It is controversial whether isolated lesions of mammillothalamic tract (MTT) produce significant amnesia. Since the MTT is small and adjacent to several important structures for memory, amnesia associated with isolated MTT infarction has been rarely reported. We report a patient who developed amnesia following an infarction of the left MTT that spared adjacent memory-related structures including the anterior thalamic nucleus. The patient s memory deficit was characterized by a severe anterograde encoding deficit and retrograde amnesia with a temporal gradient. In contrast, he did not show either frontal executive dysfunction or personality change that is frequently recognized in the anterior or medial thalamic lesion. We postulate that an amnesic syndrome can develop following discrete lesions of the MTT.
Aged ; Amnesia/*etiology ; Cerebral Infarction/*complications ; Humans ; Male ; Mamillary Bodies/*physiopathology ; Neuropsychological Tests ; Thalamus/*physiopathology

BACKGROUNDReports on mood regulating circuit (MRC) indicated different activities between depressed patients and healthy controls. The functional networks based on MRC have not been described in major depression disorder (MDD). Both the anterior cingulate cortex (ACC) and thalamus are all the key regions of MRC. This study was to investigate the two functional networks related to ACC and thalamus in MDD.

METHODSSixteen patients with MDD on first episode which never got any medication and sixteen matched health controls were scanned by 3.0 T functional magnetic resonance imaging (fMRI) during resting-state. The pregenual anterior cingulate cortex (pgACC) was used as seed region to construct the functional network by cortex section. The thalamus was used as seed region to construct the functional network by limbic section. Paired-t tests between-groups were performed for the seed-target correlations based on the individual fisher z-transformed correlation maps by SPM2.

RESULTSDepressed subjects exhibited significantly great functional connectivity (FC) between pgACC and the parahippocampus gyrus in one cluster (size 923) including left parahippocampus gyrus (-21, -49, 7), left parietal lobe (-3, -46, 52) and left frontal lobe (-27, -46, 28). The one cluster (size 962) of increased FC on thalamus network overlapped the precuneus near to right parietal lobe (9, -52, 46) and right cingulate gyrus (15, -43, 43) in health controls.

CONCLUSIONSAbnormal functional networks exist in earlier manifestation of MDD related to MRC by both cortex and limbic sections. The increased functional connectivity of pgACC and decreased functional connectivity of thalamus is mainly involved in bias mood processing and cognition.

Adult ; Depressive Disorder, Major ; physiopathology ; Female ; Gyrus Cinguli ; physiopathology ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Thalamus ; physiopathology

Acute pain is a warning protective sensation for any impending harm. However, chronic pain syndromes are often resistant diseases that may consume large amount of health care costs. It has been suggested by recent studies that pain perception may be formed in central neural networks via large-scale coding processes, which involves sensory, affective, and cognitive dimensions. Many central areas are involved in these processes, including structures from the spinal cord, the brain stem, the limbic system, to the cortices. Thus, chronic painful diseases may be the result of some abnormal coding within this network. A thorough investigation of coding mechanism of pain within the central neuromatrix will bring us great insight into the mechanisms responsible for the development of chronic pain, hence leading to novel therapeutic interventions for pain management.
Animals ; Cerebral Cortex ; physiology ; Humans ; Nociception ; physiology ; Pain ; physiopathology ; Thalamus ; physiology

As a widely recognized public health problem as well as prevalent and challenging to modern society, chronic insomnia is involved in wide brain areas (such as prefrontal cortex, anterior cingulate cortex, amygdala, hippocampus, and thalamus) and emotion-cognition neuro-circuit. It is closely related to the conditioned hyperarousal and the increased information process and/or the impaired inhibitory ability to withdraw from awaking state. Thus, some specific abnormal mode may exist in the emotion-cognition circuit, which is associated with abnormal cognition load, such as repeated retrieval/intrusion of aversive memories during night. Studies through the combination of multiple techniques including psychology, electrophysiology and neuroimaging methods are needed to further enhance the understanding of chronic insomnia.
Brain ; physiopathology ; Electrophysiology ; Gyrus Cinguli ; Hippocampus ; Humans ; Neuroimaging ; Prefrontal Cortex ; Sleep Initiation and Maintenance Disorders ; pathology ; Thalamus

OBJECTIVE: To detect the activation pattern of the thalamus in human by the functional magnetic resonance imaging (fMRI) with the electrical stimulation of different intensities, and to explore the mechanism of this area in pain modulation. METHODS: Ten healthy right-handed volunteers were given different electrical stimulations of 1-, 2-, and 3- times pain threshold respectively. The whole-brain was scanned simultaneously by GE 1.5T magnetic resonance imaging system. The data were postprocessed by analysis of functional neuroimages (AFNI) to establish the regional activity maps of the thalamus. RESULTS: Patterns of functional activity showed a positive linear relationship between the activation signals and stimulation intensity in bilateral thalamus, whereas the BOLD signal of bilateral medial thalamus demonstrated that the curve was similar to the exponential function. Meanwhile, the activation in the contralateral lateral thalamus (cThl), but not the contralateral medial thalamus (cThm), was prominent compared with the corresponding ipsilateral subregions, and only the lateral thalamus displayed a contralateral biased representation while the medial thalamus lacked this property. CONCLUSION Thalamus is one of the vital components in the pain modulation network, which can present spatial segregation activations with unique characteristics of stimulation intensity-response in each subregion. All the results are helpful to understand the crucial role of thalamus in processing the pain information.
Adult ; Electric Stimulation ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Pain ; physiopathology ; Pain Threshold ; Thalamus ; physiology

OBJECTIVETo explore the morphometric abnormalities of brain gray matter (GM) in patients with chronic low back pain (CLBP).

METHODSThirty patients with CLBP and 30 healthy individuals were enrolled and examined with a 3.0 T magnetic resonance (MR) scanner. High-resolution T1 structural MR data were acquired and data analysis was performed using voxel-based morphometry (VBM) in FMRIB Software Library. The morphological differences were compared between the two groups.

RESULTSs Compared with the healthy control subjects, patients with CLBP showed decreased GM volumes in several brain cortical areas including the bilateral superior frontal gyrus, right frontal pole, left insular cortex, left middle and left inferior temporal gyrus (P<0.05, after TFCE correction). Increased GM volumes were found in the patients in the subcortical structures including the left thalamus, bilateral putamen, bilateral nucleus accumben and right caudate nucleus (P<0.05, after TFCE correction).

CONCLUSIONPatients with CLBP have different patterns of GM abnormalities in different brain regions, characterized by reduced GM volume in cerebral cortical regions and increased GM volume in the subcortical nuclei. Such changes might be associated with the maladaptation of the brain in chronic pain state.

Cerebral Cortex ; Frontal Lobe ; Gray Matter ; diagnostic imaging ; pathology ; Humans ; Low Back Pain ; physiopathology ; Magnetic Resonance Imaging ; Temporal Lobe ; Thalamus

Acupuncture analgesia is involved in various functions of the whole nervous system. The spinal cord is the first station for processing and translating the acupuncture analgesia; the brain stem is the relay station for systematization, differentiation and analysis, excitation, synthesis of acupuncture analgesic message, playing an important role in acupuncture analgesia; the thalamus functions complicated analysis and comprehensive regulation on various messeges with many kinds of neurohumoral factors involved and it is a coordinate center for strengthening and controlling acupuncture analgesia; the limbic system and its nuclear groups with many neurotransmitters involved, play coordinate action on acupuncture analgesia; the cerebral cortex is the high center and functions not only excitation and inhibition processes, but also is a center for complicated regulation and command, strengthening acupuncture analgesia and inhibiting the excess, so as to exerts interaction of dynamic balance.
Acupuncture Analgesia ; Brain Stem ; physiology ; Cerebral Cortex ; physiology ; Humans ; Limbic System ; physiology ; Pain ; physiopathology ; Spinal Cord ; physiology ; Thalamus ; physiology

OBJECTIVETo investigate the relationship between limb tremor and neuronal firing in thalamus (Vim) and retrospectively review the clinical effects and safety of the surgical treatment of essential tremor (ET).

METHODSForty-two ET patients received microelectrode-guided thalamotomy and 11 cases were quantitatively evaluated with FAHN rating scales pre- and post-operatively.

RESULTSThere were electrophysiological tremor-related neurons in ventrolateral part of thalamus. Lesioning of those neurons abolished contralateral limb tremor in all of the patients. No permanent contralateral weakness, dysarthria and hemorrhage were observed.

CONCLUSION"Tremor cell" in thalamus plays a key role in the symptom of ET patients. Destruction of those cells may completely and permanently abolish tremor symptom.

Adult ; Aged ; Aged, 80 and over ; Electrophysiology ; Essential Tremor ; physiopathology ; surgery ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Neurons ; physiology ; Retrospective Studies ; Thalamus ; physiopathology ; surgery

The neurocircuitries that constitute the cortico-striato-thalamo-cortical (CSTC) circuit provide a framework for bridging gaps between neuroscience and executive function in attention deficit hyperactivity disorder (ADHD), but it has been difficult to identify the mechanisms for regulating emotional problems from the understanding of ADHD comorbidity with disruptive behavior disorders (DBD). Research based on "cool" and "hot" executive functional theory and the dual pathway models, which are thought of as applied response inhibition and delay aversion, respectively, within the neuropsychological view of ADHD, has shed light on emotional responding before and after decontextualized stimuli, while CSTC circuit-related domains have been suggested to explain the different emotional symptoms of ADHD with or without comorbid DBD. This review discusses the role of abnormal connections in each CSTC circuit, especially in the emotion circuit, which may be responsible for targeted executive dysfunction at the neuroscience level. Thus, the two major domains - abstract thinking (cool) and emotional trait (hot) - trigger the mechanism of onset of ADHD.
Animals ; Attention Deficit Disorder with Hyperactivity ; complications ; pathology ; psychology ; Attention Deficit and Disruptive Behavior Disorders ; complications ; pathology ; psychology ; Brain ; physiopathology ; Cerebral Cortex ; physiopathology ; Corpus Striatum ; physiopathology ; Emotions ; Humans ; Inhibition (Psychology) ; Neuropsychological Tests ; Thalamus ; physiopathology

OBJECTIVE: To examine the changes of metabolites in the bilateral thalamus of patients with secondarily generalized tonic-clonic seizure (SGTCS) and to explore the mechanism of SGTCS. METHODS: Thirty patients with SGTCS (epilepsy group) and 30 matched healthy controls (control group) were examined by 1H-magnetic resonance spectroscopy (1H-MRS). The levels of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine phosphocreatine (Cr-PCr), and myo-inositol (mI) of the bilateral thalamus were measured in both the epilepsy group and the control group. The ratios of NAA/Cr-PCr, NAA/(Cr-PCr+Cho), Cho/Cr-PCr and mI/Cr-PCr were compared and analyzed in the 2 groups. RESULTS: The ratios of NAA/Cr-PCr, and NAA/(Cr-PCr+Cho)(1.7074 ± 0.2214; 0.9333 ± 0.2173) in the left thalamus in the epilepsy group were significantly lower than those in the control group(1.8834 ±0.2093; 1.1243 ±0.2447)(P<0.05). The ratios of NAA/Cr-PCr, and NAA/(Cr- PCr+Cho) (1.7472 ±0.2439; 0.9165 ±0.2462) in the right thalamus in the epilepsy group were also significantly lower than those in the control group(1.8925 ± 0.2004; 1.0941 ± 0.2372)(P<0.05). There were no significant differences in the ratios of NAA/Cr-PCr, NAA/(Cr-PCr+Cho), Cho/Cr- PCr, and mI/Cr-PCr between the bilateral thalamis in the epilepsy group (P>0.05). CONCLUSION There is neuronal dysfunction in the bilateral thalamus in the epilepsy group. Abnormal changes of the bilateral thalamus are involved in the mechanism of SGTCS.
Adolescent ; Adult ; Aspartic Acid ; analogs & derivatives ; analysis ; Brain Chemistry ; Case-Control Studies ; Choline ; analysis ; Energy Metabolism ; physiology ; Epilepsy, Generalized ; metabolism ; physiopathology ; Epilepsy, Tonic-Clonic ; metabolism ; physiopathology ; Female ; Humans ; Magnetic Resonance Spectroscopy ; methods ; Male ; Middle Aged ; Thalamus ; metabolism ; physiopathology ; Young Adult