1,721,116 research outputs found
Effects of endocannabinoid and endovanilloid systems on aversive memory extinction
No full textIn contextual fear conditioning animals have to integrate various elemental stimuli into a coherent representation of the condition and then associate context representation with punishment. Although several studies indicated the modulating role of endocannabinoid system (ECS) on the associative learning, ECS effect on contextual fear conditioning requires further investigations. The present study assessed the effects of the increased endocannabinoid anandamide (AEA) tone on acquisition, retrieval and extinction of the contextual fear conditioning. Given that AEA may bind to cannabinoid type 1 (CB1) receptors as well as to postsynaptic ionotropic Transient Receptor Potential Vanilloid type 1 (TRPV1) channels, particular attention was paid in determining how the increased AEA tone influenced fear responses. Furthermore, it was investigated how the ECS modulated the effects of stress-sensitization on fear response. Thus, mice submitted or not to a social defeat stress protocol were treated with drugs acting on ECS, CB1 receptors or TRPV1 channels and tested in a contextual fear conditioning whose conditioning, retrieval and extinction phases were analyzed. ECS activation influenced the extinction process and contrasted the stress effects on fear memory. Furthermore, CB1 receptor antagonist blocked and TRPV1 channel antagonist promoted short- and long-term extinction. The present study indicates that ECS controls the extinction of aversive memories in the contextual fear conditioning
Alexithymia: From neurobiological basis to clinical implications
No full textAlexithymia is a construct of personality characterized by impairment in cognitive, emotional and affective processing. It describes people with deficiencies in identifying, processing, or describing subjective feelings or emotions. Although alexithymia is not a psychological disorder per se and it is normally distributed in healthy population, it is associated with enhanced risk of psychological impairment and it is present in a broad spectrum of psychiatric and psychosomatic disorders, as chronic pain, somatoform disorders, addictive disorders, anxiety and depression. By using neuroimaging studies, variations associated with functional and structural differences in people with high alexithymic traits are described in most of brain areas related to emotional awareness, as anterior cingulate cortex, fusiform gyrus, amygdala, parahippocampal gyrus and insula. Further, in the presence of alexithymia alterations are evidenced in the somato-sensory and sensorimotor cortices as well as in cerebellar areas. The link between limbic and somato-sensory systems may represent the possible neuroanatomical correlate of alexithymia. In the present chapter, the neurobiological basis and clinical implications of alexithymia are examined to clarify how the altered cognitive and affective experience of emotion may result in a deficit in the emotional awareness
Cognitive performances of cholinergically depleted rats following chronic donepezil administration
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Interference of left and right cerebellar rTMS with procedural learning
Full text linkIncreasing evidence suggests cerebellar involvement in procedural learning. To further analyze its role and to assess whether it has a lateralized influence, in the present study we used a repetitive transcranial magnetic stimulation interference approach in a group of normal subjects performing a serial reaction time task. We studied 36 normal volunteers: 13 subjects underwent repetitive transcranial magnetic stimulation on the left cerebellum and performed the task with the right (6 subjects) or left (7 subjects) hand; 10 subjects underwent repetitive transcranial magnetic stimulation on the right cerebellum and performed the task with the hand ipsilateral (5 subjects) or contralateral (5 subjects) to the stimulation; another 13 subjects served as controls and were not submitted to repetitive transcranial magnetic stimulation; 7 of them performed the task with the right hand and 6 with the left hand. The main results show that interference with the activity of the lateral cerebellum induces a significant decrease of procedural learning: Interference with the right cerebellar hemisphere activity induces a significant decrease in procedural learning regardless of the hand used to perform the serial reaction time task, whereas left cerebellar hemisphere activity seems more linked with procedural learning through the ipsilateral hand. In conclusion, the present study shows for the first time that a transient interference with the functions of the cerebellar cortex results in an impairment of procedural learning in normal subjects and it provides new evidences for interhemispheric differences in the lateral cerebellum
Cerebellar contribution to spatial event processing: do spatial procedures contribute to formation of spatial declarative knowledge?
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