Hypothalamic Supramammillary Control of Cognition and Motivation.

The supramammillary nucleus (SuM) is a small region in the ventromedial posterior hypothalamus. The SuM has been relatively understudied with much of the prior focus being on its connection with septo-hippocampal circuitry. Thus, most studies conducted until the 21st century examined its role in hippocampal processes, such as theta rhythm and learning/memory. In recent years, the SuM has been "rediscovered" as a crucial hub for several behavioral and cognitive processes, including reward-seeking, exploration, and social memory. Additionally, it has been shown to play significant roles in hippocampal plasticity and adult neurogenesis. This review highlights findings from recent studies using cutting-edge systems neuroscience tools that have shed light on these fascinating roles for the SuM.

Visibility graph analysis of speech evoked auditory brainstem response in persistent developmental stuttering.

In this research, the concept of fractality based on nonlinear science and chaos theory is explored to study and evaluate the complexity of speech-evoked auditory brainstem response (s-ABR) time series in order to capture its intrinsic multiscale dynamics. The visibility graph of the s-ABR series is proposed as a quantitative method to differentiate subjects with persistent developmental stuttering (PDS) from the normal group. Differential complexities between normal and PDS subjects is quantified using Graph index complexity (GIC). The model is applied to 14 individuals with PDS and 15 normal subjects. The results reveal the promising ability of GIC for assessment of abnormal activation of brainstem level in PDS group. It is observed that all s-ABR series have visibility graphs with a power-law topology and fractality in the s-ABR series is dictated by a mechanism associated with long-term memory of the auditory system dynamics at the brainstem level.

Long-range temporal correlation in Auditory Brainstem Responses to Spoken Syllable/da/.

The speech auditory brainstem response (sABR) is an objective clinical tool to diagnose particular impairments along the auditory brainstem pathways. We explore the scaling behavior of the brainstem in response to synthetic /da/ stimuli using a proposed pipeline including Multifractal Detrended Moving Average Analysis (MFDMA) modified by Singular Value Decomposition. The scaling exponent confirms that all normal sABR are classified into the non-stationary process. The average Hurst exponent is H = 0:77 ± 0:12 at 68% confidence interval indicating long-range correlation which shows the first universality behavior of sABR. Our findings exhibit that fluctuations in the sABR series are dictated by a mechanism associated with long-term memory of the dynamic of the auditory system in the brainstem level. The q-dependency of h(q) demonstrates that underlying data sets have multifractal nature revealing the second universality behavior of the normal sABR samples. Comparing Hurst exponent of original sABR with the results of the corresponding shuffled and surrogate series, we conclude that its multifractality is almost due to the long-range temporal correlations which are devoted to the third universality. Finally, the presence of long-range correlation which is related to the slow timescales in the subcortical level and integration of information in the brainstem network is confirmed.