Dopamine facilitates associative memory encoding in the entorhinal cortex.

Mounting evidence shows that dopamine in the striatum is critically involved in reward-based reinforcement learning. However, it remains unclear how dopamine reward signals influence the entorhinal-hippocampal circuit, another brain network that is crucial for learning and memory. Here, using cell-type-specific electrophysiological recording, we show that dopamine signals from the ventral tegmental area and substantia nigra control the encoding of cue-reward association rules in layer 2a fan cells of the lateral entorhinal cortex (LEC).

Enhanced Theta and High-Gamma Coupling during Late Stage of Rule Switching Task in Rat Hippocampus.

Hippocampal oscillations, particularly theta (6-12 Hz) and gamma (30-90 Hz) frequency bands, play an important role in several cognitive functions. Theta and gamma oscillations show cross-frequency coupling (CFC), wherein the phase of theta rhythm modulates the amplitude of the gamma oscillation, and this CFC is believed to reflect cell assembly dynamics in cognitive processes. Previous studies have reported that CFC strength correlates with the learning process.

Gamma oscillations in the entorhinal-hippocampal circuit underlying memory and dementia.

Gamma oscillations that occur within the entorhinal cortex-hippocampal circuitry play important roles in the formation and retrieval of memory in healthy brains. Recent studies report that gamma oscillations are impaired in the entorhinal-hippocampal circuit of Alzheimer's disease (AD) patients and AD animal models. Here we review the latest advancements in studies of entorhinal-hippocampal gamma oscillations in healthy memory and dementia.

Impaired Gamma Oscillations in the Medial Entorhinal Cortex of Knock-in Alzheimer Model.

The entorhinal cortex (EC) has bidirectional connections with the hippocampus and plays a critical role in memory formation and retrieval. EC is one of the most vulnerable regions in the brain in early stages of Alzheimer's disease (AD), a neurodegenerative disease with progressive memory impairments. Accumulating evidence from healthy behaving animals indicates gamma oscillations (30-100 Hz) as critical for mediating interactions in the circuit between EC and hippocampus.

Similarity in Neuronal Firing Regimes across Mammalian Species.

Unlabelled: The architectonic subdivisions of the brain are believed to be functional modules, each processing parts of global functions. Previously, we showed that neurons in different regions operate in different firing regimes in monkeys. It is possible that firing regimes reflect differences in underlying information processing, and consequently the firing regimes in homologous regions across animal species might be similar.

Theta oscillation and neuronal activity in rat hippocampus are involved in temporal discrimination of time in seconds.

The discovery of time cells revealed that the rodent hippocampus has information regarding time. Previous studies have suggested that the role of hippocampal time cells is to integrate temporally segregated events into a sequence using working memory with time perception. However, it is unclear whether hippocampal cells contribute to time perception itself because most previous studies employed delayed matching-to-sample tasks that did not separately evaluate time perception from working memory processes.

[Association between smoking and tuberculosis infection].

Purpose: Several reports show smoking as a risk factor of tuberculosis (TB) infection, especially in prisoners, emigrants, the homeless, or people in areas where TB is endemic. These reports mostly used the tuberculin test to detect TB. However, there is no report evaluating smoking as a risk factor of TB infection among people coming into contact with TB with the use of the Interferon-Gamma Release Assays (IGRA) test.

Diverse synchrony of firing reflects diverse cell-assembly coding in the prefrontal cortex.

In the present paper, we focus on the coding by cell assemblies in the prefrontal cortex (PFC) and discuss the diversity of the coding, which results in stable and dynamic representations and the processing of various information in that higher brain region. The key activity that reflects cell-assembly coding is the synchrony of the firing of multiple neurons when animals are performing cognitive and memory tasks. First, we introduce some studies that have shown task-related synchrony of neuronal firing in the monkey PFC.

[Liver dysfunction during treatment of latent tuberculosis infection].

Purpose: The indications for treatment for latent tuberculosis infection were revised in 2007 to reflect that any subject with a higher risk of tuberculosis regardless of age should be treated. We worried about the incidence of liver dysfunction due to isoniazid (INH) in patients older than 30 yrs. of age.

[Adverse effect other than liver dysfunction in treatment of latent tuberculous infection by isoniazid].

Purpose: To study the frequency and degree of adverse effect, other than liver dysfunction, of isoniazid (INH) preventive therapy in Japanese people.

Object And Method: Chart review of Japanese persons who started isoniazid preventive chemotherapy in the two clinics in Tokyo, from 2003/1/1 to 2004/12/31.

Result: There were 779 cases who did not transiently or completely stop INH preventive therapy because of adverse effect, and 20 cases who stopped INH transiently or completely because of adverse effect other than liver damage (total 799 cases).

[Liver damage in treatment of latent tuberculous infection by isoniazid].

Purpose: To study the frequency and degree of liver damage as adverse effect of isoniazid (INH) preventive therapy in Japanese people.

Object And Method: Chart review of Japanese persons who started isoniazid preventive chemotherapy in the two clinics in Tokyo, from 2003/1/1 to 2004/12/31.

Result: There were 779 cases who did not transiently or completely stop INH preventive therapy because of adverse effect, and 26 cases who stopped INH transiently or completely because of liver damage as adverse effect (total 805 cases).

[Preventive therapy in middle-aged and elderly persons selected from the population-based screening by mass miniature radiography--methodological aspect and adverse reactions].

The notification rate of tuberculosis in Japan was 31.0 per 100,000 in 2000. The rate was especially high among the elderly population, reaching 85.