Neuroscience
-
The neurodevelopmental hypothesis states that schizophrenia is a brain disease. Exploring abnormal brain activities can improve understanding of the neural pathologic mechanism of clinical characteristics and determine subjective biomarkers to differentiate patients with schizophrenia from healthy controls. We collected clinical characteristics (i.e., demographics, positive and negative syndrome scale (PANSS) scores, and cognitive scores) and magnetic resonance imaging (MRI) data from 57 first-diagnosed drug-naïve patients with schizophrenia and 50 healthy controls. ⋯ However, the related patterns of cognition of patients were different from those of healthy controls. Additionally, the combination of fALFF values in the bilateral paracentral lobule and right postcentral gyrus might distinguish patients with schizophrenia from healthy controls with high accuracy (98.13%), specificity (98.00%), and sensitivity (98.25%). Our study suggests that reduced local activities in the default mode network and sensorimotor network may be regarded as neural underpinnings of clinical characteristics and may discriminate patients with schizophrenia from healthy controls.
-
Responses in the rostral (gustatory) nucleus of the solitary tract (rNST) are modified by synaptic interactions within the nucleus and the constitutive membrane properties of the neurons themselves. The potassium current IA is one potential source of modulation. In the caudal NST, projection neurons with IA show lower fidelity to afferent stimulation compared to cells without. ⋯ Because IA reduced excitability and is hyperpolarization-sensitive, we examined whether IA contributed to the inhibition resulting from optogenetic release of GABA. Although blocking IA decreased the percent suppression induced by GABA, this effect was attributable to the increased responsiveness resulting from AmmTX3, not to a change in the absolute magnitude of suppression. We conclude that rNST responses to afferent input are regulated independently by IA and GABA.
-
A single pulse of high intensity electrical current delivered to the digits of the hand during voluntary contractions produces a period of decreased electromyographic (EMG) activity, known as a cutaneous silent period (CSP) (Caccia and Violini, 1973; Inghilleri et al., 1997; Uncini et al., 1991). Pairing transcranial magnetic stimulation (TMS) with digit stimulation results in motor evoked potentials (MEPs) with reduced amplitudes in a thenar muscle (Kofler, 2008). It is not known if similar behavior can be observed in more proximal upper-limb muscles. ⋯ The opposite relationship was seen within the PD (p < 0.047) muscle. An ANOVA test of normalized MEP values (TMS+/TMS) showed significant differences in APB vs TRI (p = 0.004) and PD (p = 0.003), and in FCR vs TRI (p = 0.046) and PD (p = 0.037) muscles. The results suggest that the CSP modulates descending drive differentially across upper-limb muscles.
-
Sleep dysfunctions in epilepsy increase the burden of seizures and cognitive impairments. Seizures and certain anti-seizure drugs (ASDs) can affect sleep quality, leading to excessive daytime sleepiness and poor cognitive performance. Therefore, it is imperative to develop non-pharmacological strategies to curb epilepsy and related sleep dysfunction. ⋯ Exposure to EE restored REM sleep duration and latency without altering WASO in epileptic rats. EE also restored delta power during non-rapid eye movement (NREM) and theta, gamma power during wake, PFC-CA1 coherence, and PV+ interneurons density. These results further strengthen the role of EE's positive effects on brain plasticity and aid in developing non-pharmacological strategies to mitigate epilepsy-associated comorbidities.
-
Social interactions play an important role in our daily lives and can profoundly impact our health for better and worse. To better understand the neural circuitry underlying social behavior, we focused on neural circuits involving vasopressin neurons of the bed nucleus of the stria terminalis (BNST) and serotonin neurons of the dorsal raphe (DR). Previous research shows that BNST vasopressin neurons are activated in male mice by interaction with a female and that vasopressin indirectly excites serotonin neurons. ⋯ Electrophysiological data suggest that most DR Avpr1a neurons behave like fast spiking interneurons found in other brain regions. Examination of RNAseq and in situ hybridization data suggests that there are glutamatergic, GABAergic, and serotonergic subtypes of Avpr1a neurons in the DR. Together our data support a model in which a subset of vasopressin-responsive interneurons in the DR may relay stimulus specific social signals from the forebrain BNST to the serotonergic DR system, which could help direct prosocial stimulus specific behavioral responses.