Behavioural brain research
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Impairment of cognitive abilities is a frequent and significant sequelae of traumatic brain injury (TBI). The purpose of this experiment was to examine the generality of the cognitive deficits observed after TBI. The performance of three tasks was evaluated. ⋯ On days 11-15 following injury, injured (n = 9) and sham-injured (n = 8) rats were trained on a constant-start version of the Morris water maze that has the animals begin the maze from a fixed start position on each trial. Additional injured (n = 8) and sham-injured (n = 8) animals were trained on days 11-15 after injury on the standard (i.e. using variable start positions) version of the Morris water maze. The results of this experiment revealed that performance of the passive avoidance and the constant-start version of the Morris water maze were not impaired by fluid percussion TBI.(ABSTRACT TRUNCATED AT 250 WORDS)
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The neural mechanisms of emotion and memory have long been thought to reside side by side, if not in overlapping structures, of the limbic system. However, the limbic system concept is no longer acceptable as an account of the neural basis of memory or emotion and is being replaced with specific circuit accounts of specific emotional and memory processes. Emotional memory, a special category of memory involving the implicit (probably unconscious) learning and storage of information about the emotional significance of events, is modeled in rodent experiments using aversive classical conditioning techniques. ⋯ The thalamo-amygdala pathway also exhibits long-term potentiation, a form of synaptic plasticity that might underlie the emotional learning functions of the circuit. The thalamo-amygdala pathway contains and uses the amino acid glutamate in synaptic transmission, suggesting the possibility that an amino-acid mediated form of synaptic plasticity is involved in the emotional learning functions of the pathway. We are thus well on the way to a systems level and a cellular understanding of at least one form of emotional learning and memory.