Presentation on theme: "The Brain Justin Hodge Aidan Zebertavage. The Brain: Basic Structure Weighs on average about 3 lb., size of 1130 cm 3 in women and 1260 cm 3 in men. The."— Presentation transcript:
The Brain Justin Hodge Aidan Zebertavage
The Brain: Basic Structure Weighs on average about 3 lb., size of 1130 cm 3 in women and 1260 cm 3 in men. The live cortex, often referred to as “Grey Matter” is actually a pinkish-beige (exterior) and slightly off white (interior).
The Brain: Basic Structure Cont. The cerebral hemispheres are the largest part of the brain and sit above most other structures. Covered with a cortical layer with a convoluted topography Cortical Layer- Outmost layer of any organ Brain Cortical Layer: Cerebral Cortex, thin gray surface layer of the cerebrum consisting of an outer molecular layer or stratum molecular, a single layer of Purkinje cells, and an inner granular layer or stratum granulosum.
The Brain: Brainstem Underneath the cerebrum is the brainstem, resembling a stalk on which the cerebellum is attached. Brainstem: Adjoins and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervations to the face and neck via the cranial nerves.
The Brain: Cerebellum Cerebellum: Horizontally furrowed surface region of the brain which plays an important role in motor control. Does not initiate movement, rather it contributes to coordination, precision and accurate timing. Receives input from the sensory systems and from other parts of the brain and integrates these inputs into to fine tune motor activity.
The Brain: Cerebral Cortex The dominant feature of the human brain is corticalization. The cerebral cortex in humans is so large that it overshadows every other part of the brain. The cerebral cortex is nearly symmetric in outward form, with left and right hemispheres. Anatomists conventionally divide each hemisphere into four "lobes", the frontal lobe, parietal lobe, temporal lobe, and occipital lobe.
The Brain: Frontal Lobe Frontal Lobe: The frontal lobe contains most of the dopamine- sensitive neurons in the cerebral cortex. The dopamine system is associated with reward, attention, long-term memory, planning, and drive. Dopamine tends to limit and select sensory information arriving from the thalamus to the fore- brain. A report from the National Institute of Mental Health says a gene variant that reduces dopamine activity in the prefrontal cortex is related to poorer performance and inefficient functioning of that brain region during working memory tasks, and to slightly increased risk for schizophrenia.
The Brain: Parietal Lobe Parietal Lobe The parietal lobe integrates sensory informatio n from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the dorsal stream of the visual system. This enables regions of the parietal cortex to map objects perceived visually into body coordinate positions.
The Brain: Temporal Lobe Temporal Lobe: The temporal lobe is involved in auditory processing and is home to the primary auditory cortex. It is also important for the processing of semantics in both speech and vision. The temporal lobe contains the hippocampus and plays a key role in the formation of long-term memory.
The Brain: Occipital Lobe Occipital Lobe: The occipital lobe is the visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex.
The Brain: Hypothalamus and Pituitary Gland Control visceral functions, body temperature and behavioral responses such as feeding, drinking, sexual response, aggression and pleasure.
The Brain: Surface Area vs. Volume The cerebral cortex is a sheet of neural tissue, folded in a way that allows a large surface area to fit within the confines of the skull. Each hemisphere has a total surface area of about 1.3 sq ft. Cortical folds = Sulcus Smooth Area Between folds = Gyrus Deep folding fearturs in the brain such as the inter-hemispheric and lateral fissure, and the insular cortex are present in most normal subject.
The Brain: Lateralization Each hemisphere of the brain interacts primarily with one half of the body. For reasons still unclear the connections are crossed. The right side of the brain controls the left side of the body and vice versa. Motor connections from the brain to the spinal cord and spinal cord to the brain cross at the midline at the brainstem level. Visual input more complex, however, the right side of the brain receives somatosensory input from the left side of the body, and visual input from the left side of the visual spectrum, thus increasing visuomotor coordination.
The Brain: Corpus Callosum Large nerve bundle known as the corpus callosum connects the two cerebral hemispheres. Main avenue of communication between the two hemispheres. Each point on the cortex is connected to the mirror-image point in the opposite hemisphere.
Deep Brain Stimulation (DBS) Surgical Treatment that uses a brain pace maker, which is implanted into brain. Device sends electrical impulses to specific parts of brain Electrical signals used to change brain activity in a controlled manner Effects are reversible
Deep Brain Stimulation Cont. Used to help treat many problems Chronic Pain Parkinson's disease (Progressive disorder that affects nerve cells in part of the brain that controls muscle movement) Tremor (Neurological disorder that causes shakes when person attempts to move) Dystonia (Involuntary muscle contractions cause twisting and repetitive movements)
How It works Thin wire attached to pulse maker is implanted to affected part of brain Stereo tactic head frame or MRI is used to pinpoint the problem area Patient kept awake during procedure Allows leads to be placed for maximum effectiveness with little side effects Can be done on one or both sides of the brain
How It Works Cont. Some side effects seen are Tingling sensation in limbs Minor paralysis Poor balance Slurred speech Most symptoms are reversible May take a few weeks until patient is healed and comfortable
How It Works Cont. Procedure is very expensive Sophisticated technology used Cost of procedure Hospitalization costs
Pro vs Con Pro No destruction of brain Electric signal can be changed Safe procedure Can be turned off at any time Con Risk of infection Interference with other appliances/devices Surgery may be needed if problems occur with device
Parkinson's Disease Many times both sides of brain need to be stimulated Thalamus stimulation not recommended Only can rid of tremor and rigidity Subthalamic nucleus or globus pallidus Eventually develop other symptoms that can be treated this way
Brain Computer Interface Other Names – Direct Neural Interface – Brain-Machine Interface Allows for direct communication between brain and external device Used for augmenting and assisting with sensory and cognitive motor functions
Brain Computer Interface Cont. Used to capture brain signals – Can be translated into commands that could control computers, communication devices, and rehabilitation technology Brain is filled with neurons – Electric signals are transmitted between these during work – Some signals escape myelin barrier These are the signals measured and interpenetrated
Methods Implanted Electrode Magnetic Resonance Imaging Electroencephalograp h (EEG) – External Electrodes
Use of Output BCI Control Device by Thought Helping Quadriplegics with tasks – Remote control – Computer mouse Bypass Damaged Muscle Amputees – Help Control Prosthetic limbs
Use of Input BCI Cochlear Implant – Most common – Oldest Working on artificial eye – Concept stays the same
Current/Future ndP8 ndP8 Paraplegics/Amputees able to control either robotic or assisted limbs to help walk Help blind people see with out eyes Help people control devices with thought Help voice impaired people communicate with words/”voice”
Brain-Computer Interfaces Based on Visual Evoked Potentials Feasibility of Practical System Designs
Overview EEG Based BCI’s are quickly becoming bases for neural engineering, rehabilitation and brain science. Journal article reviews BCI systems based on visual evoked potentials (VEP). Focus on finding ways to efficiently implement BCI systems. Steady State VEP’s can provide the most useful information regarding brain activity using the least number of electrodes, while at the same time decreasing cost and increasing usability.
Visual Evoked Potentials VEP’s reflect the visual information processing mechanism in the brain. Transient VEP (TVEP) corresond to a low stimulus rate, and those with a high stimulus rate are known as steady state VEP (SSVEP) SSVEP detection is performed by frequency analysis. SSVEP essentially puts the brain into a steady state of excitability.
Findings SSVEP provide the most consistent results. Visual stimulator devices contribute towards the outcome of each study. Fewer electrodes can reduce cost and accessibility for the BCI. Progress still needs to be made for a completely accessible BCI to be realized.