Effects of Dark Chocolate Intake on Brain Electrical Oscillations in Healthy People

Dark chocolate is rich in flavonoids that can have effects on body composition and cognitive performance. The aim of this study was to analyze the effects of acute and subchronic chocolate intake on electrical brain oscillations. A study with 20 healthy subjects (mean age of 24.15 years) and a control group with five subjects (mean age of 23.2 years) was carried out. In the acute effect study, the subjects’ intake was dark chocolate (103.72 mg/kg of body weight) rich in flavonoids and low in calories as in fasting. In the control group, the subjects intake was only low-calorie milk. For the subchronic effect, a daily dose of dark chocolate was given for eight days. The baseline electroencephalogram (EEG) was recorded before dark chocolate intake; at 30 min, the second EEG was carried out; on the eighth day, the third and fourth EEGs were performed before and after the last intake. In acute and subchronic intake, Delta Absolute Power (AP) decrease was observed in most brain regions (p < 0.05), except in the right fronto-centro-temporal regions. In the Theta band, there was a generalized decrease of the AP of predominance in the left fronto-centro-temporal regions. In contrast, an increase in AP was observed in the temporo-occipital regions in the Alpha band, and in the right temporal and parieto-occipital regions in the Beta band. The control group did not have significant changes in brain oscillations (p > 0.05). We concluded that acute and subchronic chocolate intake decreased the Delta and Theta AP and increased Alpha and Beta AP in most brain regions

Visuospatial working memory in toddlers with a history of periventricular Leukomalacia: an EEG narrow-band power analysis.

BACKGROUND: Periventricular Leukomalacia (PVL) affects white matter, but grey matter injuries have also been reported, particularly in the dorsomedial nucleus and the cortex. Both structures have been related to working memory (WM) processes. The aim of this study was to compare behavioral performances and EEG power spectra during a visuospatial working memory task (VSWMT) of toddlers with a history of PVL and healthy toddlers. METHODOLOGY/PRINCIPAL FINDINGS: A prospective, comparative study of WM was conducted in toddlers with a history of PVL and healthy toddlers. The task responses and the EEG narrow-band power spectra during a VSWMT were compared in both groups. The EEG absolute power was analyzed during the following three conditions: baseline, attention and WM retention. The number of correct responses was higher in the healthy group (20.5 ± 5.0) compared to the PVL group (16.1 ± 3.9) (p = 0.04). The healthy group had absolute power EEG increases (p ≤ 0.05) during WM compared to the attention condition in the bilateral frontal and right temporal, parietal and occipital regions in frequencies ranging from 1.17 to 2.34 Hz and in the right temporal, parietal and occipital regions in frequencies ranging from 14.06 to 15.23 Hz. In contrast, the PVL group had absolute power increases (p ≤ 0.05) in the bilateral fronto-parietal, left central and occipital regions in frequencies that ranged from 1.17 to 3.52 Hz and in the bilateral frontal and right temporal regions in frequencies ranging from 9.37 to 19.14 Hz. CONCLUSIONS/SIGNIFICANCE: This study provides evidence that PVL toddlers have visuospatial WM deficits and a very different pattern of absolute power increases compared to a healthy group of toddlers, with greater absolute power in the low frequency range and widespread neuronal networks in the WM retention phase

Clinical characteristics of the toddlers.

*<p>p≤0.05,</p>**<p>p≤0.005. MDI: BSID-II Mental Developmental Index, PDI: BSID-II Psychomotor Developmental Index.</p

Correct answer in a healthy toddler.

<p>Left: Four phases of the VSWMT, as shown in the screen viewed by the toddlers. Right: Synchronized behavioral response of the toddler. A: attention phase, B: encoding phase, C: retention or WM retention phase and D: response phase. The subject of the photograph has given written informed consent, as outlined in the PLOS consent form, to publication of their photograph.</p

Post-hoc t-test comparing differences between the attention and WM conditions in each group.

<p>Positive t values, shown in yellow on the topographic map, imply power increases during WM in comparison with attention. Negative t values, shown in blue on the topographic map, imply power decreases during WM in comparison with attention.</p

Correct and incorrect responses on the VSWMT.

<p>Responses to the VSWMT are shown in black for the PVL group and in white for the healthy group. The PVL group showed a lower number of correct responses than did the healthy group (*p≤0.05). For the different types of incorrect responses, no significant differences were identified.</p

Visuospatial Working Memory Task (VSWMT).

<p>The durations and phases in which the windows were selected for the EEG power spectrum analysis in attention and retention (WM) conditions are shown in red. The salient stimulus of the encoding phase was taken from the IAPS <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069837#pone.0069837-Lang1" target="_blank">[21]</a>.</p

Magnetic Resonance Image findings of toddlers with Periventricular Leukomalacia.

<p>PCA = Postconceptional age in weeks.</p><p>MRI = Magnetic Resonance Image.</p><p>DEHSI = Diffuse Excessive High Signal Intensity.</p

Post-hoc t-test comparing the differences between the baseline and attention conditions in each group.

<p>Positive t values, shown in yellow on the topographic map, imply power increases during the attention condition compared to baseline. Negative t values, shown in blue on the topographic map, imply power decreases during the attention condition compared to the baseline.</p