tag: neuroscience
14 proofs
Critical periods of heightened cortical plasticity close permanently after early development, rendering the adult brain largely incapable of experience-dependent reorganization comparable to juvenile levels.
Sources: Pizzorusso et al. 2002, Science 298:1248-1251, Hensch & Bilimoria 2012, Cerebrum, Gervain et al. 2013, Frontiers in Systems Neuroscience +3 more
Adult neurogenesis occurs in the human neocortex.
Sources: Bhardwaj et al. 2006 — Neocortical neurogenesis in humans is restricted to development. Proc Natl Acad Sci USA 103(33):12564-12568 (PubMed abstract), Spalding et al. 2013 — Dynamics of hippocampal neurogenesis in adult humans. Cell 153(6):1219-1227 (PMC full text)
Co-occurrence of Lewy pathology and ADNC is common (≥30% of AD cases have LP; ≥50% of DLB cases have ADNC)
Sources: Brenowitz et al. 2017, Neurobiology of Aging (NACC n=2,742; ACT n=499), Toledo et al. 2023, Alzheimer's & Dementia, Lewy Body Dementia Association (LBDA), citing NACC autopsy data +4 more
Daily mindfulness meditation for 10 minutes increases hippocampal volume by at least 1% within one month.
Sources: Harvard Gazette — 'Eight weeks to a better brain' (reporting Hölzel et al. 2011, Psychiatry Research: Neuroimaging 191(1):36–43), Psychology Today — 'Mindfulness Doesn't Change Our Brains in Ways Once Thought' (reporting Kral et al. 2022, Science Advances), PubMed — Hölzel et al. 2011, 'Mindfulness practice leads to increases in regional brain gray matter density,' Psychiatry Research: Neuroimaging 191(1):36–43
For a correctly specified discrete-time spike train model with conditional spike probabilities p_k, define A_m = sum_{k=tau_{m-1}+1}^{tau_m-1} -log(1-p_k) and R_m = A_m - log(1 - U_m * p_{tau_m}), where U_m ~ Uniform(0,1) independently. Then R_m are i.i.d. Exp(1), equivalently Z_m = 1 - exp(-R_m) are i.i.d. Uniform(0,1).
Hippocampal damage leads to anterograde amnesia for new episodic memories and does not impair skill learning or retrograde memories from early life.
Sources: Squire LR (2009) The Legacy of Patient H.M. for Neuroscience, Neuron (PMC), Wikipedia: Henry Molaison, Simply Psychology: Patient H.M. Case Study +2 more
Humans use only 10% of their brain at any one time.
Sources: Scientific American (Barry Gordon, Johns Hopkins), MIT McGovern Institute for Brain Research, Neuroscience For Kids, University of Washington (Eric Chudler)
Over 80% of the brain's neurons are located in the cerebellum.
Sources: Herculano-Houzel S (2009) The human brain in numbers: a linearly scaled-up primate brain. Front Hum Neurosci 3:31. PMC2776484, von Bartheld CS, Bahney J, Herculano-Houzel S (2016) The search for true numbers of neurons and glial cells in the human brain. J Comp Neurol 524(18):3865-3895. PMC5063692, Herculano-Houzel S, Catania K, Manger PR, Kaas JH (2010) Coordinated scaling of cortical and cerebellar numbers of neurons. Front Neuroanat 4:12
Consider a spike-train encoding model where spikes are generated by an inhomogeneous Poisson process with intensity lambda_t = f(eta_t), eta_t = x_t^T beta + h_t^T gamma + b, with convex parameter space for theta = (beta, gamma, b). If f is positive, convex, and log-concave, then the log-likelihood is concave in theta. Therefore every local maximum is global, ML fitting is a convex optimization problem, and the same holds for MAP inference under any log-concave prior on theta.
The adult human brain has approximately 86 billion neurons and an average of 7,000 synapses per neuron, resulting in a total synaptic count exceeding 6 × 10^14.
Sources: Frontiers in Human Neuroscience, Herculano-Houzel 2009 (PubMed Central), UCLA Brain Research Institute, Brain Facts, BioNumbers BNID 112055, Harvard Medical School (citing Drachman 2005, Neurology)
The correlation between human brain volume and intelligence is r = 0.4
Sources: Pietschnig et al. (2015), Neuroscience & Biobehavioral Reviews — PubMed, Nave et al. (2022), Royal Society Open Science — PMC, Wikipedia — Neuroscience and intelligence
The human brain accounts for 2% of body weight but uses 20% of the body's oxygen at rest.
Sources: Raichle & Gusnard 2002 'Appraising the brain's energy budget' PNAS (via PMC), Basic Neurochemistry (NCBI Bookshelf): Regulation of Cerebral Metabolic Rate
The human brain does not generate new neurons in adulthood.
Sources: Moreno-Jiménez et al. 2019, Nature Medicine (PubMed abstract), Kempermann et al. 2018, Cell Stem Cell (PMC), Llorens-Martín et al. 2021, Journal of Neuroscience (PMC)
The superior method for enhancing neuroplasticity in adults is neurofeedback training compared to exercise or sleep optimization.
Sources: Szuhany et al. 2014, Journal of Psychiatric Research (PMC4314337), Cardoso et al. 2024, International Journal of Exercise Science (PMC11385284), Marzbani et al. 2016, Basic and Clinical Neuroscience (PMC4892319) +1 more