Physiology and behavior Localization of Brain Function Learning

Physiology and behavior: Localization of Brain Function Learning Objectives • Discuss the use of brain imaging technologies in investigating the relationship between biological factors and behavior (SAQ) • Explain how one study related to localization of function in the brain (SAQ) • Examine one interaction between cognition and physiology in terms of behavior. (ICE) • Evaluate two relevant studies (ICE) • Discuss two effects of the environment on physiological processes. (SAQ)

Part 1: Brain Imaging What you need to know about brain imaging? 1. 2. 3. 4. What they are used for? Strengths Limitations Research examples that use technology to demonstrate your point (support the study of brain localization)

Early investigations… • Phrenology – 18 th-19 th century • Assumptions – Good certain parts of the brain related to personality and behavior – No so good you can tell by the bumps and depressions on the brain

Case studies & Naturally Occurring Brain Damage • Until the late 20 th century, most brain research was limited to case studies – Not experimental • No clear cause and effect – Unethical to ask for volunteers • Two research examples: – Broca & Wernicke • Participants developed aphasia

Broca & Wernicke • Method: Case Study • AIM: to study the brain (post-mortem) to connect the language disorder with a specific region in the brain • Procedure: – Step 1: study behavior before death – Step 2: autopsy the brain and pin point a specific region associated with the behavior • Implications: – Broca’s Aphasia: unable to produce language – Wernicke’s Aphasia: unable to comprehend speech

Modern Technology • What do you need to know? – What do we use the scan for? – Strengths/limitations – Research support • • • Electroencephalograph (EEG) Computed Tomography (CT) Magnetic Resonance imaging (MRI) Functional MRI (f. MRI) Positron Emission Tomography (PET)

EEG • What do we use the scan for? – Best known for sleep research • Brain waves change during sleep • Strengths/limitations – Strengths: clearly distinct patterns for brain waves – Limitations: not accurate enough for most localization of function research • Why? Electrodes outside the brain • Research support – Connolly 2000

Connolly 2000 • • Method: Case Study AIM: to determine the extent of cognitive loss Procedure: use EEG to measure awareness Results: individual actually had awareness and extensive rehabilitation enhanced his recovery • Implications: awareness changes brain activity

REM: Dreams

CT • What do we use the scan for? – Allows us to see soft tissue of the brain • Structure changes to do to damage or tumor • Strengths/limitations – Strengths: Great at see structural changes • Brain tumor/damage – Limitations: does not show brain activity • Research support – Ogden (2005)

Stroke

Ogden (2005) • Method: Case Study • AIM: study the impact of a brain tumor on hemineglect – Hemineglect: brain damage causes inattention to the opposite side of space • Procedure – Neurological assessments: • Scan the brain (CT) • Draw pictures, read • Implications – Patients are aware of the neglect (jokes, justifications) but a willing neglect by half the brain Tumor

MRI • What do we use the scan for? – Damage to really specific parts • Strengths/limitations – Strengths: three dimensional pictures • Allows us to see more structure – Limitations: • Safety (metal? ) but it is limited on x-ray radiation • Does not show activity

f. MRI • What do we use the scan for? – Shows brain activity in specific area – Used for a wide-range of behavior • Strengths/limitations – Strengths • Studies the brain as activity occurs • Wide range of behaviors – Limitations: correlational • not a natural environment (ecological validity) • Colors may exaggerate activities • Changes may occur for many reasons • Research support – Brefcynski-Lewis etal (2007)

Brefcynski-Lewis etal (2007) • Method: Experiment • AIM: study examine differences in brain activity resulting from meditation over a long period • Procedure – 10, 000 -54, 000 hours of meditation (Asian) – Newly trained (Caucasian) – * used f. MRI to measure attention during meditation by distracting individuals with background noise • Results – Experienced adjusted concentration (active resistance to not being disturbed • Implications: Meditation changes the brain (plasticity)

Evaluation of Brefcynski-Lewis etal (2007) • Is this a true experiment? • How else could you describe the study? • Are the conclusions valid? • Reference page 46 -47

PET • What do we use the scan for? – Abnormalities in activity level • Alzheimer’s • Strengths/limitations – Strengths: activity – Limitations: limited on specific region • Use tomography • Health problems limit availability

The Brain and Behavior **Warning…intense picture

Neurons • What do they do? – Networks produce intelligence and consciousness • Single neuron is not very smart • Neurons link together to send messages – Necessary for even a small thought • No TWO neurons are exact

Neurons • Neurons are composed of: – Cell body (soma): directs actions of the cell – Dendrites: extensions that receive information – Axon: extends from cell body, carries electrical potential, sends a chemical message to adjacent neurons via terminal buttons

Myelinated Axons

Brain Function and Ethics • Non-Invasive – Researcher does not invade the body to conduct research • Brain Scans • Experiments • Invasive – Researcher invades the body to conduct research • Brain Surgery, Autopsy • Ablation, deep lesioning

• Invasive: – Lesioned hypothalamus – Results doubled weight • Ethics: damage cannot be reversed & does it cause pain? Animals and invasive research

Video: Gazzaniga • • http: //www. youtube. com/watch? v=82 tl. Vcq 6 E 7 A TWO Researches Method AIM/Hypothesis Procedure Results Implications (how does this relate to localization of brain function) – Note…its not the hemispheres

Case Study of HM • Why is it important? – Showed us that there are different memory systems in the brain. • Original study Milner (1957) – Age 7 head injury from falling – 20 years of seizures increasingly incapacitated – Age 27 removed brain parts to stop seizures • Behavior impact: – Could not create NEW memory (Amnesia) » Semantic: factual memory » Episodic: personal memory » Personality was unchanged

Limbic System

• Corkin et al (1997) – MRI Scan – Parts missing • Pieces of temporal lobe (hearing and language) • Limbic System – Hippocampus (memory) – Amygdala (emotion and fear) – Damage wasn’t as severe as Milner thought

What did we learn about localization? • Hippocampus – Important for converting memories from short term to long term storage – temporary vs permanent storage • retained memory before surgery – He could learn a few procedural memories • Not stored by the hippocampus • Specific memory loss specific brain region – The brain has several memory stores • Memory is more complex than originally believed

Evaluation of HM Case Study • Operation was based on the assumption that the seizures would stop – Damage already done • Longitudinal – 50 years of a wide range of tests • Cognitive, observations, neuroimaging

• Ethics – Is it unethical if he cannot remember all the times he participated in research? • Justification: findings are very important • Limitations – Case Study • Findings from one research do not represent the whole population • But…Supported by years of follow-up research

Mozart Effect Rauscher at al. 1993 • Hypothesis: listening to Mozart will temporarily increase spatial reasoning ability – Why? Complex musical productions excite neurons needed to solve complex spatial tasks

Thompson et al. 2001 • Experiment • Hypothesis: when people do something they enjoy (elevated mood), they have improved spatial skills • Results: Increase in spatial skills • Implications: improvement is not based on plasticity but on increased attention • Limitation: Ecological validity

Using the Amnesia reading…answer the following questions? 1. What is the difference between anterograde and retrograde amnesia? 2. What is the difference between declarative and nondeclarative memories? – Connect to HM 3. What specific brain locations are associated with anterograde amnesia? 4. Break down ONE research discussed in reading – Who, when, method, aim, results, implications

How does the environment impact the brain? Topics • Brain Plasticity • Psychological trauma & PTSD SAQ: • Discuss two effects of the environment on physiological processes

Assumption • Brain changes behavior, behavior changes the brain – especially cerebral cortex • Higher functioning • Brain plasticity – Changes that occur as a result of learning or experience – Rearranging the connections between neurons – Adaptation to the environment

Dendritic Branching • Learn something new change in neuron connection – Dendritic branching • Example: – Musician has a thicker area of the cortex related to music • Research support: – Rosenzweig, 1972 – Limitation: unknown impact on behavior • Assumed because of an increased neuron density

Rosenzweig & Human Behavior • Psychologists cannot carry out controlled experiments to test humans • Humans differ – Genetic make-up – Environmental inputs • Importance of education in the growth of new neuron connections (synapse) • Brefcynski-Lewis et al, 2007 – Meditating monks

Environment, Brain Function and Behavior Neurology/physiology of PTSD

Environment and the Brain • Meditating monks different levels of brain functioning • MA Case Study Different areas of the brain can take over language • Taxi drivers use hippocampus to store more visual memory • Limitations and strengths – How clearly can we use cause and effect? – How clearly do we understand the interaction between cognition and physiology?

What is PTSD? • Mental Disorder: Post-Traumatic Stress Disorder • Behaviors – traumatic memories that seem different from other kinds of memories. • continue for many decades • easily triggered – Memory in PTSD patients is also characterized by impairment • not being able to remember aspects of the trauma • fragmentation of memories • dysfunction in the amygdala and hippocampus – which are important structures in the "emotional memory system" of the brain.

Physiology of PTSD • Decrease in the size of the hippocampus – Connects and organizes memories – Stanford University (2009) • children with PTSD • Used (MRI) • Researchers found that children with PTSD symptoms also tended to have a poorly functioning hippocampus. – Yale University (1995) • Vietnam Veterans with memory problems • 8 percent reduction in the size of the right hippocampus, while other portions of the brain retained their size. • Over reactive amygdala

Rauch et al. , 1998 • Method: Case Study • Hypothesis: Amygdala and Hippocampus are impacted by PTSD • Procedure: PET and MRI studies • Results – Veterans with PTSD demonstrate increased right amygdala activity when exposed to combat movies. – Both male combat veterans and women survivors of childhood sexual abuse with PTSD have lower hippocampal volumes. • Implications – Decreased volume of the hippocampus correlated with trauma exposure or memory deficits.

• How do we know PTSD caused a shrinking of the hippocampus? – Prolonged exposure to trauma shrinks the hippocampus • OR • A smaller hippocampus makes you more vulnerable to PTSD?

Harvard Medical School, 2002 • Case Study • AIM: relationship between hippocampi and PTSD • Procedure – MRI bran imaging – pairs of identical twins • one twin served in Vietnam and the other did not. • Results: – The veterans with PTSD did in fact have smaller hippocampi than the veterans who did not. – Brothers of the veterans with PTSD also had smaller than average hippocampi. • Implications – Smaller than average hippocampus is not the result of PTSD, but a risk factor for developing it.

• Video: PTSD in current military veterans • Quiz Wednesday: Behavior and physiology (localization of Brain Function) – – Brian imaging Localization of brain parts Basic neuron parts Physiology and behavior (types of memory) of amnesia – Environment and brain changes: Plasticity and PTSD