Brain Development and Cognitive-Behavioural Brain Reserve - PDF

/ Dr. Laurie Manwell Fall 2024 Week 2 1 Copyright © 2024 Laurie A. Manwell  What is Your Brain’s Story? Discuss and elaborate on Eagleman’s claims that: - We are born unfinishe...

/ Dr. Laurie Manwell Fall 2024 Week 2 1 Copyright © 2024 Laurie A. Manwell  What is Your Brain’s Story? Discuss and elaborate on Eagleman’s claims that: - We are born unfinished vulnerable + Flexible to our environment, we are more we are programmed to develop according It is not the number of neurons that matters but their connections in # of connections we have the same # of neurons, but can grow The brain develops according to its “expected” environment prunes connections we don't need in the environment moving Forward An adolescent brain’s is more sensitive than a child’s brain and less inhibited than an adult’s brain. in the development & cortex of the limbic system prefrontal a gap overdeveloped underdeveloped Plasticity does not end at adulthood made new connections being Changes in the brain change who you are and vice versa 2 Eagleman (2015). Ch. 1  a human brain allows itself to be shaped by the details of life experience more vulnerable + Flexible due to the brain's connections humans are not hardwired as their parents do from birth, we are "live wired" human brain being "unfinished" allowing creatures to move = how does our brain make connections ? Connections made through neural new connections are pruning - synapse strengthens when used synapse is eliminated when not useful  Cognitive-Behavioural Brain Reserve "brain bank" Cognitive-Behavioural Brain Reserve (CBBR): Brain structure and function shaped by environmental experience – Protective reserve against Insult Injury can affect cognition & neural connections Disease Disorder Age-related deterioration risks & disorders a better brain bank can help protect you against Manwell, Tadros, Ciccarelli, & Eikelboom (2022) 3  Cognitive-Behavioural Brain Reserve and head can increase risk & withdrawals sports injuries Higher CBBR – Enriched experiences can lead to more complex patterns and flexibility activities like reading learning skill add to your brain bank or a new can Sensory stimulating environments, attentive caregiving, quality education, interdependent psychosocial relationships, etc…can positively impact cognition, emotion, and behaviour and makes the brain more activities , it neural boosts yourbrain bank" as it strengthens pathways by engaging in Cognitive can adaptable & Flexible Fundamental capacities: “ability to adapt to uncertain, changing, and open- ended environments” (Collins & Koechlin, 2012, p. 1) , it can increase ability to deal / stress brain flexibility & adaptability our if more we give our new connections pruning = neural in circuits strengthened = successfully participates synapse Manwell, Tadros, Ciccarelli, & Eikelboom (2022) 4  Cognitive-Behavioural Brain Reserve Lower CBBR – Stressful or deprived experiences can lead to less complex patterns and rigidity health Fewer resources to maintain resilience O manage w/ stress and good cognitive Abusive or neglectful environments and non-normative stimulation can negatively impact: – attention, inhibitory control, focused concentration, learning, memory, reasoning, and creativity, particularly during critical periods in brain development to develop normally "expected environment" (proper care) struggle then then brain will if the brain develops not in an Increased risk of psychopathology and neurodegenerative conditions Manwell, Tadros, Ciccarelli, & Eikelboom (2022) 5  Cognitive-Behavioural Brain Reserve Accounts for stressful and enriched experiences and their cumulative effects Continuum of sensory-motor and cognitive-emotional stimulation: No stimulation (deprivation) Understimulation little or too mild, moderate, severe (neglect) having either too much stimulation is both equally Adequate stimulation (average, normative) Enriched stimulation as damaging Ex Screen time. Overstimulation (non-normative): mild, moderate, severe (abuse) Exphysical abuse triggers-somaticsensory System - cortisol small brain e.g., effects of proximal separation on nervous system 6 Screen Time and Proximal Separation 7 https://www.youtube.com/watch?v=bOR7jId8wYk https://www.youtube.com/watch?v=bOR7jId8wYk  Sensory Isolation in Development · Studies that René Spitz conducted in the 1940s in Hungary · First to show more systematically that: · Social interactions with other humans are essential for children’s development. · Spitz followed two groups of children from the time they were born until they were several years old. 8 http://thebrain.mcgill.ca/flash/capsules/histoire_bleu06.html  Sensory Isolation in Development First group: Babies raised in orphanage, where they were more or less cut off from human contact in their cribs Or a single nurse had to care for seven children. Second group: Babies were raised in a nursery in a prison where their mothers were incarcerated Mothers allowed to give their babies care and affection every day, and babies were able to see one another and the prison staff throughout the day. more cognitive stimulation = more connections & protection against disease + damage 9 http://thebrain.mcgill.ca/flash/capsules/histoire_bleu06.html  Sensory Isolation in Development Age 4 months: · State of development of the two groups of babies was similar; · Babies in the orphanage even scored a higher average on certain tests. Age 1 year: · Motor and intellectual performance of those reared in the orphanage lagged badly behind those reared in the prison nursery; · Orphanage babies were also less curious, less playful, and more subject to infections. 10 http://thebrain.mcgill.ca/flash/capsules/histoire_bleu06.html  Sensory Isolation in Development Age 2-3 years: · Children raised by mothers in prison walked, talked confidently · Showed development comparable to that of children raised in normal family settings. · Of 26 children reared in the orphanage, only 2 could walk and manage a few words. · Since the time of Spitz’s pioneering study, many other experiments have shown what catastrophic effects sensory and social deprivation at certain critical periods in early childhood can have on children’s subsequent development. 11 http://thebrain.mcgill.ca/flash/capsules/histoire_bleu06.html Emotional Deprivation in Infancy - Dr. Rene Spitz 1952 12 http://www.youtube.com/watch?v=VvdOe10vrs4&feature=related Developmental Effects of Aversive Environments Brain Plasticity Brain constantly changing with experience – Internal events – External events Case of Romanian orphans in 1980s Early environmental effects can profoundly influence brain development Age of adoption is critical Adverse Childhood Experiences (ACEs) Increase risk of addiction, suicide May affect frontal-lobe development, function Generational effects Kolb & Wishaw (2015) Ch. 23 13 Developmental Effects of Aversive Environments Kolb & Wishaw (2015) Ch. 23 14 Developmental Effects of Aversive Environments ACE Pyramid: Centres for Disease Control and Prevention Kolb & Wishaw (2015) Ch. 23 ACE Pyramid: Centres for Disease Control and Prevention 15  The Adolescent Brain the jump From childhood to adolescence , the brain increases Brain qualitatively different from child’s response to rewards pleasure - area is as high as adults but as a child executive decision making is the same and adult’s brain emotions cortex-teens unable to control mature pleasure seeking system t immature Orbitofrontal Rapid synaptic pruning, growth of connections Differences in volumes of gray and white matter Differences in levels of transmitters (DA, GABA) Behavior qualitatively different from children and adults teens are more self-conscious = More risk-taking, impulsivity, novelty- and reward- seeking, less inhibition peer pressure , Vulnerability to drugs of abuse; related to overexpression of DA, 5-HT, CB receptors Vulnerability to onset of mental disorders; related to pubertal hormones, stressful psychosocial factors Kolb & Wishaw (2015) Ch. 23; Paus et al (2008) 16  Transformational Education Focuses on developing active learning skills in students through: – student-centered, problem-based, exploratory, experiential, and collaborative interactions – promoting paradigmatic shifts in thinking for personal and professional growth Activities aim to increase students’ efficacy and mastery in course concepts and to produce positive shifts in students’ learning-related cognitions, emotions, and behaviour Essential in facilitating student learning that can be transferred beyond the classroom for academic, workplace, and community success 18 (Slavich & Zimbardo, 2012)  Active vs. Passive Learning What are differences between active and passive learning? active learning involved within the learning being passive learning learning w/o interaction How are those differences related to the brain? and recalled In terms of how information is processed, retained 19  Human Memory Memory: – learners’ ability to mentally “save” newly acquired information and behaviors Can be a process of saving knowledge or skills Can be a location where the knowledge is held (e.g., working and long-term memory) Storage: – involves putting something into memory Retrieval: – involves finding something in memory 20 Ormrod & Jones (2018) How Does Memory Work? Ormrod & Jones (2018) 21 Meaningful Learning & Memory Retention Meaningful learning that is retained long-term usually involves: Organization Visual imagery Elaboration Ormrod & Jones (2018) 22 Meaningful Learning & Memory Retention Organization: – making connections among new pieces of information Visual imagery: – forming a mental picture of an object or idea Elaboration: – using prior knowledge to embellish on new information Practice: – practice over time leads to automaticity that is quick and efficient Learning strategies: – intentionally using one or more cognitive processes for a learning task Ormrod & Jones (2018) 23  10 Principles of Brain Plasticity 1. Plasticity is common to all nervous systems and the principles are conserved 2. Plasticity can be analyzed at many levels 3. The two general types of plasticity derive from experience 4. Similar behavioral changes can correlate with different plastic changes 5. Experience-dependent changes interact 6. Plasticity is age-dependent 7. Plastic changes are time-dependent 8. Plasticity is related to an experience’s relevance to the animal 9. Plasticity is related to the intensity or frequency of experiences 10. Plasticity can be maladaptive 24 Kolb & Wishaw (1998, 2015)  Applying Principles of Neuroplasticity R Relevant to organism E Experience-expectant: “rough draft”, undifferentiated C Conserved, common L Levels: whole organism, neural circuits cellular/molecular A Age-related I Interacts: Experience-Expectant X Experience-Dependent M Maladaptive vs adaptive (also more rigid or flexible) E Experience-dependent: “fine details”, differentiated D Degrees: intensity, frequency, duration T Time-dependent: exposure parameters 25 Misperceptions about Learning 26  Misperceptions about Learning Illusion of Knowing Preferences ≠ Performance Print vs. Digital Massed vs. Spaced Practice Dunning-Kruger Effect 27  Cognitive Neuroscience History Key questions to consider: – What is cognitive neuroscience? how the brain enables the mind – What historical evidence suggested that the brain’s activities produce the mind? lesions & investigations humans and animals w/ brain on studying patients – What can we learn about the mind and brain from modern research methods? o measuring changes in biological activity.... brain regions activity ofwhite neurons matter grey & 28 Gazzaniga et al. (2019). Ch. 1  Aims of Cognitive Neuroscience Study of how the brain enables the mind – Considers relationship between brain structure and function – Mechanisms underlying affect, behaviour, and cognition (ABCs) – Factors that alter the brain and mind – Focuses on human brain with information from other animals 29 Gazzaniga et al. (2019). Ch. 1  Study of Brain – Mind Connection Historical evidence that brain activity produces the mind – Studying patients with brain lesions changes to structure/function of brain affect/alter activities of the mind – e.g., consciousness, learning, memory, language, etc.. – Scientific investigations with healthy people and animals 30 Gazzaniga et al. (2019). Ch. 1 The Scientific Method Morris (2013) Ch.1  The Scientific Method Experiment: tests one or more falsifiable hypotheses one or more variables are systematically manipulated to observe their effect(s) on an outcome variable Variables: Independent (IV): predictor variable manipulated by experimenter Dependent (DV): outcome variable observed by experimenter changes in value associated with manipulation 32 Morris (2013) Ch.1  The Scientific Method Hypothesis: prediction about the state of the world Null hypothesis: H0 Alternative (experimental) hypothesis: H1 Finding: evidence that disproves or fails to disprove hypothesis (H0) Theory: explanatory framework Empirical theory: set of hypotheses supported by large body of evidence from observations and experiments Non-empirical theory: explanations based on contemplative, rational type of abstract or generalizing thinking  Modern Research Methods We learn about the mind and brain from: – Measuring changes in biological activity of brain regions Changes in electrical impulses Fluctuations in blood flow Shifts in oxygen and glucose levels – Measuring changes in biological activity of neurons Changes in neurotransmitters Changes in electrical potentials – Measuring changes in grey and white matter structures Collections of cell bodies Collections of axons 34 Gazzaniga et al. (2019). Ch. 1  Mind-Body Problem How do physiological processes become transformed into our perceptual experience of the world? – Easy problem of consciousness Neural correlate of consciousness (NCC) How physiological responses correlate with experience – Hard problem of consciousness How do physiological responses cause experience? 35 Goldstein (2010). Sensation and Perception. Chapter 2. Dr. Laurie Manwell Fall 2024 Week 3 1 Copyright © 2024 Laurie A. Manwell  Nervous System Three key questions: What are the organizing principles of the brain? What are the emergent properties arising from the nervous system? How do these principles and properties relate to behaviour? 2 Nervous System Structure & Function 3  The Human Brain Three Divisions of the Brain – Forebrain Cerebral cortex, limbic system, basal ganglia Performs higher functions like thinking, perception, and planning Prenatal development – Brainstem Underlying tube Performs regulatory and movement-producing functions – Spinal Cord Connected to brainstem and descends down the back Conveys sensory info to the brain and sends commands from the brain telling muscles to move 4 Kolb & Wishaw (2015) Ch. 1 Navigating the Human Brain 5 Gazzaniga et al. (2019) Ch. 2 Navigating the Human Brain 6 Kolb & Wishaw (2015) Ch. 1  2 types of tissue Found in the brain & spinal cord White Matter and Grey Matter axons, acts as a communication network between brain and spinal cord white matter-myelinate signals and send out instructions bodies, dendrites and involved in processing information process grey matter = neuron cell unmyelinated axons glial cells , , , Gazzaniga et al. (2019) Ch. 2 15 Ventricles of the Human Brain 8 Gazzaniga et al. (2019) Ch. 2  Central Nervous System Acts as the command-and-control centre of the nervous system Consists of the brain and the spinal cord Has many functions Integration of information Learning and memory Coordination of activity Pinel & Barnes (2018) Ch. 3; Gazzaniga et al. (2019) 13  Telencephalon Characterized by cortex (gyri and sulci) Commissures connect two hemispheres Manages complex cognitive functions Cerebrum – Four Lobes Frontal Temporal Parietal Occipital – Limbic System – Basal Ganglia Landmarks Gazzaniga et al. (2019) Ch. 2 10 Lobes of the Cerebral Hemispheres Pinel & Barnes (2018) Ch. 3 15  Lobes of the Cerebral Hemispheres birth canal, but then 3x in size limited in size when we are born , as we must pass through the grows Our brain is Gazzaniga et al. (2019) Ch. 2 15  Our ability to navigate spatial environments Topographical Memory these maps are a representation of the spatial information , they can shrink or grow depending on their input retintopic visual in put = chemotopic olfactory smell - tonotopic-sound gustotopic-taste which stimulates the topographical map close to the removed limb /organ activating is neurons near by , Limb phantom neurons = Gazzaniga et al. (2019) Ch. 2 15  Limbic System and Basal Ganglia Limbic System – Regulates motivated behaviors – Structures formation , and the of rewards & motivations processing plays a key role in emotional regulation, memory Basal Ganglia – Regulates movement – Structures involved in of interconnected nuclei located at the base of the Forebrain are primarily a group , reward based learning, motor preparation timing, task switching and more gating, , action selection action , 14 Gazzaniga et al. (2019) Ch. 2 Limbic System Limbic system: Amygdala Fear Memory Hippocampus Spatial Memory Cingulate cortex quick decision making Fornix tract connecting nuclei Septum recollective memory Mammillary body memory processing Pinel & Barnes (2018) Ch. 3; Gazzaniga et al. (2019) 43 Basal Ganglia Basal Ganglia: decision makinga reward system Amygdala Dorsal striatum (caudate, putamen, globus pallidus) Ventral striatum (nucleus accumbens, olfactory tubercle) Pinel & Barnes (2018) Ch. 3; Gazzaniga et al. (2019) 44 Diencephalon all sensory systems except olfactory Thalamus Nuclei LGN Vision lateral geniculate nucleus Medial GN hearing Ventral posterior nucleus - Somatosensory Thalamus Sensory relay nuclei Reciprocal connections HPA-Stress Response Hypothalamus Above pituitary gland Endocrine function Motivated behaviors Mammillary Bodies inferior to hypothalamus Optic Chiasm endocrine long distance signaling - Pinel & Barnes (2018) Ch. 3; Gazzaniga et al. (2019) 45 Hypothalamus Main link between nervous system and endocrine system Regulates essential bodily Functions such as.... temperature Hunger Thirst Circadian Rhythms Release of hormones from pituitary gland maintaining homeostasis influences emotional responses Pinel & Barnes (2018) Ch. 3; Gazzaniga et al. (2019) 46 Mesencephalon (midbrain) sensory input and motor output Tectum motor Superior colliculi 2 main nuclei auditory Inferior colliculi Tegmentum Reticular formation Red nucleus Substantia nigra Periaqueductal gray Pinel & Barnes (2018) Ch. 3; Gazzaniga et al. (2019) 47 Myelencephalon/Metencephalon most posterior part of brain Myelencephalon (medulla) I Medulla Reticular formation (Little net) Metencephalon Cerebellum Pons Pinel & Barnes (2018) Ch. 3; Gazzaniga et al. (2019) 48 Divisions of the Nervous System CNS PNS : : Central Nervous System Peripheral NerVOUS System Somatic Autonomic Brain External Environment Internal Environment and motor muscles sensory Spinal Cord and Skeleton afferent-motor efferent motor input output Sympathetic Fight, Parasympathetic rest and Flight digest signals to internal organs 29 Gazzaniga et al. (2019)  Peripheral Nervous System Somatic Autonomic Effects Means by which CNS Regulates organs and (brain and spinal cord) regulatory systems we receive information are not usually and allows us to conscious of for interact with our normal functioning environment Anatomical distributions Organs that we Organs that we normally have normally do not have voluntary control over voluntary control over Cranial nerves, Heart muscles, striated muscle, etc.. intestines, glands, etc.. Location Peripheral Peripheral McKim & Hanock (2013) Ch.35 22  PNS: Autonomic Nervous System Sympathetic Parasympathetic Effects “Fight-or-Flight” “Rest-and-Digest” Arousal and increased Internal functioning activity Anatomical distributions Middle region of spinal Brain and lower levels of cord spinal cord Location Autonomic Autonomic Neurotransmitter Norepinephrine Acetylcholine Morris (2013) Ch.35 23 PNS: Autonomic Nervous System Morris (2013) Ch.35  Components of the Nervous System Parts of a Neuron transmits Nucleus Axon Axon (initial Myelin sheath Postsynaptic hillock segment) neuron transmission of electrical/chemical signal Synapse: The region where an Cell Presynaptic Synaptic Postsynaptic axon terminal Dendrites body axon terminal cleft dendrite communicates with soma its postsynaptic when other neurons make target cell Receives when their axon's output synapse at input make connections on to other neurons a connection dendrites synapses onto their Input Integration Output signal signal Action Potential these differences relate to function weed upsets neurons vary in their form , location , interconnectivity retrograde this balance Neurons: basic units that analyze and transmit information pre post of neurompeculators Around 86+ billion neurons in system anterograde  Stimulation of receptors by natural ligands or psychoactive drugs can activate or inhibit a neuron and can alter affect, behaviour, and cognition 25  Components of the Nervous System Glial cells (Glia) structural support & electrical insulation Provide firmness/structure to the brain Get nutrients into the system Eliminate waste Form myelin Create the blood-brain barrier Communicate with other glia & neurons CNS has 3 types of glial cells : astrocytes, microglial cells oligodendrocytes , astrocytes to the brain's blood vessels cells that surround and are neurons closely connected large glial the blood brain barrier astrocytes create CNS oligodendrocytes Forms myelin in : electrical insulator the axon and acts as an around wrapped enhancing the speed & substance distance myelin Fatty is a reduces current loss and microglial cells small & : irregularly shaped phagocytes , devour and remove damaged cells 26 Hart et al. (2019). Ch. 4  Blood-Brain Barrier (BBB) molecules/hormones to also blocks from entering the brain while allowing small hydrophobic pass through large hydrophilic molecules , most bacteria and prevents the CNS From harmful substances a pathogens in the blood many drugs and neuroactive agents , protecting Blood-Brain Barrier Tightly packed cells Protects the brain from toxic chemicals in the blood. Molecules have to be small and lipophilic to cross the blood brain barrier Active transport for large molecules 27 Gazzaniga et al. (2019) Ch. 2 Blood Brain Barrier (BBB) Silverthorn (2016). Ch. 9 28  The Nervous System Integration of function across many levels of organization – Complex systems have emergent properties Emergent Properties – Cannot be predicted to exist based only on knowledge of system’s individual components – Greater than a simple sum of components – Result from complex, nonlinear interactions of components – Examples: Emotions Reasoning Self-awareness 29 Silverthorn (2016). Ch. 1  Neurons Parts of a Neuron Nucleus Axon Axon (initial Myelin sheath Postsynaptic hillock segment) neuron Synapse: The region where an Cell Presynaptic Synaptic Postsynaptic axon terminal Dendrites body axon terminal cleft dendrite communicates with its postsynaptic target cell Input Integration Output signal signal Analyze and transmit information Over 86+ billion neurons in system  Stimulation of receptors by psychoactive drugs can activate or inhibit a neuron 30 Signals in a Multipolar Neuron graded Potentials : changes in the cell membrane's small charge electrical are based on whether they make the neuron post-synaptic potentials more or less likely to Fire an action potential excitatory post synaptic potential depolarizing change in the PSP, making it more positive , bringing the neuron closer to the threshold needed to initiate an action potential when Nations flow into neuron , creating a depolarization Inhibitory post synaptic potential in the postsynaptic neuron's membrane potential making , a hyper-polarizing change neuron further from the action potential threshold , the away it more negative , moving will Fire the likelihood that a neuron decreasing when Cl enters the neuron a small hyperpolarization makes it less likely for the neuron to reach the threshold to Fire an action potential Copyright © 2018, 2014, 2011 Pearson Education, Inc. All Rights Reserved 4 Pinel & Barnes (2018, 2021) Ch. 4  in the electrical state of neuron neurons receive evaluate and transmit information = neuronal signaling, information moves from in put synapses to output synapses through changes electrical currents within the neuron caused by the Flow of Ionic Basis of Resting Membrane Potential Between neurons , info is transferred across synapses and mediated chemically by neurotransmitters chemical synapses - between neurons travel via transsynaptic electrical currents electrical synapses signals - Resting Membrane Potential voltage difference across the neuronal membrane in the resting state is 70 m inside - Concentrations of Ions – Na+ High Nat outside & low Nat inside = – K+ High K inside & low K outside = + + Diffusion Pressure = concentration gradient ; high to low (Nat/k pump) + Gestabl i s h resting Electrostatic Pressure membrane potential Fions are & son movement attracted to regions with opposite electrical charge I repelled by same charge Nat is pulled into cell by the negative charge & It is Kept inside by the negative charge , encouraged to leave by diffusion electrochemical & concentration gradients Ion Channels = Proteins w/ a pore through the center and they allow certain ions to flow down their Ion Pumps the membrane against their concentration gradients energy to actively transportions = use across Nat/k + pump that pumps Nations Itions into the Sodium-Potassium Pump neurons use = a out of the cell and cell 3 Nations out + 2 K+ ions in 32 Pinel & Barnes (2018, 2021) Ch. 4 Resting Membrane Potential 33 Morris et al. (2015) Resting Membrane Potential https://www.youtube.com/watch?v=nSKLKc6ictI 34 https://www.youtube.com/watch?v=nSKLKc6ictI  Electrical Signals: Ion Movement Resting membrane potential determined primarily by – K+ concentration gradient – Cell’s resting permeability to K+, Na+, and Cl– Gated channels control ion permeability – mechanically gated – chemically gated – voltage-gated Threshold voltage varies from one channel type to another Action potentials are short Graded potentials are variable 35 Silverthorn (2016). Ch. 8  Neurotransmission Action potential a brief electrical signal transmitted along the axon Neurotransmitters are the chemical “messengers” Resting membrane potential is caused by uneven distribution of ions Action potential occurs when sodium ions move across channels Blocking channels prevents action potential disrupts communication between neurons 36 Hart et al. (2019). Ch. 4 Generation of an Action Potential https://www.youtube.com/watch?v=-h_kWFM2faQ https://www.youtube.com/watch?v=-h_kWFM2faQ Action Potential 38 Hart et al. (2019). Ch. 4 Propagation of an Action Potential 39 Silverthorn (2016). Ch. 8  A single channel shown during a Where more than one channel of a phase means that the majority of particular type is shown, the channels are in this state. population is split between the states. Both Na Both channels channels Na channels close and Na channels reset to original position channels closed open. K channels open. while K channels remain open. closed Na Na and K channels K K K Absolute refractory period Relative refractory period During the absolute refractory period, no During the relative refractory period, only a stimulus can trigger another action potential. larger-than-normal stimulus can initiate a new action potential. High 30 Action potential 0 Membrane potential (mV) Na Ion permeability K 55 70 Low High High Excitability Increasing Zero 0 1 2 3 4 40 Time (msec) Action potentials appear to jump from one node of Ranvier to the next. Only the nodes have voltage-gated Na channels. Node Node 1 2 Myelin sheath Node of Ranvier Na Depolarization Demyelinating diseases reduce or block conduction when current leaks out of the previously insulated regions between the nodes. Degenerated myelin sheath Na Current leak reduces conduction. 41  Slide 2 where transmission occurs Synaptic Communication Neurotransmitter Release An action potential depolarizes the axon terminal. Synaptic vesicle Action potential with neurotransmitter arrives at molecules axon terminal. Synaptic cleft Receptor Postsynaptic cell 42 Silverthorn (2016). Ch. 8  Synaptic Communication Neurotransmitter Release An action potential depolarizes the axon terminal. Synaptic vesicle Action potential with neurotransmitter The depolarization opens voltage- arrives at molecules gated Ca2 channels, and Ca2 axon terminal. enters the cell. Ca2 Synaptic cleft Receptor Postsynaptic cell Voltage-gated Ca2 channel 43 Silverthorn (2016). Ch. 8  Synaptic Communication Neurotransmitter Release An action potential depolarizes the axon terminal. Synaptic vesicle Action potential with neurotransmitter The depolarization opens voltage- arrives at molecules gated Ca2 channels, and Ca2 axon terminal. enters the cell. Calcium entry triggers exocytosis of synaptic vesicle contents. Docking protein Ca2 Synaptic cleft Receptor Postsynaptic cell Voltage-gated Ca2 channel 44 Silverthorn (2016). Ch. 8  Synaptic Communication Neurotransmitter Release An action potential depolarizes the axon terminal. Synaptic vesicle Action potential with neurotransmitter The depolarization opens voltage- arrives at molecules gated Ca2 channels, and Ca2 axon terminal. enters the cell. Calcium entry triggers exocytosis of synaptic vesicle contents. Neurotransmitter diffuses across Docking protein Ca2 the synaptic cleft and binds with Synaptic receptors on the postsynaptic cell. cleft Receptor Postsynaptic cell Voltage-gated Ca2 channel 45 Silverthorn (2016). Ch. 8  Synaptic Communication Neurotransmitter Release presynaptic neuron An action potential depolarizes the axon terminal. Synaptic vesicle Action potential with neurotransmitter The depolarization opens voltage- arrives at molecules gated Ca2 channels, and Ca2 axon terminal. enters the cell. Calcium entry triggers exocytosis of synaptic vesicle contents. Neurotransmitter diffuses across Docking protein Ca2 the synaptic cleft and binds with Synaptic receptors on the postsynaptic cell. cleft Neurotransmitter binding initiates a response in the postsynaptic cell. Receptor Postsynaptic cell Voltage-gated Ca2 channel Cell response neuron postsynaptic 46 Silverthorn (2016). Ch. 8  Termination of Neurotransmitter Activity Diffusion = the neurotransmitter can diffuse away from the synapse reducing its concentration in the cleft , Enzymatic breakdown = enzymes in the synaptic cleft break down the neurotransmitter into inactive components Uptake by presynaptic axon terminal transmembrane proteins called active transporters Reuptake- neurotransmitters are actively transported back into the presynaptic terminal by For reuse or degradation Frequency of action potentials: – determines how much neurotransmitter is released 47 Silverthorn (2016). Ch. 8 Termination of Neurotransmitter Activity Copyright © 2018, 2014, 2011 Pearson Education, Inc. All Rights Reserved Pinel & Barnes (2018, 2021) Ch. 4 Seven Steps in Neurotransmitter Action Copyright © 2018, 2014, 2011 Pearson Education, Inc. All Rights Reserved Pinel & Barnes (2018, 2021) Ch. 4 Mechanisms of Drug Action Copyright © 2018, 2014, 2011 Pearson Education, Inc. All Rights Reserved Pinel & Barnes (2018, 2021) Ch. 4  Neurotransmitter Receptors Ionotropic receptors (receptor-channels) – mediate rapid responses – alter ion flow across membranes Metabotropic receptors – G protein–mediated receptors – mediate slower responses – some open or close ion channels 51 Silverthorn (2016). Ch. 8 Ionotropic Receptor 52 Kolb & Wishaw (2015) Ch. 5  Metabotropic Receptor 53 Kolb & Wishaw (2015) Ch. 5  Neurotransmitter Activating Systems Neurotransmission of the Central Nervous System – Cell bodies of ACH, NE, DA, 5-HT within restricted regions of the brainstem – Axons widely distributed in the forebrain, brainstem, spinal cord – Activating Systems Systems of neurons that coordinate wide areas of the brain to act in concert 54 Kolb & Wishaw (2015) Ch. 5 Activating Systems 55 Kolb & Wishaw (2015) Ch. 5 Activating Systems 56 Kolb & Wishaw (2015) Ch. 5 Activating Systems 57 Kolb & Wishaw (2015) Ch. 5 Activating Systems 58 Kolb & Wishaw (2015) Ch. 5 Dr. Laurie Manwell Fall 2024 Week 4 1 Copyright © 2024 Laurie A. Manwell  Methods of Cognitive Neuroscience Three key questions: Why is cognitive neuroscience an interdisciplinary field? How do the various methods differ in terms of their spatial and temporal resolution? How do these differences impact the kinds of insights that can be drawn? 2  Controlling Neural Activity With Light Optogenetics: (Six Steps) type of invasive stimulation method a Research technique that uses light to control the activity of cells, usually neurons, which are transfected with genes expressing light-sensitive ion channels http://www.nature.com/news/2010/100505/pdf/465026a.pdf Doidge (2015). Ch. 4 http://www.nature.com/news/2010/100505/pdf/465026a.pdf 3 Controlling Neural Activity With Light 4 https://www.youtube.com/watch?v=I64X7vHSHOE https://www.youtube.com/watch?v=I64X7vHSHOE  Single Cell Recordings from individual neurons in living measures action potentials animals Animals Humans Extensively used in a variety Occasionally used in treating epilepsy of visual and auditory tasks of the medial temporal lobe (MTL) movement respond to sensory input produce , and adapt through learning the skull of the brain , and changes a thin electrode is inserted through the neur on al membrane are recorded in electrical activity near Gazzaniga et al. (2019) Ch. 3 5  Brain Imaging Techniques Brain Imaging: – Allows rapid correlation (instead of waiting for autopsy) between symptoms and brain – Uses computers to produce 2- and 3- dimensional images of the brain Computed Tomography (CT) Positron Emission Tomography (PET) Magnetic Resonance Imaging (MRI) Diffusion Tensor Imaging (DTI) 6 Gazzaniga et al. (2019); Kolb & Wishaw (2015) Ch. 7  X-Ray Imaging Computerized Tomography (CT scan) – Passes narrow X-ray beams through brain at different angles – Combines images to create a 3-D image of the brain combines 2D images to provide a clear overall structure of the brain – Bone shows white; fluid shows darker – CT scan cannot discriminate between gray and white matter – Ventricles and major fissures can be seen Damaged areas have fewer neurons and more fluid, so show dark 7 Kolb & Wishaw (2015) Ch. 7  Dynamic Brain Imaging Provides a way to look at the brain without using dangerous or unpleasant procedures Can measure changes in blood flow and oxygen in the brain to infer brain activity Produces more sophisticated images: – Positron Emission Tomography (PET) – Magnetic Resonance Imaging (MRI) – Diffusion Tensor Imaging (DTI) 8 Kolb & Wishaw (2015) Ch. 7  Dynamic Imaging Techniques: PET Positron Emission Tomography (PET) – Radioactive substances (e.g., 15O) injected into the blood – More active neurons use more oxygen – As the radioactive substance decays, it gives off photons – Computers detect origin of photons construct image of brain Advantages: of disease highly sensitive-excellent for identifying early signs Functional insight Disadvantages: invasive radiation exposure expensive 9 time-consuming Kolb & Wishaw (2015) Ch. 7 PET Scanner and Image 10 Kolb & Wishaw (2015) Ch. 7 Technique of PET Imaging 11 Kolb & Wishaw (2015) Ch. 7 The Procedure of Subtraction 12  Dynamic Imaging Techniques: MRI preferred method for whole-brain imaging due to its much higher resolution compared to CT Magnetic Resonance Imaging (MRI): magnetic properties of atoms , It protons – Identifies location of moving molecules by detecting the electrical charge generated by their movement which Field CTesla) aligning the protons , radio waves are applied creates a strong magnetic measured signals they release the are temporarily perturb protons' orientation, as protons realign , – Uses high resolution creates images a grey matter between white Superior to CT as it can distinguish – Can use relative concentrations of oxygen and carbon dioxide to determine regional differences in brain activity fMRI: superimposes MRI on brain anatomy Kolb & Wishaw (2015) Ch. 7 13 The Physics of MRI 14 The Physics of MRI 15  Dynamic Imaging Techniques: DTI Diffusion Tensor Imaging (DTI) white matter – MRI method that images fiber pathways by detecting directional movements of water molecules in ventricles density& movement – Movement in nerve fibers tends to follow the longitudinal axis, a property called anisotropy the diffusion properties uses water to detect of boundaries that restrict water movement providing map a , – Can detect degeneration of axons and matter pathways of white distortion of and damage to fibers – Can be combined with MRI, fMRI, ERP 16 Kolb & Wishaw (2015) Ch. 7  Dynamic Brain Imaging: fMRI tracks the movement of molecules by detecting the magnetic properties of deoxygenated hemoglobin Functional Magnetic Resonance Imaging BOLD (blood measures oxygen level dependent) (fMRI) bloodFlow increases active brain in regions Active neurons increase their use of oxygen and increase blood flow to the area Before neural activation, deoxyhemoglobin and oxyhemoglobin are about equal After neural activation, oxyhemoglobin is higher Different relaxation curves for protons in oxygenated and unoxygenated blood provides the means for obtaining a functional image (T2 most sensitive) – Advantages: non-invasive resolution high-spatial entire brain measures activity across the levels blood oxygen activity indirectly by tracking changes in measures brain – Disadvantages: intensive costly & resource noisy environment resolution poor temporal Kolb & Wishaw (2015) Ch. 7 17 Imaging Changes in Brain Activity 18 Kolb & Wishaw (2015) Ch. 7  Comparing Brain-Imaging Techniques X-ray PET MRI and fMRI Quick static snapshot Shows biochemical High resolution status of the brain 19 Kolb & Wishaw (2015) Ch. 7  Toward Multimodal Atlases of the Brain 20 Kolb & Wishaw (2015) Ch. 7  Experience, Perception, and Reality Three key questions: How does experience affect brain development? How does the brain give rise to one’s individual experience of conscious awareness? How does this relate to explanations of reality in Plato’s Allegory of the Cave? 21  Brain Development and Plasticity Kolb & Wishaw (2015) Ch. 23 Nutton et al (2011) The First Five Years. 22 Approaches to Studying Brain Development Correlate nervous system development with the development of specific behaviors Look at behavior and make inferences about brain development Examine factors that influence both brain development and behavioral development Serfaty (2011) Handbook of Behavior, Food and Nutrition. Kolb & Wishaw (2015) Ch. 23 Serfaty (2011) Handbook of Behavior, Food and Nutrition. 23 Stages of Brain Development Pinel & Barnes (2018) Ch. 3 24  Development of the Human Brain Stages Cell birth (neurogenesis; gliogenesis) Cell migration Cell differentiation Cell maturation (dendrite and axon growth) Synaptogenesis (formation of synapses) Cell death and synaptic pruning Myelogenesis (formation of myelin) Developmental Abnormalities Due to deficits in genetic program, trauma, toxins – Anencephaly – Microencephaly – Callosal agenesis – Cerebellar agenesis Kolb & Wishaw (2015) Ch. 23 25 Embryonic Brain Development 15 Copyright © 2018, 2014, 2011 Pearson Education, Inc. All Rights Reserved Gazzaniga et al. (2019) Ch. 2 Embryonic Brain Development Silverthorn (2016). Ch. 9 27 Post-Natal Brain Development 28 Silverthorn (2016). Ch. 9  Imaging Studies of Brain Development Shifting patterns in brain matter: Reduction in gray matter begins (age 6-7) in dorsal parietal and sensorimotor regions and spreads Increase in white matter begins (age 6-7); continues through adolescence Decline in gray matter may continue though age 30 and until age 60 Kolb & Wishaw (2015) Ch. 23 29  Mechanisms of Brain Development Experience-expectant common universal experience = experience Experience-dependent = unique individual 30 Kolb & Wishaw (2015) Ch. 23 Environmental Influences on Brain Organization Brain differences between animals raised in the wild and those raised in the laboratory Effects of complex vs. impoverished environments Old and young brains respond differently to experiences Prenatal experience can influence brain development Gibb (2014) manipulated prenatal and preconceptual experience in rats Effects of Complex Kolb & Wishaw (2015) Ch. 23 Housing on Rats 31  Brain Injury and Plasticity Kennard Principle (e.g., 1942) Functions are spared when injury occurs during infancy Effects of brain injury depend on: Brain region injured Precise developmental stage at injury Age at assessment Type of behavior measured Exposure to gonadal hormones Newborn Babies Who Suffered Stroke Regain Language Function in Opposite Side of Brain Newborn Babies Who Suffered Stroke Regain Language Function in Opposite Side of Brain 32 Kolb & Wishaw (2015) Ch. 23 Michelle Mack: Born with Half a Brain 33 http://www.huffingtonpost.com/2009/10/13/michelle-mack-woman-born_n_318179.html Studying Plasticity After Early Brain Injury Early brain lesions affect behaviors later in life Complete recovery of function if injury occurs during neurogenesis Injury during migration and differentiation is devastating After migration and differentiation the brain can recover Kolb & Wishaw (2015) Ch. 23 34 Early Brain Lesions & Later Life Brain Structure Brain plasticity to support recovery after early injury: Can change the organization of the remaining, intact circuits Can generate new circuitry Can generate neurons and glia to replace at least some lost neurons Kolb & Wishaw (2015) Ch. 23 35 Nervous System Changes During Normal Aging 36 Nervous System Changes During Normal Aging Four main changes occur in the brain during normal aging: – Reduction of brain weight – Loss of grey matter – Decline in the density of dendrites – Slower synaptic speed Loss of dendrites is not only primary aging, but is linked to education: – less cerebral cortex atrophy occurs in those with more education When significant interconnectivity is lost, "computational power" declines 37  Using Light to Heal the Brain Photobiomodulation (PBM): – Use of red or near-infrared light to stimulate, heal, regenerate, and protect tissue that has been either injured, is degenerating, or else at risk of dying – Also known as low level laser/light therapy (LLLT) light measured in nanometers (nm) mu is Mechanisms of action yellow Orange red infrared Mitochondria and cytochrome c oxidase violet Blue Green 708 800 + 400 nm Reactive oxygen species, nitric oxide, blood flow Light sensitive ion channels and calcium Signaling mediators and activation of transcription factors Biphasic dose response and effect of coherence http://www.sciencedirect.com/science/article/pii/S2214647416300381 Doidge (2015). Ch. 4; Hamblin (2016) http://www.sciencedirect.com/science/article/pii/S2214647416300381 38  Photobiomodulation cellular level http://www.sciencedirect.com/science/article/pii/S2214647416300381 Hamblin (2016). BBA Clinical, Volume 6, 2016, 113–124 http://www.sciencedirect.com/science/article/pii/S2214647416300381 39  Photobiomodulation tissue Level http://www.sciencedirect.com/science/article/pii/S2214647416300381 Hamblin (2016). BBA Clinical, Volume 6, 2016, 113–124 http://www.sciencedirect.com/science/article/pii/S2214647416300381 40  Photobiomodulation Fig. 4. tPBM for controlled cortical impact TBI in a mouse model. (A) Mice received a single exposure (810 nm laser, 36 J/cm2 delivered at 50 mW/cm2 over 12 min). (B) Mice received 3 daily exposures starting 4 h post-TBI and were sacrificed after 7 or 28 days. BDNF and neurogenesis (BrdU) were increased at 7 days , while synaptogenesis was increased at 28 days. mice in a closed head Research W/ cortical injury-controlled impact Scale NSS Neurological Severity = http://www.sciencedirect.com/science/article/pii/S2214647416300381 Hamblin (2016). BBA Clinical, Volume 6, 2016, 113–124 http://www.sciencedirect.com/science/article/pii/S2214647416300381 41  Photobiomodulation had the greatest pulsed wave group improvements in aneurological scale Fig. NSS scores after laser treatment. (A) Time course of neurological severity score (NSS) of mice with TBI receiving either control (no laser-treatment), or 810-nm laser (36 J/cm2 delivered at 50 mW/cm2 with a spot size of 0.78 cm2) in either CW, PW 10 Hz or PW 100 Hz modes. Results are expressed as mean ± S.E.M (n = 10). *** P