The Neural Basis of Cognition PDF

The Neural Basis of Cognition Understand how we link the brain to cognition Ch 2 JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 1 The Study of the Bra...

The Neural Basis of Cognition Understand how we link the brain to cognition Ch 2 JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 1 The Study of the Brain JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 2 Brain organization Structural organization Functional organization The brain has physically Different brain regions do distinct structures different things JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 4 Structural organization Hindbrain Top of the spinal cord (i.e., brain stem) Key life functions Includes: Cerebellum: largest region of the hindbrain Pons Medulla JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 5 Structural organization Midbrain functions include Coordinating precise eye movement Relaying auditory information from ears to forebrain Regulating pain experiences JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 6  Structural organization Forebrain Includes: Cortex: Top outer surface of the forebrain Four lobes: Occipital lobe, Temporal lobe, Frontal lobe, Parietal lobe Subcortical structures Divided into two cerebral hemispheres by the longitudinal fissure JABBARI-PSYCH 2H03 HASHEMI – PSYCH 2H03 7 Structural organization Forebrain’s subcortical parts: Thalamus: sensory relay station Hypothalamus: controls behaviors that serve specific biological needs (e.g., eating) Amygdala: emotional processing Hippocampus: learning and memory Limbic system JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 8 Structural organization Left hemispheres Right hemispheres Hemispheres are connected via several commissures, including the corpus callosum Split-brain patients -> corpus callosum removed JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 9 Motor Areas Primary motor projection areas: departure points in the motor cortex for signals that control muscle movement Primary sensory projection areas: arrival points in the motor cortex for signals from the sensory Contralateral control More cortical coverage reflects greater motor precision. JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 Sensory Areas Somatosensory area: skin sensations Primary auditory cortex: auditory sensations Primary visual cortex: visual sensations Contralateral organization Cortical space assigned based on acuity JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 Understanding cognition requires a basic understanding of the brain Capgras syndrome: Patients can recognize loved ones, but patients think that they are impostors. Reason: Normal facial recognition involves two systems: 1. Cognitive appraisal 2. Emotional appraisal In Capgras, Emotional appraisal is absent/dysfunctional Linked with amygdala & prefrontal cortex damage JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 12 What do we learn from Capgras syndrome? Capgras syndrome has been linked to abnormalities in the amygdala and prefrontal cortex Prefrontal cortex damage impairs analytical reasoning. Amygdala damage linked to lack of emotional response to seeing familiar people We can use Capgras syndrome to: understand that the amygdala plays a crucial role in supporting the feeling of familiarity. Recognize that "emotional evaluator" works in a fashion separate from the evaluation of factual information. Know different parts of the brain perform different jobs. JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 13 Studying the Brain JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 14 Studying the brain Cognitive neuroscience relies on a variety of methods to study the brain and nervous system. Neuropsychology Neuroimaging Electrical recordings Manipulation of brain function JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 15 Studying the brain: Neuroimaging Structural neuroimaging techniques Computerized axial tomography (CT) scans Magnetic resonance imaging (MRI) scans Vemuri, P., Jack, C.R. Role of structural MRI in Alzheimer's disease. Alz Res Therapy 2, 23 (2010). https://doi.org/10.1186/alzrt47 JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 16 Studying the brain: Neuroimaging Functional neuroimaging techniques Positron emission tomography (PET) scans Functional magnetic resonance imaging (fMRI) scans JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 17 Studying the brain: Electrical recordings Electroencephalogram (EEG) Recording of the electrical communication within neurons Used to study: Broad rhythms (e.g., sleep stages) Event-related potentials (ERPs) JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 18 Studying the brain: Electrical recordings Communication between neurons is chemical. Neurons communicate with one another via neurotransmitters. Communication within a neuron is electrical. "Input" end of a neuron receives neurotransmitters; "output" end releases neurotransmitters. An electrical impulse conveys the signal from the input end to the output end. JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 19 Comparing techniques Every method has strengths and weaknesses. EEG Strength: Excellent for determining the timing of neural activity Weakness: Poor at determining the exact location of the activity fMRI scans Strength: locate the brain activity precisely (within a millimeter or two) Weakness: less precise about when the brain activity took place MRI scans Strength: : detect shape and size of brain structures Weakness: tell nothing about the activity levels within these structures Researchers can overcome limitations by combining techniques. JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 20 The Power of Combining Techniques Problem: Most neuroimaging techniques used to study brain activity and structures provide only correlational data. Causal Data Brain lesions Transcranial magnetic stimulation (TMS) Magnetic pulses activate neurons Produces temporary lesions JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 Manipulation of brain function (TMS) Temporarily disrupt brain activity using focal magnetic pulses targeted over different areas of the scalp We can use TMS to find cause JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 22 Next So far, Week 1, Ch 1 and Ch 2 Next week: Chapter 3, 4, and 5 (Perception, Attention, and Recognition) JABBARI-PSYCH HASHEMI – PSYCH2H03 2H03 23