Human high intelligence is involved in spectral redshift of biophotonic activities in the brain

Abstract

Human beings hold higher intelligence than other animals on Earth; however, it is still unclear which brain properties might explain the underlying mechanisms. The brain is a major energy-consuming organ compared with other organs. Neural signal communications and information processing in neural circuits play an important role in the realization of various neural functions, whereas improvement in cognitive function is driven by the need for more effective communication that requires less energy. Combining the ultraweak biophoton imaging system (UBIS) with the biophoton spectral analysis device (BSAD), we found that glutamate-induced biophotonic activities and transmission in the brain, which has recently been demonstrated as a novel neural signal communication mechanism, present a spectral redshift from animals (in order of bullfrog, mouse, chicken, pig, and monkey) to humans, even up to a near-infrared wavelength (∼865 nm) in the human brain. This brain property may be a key biophysical basis for explaining high intelligence in humans because biophoton spectral redshift could be a more economical and effective measure of biophotonic signal communications and information processing in the human brain.

Keywords: biophoton imaging; brain slices; glutamate; intelligence; ultraweak photon emissions.

Fig. 1.

Schematic drawing of the UBIS and BSAD. UBIS was described in detail in a previous report (12). BSAD consists of a slit (1 mm wide and 1 cm long) and a transmission grating (1,200 per millimeter) and is placed just above the sample during biophoton imaging. The right plane is an enlarged drawing of the BSAD in the left plane. The brain slice is incubated in a chamber containing perfusion solution (also see SI Methods).

Fig. 2.

Photon spectral images for calibration and reliability confirmation. (A and B) Photon spectral images were obtained from three wavelength lasers (405 nm, 532 nm, and 650 nm) (A) and four wavelength LED lights (blue, green, yellow, and red) (B) under conditions of normal intensities (up planes) and ultraweak intensities (down planes) (also see the detailed explanation in SI Methods), showing one zero-order fringe and two first-grade fringes. The two first-grade fringes present a trend away from the zero-order fringe from short to long wavelengths (blue to red). (C) Schematic drawing of a spectral image to analyze the relative central distance (△L_c), minimum (△L_min), and maximum (△L_max) edge distances from the first-grade fringe (digit 1) to the center of the zero-order fringe (digit 0) with an image analysis software (also see Fig. S1A ). (D and E) There are linear relations between the wavelengths and △L_c, △L_min, or △L_max in three lasers under the conditions of normal (D) and ultraweak (E) intensities. The linear regression coefficients (R²) are 0.9999, 0.9989, and 0.9978 for △L_c, △L_min, and △L_max, respectively, in D, and 0.9999, 0.9996, and 0.9990, respectively, in E; P = 0.005–0.042 (also see Table S1). (F) The relations between the calculated wavelengths (λ_ave, λ_min, and λ_max) of four LED light sources (bigger color symbols) based on the spectral images under the conditions of ultraweak light intensities and the known pick and wavelength ranges [smaller black symbols; 451 nm (410–492 nm; blue), 518 nm (450–586 nm; green), 590 nm (555–625 nm; yellow), and 632 nm (595–669 nm; red)] measured with a spectrometer (also see Fig. S2). The calculated λ_ave is almost same as the known pick wavelength of each LED light. (G) Representative biophoton spectral image obtained from a tree leaf (sweet-scented osmanthus tree), showing the clear zero-order fringe and two first-grade fringes (60-s imaging time). (H) The calculated wavelengths (λ_ave, λ_min, and λ_max) from five leaves of this type of tree according to regression Eqs. 1–3.

Fig. S1.

Photon spectral images for calibration and reliability confirmation. (A) Visual judgment of the spectral image with an image analysis software program (Andor Solis for Imaging Version 4.27.30001.0; Andor) for evaluating preliminarily the range of the edges; the “cross-sign” indicates the position of the far edge of one first-grade fringe. The position pixel values are shown at the bottom of the spectral image. (B) A representative distribution curve of the sum of GVs of a 1D matrix (512 pixels) parallel to the first-grade fringe (digit 1) and zero-order fringe (digit 0). (C–F) The sectioned range of numerical values of the sum of GVs near the two edges of the zero-order fringe (C and D) and first-grade fringe (E and F). The four numerical values (a–d) are marked by red color and are defined as the pixel number for calculating △L_c, △L_min, and △L_max. If, F₀ = (a + b)/2 and F₁ = (c + d)/2, then △L_c = F1 − F0, △L_min = c − F0, and △L_max = d – F0.

Fig. S2.

The spectral curves of four LED lights. The spectra were obtained for each LED light source by a spectrometer. The start, pick, and stop wavelengths (nm) of blue (410, 451, and 492 nm), green (450, 518, and 586 nm), yellow (555, 590, and 625 nm), and red (595, 632, and 677 nm) are used to evaluate the references.

Fig. 3.

Spectral redshift of glutamate-induced biophotonic emissions in brain slices presents an evolutional trend from animals to human. (A) Schematic drawing of the preparation of a particular sagittal brain slice (∼2 mm thickness) from a hemisphere of the mouse brain, which is identical in bullfrog and chicken brains. (B) The detailed regions of brain gyri dissected from primary occipital, motor, and sensory cortexes, the medial frontal cortex, and superior temporal cortex in a representative monkey brain (arrows), which are also similar in pig and human brains. (C) The preparation of a cortical slice (∼3 mm thickness) from a block of cortical gyrus of pig, monkey, and human; the dotted line indicates the cut position. This cortical slice contains all of the cortical layers and could ensure that the cut ends of the projection fibers originating from cortical neurons are directed toward the lens of the UBIS during imaging. (D) The representative dynamic change of biophotonic activities was demonstrated by relative GVs (RGVs) after the application of 50 mM glutamate in a mouse brain slice (blue curved line), a pig hippocampus slice (Pig-Hi) (green curved line), and a human motor cortical slice (human-Mc) [red curved line; CBBC no. 20160107; Table S2], presenting the four typical stages (initiation, maintenance, washing, and reapplication). These two human and pig brain slices were stored in modified ACSF (M-ACSF) at 0–4 °C for 12 and 24 h, respectively, before imaging. Real-time imaging is 120 min for regular biophoton images (an image every 1 min without BSAD) and 100 min for biophoton spectral images (an image every 25 min with BSAD) through the periods of maintenance (0–170 min), washing (171–195 min), and reapplication (196–220 min). The arrows indicate the start and stop time points for capturing biophoton spectral images. (E) Representative biophoton spectral images in animal and human brain slices. The first-order fringes present a trend away from the zero-order fringes in the order of bullfrog, mouse, chicken, pig, monkey, and human, indicating a spectral redshift from animals to humans. (F) Change trends of glutamate-induced biophoton spectral ranges (λ_ave, λ_min, or λ_max) in the bullfrog, mouse, chicken, pig, monkey, and human. (G–I) Comparison of the spectral differences in λ_ave (F = 399; P < 0.0001) (G), λ_min (F = 82; P < 0.0001) (H), or λ_max (F = 569; P < 0.0001) (I) in the bullfrog, mouse, chicken, pig, monkey, and human. (J and K) Comparison of the spectral differences in λ_ave, λ_min, or λ_max in different brain regions in the pig (J) and human (K). Data show the means ± SEM. The number of brain slices in F–I: bullfrog (n = 5), mouse (n = 5), chicken (n = 5), pig (n = 34), monkey (n = 11), and human (n = 31). The number of brain slices in different brain regions (N): 6, 6, 5, 7, 4, and 6 for frontal cortex (Fc), motor cortex (Mc), sensory cortex (Sc), primary occipital cortex (Oc), temporal cortex (Tc), and hippocampus (Hi), respectively, in the pig and 6, 5, 4, 6, 3, and 7 for Fc, Mc, Sc, Oc, Tc, and Hi, respectively, in the human. Asterisks indicate a significant difference between the neighboring two groups in G–I: *P < 0.01; **P < 0.001; ***P < 0.0001. Asterisks indicate a significant difference in different areas in J: Fc vs. Mc (**); Fc vs. Tc (*); Mc vs. Hi (*). *P < 0.05. **P < 0.01.