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Malekizadeh H, Saed O, Rashtbari A, Sajjadi M, Ahmadi D, Ronold EH. Deficits in specific executive functions manifest by severity in major depressive disorder: a comparison of antidepressant naïve inpatient, outpatient, subclinical, and healthy control groups. Front Psychiatry 2023; 14:1225062. [PMID: 37854445 PMCID: PMC10580982 DOI: 10.3389/fpsyt.2023.1225062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 09/12/2023] [Indexed: 10/20/2023] Open
Abstract
Introduction Previous research has highlighted the executive function (EF) deficits present in depressed patients; however, conflicting results exist regarding the impact of depression severity on the size of these deficits. This study aimed to compare deficits in EF between antidepressant naïve inpatient and outpatient depressed, a group with subclinical depression symptoms, and a healthy control group while controlling for education, sex, and age. Methods In cross-sectional research, 245 antidepressant naive participants (46 inpatient, 68 outpatient, 65 subclinical, and 67 healthy control individuals) were recruited by convenience sampling. The Structured Clinical Interview for DSM-5 Disorders (SCID-5) and Beck Depression Inventory-II (BDI-II) were used to assess depression. EF was measured using several neuropsychological tests, including the Stroop Color-Word Test, the Wisconsin Card Sorting Test, and the N-back Test, which assessed the components of Inhibition, Shifting, and Updating, respectively. Multivariate analysis of covariance revealed a significant difference between the groups in EF components (p < 0.001). Pairwise comparisons further showed that inpatient and outpatient patients had more depressive symptoms and worse EF performance than subclinical and healthy control groups (p < 0.05). Results In the analysis of EF measures, a significant difference was found among the four groups, with post-hoc tests revealing variations in specific EF components. Overall, patients with more severe depressive symptoms show more deficits in EF. Additionally, correlations between clinical characteristics and EF measures varied across patient groups, but many correlations became non-significant after adjusting for the false discovery rate (FDR). Discussion This study emphasizes the impact of depression severity on deficits in the EF of depressed patients and at-risk populations. Consequently, it is important to consider executive dysfunctions as an underlying vulnerability in the development and persistence of depressive disorder.
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Affiliation(s)
- Hossein Malekizadeh
- Department of Clinical Psychology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Omid Saed
- Department of Clinical Psychology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Alireza Rashtbari
- Department of Clinical Psychology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Mozhdeh Sajjadi
- Faculty of Psychology and Education, University of Tehran, Tehran, Iran
| | - Davoud Ahmadi
- Department of Clinical Psychology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Eivind Haga Ronold
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
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Zainal NH, Newman MG. Elevated Anxious and Depressed Mood Relates to Future Executive Dysfunction in Older Adults: A Longitudinal Network Analysis of Psychopathology and Cognitive Functioning. Clin Psychol Sci 2022; 11:218-238. [PMID: 36993876 PMCID: PMC10046395 DOI: 10.1177/21677026221114076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Vulnerability models posit that executive-functioning (EF) problems centrally affect future common (vs. rare) psychopathology symptoms. Conversely, scar theory postulates that depression/anxiety (vs. other psychopathology) symptoms centrally influence reduced EF. However, most studies so far have been cross-sectional. We used cross-lagged panel network analysis to determine temporal and component-to-component relations on this topic. Community older adults participated across four time points. Cognitive tests and the caregiver-rated Neuropsychiatric Inventory assessed nine psychopathology and eight cognitive-functioning nodes. Nodes with the highest bridge expected influence cross-sectionally were agitation and episodic memory. Episodic memory had the strongest inverse relation with age. Agitation had the strongest negative association with global cognition. EF nodes tended to be centrally affected by prior depressed and anxious moods rather than influential on any future nodes. Heightened anxious and depressed mood (vs. other nodes) centrally predicted future decreased EF-related (vs. non-EF-related) nodes in older adults, supporting scar (vs. vulnerability) theory.
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Affiliation(s)
- Nur Hani Zainal
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School
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3
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Domain L, Guillery M, Linz N, König A, Batail JM, David R, Corouge I, Bannier E, Ferré JC, Dondaine T, Drapier D, Robert GH. Multimodal MRI cerebral correlates of verbal fluency switching and its impairment in women with depression. Neuroimage Clin 2021; 33:102910. [PMID: 34942588 PMCID: PMC8713114 DOI: 10.1016/j.nicl.2021.102910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 12/03/2021] [Accepted: 12/04/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The search of biomarkers in the field of depression requires easy implementable tests that are biologically rooted. Qualitative analysis of verbal fluency tests (VFT) are good candidates, but its cerebral correlates are unknown. METHODS We collected qualitative semantic and phonemic VFT scores along with grey and white matter anatomical MRI of depressed (n = 26) and healthy controls (HC, n = 25) women. Qualitative VFT variables are the "clustering score" (i.e. the ability to produce words within subcategories) and the "switching score" (i.e. the ability to switch between clusters). The clustering and switching scores were automatically calculated using a data-driven approach. Brain measures were cortical thickness (CT) and fractional anisotropy (FA). We tested for associations between CT, FA and qualitative VFT variables within each group. RESULTS Patients had reduced switching VFT scores compared to HC. Thicker cortex was associated with better switching score in semantic VFT bilaterally in the frontal (superior, rostral middle and inferior gyri), parietal (inferior parietal lobule including the supramarginal gyri), temporal (transverse and fusiform gyri) and occipital (lingual gyri) lobes in the depressed group. Positive association between FA and the switching score in semantic VFT was retrieved in depressed patients within the corpus callosum, right inferior fronto-occipital fasciculus, right superior longitudinal fasciculus extending to the anterior thalamic radiation (all p < 0.05, corrected). CONCLUSION Together, these results suggest that automatic qualitative VFT scores are associated with brain anatomy and reinforce its potential use as a surrogate for depression cerebral bases.
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Affiliation(s)
- L Domain
- Universitary Department of Psychiatry, Centre Hospitalier Guillaume Régnier, Rennes, France
| | - M Guillery
- Universitary Department of Psychiatry, Centre Hospitalier Guillaume Régnier, Rennes, France
| | - N Linz
- ki:elements, Saarbrücken, Germany
| | - A König
- Stars Team, Institut National de Recherche en Informatique et en Automatique (INRIA), Sophia Antipolis, France; CoBTeK (Cognition-Behaviour-Technology) Lab, FRIS-University Côte d'Azur, Nice, France
| | - J M Batail
- Universitary Department of Psychiatry, Centre Hospitalier Guillaume Régnier, Rennes, France
| | - R David
- Old-age Psychiatry DEPARTMENT, Geriatry Division, University of Nice, France
| | - I Corouge
- U1228 Empenn, UMR 6074, IRISA, University of Rennes 1, France
| | - E Bannier
- U1228 Empenn, UMR 6074, IRISA, University of Rennes 1, France
| | - J C Ferré
- U1228 Empenn, UMR 6074, IRISA, University of Rennes 1, France
| | - T Dondaine
- Univ. Lille, Inserm, CHU Lille, LilNCog, Lille Neuroscience & Cognition, F-59000 Lille, France
| | - D Drapier
- Universitary Department of Psychiatry, Centre Hospitalier Guillaume Régnier, Rennes, France
| | - G H Robert
- Universitary Department of Psychiatry, Centre Hospitalier Guillaume Régnier, Rennes, France; U1228 Empenn, UMR 6074, IRISA, University of Rennes 1, France
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Alesci A, Fumia A, Lo Cascio P, Miller A, Cicero N. Immunostimulant and Antidepressant Effect of Natural Compounds in the Management of Covid-19 Symptoms. J Am Coll Nutr 2021; 41:840-854. [PMID: 34550044 DOI: 10.1080/07315724.2021.1965503] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In recent years, the use of natural compounds as adjuvant treatments and alternatives to traditional pharmacological therapies has become increasingly popular. These compounds have a wide range of biological effects, such as: antioxidant, anti-aging, hypocholesterolizing, hypoglycemic, antitumoral, antidepressant, anxiolytic activity, etc. Almost all of these compounds are easily available and are contained in different foods. At the end of 2019 the Coronavirus SARS-CoV-2 appeared in China and quickly spread throughout the world, causing a pandemic. The most common symptoms of this infection are dry cough, fever, dyspnea, and in severe cases bilateral interstitial pneumonia, with consequences that can lead to death. The nations, in trying to prevent the spread of infection, have imposed social distancing and lockdown measures on their citizens. This had a strong psychological-social impact, leading to phobic, anxious and depressive states. Pharmacological therapy could be accompanied by treatment with several natural compounds, such as vitamins, baicalein, zinc and essential oils. These compounds possess marked immunostimulant activity, strengthening the immune response and mitigating interactions between the virus and the host cell. They also have an antidepressant effect, acting on certain neurotransmitters.
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Affiliation(s)
- Alessio Alesci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Angelo Fumia
- Department of Clinical and Experimental Medicine, University of Messina, Padiglione C, A. O. U. Policlinico "G. Martino", Messina, Italy
| | - Patrizia Lo Cascio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | | | - Nicola Cicero
- Department of Biomedical and Dental Science and Morphofunctional Imaging, University of Messina, Messina, Italy
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Benke T, Marksteiner J, Ruepp B, Weiss EM, Zamarian L. Decision Making under Risk in Patients Suffering from Schizophrenia or Depression. Brain Sci 2021; 11:brainsci11091178. [PMID: 34573199 PMCID: PMC8470442 DOI: 10.3390/brainsci11091178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/31/2021] [Accepted: 09/05/2021] [Indexed: 11/16/2022] Open
Abstract
Studies have reported difficulties in decision making for patients with schizophrenia or depression. Here, we investigated whether there are differences between schizophrenia patients, depressed patients, and healthy individuals (HC) when decisions are to be made under risk and cognitive flexibility is required. We were also interested in the relationships between decision making, cognitive functioning, and disease severity. Thirty HC, 28 schizophrenia patients, and 28 depressed patients underwent structured clinical assessments and were assessed by the Positive and Negative Syndrome Scale or Hamilton Rating Scale. They performed the Probability-Associated Gambling (PAG) Task and a neuropsychological test battery. Both patient groups obtained lower scores than HC in memory and executive function measures. In the PAG task, relative to HC, depressed patients made slower decisions but showed a comparable number of advantageous decisions or strategy flexibility. Schizophrenia patients were slower, riskier, and less flexible compared to HC. For them, the decision making behavior correlated with the symptom severity. In both groups, decision making scores correlated with memory and executive function scores. Patients with schizophrenia or depression may have difficulties under risk when quick and flexible decisions are required. These difficulties may be more pronounced in patients who have marked cognitive deficits or severe clinical symptoms.
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Affiliation(s)
- Theresa Benke
- Department of Psychiatry and Psychotherapy A, Hall State Hospital, 6060 Hall in Tirol, Austria; (T.B.); (J.M.); (B.R.)
| | - Josef Marksteiner
- Department of Psychiatry and Psychotherapy A, Hall State Hospital, 6060 Hall in Tirol, Austria; (T.B.); (J.M.); (B.R.)
| | - Beatrix Ruepp
- Department of Psychiatry and Psychotherapy A, Hall State Hospital, 6060 Hall in Tirol, Austria; (T.B.); (J.M.); (B.R.)
| | - Elisabeth M. Weiss
- Department of Psychology, University of Innsbruck, 6020 Innsbruck, Austria;
| | - Laura Zamarian
- Department of Neurology, Medical University of Innsbruck, 6020 Innsbruck, Austria
- Correspondence:
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Lee A, Lah S, Joplin S, Haroutonian C, Pye J, Mowszowski L, Duffy SL, Naismith SL. Actigraphy-recorded sleep efficiency and hippocampal volume are related to visual and verbal rate of forgetting in older adults. AGING NEUROPSYCHOLOGY AND COGNITION 2020; 28:936-958. [PMID: 33141652 DOI: 10.1080/13825585.2020.1842849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study aimed to determine if older adults "at-risk" for dementia (those with MCI or SMC) exhibit accelerated long-term forgetting (ALF) and whether rate of forgetting (RoF) is associated with sleep efficiency, hippocampal volume and demographic/clinical features. Forty-nine "at-risk" participants and eighteen controls underwent examination. Memory was assessed using the Scene Memory Task (SMT) and WMS-III Logical Memory (LM) subtest. Tests were administered at baseline, 24 hours and 2 weeks. While our study did not find ALF in those "at-risk" for dementia, on the SMT, RoF over 24 hours and 2 weeks was negatively correlated with sleep efficiency. For LM, RoF at 2 weeks was moderately associated with left hippocampal volume. Neither visual or verbal RoF was correlated with demographic or clinical variables (age, MMSE, IQ, GDS-15). While ALF was not observed in this sample, our results suggest that visual and verbal forgetting have differential predictors.
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Affiliation(s)
- Alessandra Lee
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia.,Healthy Brain Ageing Program, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Suncica Lah
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia
| | - Samantha Joplin
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Carla Haroutonian
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia.,Healthy Brain Ageing Program, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia.,Neurosleep, Australian National Health and Medical Research Council Centre of Research Excellence, Sydney, Australia
| | - Jonathon Pye
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia.,Healthy Brain Ageing Program, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Loren Mowszowski
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia.,Healthy Brain Ageing Program, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia.,Neurosleep, Australian National Health and Medical Research Council Centre of Research Excellence, Sydney, Australia
| | - Shantel L Duffy
- Healthy Brain Ageing Program, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia.,Neurosleep, Australian National Health and Medical Research Council Centre of Research Excellence, Sydney, Australia
| | - Sharon L Naismith
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia.,Healthy Brain Ageing Program, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia.,Neurosleep, Australian National Health and Medical Research Council Centre of Research Excellence, Sydney, Australia
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Zhou Z, Fu S, Liu Y, Wang Y, Bu H, Mei Y, Tong Y, Yu C. Study of efficacy and safety of Jiaotai pill in the treatment of depression. Medicine (Baltimore) 2020; 99:e19999. [PMID: 32358376 PMCID: PMC7440333 DOI: 10.1097/md.0000000000019999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 03/24/2020] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Depression is a common affective disorder characterized by marked and lasting melancholia, with corresponding thought and behavior changes. Due to an accelerated pace of life and increased work pressure, the incidence of depression has risen sharply, causing great harm to family and social life. Jiaotai pill (JTP) is a Chinese herbal formula that is commonly prescribed for depression and insomnia in clinical treatment, and exhibits antidepressant effects as shown in animal experimental research. However, there are no standard clinical trials to confirm its efficacy in treating depression. OBJECTIVE This study aims to assess the efficacy and safety of JTP in the treatment of depression, so as to tap the clinical efficacy advantages of JTP and provide data support for its clinical application. METHODS A randomized, multicenter clinical trial with parallel groups was designed in this study. A total of 40 patients with depression were included and randomly divided to either the treatment or the control group with a ratio of 1:1. The patients received JTP plus fluoxetine or fluoxetine alone once per day for 8 weeks. The primary outcome included the Hamilton Depression Rating Scale score for patients and brain structure and function by functional magnetic resonance imaging. The secondary outcomes included Traditional Chinese medicine syndrome integral scale scores, Wisconsin Card Sorting Test, blood metabonomics, urine metabonomics. CONCLUSION The results of this trial will find changes in brain structure, brain function, and metabolism in patients with depression, and provide critical evidence for JTP in the treatment of depression.
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Affiliation(s)
| | - Shufei Fu
- College of Traditional Chinese Medicine
| | - Yijia Liu
- Graduate School, Tianjin University of Traditional Chinese Medicine
| | - Yuhan Wang
- Department of Psychosomatic Disease, Tianjin Hospital of ITCWM Nankai Hospital
| | - Huaien Bu
- College of Traditional Chinese Medicine
| | - Yan Mei
- Department of Psychosomatic Disease, Tianjin Academy of Traditional Chinese Medicine Affiliated Hospital
| | - Yi Tong
- Clinical Department, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine
| | - Chunquan Yu
- Editorial Department, Tianjin University of Traditional Chinese Medicine, Tianjin, China
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Dannehl K, Rief W, Euteneuer F. Effects of cognitive behavioural therapy on verbal learning and memory in major depression: Results of a randomized controlled trial. Clin Psychol Psychother 2019; 26:291-297. [DOI: 10.1002/cpp.2350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Katharina Dannehl
- Clinical Psychology and PsychotherapyPhilipps University Marburg Marburg Germany
| | - Winfried Rief
- Clinical Psychology and PsychotherapyPhilipps University Marburg Marburg Germany
| | - Frank Euteneuer
- Clinical Psychology and PsychotherapyPhilipps University Marburg Marburg Germany
- Clinical Psychology and PsychotherapyMedical School Berlin Berlin Germany
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McGinn MA, Pahng AR. Pathophysiology of affective disorders: functional interaction of stress hormones and hippocampal excitation. J Neurophysiol 2017; 117:477-479. [PMID: 27169510 DOI: 10.1152/jn.01065.2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 05/10/2016] [Indexed: 11/22/2022] Open
Abstract
An important new study by Kvarta, Bradbrook, Dantrassy, Bailey, and Thompson (J Neurophysiol 114: 1713-1724, 2015) examined the effects of persistent stress and excessive glucocorticoid levels on hippocampal function and emotional behavior in rodents. The authors specifically implicate the temporoammonic pathway as being susceptible to reductions in excitatory function in the context of chronic stress. We discuss the importance of this new finding in the broader context of medication development for major depressive disorder.
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Affiliation(s)
- M Adrienne McGinn
- Department of Physiology, Alcohol & Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Amanda R Pahng
- Department of Physiology, Alcohol & Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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The effects of prolonged administration of norepinephrine reuptake inhibitors on long-term potentiation in dentate gyrus, and on tests of spatial and object recognition memory in rats. Neurobiol Learn Mem 2016; 128:92-102. [PMID: 26774023 DOI: 10.1016/j.nlm.2015.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/16/2015] [Accepted: 12/30/2015] [Indexed: 11/23/2022]
Abstract
Phasic norepinephrine (NE) release events are involved in arousal, novelty detection and in plasticity processes underlying learning and memory in mammalian systems. Although the effects of phasic NE release events on plasticity and memory are prevalently documented, it is less understood what effects chronic NE reuptake inhibition and sustained increases in noradrenergic tone, might have on plasticity and cognitive processes in rodent models of learning and memory. This study investigates the effects of chronic NE reuptake inhibition on hippocampal plasticity and memory in rats. Rats were administered NE reuptake inhibitors (NRIs) desipramine (DMI; 0, 3, or 7.5mg/kg/day) or nortriptyline (NTP; 0, 10 or 20mg/kg/day) in drinking water. Long-term potentiation (LTP; 200 Hz) of the perforant path-dentate gyrus evoked potential was examined in urethane anesthetized rats after 30-32 days of DMI treatment. Short- (4-h) and long-term (24-h) spatial memory was tested in separate rats administered 0 or 7.5mg/kg/day DMI (25-30 days) using a two-trial spatial memory test. Additionally, the effects of chronically administered DMI and NTP were tested in rats using a two-trial, Object Recognition Test (ORT) at 2- and 24-h after 45 and 60 days of drug administration. Rats administered 3 or 7.5mg/kg/day DMI had attenuated LTP of the EPSP slope but not the population spike at the perforant path-dentate gyrus synapse. Short- and long-term memory for objects is differentially disrupted in rats after prolonged administration of DMI and NTP. Rats that were administered 7.5mg/kg/day DMI showed decreased memory for a two-trial spatial task when tested at 4-h. In the novel ORT, rats receiving 0 or 7.5mg/kg/day DMI showed a preference for the arm containing a Novel object when tested at both 2- and 24-h demonstrating both short- and long-term memory retention of the Familiar object. Rats that received either dose of NTP or 3mg/kg/day DMI showed impaired memory at 2-h, however this impairment was largely reversed at 24-h. Animals in the high-dose NTP (20mg/kg/day) group were impaired at both short- and long-term intervals. Activity levels, used as an index of location memory during the ORT, demonstrated that rats receiving DMI were again impaired at retaining memory for location. DMI dose-dependently disrupts LTP in the dentate gyrus of anesthetized rats and also disrupts memory for tests of spatial memory when administered for long periods.
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