Neuroscience and Neurobiology Commons^™

Rapid Microscopic Fractional Anisotropy Imaging Via An Optimized Linear Regression Formulation., N J J Arezza, D H Y Tse, C A Baron

Medical Biophysics Publications

Water diffusion anisotropy in the human brain is affected by disease, trauma, and development. Microscopic fractional anisotropy (μFA) is a diffusion MRI (dMRI) metric that can quantify water diffusion anisotropy independent of neuron fiber orientation dispersion. However, there are several different techniques to estimate μFA and few have demonstrated full brain imaging capabilities within clinically viable scan times and resolutions. Here, we present an optimized spherical tensor encoding (STE) technique to acquire μFA directly from the 2nd order cumulant expansion of the powder averaged dMRI signal obtained from direct linear regression (i.e. diffusion kurtosis) which requires fewer powder-averaged signals than …

Imaging Of Neurotransmitters And Small Molecules In Brain Tissues Using Laser Desorption/Ionization Mass Spectrometry Assisted With Zinc Oxide Nanoparticles., Chaochao Chen, Steven R Laviolette, Shawn N Whitehead, Justin B Renaud, Ken K-C Yeung

Chemistry Publications

Inorganic nanostructured materials such as silicon, carbon, metals, and metal oxides have been explored as matrices of low-background signals to assist the laser desorption/ionization (LDI) mass spectrometric (MS) analysis of small molecules, but their applications for imaging of small molecules in biological tissues remain limited in the literature. Titanium dioxide is one of the known nanoparticles (NP) that can effectively assist LDI MS imaging of low molecular weight molecules (LMWM). TiO₂ NP is commercially available as dispersions, which can be applied using a chemical solution sprayer. However, aggregation of NP can occur in the dispersions and the aggregated NP …

Assessing Time-Resolved Fnirs For Brain-Computer Interface Applications Of Mental Communication, Androu Abdalmalak, Daniel Milej, Lawrence C.M. Yip, Ali R. Khan, Mamadou Diop, Adrian M. Owen, Keith St. Lawrence

BrainsCAN Publications

© 2020 Abdalmalak, Milej, Yip, Khan, Diop, Owen and St. Lawrence. Brain-computer interfaces (BCIs) are becoming increasingly popular as a tool to improve the quality of life of patients with disabilities. Recently, time-resolved functional near-infrared spectroscopy (TR-fNIRS) based BCIs are gaining traction because of their enhanced depth sensitivity leading to lower signal contamination from the extracerebral layers. This study presents the first account of TR-fNIRS based BCI for “mental communication” on healthy participants. Twenty-one (21) participants were recruited and were repeatedly asked a series of questions where they were instructed to imagine playing tennis for “yes” and to stay relaxed …

Review Of The Literature: Can Music Training Improve Memory?, Prisca Hsu

2020 Undergraduate Awards

Music training typically starts at an early age when the brain is most receptive to plastic changes. Musicians practice countless hours in an extended amount of time to master their music-making abilities, making them an excellent model to study brain plasticity. Yet, the specific mechanisms that bring about changes following music training are unclear. Though the “Mozart effect” myth has been rejected by numerous researchers, the myth that music training will increase intelligence is still embraced by many teachers, parents and even policy-makers in the education system. In addition, an increasing number of studies now suggest that music training is …

Using Fmri To Investigate The Potential Cause Of Inverse Oxygenation Reported In Fnirs Studies Of Motor Imagery, Androu Abdalmalak, Daniel Milej, David J. Cohen, Udunna Anazodo, Tracy Ssali, Mamadou Diop, Adrian M. Owen, Keith St. Lawrence

BrainsCAN Publications

© 2019 Elsevier B.V. Motor imagery (MI) is a commonly used cognitive task in brain–computer interface (BCI) applications because it produces reliable activity in motor-planning regions. However, a number of functional near-infrared spectroscopy (fNIRS) studies have reported the unexpected finding of inverse oxygenation: increased deoxyhemoglobin and decreased oxyhemoglobin during task periods. This finding questions the reliability of fNIRS for BCI applications given that MI activation should result in a focal increase in blood oxygenation. In an attempt to elucidate this phenomenon, fMRI and fNIRS data were acquired on 15 healthy participants performing a MI task. The fMRI data provided global …

Cognition And The Brain Of Brood Parasitic Cowbirds., David F Sherry, Mélanie F Guigueno

Psychology Publications

Cowbirds are brood parasites. Females lay their eggs in the nests of other species, which then incubate the cowbird eggs and raise the young cowbirds. Finding and returning to heterospecific nests presents cowbirds with several cognitive challenges. In some species, such as brown-headed cowbirds (Molothrus ater), females but not males search for and remember the locations of potential host nests. We describe recent research on sex differences in cognition and the hippocampus associated with this sex difference in search for host nests. Female brown-headed cowbirds perform better than males on some, but not all, tests of spatial memory and females …

Role Of Dimensionality In Predicting The Spontaneous Behavior Of The Brain Using The Classical Ising Model And The Ising Model Implemented On A Structural Connectome, Pubuditha M. Abeyasinghe, Demetrius Ribeiro De Paula, Sina Khajehabdollahi, Sree Ram Valluri, Adrian M. Owen, Andrea Soddu

BrainsCAN Publications

© Pubuditha M. Abeyasinghe et al. 2018. There is accumulating evidence that spontaneous fluctuations of the brain are sustained by a structural architecture of axonal fiber bundles. Various models have been used to investigate this structure-function relationship. In this work, we implemented the Ising model using the number of fibers between each pair of brain regions as input. The output of the Ising model simulations on a structural connectome was then compared with empirical functional connectivity data. A simpler two-dimensional classical Ising model was used as the baseline model for comparison purpose. Thermodynamic properties, such as the magnetic susceptibility and …

Immature Auditory Evoked Potentials In Children With Moderate-Severe Developmental Language Disorder., Elaine Yuen Ling Kwok, Marc F Joanisse, Lisa Archibald, Janis Oram Cardy

Health and Rehabilitation Sciences Publications

Purpose: Immature auditory processing has been proposed to underlie language impairments in children with developmental language disorder (DLD; also known as specific language impairment). Using newly available normative auditory evoked potential (AEP) waveforms, we estimated AEP maturity in individual children with DLD and explored whether this maturational index was related to their language abilities.

Method: AEPs were elicited by 225 trials of a 490-Hz pure tone. Using intraclass correlation and our previously established normative AEP waveforms of 7- to 10-year-old children with typical development, we estimated the age equivalent of the AEPs (AEP-age) from 21 children with DLD. The relation …

Maturation In Auditory Event-Related Potentials Explains Variation In Language Ability In Children., Elaine Yuen Ling Kwok, Marc F Joanisse, Lisa Archibald, Margot E. Stothers, Heather M Brown, Janis Oram Cardy

Health and Rehabilitation Sciences Publications

Processing of auditory information in the cortex continues to develop into later childhood and adolescence. Recent research has indicated that intraclass correlation (ICC) is the best method for capturing maturation in auditory event-related potentials (AEPs) of school-age children. However, the sensitivity of the ICC approach in discerning AEP changes in children has not been consistently demonstrated and positive results have not been replicated. We attempted this replication and further explored whether AEP maturation estimated using the ICC approach predicts cognitive and linguistic abilities in addition to chronological age. We measured AEPs in response to simple tones in groups of 7-, …

Disruption Of Hippocampal Multisynaptic Networks By General Anesthetics., Min-Ching Kuo, L Stan Leung

Physiology and Pharmacology Publications

BACKGROUND: Previous studies showed that synaptic transmission is affected by general anesthetics, but an anesthetic dose response in freely moving animals has not been done. The hippocampus provides a neural network for the evaluation of isoflurane and pentobarbital on multisynaptic transmission that is relevant to memory function.

METHODS: Male Long-Evans rats were implanted with multichannel and single electrodes in the hippocampus. Spontaneous local field potentials and evoked field potentials were recorded in freely behaving rats before (baseline) and after various doses of isoflurane (0.25 to 1.5%) and sodium pentobarbital (10 mg/kg intraperitoneal).

RESULTS: Monosynaptic population excitatory postsynaptic potentials at the …

Dynamics Of Motor System Excitability During Auditory Anticipation, Justine Czajka

Undergraduate Honors Posters

The ability to anticipate complex sounds, like words in speech or the beat in music, is an important aspect of human perception. However, the changes of excitability in the motor system during auditory anticipation have not been characterized. Here, we applied single-pulse Transcranial Magnetic Stimulation (TMS) to the primary motor cortex to elicit motor evoked potentials (MEPs) from the first dorsal interosseous muscle, the amplitude of which indexes motor system excitability. Healthy right-handed participants (N = 20) underwent TMS stimulation during listening to regular (periodic) tone sequences at three rates (200ms, 550ms, and 900ms) and irregular tone sequences. We assessed …

Pearls And Perils Of Pupillometry Using A Webcam, Mason Kadem, Rhodri Cusack

Undergraduate Honors Posters

Current methods to measure infants’ cognitive repertoire (i.e., collection of cognitive abilities) are limited. Previous testing paradigms required acquisition of non-age contextualized responses, and relied on measures that involved acquisition of other functions (e.g., language, motor). In addition to response limitations, cognitive functions may be difficult to observe in infants due to the difficulty in infant recruitment. Online testing has increased infant recruitment efforts and physiological responses have bypassed the motor, behavioural and linguistic limitations of infants. Recently, it has been shown that heart rate measures can be acquired through a webcam. Another feasible and reliable physiological measure is pupillometery, …

Origins Of Thalamic And Cortical Projections To The Posterior Auditory Field In Congenitally Deaf Cats., Blake E Butler, Nicole Chabot, Andrej Kral, Stephen G Lomber

Psychology Publications

Crossmodal plasticity takes place following sensory loss, such that areas that normally process the missing modality are reorganized to provide compensatory function in the remaining sensory systems. For example, congenitally deaf cats outperform normal hearing animals on localization of visual stimuli presented in the periphery, and this advantage has been shown to be mediated by the posterior auditory field (PAF). In order to determine the nature of the anatomical differences that underlie this phenomenon, we injected a retrograde tracer into PAF of congenitally deaf animals and quantified the thalamic and cortical projections to this field. The pattern of projections from …

Are There Place Cells In The Avian Hippocampus?, David F Sherry, Stephanie L Grella, Mélanie F Guigueno, David J White, Diano F Marrone

Psychology Publications

Birds possess a hippocampus that serves many of the same spatial and mnemonic functions as the mammalian hippocampus but achieves these outcomes with a dramatically different neuroanatomical organization. The properties of spatially responsive neurons in birds and mammals are also different. Much of the contemporary interest in the role of the mammalian hippocampus in spatial representation dates to the discovery of place cells in the rat hippocampus. Since that time, cells that respond to head direction and cells that encode a grid-like representation of space have been described in the rat brain. Research with homing pigeons has discovered hippocampal cells, …

Resting State Functional Network Disruptions In A Kainic Acid Model Of Temporal Lobe Epilepsy., Ravnoor Singh Gill, Seyed M Mirsattari, L Stan Leung

Physiology and Pharmacology Publications

We studied the graph topological properties of brain networks derived from resting-state functional magnetic resonance imaging in a kainic acid induced model of temporal lobe epilepsy (TLE) in rats. Functional connectivity was determined by temporal correlation of the resting-state Blood Oxygen Level Dependent (BOLD) signals between two brain regions during 1.5% and 2% isoflurane, and analyzed as networks in epileptic and control rats. Graph theoretical analysis revealed a significant increase in functional connectivity between brain areas in epileptic than control rats, and the connected brain areas could be categorized as a limbic network and a default mode network (DMN). The …

Associative Spike Timing-Dependent Potentiation Of The Basal Dendritic Excitatory Synapses In The Hippocampus In Vivo., Thomas K Fung, Clayton S Law, L Stan Leung

Physiology and Pharmacology Publications

Spike timing-dependent plasticity in the hippocampus has rarely been studied in vivo. Using extracellular potential and current source density analysis in urethane-anesthetized adult rats, we studied synaptic plasticity at the basal dendritic excitatory synapse in CA1 after excitation-spike (ES) pairing; E was a weak basal dendritic excitation evoked by stratum oriens stimulation, and S was a population spike evoked by stratum radiatum apical dendritic excitation. We hypothesize that positive ES pairing-generating synaptic excitation before a spike-results in long-term potentiation (LTP) while negative ES pairing results in long-term depression (LTD). Pairing (50 pairs at 5 Hz) at ES intervals of -10 …

Loss Of Dendritic Inhibition In The Hippocampus After Repeated Early-Life Hyperthermic Seizures In Rats., Richard Boyce, L Stan Leung

Physiology and Pharmacology Publications

Seizures are relatively common in children and are a risk factor for subsequent temporal lobe epilepsy. To investigate whether early-life seizures themselves are detrimental to the proper function of the adult brain, we studied whether dendritic excitation and inhibition in the hippocampus of adult rats were altered after hyperthermia-induced seizures in immature rats. In particular, we hypothesized that apical dendritic inhibition in hippocampal CA1 pyramidal cells would be disrupted following hyperthermia-induced seizures in early life. Seizure rats were given three hyperthermia-induced seizures per day for three days from postnatal day (PND) 13 to 15; control rats were handled similarly but …

Septohippocampal Gabaergic Neurons Mediate The Altered Behaviors Induced By N-Methyl-D-Aspartate Receptor Antagonists., Jingyi Ma, Siew Kian Tai, L Stan Leung

Physiology and Pharmacology Publications

We hypothesize that selective lesion of the septohippocampal GABAergic neurons suppresses the altered behaviors induced by an N-methyl-D-aspartate (NMDA) receptor antagonist, ketamine or MK-801. In addition, we hypothesize that septohippocampal GABAergic neurons generate an atropine-resistant theta rhythm that coexists with an atropine-sensitive theta rhythm in the hippocampus. Infusion of orexin-saporin (ore-SAP) into the medial septal area decreased parvalbumin-immunoreactive (GABAergic) neurons by ~80%, without significantly affecting choline-acetyltransferase-immunoreactive (cholinergic) neurons. The theta rhythm during walking, or the immobility-associated theta induced by pilocarpine, was not different between ore-SAP and sham-lesion rats. Walking theta was, however, more disrupted by atropine sulfate in ore-SAP than …

Resting-State Connectivity Identifies Distinct Functional Networks In Macaque Cingulate Cortex., R Matthew Hutchison, Thilo Womelsdorf, Joseph S Gati, L Stan Leung, Ravi S Menon, Stefan Everling

Physiology and Pharmacology Publications

Subregions of the cingulate cortex represent prominent intersections in the structural networks of the primate brain. The relevance of the cingulate to the structure and dynamics of large-scale networks ultimately requires a link to functional connectivity. Here, we map fine-grained functional connectivity across the complete extent of the macaque (Macaca fascicularis) cingulate cortex and delineate subdivisions pertaining to distinct identifiable networks. In particular, we identified 4 primary networks representing the functional spectrum of the cingulate: somatomotor, attention-orienting, executive, and limbic. The cingulate nodes of these networks originated from separable subfields along the rostral-to-caudal axis and were characterized by positive and …

A Model Of Intracellular Θ Phase Precession Dependent On Intrinsic Subthreshold Membrane Currents., L Stan Leung

Physiology and Pharmacology Publications

A hippocampal place cell fires at an increasingly earlier phase in relation to the extracellular theta rhythm as a rodent moves through the place field. The present report presents a compartment model of a CA1 pyramidal cell that explains the increase in amplitude and the phase precession of intracellular theta oscillations, with the assumption that the cell receives an asymmetric ramp depolarization (<10 >mV) in the place field and rhythmic inhibitory and/or excitatory synaptic driving. Intracellular subthreshold membrane potential oscillations (MPOs) increase in amplitude and frequency, and show phase precession within the place field. Theta phase precession and MPO power …

Seasonal Hippocampal Plasticity In Food-Storing Birds., David F Sherry, Jennifer S Hoshooley

Psychology Publications

Both food-storing behaviour and the hippocampus change annually in food-storing birds. Food storing increases substantially in autumn and winter in chickadees and tits, jays and nutcrackers and nuthatches. The total size of the chickadee hippocampus increases in autumn and winter as does the rate of hippocampal neurogenesis. The hippocampus is necessary for accurate cache retrieval in food-storing birds and is much larger in food-storing birds than in non-storing passerines. It therefore seems probable that seasonal change in caching and seasonal change in the hippocampus are causally related. The peak in recruitment of new neurons into the hippocampus occurs before birds …