The Intensity Of Ventral And Dorsal Streams

Following classical conditioning the data show a decrease in variability and in the latency between stimulus presentation and the response. There is also a change in trend from increasing to no trend.

Attention is thought to be selective-focused on one subject at a time. Traditionally, it has been assumed that automatic processing is involuntary, it does not require attention, and is relatively fast; whereas, controlled processing is voluntary, does require attention, and is relatively slow. We can conclude from this that the more we repeat a certain material or tasks the more it becomes automatic and effortless to us.

When you repeat the same task over a long period, your brain constructs specialized neural circuits dedicated to the activity.” (insert page number) In this

The purpose of the study was to measure the effect that the Flicker Paradigm had on visual perception. The Flicker Paradigm causes a distraction while there is a change made in the image. It was designed to test how long the groups took to react to a change in the visual field. The test is meant to show that the disturbance in the visual field made it much more challenging for the viewer to notice any changes that were made in the image. The hypothesis stated that the experimental group, the group using the Flicker Paradigm, would take longer to notice the change in the visual field than the control group, which had no flicker between the altered images. This is because the disturbance in the visual field caused the brain to miss the change that was made to the image because the information was deemed as unimportant. The majority of the perceived changes occurred in the background of the scene, and were considered minor in reference to the whole scene. This was proven true from the data collected, and coincided with previous tests. (Rensink, R. A. 2000). The data in tables 1.1 and 1.3 shows the individual participant data for the test with a flicker for both tests one and two. Tables 1.2 and 1.4 represent the individual results for the tests with no flicker, or the control group. Graphs 1.1 and 1.2 showed the relationship between the time taken to recognize alterations in the images. The data was taken from the average time to recognize the change from all

Abrupt appearance of an object within peripheral visual fields are sudden onset distractors (SOD) and they can have effects on attention and reaction times. Attentional capture occurs when a distractor stimulus appears in a field of vision and pulls focus away from the task at hand. This has the effect of increasing reaction times as it diverts a subject’s attention while the brain registers and processes the new information. When the brain is focussed upon a specific task the distractor captures attention and thus can increase reaction time through this visual processing mechanism. This demonstrates automaticity, a reflex which is both not inhibited by increasing cognitive load (load-insensitivity criterion) and not voluntarily controlled (intentionality criterion). The attentional

Floresco SB, Seamans JK, Phillips AG. Selective roles for hippocampal, prefrontal cortical, and ventral striatal circuits in radial-arm maze tasks with or without a delay. J Neurosci. 1997;17(5):1880-1890.

The primate visual system is usually separated in two partially independent pathways; the dorsal pathway subserves mostly motion perception, while the ventral one subserves object feature recognition. The primary visual cortex (V1) receives most of its retinal input through the lateral geniculate nucleus (LGN). Anatomical and functional segregation of visual perception starts at the level of the retina, where parvocellular (P) ganglion cells have small receptive fields and have sustained colour-sensitive synaptic response to light, whereas magnocellular (M) ganglion cells have larger receptive fields and a faster adapting achromatic response to light [Livingston et al., 1992]. Both types of cells project to the layers 3-6 and 1-2 of the LGN, respectively, which in turn send most of their outputs to layers 4Cβ and 4Cα of V1, forming what is known as the P and M pathways [Refs].

The brain identifies what it sees in a series of steps. The brain makes a feature map of the eye breaking the visual field into sections. Information collected in a particular section of the visual field will always be sent to the

The purpose of this experiment is to examine the functional role the dorsal periaqueductal gray (PAG) plays in initiating fear behavior by associative auditory and context fear conditioning. The dorsal PAG has been previously studied to coordinate defensive behavior via a freezing response. It has been noted that the dPAG relays unconditioned stimulus information to the basolateral amygdalar complex (BLA), which directs learned and innate responses to fear and that the neuronal activity spike rates evoked are modulated by context (Kim et al, 2013). After linking the dPAG’s relationship in fear conditioning, it is hypothesized that if the dPAG is necessary for associative fear conditioning, then after several paired unconditioned and conditioned stimuli trials, neuronal firing should augment in the dPAG. Moreover, in an additional experiment, after considering NMDA’s high associability with glutamate (excitatory neurotransmitter), it is predicted that the infusion of NMDA-R inhibitor within the dPAG will block excitation of the structure and function, which may lead to little to no freezing behavior when presented with the conditioned stimuli.

Vison allows the eyes and brain to get the information needed to make appropriate decision about manipulating objects and hand movements.

The source of the ERN is thought to be located in the anterior cingulate cortex Carter, et al., 1998; Dehaene et al., 1994). In other words, ERN occurs at the moment an individual makes a response (s) he realizes is incorrect. The ERN is assumed to signal other brain regions to inhibit or correct errors in progress, and also to avoid future errors via enhanced control strategies (Gehring, et al., 1993).The ERN as a result provides an index of internal feedback processing. Closely related to the ERN is the feedback-related negativity (FRN). The FRN is a front central negative deflection that occurs 200–300 ms after a negative feedback is presented (Holroyd & Coles, 2002; Talmi, Atkinson, & El-Deredy, 2013). The morphology and topography of the FRN and ERN are highly similar, and they presumably reflect the activity of feedback processing during learning, Wherein the FRN reflects internalization of external feedback, and the ERN reflects an internal feedback loop (Holroyd & Coles, 2002). In line with this, there is evidence from reinforcement learning tasks that, as the magnitude of the ERN increases, the FRN decreases (Holroyd & Coles, 2002; Nieuwenhuis, Yeung, & Ridderinkhof,

1.) Visual Search - In this activity I participated in a classic psychological experiment that uses visual search tasks to explore fundamental process of visual perception and attention. In general I learned that selective attention filters enable us to make more automatic decisions about the stimuli around us, including which items to pay attention to during a visual search. Also, since your brain is always active and sees visual sights and sensory information, your mind copes by automatically screening or filtering incoming sensory information to let in only what is most important. Specifically, I learned that the first set of trials I did were the feature search part of the experience and the second set of trials were the conjunction search part of the experience. What I learned about my self after doing this activity is that I had a quick reaction time on the first set of trials as I was asked to find a blue circle amid orange squares and circles. But, on the second set of trials my reaction time was not as quick as it first was. On the second set of trials, I was asked to find the blue circle amid blue squares and orange circles. I believe my reaction time was quicker on the first set of trials due to the fact that I was just looking for the color blue among orange squares and circles, but on the second set of trials I was looking for a blue circle among blue squares and orange squares. Therefore, the blue squares were distractors from the blue circle and I was forced

Visual processing for humans is split up into two different channels called the dorsal and ventral streams (or pathways). Before information is sent to one stream or the other it must be sent through a series of structures, which begins in the retina. When light enters the eye and hits the photoreceptors (rods and cones) located in the retina, the retinal ganglion cells are activated. The retinal ganglion cells are organized in the retina and then are sent to the optic nerve, which is located at the back of the eye. The optic nerve transports the signals from the retinal ganglion cells to the lateral geniculate nucleus (also abbreviated as the LGN). The thalamus is the structure that houses the lateral geniculate nucleus. The primary function

Figure 3 consists of five main parts including the SR, encoding, STM, WM, and LTM. In the following, each of them is briefly described. SR retains a quite accurate and the whole of the information, such as visual, auditory, tactile, taste, and olfactory, that is sensed and attended to. It is characterized by being outside of conscious control and occurs automatically. These steps include extracting and identifying the features of a stimulus after the initial reception of information regarding the stimulus. Here, thalamus is acted as a distributor of information, and all sensory information except the olfactory is passed through this part. In this level, attention

contrast, view perception as a direct process not relying upon memory). For example, within this stage a person might assemble a series of changing visual features