta-1 (13.5-18.0 Hz) and beta-2 (18.5-30.0 Hz) frequency bands. The influence of inter- and intra-hemispheric coherence on EEG activity with eyes closed was examined using fast Fourier transformation from the 16 sampled channels.

RESULTSDuring working memory tasks, the inter- and intra-hemispheric EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group (P<0.05). However, there was no significant difference in inter- and intra-hemispheric EEG coherences between two groups at rest.

CONCLUSIONExperimental results comprise evidence that MCI patients have higher degree of functional connectivity between hemispheres and in hemispheres during working condition. It suggests that MCI may be associated with compensatory processes during working memory tasks between hemispheres and in hemispheres. Moreover, failure of normal cortical connections may exist in MCI patients.

Aged ; Cognition Disorders ; physiopathology ; Electrodes ; Electroencephalography ; Female ; Humans ; Male ; Memory ; physiology ; Middle Aged ; Rest ; physiology

OBJECTIVEThe functional relationship between calculated alpha band spectral power and inter-/intra-hemispheric coherence during a three-level working memory task of patients with mild cognitive impairment (MCI) was investigated.

METHODSSubjects included 35 MCI patients according to the DSM-IV criteria (mean age: 62.3, SD: 6.5) and 34 healthy controls (mean age: 57.4, SD: 4.0) were selected from the community at large. All subjects performed a simple calculation and recall task with three levels of working memory load while electroencephalograph (EEG) signal was recorded. The spectral EEG power was computed over alpha1 (8.0-10.0 Hz) and alpha2 (10.5-13.0 Hz) frequency bands and was compared between rest stage and working memory processing stage by two-way ANOVA. Post hoc testing analyzed the differences between each two levels of working memory load during task processing. The inter-hemisphere EEG coherence of frontal (F3-F4), central (C3-C4), parietal (P3-P4), temporal (T5-T6) as well as occipital (O1-O2) was compared between MCI patients and normal controls. The EEG signals from F3-C3, F4-C4, C3-P3, C4-P4, P3-O1, P4-O2, T5-C3, T6-C4, T5-P3 and T6-P4 electrode pairs resulted from the intra-hemispheric action for alpha1 and alpha2 frequency bands.

RESULTThere was significantly higher EEG power from MCI patients than from normal controls both at rest and during working memory processing. Significant differences existed between rest condition and three-level working memory tasks (P<0.001). The inter- and intra-hemispheric coherence during working memory tasks showed a "drop to rise" tendency compared to that at rest condition. There was significantly higher coherence in MCI patients than in the controls. When task difficulties increased, the cortical connectivity of intra-hemispheric diminished while the inter-hemispheric connectivity dominantly maintained the cognitive processing in MCI patients.

CONCLUSIONThe results of the present study indicate that the alpha frequency band may be the characteristic band in distinguishing MCI patients from normal controls during working memory tasks. MCI patients exhibit greater inter-hemispheric connectivity than intra-hemispheric connectivity when memory demands increase. MCI patients mobilize a compensatory mechanism to maintain the processing effectiveness while the processing efficiency is reduced.

Aged ; Cognition Disorders ; physiopathology ; Electroencephalography ; Electrophysiology ; Female ; Humans ; Male ; Memory ; Middle Aged

The accumulation of amyloid β-protein (Aβ) plaques is identified as a major pathological feature of Alzheimer's disease (AD). Recent studies show that soluble species of Aβ are involved in the early memory dysfunction long before neurodegenerative changes. However, the mechanism underlying the neurotoxicity of soluble Aβ is still unclear. Long-term potentiation (LTP) has been thought as an important cellular model of synaptic plasticity for many years. The studies on the hippocampal LTP and Aβ, especially those using AD transgenic models, provided more evidence for the Aβ-induced dysfunction of learning and memory. Based on the recent researches on AD, this article reviewed the effects of Aβ, especially soluble Aβ and its active fragments, on the hippocampal LTP. The possible mechanisms by which Aβ impairs hippocampal LTP are also discussed.
Alzheimer Disease ; physiopathology ; Amyloid beta-Peptides ; physiology ; Animals ; Hippocampus ; physiology ; Humans ; Learning Disorders ; physiopathology ; Long-Term Potentiation ; physiology ; Memory Disorders ; physiopathology ; Neuronal Plasticity ; Synapses ; physiology

This study explored the possibility of using event-related potentials (ERP) for the measurement of picture-recognition memory and examined its correlation with the Chinese Wechsler Memory Scale-revised (WMS-RC) in patients with memory disorder caused by severe traumatic brain injury (sTBI). The subjects included 20 sTBI patients with memory disorder and 22 healthy individuals. Memory function was measured by using WMS-RC. Behavioral and ERP responses were recorded on-line during performance on a battery of picture recognition and the responses were analyzed off-line for recognition memory effects. Mean memory quotient (MQ) of patients with sTBI was significantly lower than that of the control group. Mean reaction time (RT) was significantly longer and the mean correctness rate (CR) of picture recognition was significantly lower in sTBI group than that of the controls. In controls, the main components of average ERP of picture recognition includes two positive-going waves, designated as P(170) and P(500), that appear 170 ms and 500 ms after stimulation when the subject could later successfully recall and recognize the pictures. P(500) amplitude of target stimulus was significantly higher than that of non-target stimulus. Compared to controls, P(500) responses of sTBI group were significantly delayed in latency (P<0.001) and lower in amplitude (P<0.001). P(500) latency showed significant negative correlation with MQ and the scores of "addition", "visual recognition", "picture recall", "visual reproduction" and "tactile memory" in WMS-RC. ERP of picture recognition provides a neurophysiological approach to directly assess memory impairment, and P(500) may serve as a helpful index for memory disorder caused by sTBI in forensic practice.
Brain Injuries/*complications ; Case-Control Studies ; Evoked Potentials/*physiology ; Memory Disorders/*etiology ; Memory Disorders/*physiopathology ; Pattern Recognition, Physiological/*physiology ; Wechsler Scales ; Young Adult

The present study was designed to observe the influence of cerebral ischemia/reperfusion injury on learning and memory in hyperlipidemic rats and estimate the changes of activity of autonomic nervous system. Twenty-three male Wistar rats were randomly divided into three groups, named control group (C group, n=10), hyperlipidemia group (H group, n=6) and hyperlipidemia-ischemia group (HI group, n=7), respectively. The rats in H and HI group were fed a high-fat diet for 2 weeks and the rats in all groups were examined through Morris water maze (MWM) task. The rats in HI group underwent ischemia/reperfusion by 2-vessel occlusion (2-VO) method, and had electrocardiogram (ECG) recording simultaneously. The MWM task and ECG recording were taken again after 7 d of recuperation. The following results were obtained: (1) In the second place navigation performance and probe trial performance, the frequency of memory in quadrant of hidden-platform and memory score decreased significantly in HI group compared to that in C and H groups. (2) The heart rate in HI group decreased slowly after ischemia; the power at high frequency band (HF) reduced gradually, meanwhile the power at middle frequency band (MF) and the ratio of power at MF and HF decreased clearly compared to baseline value. (3) After 7 d of ischemia/reperfusion, the heart rate in HI group was significantly higher than that in H group (P<0.05). While there was no statistical change in the power at MF, the power at HF decreased and the ratio of MF/HF increased significantly (P<0.05). The data demonstrated that ischemia/reperfusion decreased the activity of autonomic nervous system, and the reduction of sympathetic nerve activity was much more than that of vagus nerve activity. The results suggest that the hippocampus neuron injury caused by ischemia induces cognitive disorder and imbalance of vago-sympathetic nerve activity accompanied by vagus nerve suppression.
Animals ; Autonomic Nervous System ; physiopathology ; Brain Ischemia ; etiology ; physiopathology ; Heart Rate ; physiology ; Hippocampus ; physiopathology ; Hyperlipidemias ; complications ; Learning Disorders ; etiology ; physiopathology ; Male ; Memory Disorders ; etiology ; physiopathology ; Random Allocation ; Rats ; Rats, Wistar ; Reperfusion Injury ; pathology ; physiopathology

OBJECTIVETo investigate effect of chronic transauricular kindled seizures on passive-avoidance test memory retention in rats.

METHODSChronic transauricular kindled seizures was induced by repeated application of initially subconvulsive electrical stimulation through ear-clip electrodes once every 24 h until the occurrence of 3 consecutive clonic-tonic seizures. A passive avoidance test was used to measure memory retention ability. Morphological changes in neurons of hippocampal CA1 region was examined after HE staining. Histamine, gamma-aminobutyric acid (GABA) and glutamate levels in the hippocampus were measured by high performance liquid chromatography (HPLC).

RESULTChronic transauricular kindled seizures impaired passive-avoidance test memory retention in rats. The damaged CA1 neurons were observed and histamine content in the hippocampus markedly decreased 24 h after the end of kindling in the chronic transauricular kindled rats.

CONCLUSIONChronic transauricular kindled seizure impaired passive-avoidance test memory retention, and it might be due to the damaged CA1 neurons and a decrease of histamine in the hippocampus induced by epilepsy.

Animals ; Avoidance Learning ; Hippocampus ; metabolism ; pathology ; physiopathology ; Histamine ; metabolism ; Kindling, Neurologic ; Male ; Memory Disorders ; etiology ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Seizures ; metabolism ; pathology ; physiopathology ; gamma-Aminobutyric Acid ; metabolism

OBJECTIVETo observe the changes in the learning and memory functions and the hippocampal expression of phosphorylated cAMP response element-binding protein (pCREB) in rats with status epilepticus and generalized nonconvulsive status epilepticus.

METHODSStatus epilepticus (SE) and generalized nonconvulsive status epilepticus (GNCSE) was induced by pentylenetetrazol kindling in SD rats, and the learning and memory function changes of the kindled rats were assessed by means of Morris water-maze test and Y-maze test with alternative electric stimulation. Immunocytochemistry was used for analysis pCREB protein expression in the hippocampus of the rats.

RESULTSIn Morris water-maze test, the rats with SE showed prolonged mean escape latency (P<0.05), shortened swimming time in the platform quadrant (P<0.05), and reduced number of times of platform crossing (P<0.05) in the short term after kindling. But these changes were reversed and became normal a month after the kindling (P>0.05). In the Y-maze test with alternative electric stimulation, the total error (TE) of SE rats increased significantly in the short term after epilepsy (P<0.05), but recovered the normal level a month after kindling (P>0.05). The GNCSE rats showed prolonged mean escape latency at only certain time periods (P<0.05) in the short term, but with swimming time in the platform quadrant and number of platform crossings similar to the control group (P>0.05). The short-term TE of GNCSE rats increased significantly (P<0.05), but in the long term, TE was similar to that in the control group (P>0.05). The expression of pCREB decreased significantly in SE group in comparison with the control group in the short term.

CONCLUSIONEpileptic seizures can lead to learning and memory function impairment in rats, and SE seems to cause greater impact than GNCSE on the learning and memory functions. pCREB might be involved in the pathophysiology of learning and memory deficit in epileptic rats.

Animals ; CREB-Binding Protein ; metabolism ; Hippocampus ; metabolism ; physiopathology ; Kindling, Neurologic ; Maze Learning ; Memory Disorders ; physiopathology ; Pentylenetetrazole ; Rats ; Rats, Sprague-Dawley ; Status Epilepticus ; chemically induced ; metabolism ; physiopathology