up: [[HD 2230 Introduction to Behavioral Neuroscience]] Tags: # Major Areas and Functions of the Brain [[Brain function is localized]] so it's important to understand what each areas of the brain are responsible for what function. #### Major Regional Functions of the Brain The three major divisions of the brain are the forebrain, midbrain, and hindbrain. You can differentiate the positions between them using [[Neuroanatomy position names#^ab251e|anatomy position names]]. ![[Pasted image 20220915181416.png]] ### Meningeal Layer The three meningeal layers, from outer to inner, are: the ==dura mater== (meaning “tough mother”), the ==arachnoid layer== (meaning “spiderweb-like”) and the ==pia mater== (meaning &ldquotender mother”). Of these, it is the ==arachnoid layer== filled with cerebrospinal fluid (CSF). CSF is produced by a highly vascular tissue named the choroid plexus, which is found in the ==ventricular== system of the brain. ![[Pasted image 20220829091109.png]] ### Corpus Callosum The brain is split into the right and left hemispheres which are combined by the Corpus Callosum. The corpus callosum is made up of huge bundles of myelinated nerve fibers permitting communication between the right and left side of the brain. Because it's made of fat it appears white as fat is white. Unfortunately, the belief that the right brain corresponds to creativity and the left brain corresponds to analytical thought is not true. They do perform slightly different functions but it's not drastic. ##### What are the responsibilities of the front and back half of the brain? In general the front half of the brain is responsible for motor control, intention, decision making, and conscious thought. The back half of the brain is responsible for sensation and processing. ![[Pasted image 20220824103719.png]] ## The Four Lobes of the Brain The brain is made up of four lobes each made up of different areas. Each of these lobes have different responsibilities in the brain. The four lobes: ![[Pasted image 20221012103359.png|700]] The four lobes and their areas: ![[Pasted image 20221019084634.png]] ##### Frontal Lobe The ==frontal lobe== is largely responsible for motor control, decision making, attention, and conscious thought. At it's back is the primary motor cortex which deals with the execution of movements. Lateral to the primary motor cortex is the premotor cortex which deals with the selection of which movements to undergo. Medial to the premotor cortex is the supplemental motor area which deals with more planned routine movements. At it's front is the prefrontal cortex which deals with complex decision making, thought, and personality behavior. This is why it's said to be responsible for executive function. ![[Pasted image 20221129074403.png]] One theory postulates that the posterior PFC is more specific than anterior. It begins with direct sensory control and motor monitoring at the posterior and orients more to abstract thinking and long term planning in the anterior of the brain. ##### Temporal Lobe The ==temporal lobe== is largely responsible for interpreting sound and language (see: [[Hearing sensation and perception]]) as well as determining what object, color, or face you are looking at because it includes regions of the ventral stream. ##### Parietal Lobe The ==parietal lobe== is largely responsible for reception and correlation of sensory information like pain, temperature, and touch across the body from the [[Somatosensory cortex]]. It's also responsible for the sensation and perception of where and how movements from stimuli coming into the body from the dorsal stream. ^98e840 The parietal cortex is largely responsible for understanding spatial relations and the associations between objects, places, and actions in the present moment as well as encoding memories for these things. ##### Occipital Lobe The ==occipital lobe== is largely responsible for the processing of ==visual information.== (see: [[Visual sensation and perception]]). It contains a portion of the ventral stream (other portion in temporal lobe) which is responsible for the identification of color, objects, and faces. ## The Cortex The cerebral cortex covers the outer surface of the brain and about a centimeter thick. It is squished together so that more axon lengths can fit in. The cortex itself is comprised of 6 layers each of which have different roles in [[Neuron signaling]]. Brodman is famous for mapping all 52 areas of the cortex and looking at the differences in the 6 layers between each. ![[Pasted image 20220826103754.png]] ###### What areas of the cortex do what functions? Layer five is responsible for sending information outside of the cortex of the brain. Layer 4 is responsible for information coming into the brain. ###### How do the six cortex layers differ between parts of the brain? The parts of the brain more involved in motor control have a thick layer five because layer five is responsible for sending information outside of the cortex where as parts of the brain more involved in sensory perception and processing have a thick layer four of the cortex. Layers 2 and three are involved more in local communication. # Fore Brain ## The Limbic System The limbic system is a combination of different parts of the brain located more towards the bottom of the brain in the temporal lobe. It is comprised of the hippocampus, amygdala, hypothalamus, and thalamus. The amygdala and hippocampus are technically part of the cortex. ![[Pasted image 20221129075507.png]] ##### What are it's main roles? It's main roles have to do with memory, emotion, and learning. #### Thalamus The thalamus is the main information relay station. Most sensory and motor information (except smell) comes to it before being sent to the cerebral cortex for interpretation. This is the system of [[Sensory informational flow]]. #### Hypothalamus The hypothalamus is the master regulator of the brain. It's largely responsible for keeping our body in homeostasis by receiving information about temperature, food, and water, and sending signals to other parts of the brain. The [[Hypothalamus]] communicates with the [[Hormones and Behavior#Anterior Pituitary|anterior pituitary ]]with releasing hormone. #### Basal Ganglia A group of structures made up of grey matter and linked to the thalamus in the base of the brain involved modulation of other motor control systems in the brain. ![[Pasted image 20221129075715.png]] #### Hippocampus The [[Hippocampus]] is the central site at which new neurons are produced and new memories are formed specifically pertaining to episodic memory. It is also integral in spatial navigation meaning a damaged hippocampus leads to problems in movement. ### Amygdala and anterior cingulate The amygdala and anterior cingulate directly inhibit each other. They both are highly effected by our memories incorporating emotional information. Our amygdala is responsible for our automatic emotional based reactions ([[Protopassion]]s) and our anterior cingulate is responsible for our intentional emotional responses. ![[Pasted image 20221107105542.png]] #### Amygdala The amygdala is largely responsible for our fight or flight response. It applies more automatic responses to strong emotional situations. ###### What does damaging the amygdala do? Damaging the amygdala results in decreased fear and even wipes out prior fear learning. #### Anterior cingulate It applies intention to emotional situations. It becomes active not only when you feel pain but from the pain of others. ![[Pasted image 20221109104015.png]] #### Olfactory Bulb The olfactory bulb contains all of our glomeruli which receive signals from our olfactory receptors. The pattern of glomeruli that are stimulated by these receptors are how we sense a certain smell. (see: [[Smell sensation and perception]]). # Midbrain #### The Pineal Gland The pineal gland is largely responsible for releasing the indoleamine transmitter [[Melatonin]]. #### The Substantia Nigra The substantia nigra is the main source of neurons containing the neurotransmitter ==[[Dopamine]].== ![[Pasted image 20220829091332.png]] ### The Blood Brain Barrier The blood brain barrier is a network of blood vessels and capillaries that are made up of closely spaced endothelial cells. This property prevents large molecules from diffusing out of the bloodstream and into the brain. ![[Pasted image 20220829085307.png]] # Hindbrain ### Cerebellum Helps control the planning and regulation of movement and balance. It can also cause motor inhibition. ![[Pasted image 20220922100537.png]] Related: [[Brains and Neurons]] [[Neuroanatomy position names]] [[Hormones and Behavior]]